diff --git a/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp b/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp
index 24342d87f5c..44ceb5b3cfe 100644
--- a/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp
+++ b/Libraries/LibWeb/CSS/Parser/ValueParsing.cpp
@@ -3515,8 +3515,11 @@ RefPtr<CalculationNode const> Parser::parse_a_calc_function_node(Function const&
     if (function.name.equals_ignoring_ascii_case("calc"sv))
         return parse_a_calculation(function.value, context);
 
-    if (auto maybe_function = parse_math_function(function, context))
-        return maybe_function;
+    if (auto maybe_function = parse_math_function(function, context)) {
+        // NOTE: We have to simplify manually here, since parse_math_function() is a helper for calc() parsing
+        //       that doesn't do it directly by itself.
+        return simplify_a_calculation_tree(*maybe_function, context, CalculationResolutionContext {});
+    }
 
     return nullptr;
 }
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-values/clamp-length-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/clamp-length-computed.txt
new file mode 100644
index 00000000000..128ccf34419
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/clamp-length-computed.txt
@@ -0,0 +1,22 @@
+Harness status: OK
+
+Found 17 tests
+
+17 Pass
+Pass	Property letter-spacing value 'clamp(10px, 20px, 30px)'
+Pass	Property letter-spacing value 'clamp(10px, 5px, 30px)'
+Pass	Property letter-spacing value 'clamp(10px, 35px, 30px)'
+Pass	Property letter-spacing value 'clamp(10px, 35px , 30px)'
+Pass	Property letter-spacing value 'clamp(10px, 35px /*foo*/, 30px)'
+Pass	Property letter-spacing value 'clamp(10px /* foo */ , 35px, 30px)'
+Pass	Property letter-spacing value 'clamp(10px , 35px, 30px)'
+Pass	Property letter-spacing value 'clamp(30px, 100px, 20px)'
+Pass	Property letter-spacing value 'clamp(-30px, -20px, -10px)'
+Pass	Property letter-spacing value 'clamp(-30px, -100px, -10px)'
+Pass	Property letter-spacing value 'clamp(-30px, 100px, -10px)'
+Pass	Property letter-spacing value 'clamp(-10px, 100px, -30px)'
+Pass	Property letter-spacing value 'clamp(-10px, -100px, -30px)'
+Pass	Property letter-spacing value 'calc(0px + clamp(10px, 20px, 30px))'
+Pass	Property letter-spacing value 'calc(0px - clamp(10px, 20px, 30px))'
+Pass	Property letter-spacing value 'calc(0px + clamp(30px, 100px, 20px))'
+Pass	Property letter-spacing value 'calc(0px - clamp(30px, 100px, 20px))'
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-values/minmax-angle-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/minmax-angle-computed.txt
new file mode 100644
index 00000000000..93b859ba372
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/minmax-angle-computed.txt
@@ -0,0 +1,37 @@
+Harness status: OK
+
+Found 32 tests
+
+32 Pass
+Pass	min(1deg) should be used-value-equivalent to 1deg
+Pass	min(1grad) should be used-value-equivalent to 1grad
+Pass	min(1rad) should be used-value-equivalent to 1rad
+Pass	min(1turn) should be used-value-equivalent to 1turn
+Pass	max(1deg) should be used-value-equivalent to 1deg
+Pass	max(1grad) should be used-value-equivalent to 1grad
+Pass	max(1rad) should be used-value-equivalent to 1rad
+Pass	max(1turn) should be used-value-equivalent to 1turn
+Pass	min(1deg, 2deg) should be used-value-equivalent to 1deg
+Pass	min(1grad, 2grad) should be used-value-equivalent to 1grad
+Pass	min(1rad, 2rad) should be used-value-equivalent to 1rad
+Pass	min(1turn, 2turn) should be used-value-equivalent to 1turn
+Pass	max(1deg, 2deg) should be used-value-equivalent to 2deg
+Pass	max(1grad, 2grad) should be used-value-equivalent to 2grad
+Pass	max(1rad, 2rad) should be used-value-equivalent to 2rad
+Pass	max(1turn, 2turn) should be used-value-equivalent to 2turn
+Pass	min(90deg, 0.26turn) should be used-value-equivalent to 90deg
+Pass	min(1.57rad, 95deg) should be used-value-equivalent to 1.57rad
+Pass	max(91deg, 0.25turn) should be used-value-equivalent to 91deg
+Pass	max(1.58rad, 90deg) should be used-value-equivalent to 1.58rad
+Pass	min(270deg, max(0.25turn, 3.14rad)) should be used-value-equivalent to 3.14rad
+Pass	max(0.25turn, min(270deg, 3.14rad)) should be used-value-equivalent to 3.14rad
+Pass	calc(min(90deg, 1.58rad) + 0.125turn) should be used-value-equivalent to 135deg
+Pass	calc(min(90deg, 1.58rad) - 0.125turn) should be used-value-equivalent to 45deg
+Pass	calc(min(90deg, 1.58rad) * 1.5 should be used-value-equivalent to 135deg
+Pass	calc(min(90deg, 1.58rad) / 2 should be used-value-equivalent to 45deg
+Pass	calc(max(90deg, 1.56rad) + 0.125turn should be used-value-equivalent to 135deg
+Pass	calc(max(90deg, 1.56rad) - 0.125turn) should be used-value-equivalent to 45deg
+Pass	calc(max(90deg, 1.56rad) * 1.5 should be used-value-equivalent to 135deg
+Pass	calc(max(90deg, 1.56rad) / 2 should be used-value-equivalent to 45deg
+Pass	calc(min(90deg, 1.58rad) + max(0.125turn, 49grad)) should be used-value-equivalent to 135deg
+Pass	calc(min(90deg, 1.58rad) - max(0.25turn, 99grad)) should be used-value-equivalent to 0deg
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-values/round-mod-rem-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/round-mod-rem-computed.txt
new file mode 100644
index 00000000000..580bd5e928f
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/round-mod-rem-computed.txt
@@ -0,0 +1,235 @@
+Harness status: OK
+
+Found 229 tests
+
+195 Pass
+34 Fail
+Pass	round(10,10) should be used-value-equivalent to 10
+Pass	mod(1,1) should be used-value-equivalent to 0
+Pass	rem(1,1) should be used-value-equivalent to 0
+Pass	calc(round(100,10)) should be used-value-equivalent to 100
+Pass	calc(round(up, 101,10)) should be used-value-equivalent to 110
+Pass	calc(round(down, 106,10)) should be used-value-equivalent to 100
+Pass	calc(round(to-zero, 105, 10)) should be used-value-equivalent to 100
+Pass	calc(round(to-zero, -105, 10)) should be used-value-equivalent to -100
+Pass	calc(round(-100, 10)) should be used-value-equivalent to -100
+Pass	calc(round(up, -103, 10)) should be used-value-equivalent to -100
+Pass	round(up, 0, 5) should be used-value-equivalent to 0
+Pass	round(down, 0, 5) should be used-value-equivalent to 0
+Pass	round(nearest, 0, 5) should be used-value-equivalent to 0
+Pass	round(to-zero, 0, 5) should be used-value-equivalent to 0
+Pass	round(up, 5, 5) should be used-value-equivalent to 5
+Pass	round(down, 5, 5) should be used-value-equivalent to 5
+Pass	round(nearest, 5, 5) should be used-value-equivalent to 5
+Pass	round(to-zero, 5, 5) should be used-value-equivalent to 5
+Pass	round(up, -5, 5) should be used-value-equivalent to -5
+Pass	round(down, -5, 5) should be used-value-equivalent to -5
+Pass	round(nearest, -5, 5) should be used-value-equivalent to -5
+Pass	round(to-zero, -5, 5) should be used-value-equivalent to -5
+Pass	round(up, 10, 5) should be used-value-equivalent to 10
+Pass	round(down, 10, 5) should be used-value-equivalent to 10
+Pass	round(nearest, 10, 5) should be used-value-equivalent to 10
+Pass	round(to-zero, 10, 5) should be used-value-equivalent to 10
+Pass	round(up, -10, 5) should be used-value-equivalent to -10
+Pass	round(down, -10, 5) should be used-value-equivalent to -10
+Pass	round(nearest, -10, 5) should be used-value-equivalent to -10
+Pass	round(to-zero, -10, 5) should be used-value-equivalent to -10
+Pass	round(up, 20, 5) should be used-value-equivalent to 20
+Pass	round(down, 20, 5) should be used-value-equivalent to 20
+Pass	round(nearest, 20, 5) should be used-value-equivalent to 20
+Pass	round(to-zero, 20, 5) should be used-value-equivalent to 20
+Pass	round(up, -20, 5) should be used-value-equivalent to -20
+Pass	round(down, -20, 5) should be used-value-equivalent to -20
+Pass	round(nearest, -20, 5) should be used-value-equivalent to -20
+Pass	round(to-zero, -20, 5) should be used-value-equivalent to -20
+Pass	mod(18,5) should be used-value-equivalent to 3
+Pass	rem(18,5) should be used-value-equivalent to 3
+Pass	mod(-140,-90) should be used-value-equivalent to -50
+Pass	mod(-18,5) should be used-value-equivalent to 2
+Pass	rem(-18,5) should be used-value-equivalent to -3
+Pass	mod(140,-90) should be used-value-equivalent to -40
+Pass	rem(140,-90) should be used-value-equivalent to 50
+Pass	calc(round(round(100,10), 10)) should be used-value-equivalent to 100
+Pass	calc(round(up, round(100,10) + 1,10)) should be used-value-equivalent to 110
+Pass	calc(round(down, round(100,10) + 2 * 3,10)) should be used-value-equivalent to 100
+Pass	calc(round(to-zero,round(100,10) * 2 - 95, 10)) should be used-value-equivalent to 100
+Pass	calc(round(round(100,10)* -1,10)) should be used-value-equivalent to -100
+Pass	calc(round(up, -103 + -103 / -103 - 1,10)) should be used-value-equivalent to -100
+Pass	calc(mod(18,5) * 2 + mod(17,5)) should be used-value-equivalent to 8
+Pass	calc(rem(mod(18,5),5)) should be used-value-equivalent to 3
+Pass	calc(rem(mod(18,5),mod(17,5))) should be used-value-equivalent to 1
+Pass	calc(mod(-140,-90)) should be used-value-equivalent to -50
+Pass	calc(mod(rem(1,18)* -1,5)) should be used-value-equivalent to 4
+Pass	round(10px,6px) should be used-value-equivalent to 12px
+Fail	round(10cm,6cm) should be used-value-equivalent to 12cm
+Fail	round(10mm,6mm) should be used-value-equivalent to 12mm
+Pass	round(10Q, 6Q) should be used-value-equivalent to 12Q
+Pass	round(10in,6in) should be used-value-equivalent to 12in
+Pass	round(10pc,6pc) should be used-value-equivalent to 12pc
+Pass	round(10pt,6pt) should be used-value-equivalent to 12pt
+Pass	round(10em,6em) should be used-value-equivalent to 12em
+Pass	round(10ex,6ex) should be used-value-equivalent to 12ex
+Pass	round(10ch,6ch) should be used-value-equivalent to 12ch
+Pass	round(10rem,6rem) should be used-value-equivalent to 12rem
+Pass	round(10vh,6vh) should be used-value-equivalent to 12vh
+Pass	round(10vw,6vw) should be used-value-equivalent to 12vw
+Pass	round(10vmin,6vmin) should be used-value-equivalent to 12vmin
+Pass	round(10vmax,6vmax) should be used-value-equivalent to 12vmax
+Pass	round(10s,6s) should be used-value-equivalent to 12s
+Pass	round(10ms,6ms) should be used-value-equivalent to 12ms
+Pass	round(10deg,6deg) should be used-value-equivalent to 12deg
+Pass	round(10grad,6grad) should be used-value-equivalent to 12grad
+Pass	round(10rad,6rad) should be used-value-equivalent to 12rad
+Pass	round(10turn,6turn) should be used-value-equivalent to 12turn
+Pass	mod(10px,6px) should be used-value-equivalent to 4px
+Pass	mod(10cm,6cm) should be used-value-equivalent to 4cm
+Pass	mod(10mm,6mm) should be used-value-equivalent to 4mm
+Pass	mod(10Q, 6Q) should be used-value-equivalent to 4Q
+Pass	mod(10in,6in) should be used-value-equivalent to 4in
+Pass	mod(10pc,6pc) should be used-value-equivalent to 4pc
+Pass	mod(10em,6em) should be used-value-equivalent to 4em
+Pass	mod(10ex,6ex) should be used-value-equivalent to 4ex
+Pass	mod(10ch,6ch) should be used-value-equivalent to 4ch
+Pass	mod(10rem,6rem) should be used-value-equivalent to 4rem
+Pass	mod(10vh,6vh) should be used-value-equivalent to 4vh
+Pass	mod(10vw,6vw) should be used-value-equivalent to 4vw
+Pass	mod(10vmin,6vmin) should be used-value-equivalent to 4vmin
+Pass	mod(10vmax,6vmax) should be used-value-equivalent to 4vmax
+Pass	mod(10s,6s) should be used-value-equivalent to 4s
+Pass	mod(10ms,6ms) should be used-value-equivalent to 4ms
+Pass	mod(10deg,6deg) should be used-value-equivalent to 4deg
+Pass	mod(10grad,6grad) should be used-value-equivalent to 4grad
+Pass	mod(10rad,6rad) should be used-value-equivalent to 4rad
+Pass	mod(10turn,6turn) should be used-value-equivalent to 4turn
+Pass	rem(10px,6px) should be used-value-equivalent to 4px
+Pass	rem(10cm,6cm) should be used-value-equivalent to 4cm
+Pass	rem(10mm,6mm) should be used-value-equivalent to 4mm
+Pass	rem(10Q, 6Q) should be used-value-equivalent to 4Q
+Pass	rem(10in,6in) should be used-value-equivalent to 4in
+Pass	rem(10pc,6pc) should be used-value-equivalent to 4pc
+Pass	rem(10em,6em) should be used-value-equivalent to 4em
+Pass	rem(10ex,6ex) should be used-value-equivalent to 4ex
+Pass	rem(10ch,6ch) should be used-value-equivalent to 4ch
+Pass	rem(10rem,6rem) should be used-value-equivalent to 4rem
+Pass	rem(10vh,6vh) should be used-value-equivalent to 4vh
+Pass	rem(10vw,6vw) should be used-value-equivalent to 4vw
+Pass	rem(10vmin,6vmin) should be used-value-equivalent to 4vmin
+Pass	rem(10vmax,6vmax) should be used-value-equivalent to 4vmax
+Pass	rem(10s,6s) should be used-value-equivalent to 4s
+Pass	rem(10ms,6ms) should be used-value-equivalent to 4ms
+Pass	rem(10deg,6deg) should be used-value-equivalent to 4deg
+Pass	rem(10grad,6grad) should be used-value-equivalent to 4grad
+Pass	rem(10rad,6rad) should be used-value-equivalent to 4rad
+Pass	rem(10turn,6turn) should be used-value-equivalent to 4turn
+Fail	round(10%,1px) should be used-value-equivalent to 8px
+Fail	round(10%,5px) should be used-value-equivalent to 10px
+Pass	round(2rem,5px) should be used-value-equivalent to 30px
+Pass	round(100px,1rem) should be used-value-equivalent to 96px
+Pass	round(10s,6000ms) should be used-value-equivalent to 12s
+Pass	round(10000ms,6s) should be used-value-equivalent to 12s
+Fail	mod(10%,1px) should be used-value-equivalent to 0.5px
+Fail	mod(10%,5px) should be used-value-equivalent to 2.5px
+Pass	mod(2rem,5px) should be used-value-equivalent to 2px
+Pass	mod(100px,1rem) should be used-value-equivalent to 4px
+Pass	mod(10s,6000ms) should be used-value-equivalent to 4s
+Pass	mod(10000ms,6s) should be used-value-equivalent to 4s
+Fail	mod(18px,100% / 15) should be used-value-equivalent to 3px
+Fail	mod(-18px,100% / 10) should be used-value-equivalent to 4.5px
+Pass	mod(18%,5%) should be used-value-equivalent to 3%
+Pass	mod(-19%,5%) should be used-value-equivalent to 1%
+Pass	mod(18vw,5vw) should be used-value-equivalent to 3vw
+Pass	mod(-18vw,5vw) should be used-value-equivalent to 2vw
+Fail	rem(10%,1px) should be used-value-equivalent to 0.5px
+Fail	rem(10%,5px) should be used-value-equivalent to 2.5px
+Pass	rem(2rem,5px) should be used-value-equivalent to 2px
+Pass	rem(100px,1rem) should be used-value-equivalent to 4px
+Pass	rem(10s,6000ms) should be used-value-equivalent to 4s
+Pass	rem(10000ms,6s) should be used-value-equivalent to 4s
+Fail	rem(18px,100% / 15) should be used-value-equivalent to 3px
+Fail	rem(-18px,100% / 15) should be used-value-equivalent to -3px
+Pass	rem(18vw,5vw) should be used-value-equivalent to 3vw
+Pass	rem(-18vw,5vw) should be used-value-equivalent to -3vw
+Pass	calc(round(1px + 0%, 1px + 0%)) should be used-value-equivalent to 1px
+Pass	calc(mod(3px + 0%, 2px + 0%)) should be used-value-equivalent to 1px
+Pass	calc(rem(3px + 0%, 2px + 0%)) should be used-value-equivalent to 1px
+Pass	round(1px + 0%, 1px) should be used-value-equivalent to 1px
+Fail	mod(3px + 0%, 2px) should be used-value-equivalent to 1px
+Fail	rem(3px + 0%, 2px) should be used-value-equivalent to 1px
+Pass	round(0, 0) should be used-value-equivalent to calc(NaN)
+Pass	round(-0, 0) should be used-value-equivalent to calc(NaN)
+Pass	round(Infinity, 0) should be used-value-equivalent to calc(NaN)
+Pass	round(-Infinity, 0) should be used-value-equivalent to calc(NaN)
+Pass	round(-4, 0) should be used-value-equivalent to calc(NaN)
+Pass	round(4, 0) should be used-value-equivalent to calc(NaN)
+Pass	round(Infinity, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	round(-Infinity, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	round(Infinity, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	round(-Infinity, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(0, 0) should be used-value-equivalent to calc(NaN)
+Pass	mod(-0, 0) should be used-value-equivalent to calc(NaN)
+Pass	mod(Infinity, 0) should be used-value-equivalent to calc(NaN)
+Pass	mod(-Infinity, 0) should be used-value-equivalent to calc(NaN)
+Pass	mod(-4, 0) should be used-value-equivalent to calc(NaN)
+Pass	mod(4, 0) should be used-value-equivalent to calc(NaN)
+Pass	mod(Infinity, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(-Infinity, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(Infinity, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(-Infinity, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	rem(0, 0) should be used-value-equivalent to calc(NaN)
+Pass	rem(-0, 0) should be used-value-equivalent to calc(NaN)
+Pass	rem(Infinity, 0) should be used-value-equivalent to calc(NaN)
+Pass	rem(-Infinity, 0) should be used-value-equivalent to calc(NaN)
+Pass	rem(-4, 0) should be used-value-equivalent to calc(NaN)
+Pass	rem(4, 0) should be used-value-equivalent to calc(NaN)
+Pass	rem(Infinity, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	rem(-Infinity, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	rem(Infinity, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	rem(-Infinity, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	round(up, Infinity, 4) should be used-value-equivalent to calc(Infinity)
+Pass	round(up, -Infinity, 4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(up, Infinity, -4) should be used-value-equivalent to calc(Infinity)
+Pass	round(up, -Infinity, -4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(down, Infinity, 4) should be used-value-equivalent to calc(Infinity)
+Pass	round(down, -Infinity, 4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(down, Infinity, -4) should be used-value-equivalent to calc(Infinity)
+Pass	round(down, -Infinity, -4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(nearest, Infinity, 4) should be used-value-equivalent to calc(Infinity)
+Pass	round(nearest, -Infinity, 4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(nearest, Infinity, -4) should be used-value-equivalent to calc(Infinity)
+Pass	round(nearest, -Infinity, -4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(to-zero, Infinity, 4) should be used-value-equivalent to calc(Infinity)
+Pass	round(to-zero, -Infinity, 4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(to-zero, Infinity, -4) should be used-value-equivalent to calc(Infinity)
+Pass	round(to-zero, -Infinity, -4) should be used-value-equivalent to calc(-Infinity)
+Pass	round(nearest, 0, Infinity) should be used-value-equivalent to 0
+Fail	round(nearest, 4, Infinity) should be used-value-equivalent to 0
+Fail	round(nearest, -0, Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(nearest, -4, Infinity) should be used-value-equivalent to calc(-0)
+Pass	round(nearest, 0, -Infinity) should be used-value-equivalent to 0
+Fail	round(nearest, 4, -Infinity) should be used-value-equivalent to 0
+Fail	round(nearest, -0, -Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(nearest, -4, -Infinity) should be used-value-equivalent to calc(-0)
+Pass	round(to-zero, 0, Infinity) should be used-value-equivalent to 0
+Fail	round(to-zero, 4, Infinity) should be used-value-equivalent to 0
+Fail	round(to-zero, -0, Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(to-zero, -4, Infinity) should be used-value-equivalent to calc(-0)
+Pass	round(to-zero, 0, -Infinity) should be used-value-equivalent to 0
+Fail	round(to-zero, 4, -Infinity) should be used-value-equivalent to 0
+Fail	round(to-zero, -0, -Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(to-zero, -4, -Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(up, 1, Infinity) should be used-value-equivalent to calc(Infinity)
+Pass	round(up, 0, Infinity) should be used-value-equivalent to 0
+Fail	round(up, -1, Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(up, 1, -Infinity) should be used-value-equivalent to calc(Infinity)
+Pass	round(up, 0, -Infinity) should be used-value-equivalent to 0
+Fail	round(up, -1, -Infinity) should be used-value-equivalent to calc(-0)
+Fail	round(down, 1, Infinity) should be used-value-equivalent to calc(-0)
+Pass	round(down, 0, Infinity) should be used-value-equivalent to 0
+Fail	round(down, -1, Infinity) should be used-value-equivalent to calc(-Infinity)
+Fail	round(down, 1, -Infinity) should be used-value-equivalent to calc(-0)
+Pass	round(down, 0, -Infinity) should be used-value-equivalent to 0
+Fail	round(down, -1, -Infinity) should be used-value-equivalent to calc(-Infinity)
+Pass	mod(-0, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(0, -Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(-4, Infinity) should be used-value-equivalent to calc(NaN)
+Pass	mod(4, -Infinity) should be used-value-equivalent to calc(NaN)
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-values/signs-abs-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/signs-abs-computed.txt
new file mode 100644
index 00000000000..4f4b13f7d3f
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-values/signs-abs-computed.txt
@@ -0,0 +1,239 @@
+Harness status: OK
+
+Found 233 tests
+
+120 Pass
+113 Fail
+Pass	abs(1) should be used-value-equivalent to 1
+Pass	sign(1) should be used-value-equivalent to 1
+Pass	abs(-1) should be used-value-equivalent to 1
+Pass	sign(-1) should be used-value-equivalent to -1
+Pass	abs(sign(1)) should be used-value-equivalent to 1
+Pass	abs(sign(sign(1))) should be used-value-equivalent to 1
+Pass	sign(sign(sign(1) + sign(1))) should be used-value-equivalent to 1
+Pass	calc(abs(0.1 + 0.2) + 0.05) should be used-value-equivalent to 0.35
+Pass	calc(sign(0.1 + 0.2) - 0.05) should be used-value-equivalent to 0.95
+Pass	calc(abs(0.1 + 0.2) * 2) should be used-value-equivalent to 0.6
+Pass	calc(abs(sign(0.1) + 0.2) / 2) should be used-value-equivalent to 0.6
+Pass	calc(abs(0.1 + 0.2) * -2) should be used-value-equivalent to -0.6
+Pass	calc(sign(0.1 - 0.2) - 0.05) should be used-value-equivalent to -1.05
+Pass	calc(sign(1) + sign(1) - 0.05) should be used-value-equivalent to 1.95
+Pass	abs(10px) should be used-value-equivalent to 10px
+Fail	abs(10%) should be used-value-equivalent to 10px
+Fail	abs(10px + 10%) should be used-value-equivalent to 20px
+Fail	calc(10px + abs(10%)) should be used-value-equivalent to 20px
+Pass	abs(-10px) should be used-value-equivalent to 10px
+Fail	abs(-10%) should be used-value-equivalent to 10px
+Fail	calc((1em + 1px) * (sign(1em - 10px - 10%) + 1)) should be used-value-equivalent to 21px
+Pass	calc(calc(sign(-0))) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(calc(sign(-0)))), 1) should be used-value-equivalent to -1
+Pass	calc(calc(sign(0))) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(calc(sign(0)))), 1) should be used-value-equivalent to 1
+Pass	abs(infinity) should be used-value-equivalent to calc(infinity)
+Pass	abs(-infinity) should be used-value-equivalent to calc(infinity)
+Pass	abs(NaN) should be used-value-equivalent to calc(NaN)
+Pass	calc(20 - abs(-10)) should be used-value-equivalent to 10
+Pass	calc(20 - abs(10)) should be used-value-equivalent to 10
+Pass	calc(10 - abs(10 - abs(-30)) should be used-value-equivalent to -10
+Pass	calc(2 - sign(1)) should be used-value-equivalent to 1
+Pass	calc(2 - sign(-1)) should be used-value-equivalent to 3
+Pass	calc(2 - sign(1 - sign(-1))) should be used-value-equivalent to 1
+Pass	calc(10 - abs(20 - sign(2 - abs(-20)))) should be used-value-equivalent to -11
+Pass	sign(1px) should be used-value-equivalent to 1
+Pass	sign(1cm) should be used-value-equivalent to 1
+Pass	sign(1mm) should be used-value-equivalent to 1
+Pass	sign(1Q) should be used-value-equivalent to 1
+Pass	sign(1in) should be used-value-equivalent to 1
+Pass	sign(1pc) should be used-value-equivalent to 1
+Pass	sign(1pt) should be used-value-equivalent to 1
+Fail	sign(1em) should be used-value-equivalent to 1
+Fail	sign(1ex) should be used-value-equivalent to 1
+Fail	sign(1ch) should be used-value-equivalent to 1
+Fail	sign(1rem) should be used-value-equivalent to 1
+Fail	sign(1vh) should be used-value-equivalent to 1
+Fail	sign(1vw) should be used-value-equivalent to 1
+Fail	sign(1vmin) should be used-value-equivalent to 1
+Fail	sign(1vmax) should be used-value-equivalent to 1
+Pass	sign(-1px) should be used-value-equivalent to -1
+Pass	sign(-1cm) should be used-value-equivalent to -1
+Pass	sign(-1mm) should be used-value-equivalent to -1
+Pass	sign(-1Q) should be used-value-equivalent to -1
+Pass	sign(-1in) should be used-value-equivalent to -1
+Pass	sign(-1pc) should be used-value-equivalent to -1
+Pass	sign(-1pt) should be used-value-equivalent to -1
+Fail	sign(-1em) should be used-value-equivalent to -1
+Fail	sign(-1ex) should be used-value-equivalent to -1
+Fail	sign(-1ch) should be used-value-equivalent to -1
+Fail	sign(-1rem) should be used-value-equivalent to -1
+Fail	sign(-1vh) should be used-value-equivalent to -1
+Fail	sign(-1vw) should be used-value-equivalent to -1
+Fail	sign(-1vmin) should be used-value-equivalent to -1
+Fail	sign(-1vmax) should be used-value-equivalent to -1
+Pass	sign(1s) should be used-value-equivalent to 1
+Pass	sign(1ms) should be used-value-equivalent to 1
+Pass	sign(-1s) should be used-value-equivalent to -1
+Pass	sign(-1ms) should be used-value-equivalent to -1
+Pass	sign(1deg) should be used-value-equivalent to 1
+Pass	sign(1grad) should be used-value-equivalent to 1
+Pass	sign(1rad) should be used-value-equivalent to 1
+Pass	sign(1turn) should be used-value-equivalent to 1
+Pass	sign(-1deg) should be used-value-equivalent to -1
+Pass	sign(-1grad) should be used-value-equivalent to -1
+Pass	sign(-1rad) should be used-value-equivalent to -1
+Pass	sign(-1turn) should be used-value-equivalent to -1
+Pass	calc(sign(0px)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0px))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0cm)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0cm))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0mm)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0mm))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0Q)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0Q))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0in)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0in))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0pc)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0pc))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0pt)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0pt))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0em)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0em))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0ex)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0ex))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0ch)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0ch))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0rem)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0rem))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0vh)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0vh))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0vw)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0vw))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0vmin)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0vmin))), 1) should be used-value-equivalent to 1
+Fail	calc(sign(0vmax)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(0vmax))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(-0px)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0px))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0cm)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0cm))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0mm)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0mm))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0Q)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0Q))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0in)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0in))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0pc)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0pc))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0pt)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0pt))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0em)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0em))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0ex)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0ex))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0ch)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0ch))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0rem)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0rem))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0vh)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0vh))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0vw)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0vw))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0vmin)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0vmin))), 1) should be used-value-equivalent to -1
+Fail	calc(sign(-0vmax)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0vmax))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(0s)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0s))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0ms)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0ms))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(-0s)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0s))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0ms)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0ms))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(0deg)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0deg))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0grad)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0grad))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0rad)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0rad))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(0turn)) should be used-value-equivalent to 0
+Pass	clamp(-1, calc( 1 / sign(sign(0turn))), 1) should be used-value-equivalent to 1
+Pass	calc(sign(-0deg)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0deg))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0grad)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0grad))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0rad)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0rad))), 1) should be used-value-equivalent to -1
+Pass	calc(sign(-0turn)) should be used-value-equivalent to 0
+Fail	clamp(-1, calc( 1 / sign(sign(-0turn))), 1) should be used-value-equivalent to -1
+Pass	abs(1px) should be used-value-equivalent to 1px
+Pass	abs(1cm) should be used-value-equivalent to 1cm
+Pass	abs(1mm) should be used-value-equivalent to 1mm
+Pass	abs(1Q) should be used-value-equivalent to 1Q
+Pass	abs(1in) should be used-value-equivalent to 1in
+Pass	abs(1pc) should be used-value-equivalent to 1pc
+Pass	abs(1pt) should be used-value-equivalent to 1pt
+Fail	abs(1em) should be used-value-equivalent to 1em
+Fail	abs(1ex) should be used-value-equivalent to 1ex
+Fail	abs(1ch) should be used-value-equivalent to 1ch
+Fail	abs(1rem) should be used-value-equivalent to 1rem
+Fail	abs(1vh) should be used-value-equivalent to 1vh
+Fail	abs(1vw) should be used-value-equivalent to 1vw
+Fail	abs(1vmin) should be used-value-equivalent to 1vmin
+Fail	abs(1vmax) should be used-value-equivalent to 1vmax
+Pass	abs(-1px) should be used-value-equivalent to 1px
+Pass	abs(-1cm) should be used-value-equivalent to 1cm
+Pass	abs(-1mm) should be used-value-equivalent to 1mm
+Pass	abs(-1Q) should be used-value-equivalent to 1Q
+Pass	abs(-1in) should be used-value-equivalent to 1in
+Pass	abs(-1pc) should be used-value-equivalent to 1pc
+Pass	abs(-1pt) should be used-value-equivalent to 1pt
+Fail	abs(-1em) should be used-value-equivalent to 1em
+Fail	abs(-1ex) should be used-value-equivalent to 1ex
+Fail	abs(-1ch) should be used-value-equivalent to 1ch
+Fail	abs(-1rem) should be used-value-equivalent to 1rem
+Fail	abs(-1vh) should be used-value-equivalent to 1vh
+Fail	abs(-1vw) should be used-value-equivalent to 1vw
+Fail	abs(-1vmin) should be used-value-equivalent to 1vmin
+Fail	abs(-1vmax) should be used-value-equivalent to 1vmax
+Pass	abs(1s) should be used-value-equivalent to 1s
+Pass	abs(1ms) should be used-value-equivalent to 1ms
+Pass	abs(-1s) should be used-value-equivalent to 1s
+Pass	abs(-1ms) should be used-value-equivalent to 1ms
+Pass	abs(1deg) should be used-value-equivalent to 1deg
+Pass	abs(1grad) should be used-value-equivalent to 1grad
+Pass	abs(1rad) should be used-value-equivalent to 1rad
+Pass	abs(1turn) should be used-value-equivalent to 1turn
+Pass	abs(-1deg) should be used-value-equivalent to 1deg
+Pass	abs(-1grad) should be used-value-equivalent to 1grad
+Pass	abs(-1rad) should be used-value-equivalent to 1rad
+Pass	abs(-1turn) should be used-value-equivalent to 1turn
+Fail	sign(10px - 1em) should be used-value-equivalent to 0; fontSize=10px
+Fail	sign(10px - 2em) should be used-value-equivalent to -1; fontSize=10px
+Fail	calc(sign(10%) * 100px) should be used-value-equivalent to 100px
+Fail	calc(2.5 - sign(41px - 2em) / 2) should be used-value-equivalent to 2
+Fail	calc(2.5 - sign(40px - 2em) / 2) should be used-value-equivalent to 2.5
+Fail	calc(2.5 - sign(39px - 2em) / 2) should be used-value-equivalent to 3
+Fail	calc(3 + sign(42px - 2em)) should be used-value-equivalent to 4
+Fail	calc(3 + sign(40px - 2em)) should be used-value-equivalent to 3
+Fail	calc(3 + sign(38px - 2em)) should be used-value-equivalent to 2
+Fail	calc(50px + 100px * sign(42px - 2em)) should be used-value-equivalent to 150px
+Fail	calc(50px + 100px * sign(40px - 2em)) should be used-value-equivalent to 50px
+Fail	calc(50px + 100px * sign(38px - 2em)) should be used-value-equivalent to -50px
+Fail	calc(90deg + 30deg * sign(42px - 2em)) should be used-value-equivalent to 120deg
+Fail	calc(90deg + 30deg * sign(40px - 2em)) should be used-value-equivalent to 90deg
+Fail	calc(90deg + 30deg * sign(38px - 2em)) should be used-value-equivalent to 60deg
+Fail	calc(5s + 15s * sign(42px - 2em)) should be used-value-equivalent to 20s
+Fail	calc(5s + 15s * sign(40px - 2em)) should be used-value-equivalent to 5s
+Fail	calc(5s + 15s * sign(38px - 2em)) should be used-value-equivalent to -10s
+Fail	calc(100dpi + 20dpi * sign(42px - 2em)) should be used-value-equivalent to 120dpi
+Fail	calc(100dpi + 20dpi * sign(40px - 2em)) should be used-value-equivalent to 100dpi
+Fail	calc(100dpi + 20dpi * sign(38px - 2em)) should be used-value-equivalent to 80dpi
+Fail	calc(3fr + 1fr * sign(42px - 2em)) should be used-value-equivalent to 4fr
+Fail	calc(3fr + 1fr * sign(40px - 2em)) should be used-value-equivalent to 3fr
+Fail	calc(3fr + 1fr * sign(38px - 2em)) should be used-value-equivalent to 2fr
+Fail	calc(2.5 - sign(33px - 2rem) / 2) should be used-value-equivalent to 2
+Fail	calc(2.5 - sign(32px - 2rem) / 2) should be used-value-equivalent to 2.5
+Fail	calc(2.5 - sign(31px - 2rem) / 2) should be used-value-equivalent to 3
+Fail	calc(50px + 100px * sign(34px - 2rem)) should be used-value-equivalent to 150px
+Fail	calc(50px + 100px * sign(32px - 2rem)) should be used-value-equivalent to 50px
+Fail	calc(50px + 100px * sign(30px - 2rem)) should be used-value-equivalent to -50px
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-values/clamp-length-computed.html b/Tests/LibWeb/Text/input/wpt-import/css/css-values/clamp-length-computed.html
new file mode 100644
index 00000000000..0b776ee4991
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-values/clamp-length-computed.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#comp-func">
+<link rel="author" title="Xiaocheng Hu" href="mailto:xiaochengh@chromium.org">
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script src="../support/computed-testcommon.js"></script>
+<div id="container" style="font-size: 20px">
+  <div id="target"></div>
+  <div id="reference"></div>
+</div>
+<script>
+const property = 'letter-spacing';
+
+function test_length_equals(value, expected) {
+  const reference = document.getElementById('reference');
+  reference.style[property] = '';
+  reference.style[property] = expected;
+  const computed = getComputedStyle(reference)[property];
+  test_computed_value(property, value, computed);
+}
+
+test_length_equals('clamp(10px, 20px, 30px)', '20px');
+test_length_equals('clamp(10px, 5px, 30px)', '10px');
+test_length_equals('clamp(10px, 35px, 30px)', '30px');
+test_length_equals('clamp(10px, 35px , 30px)', '30px');
+test_length_equals('clamp(10px, 35px /*foo*/, 30px)', '30px');
+test_length_equals('clamp(10px /* foo */ , 35px, 30px)', '30px');
+test_length_equals('clamp(10px , 35px, 30px)', '30px');
+
+// clamp(MIN, VAL, MAX) is identical to max(MIN, min(VAL, MAX)),
+// so MIN wins over MAX if they are in the wrong order.
+test_length_equals('clamp(30px, 100px, 20px)', '30px');
+
+// also test with negative values
+test_length_equals('clamp(-30px, -20px, -10px)', '-20px');
+test_length_equals('clamp(-30px, -100px, -10px)', '-30px');
+test_length_equals('clamp(-30px, 100px, -10px)', '-10px');
+test_length_equals('clamp(-10px, 100px, -30px)', '-10px');
+test_length_equals('clamp(-10px, -100px, -30px)', '-10px');
+
+// and negating the result of clamp
+test_length_equals('calc(0px + clamp(10px, 20px, 30px))', '20px');
+test_length_equals('calc(0px - clamp(10px, 20px, 30px))', '-20px');
+test_length_equals('calc(0px + clamp(30px, 100px, 20px))', '30px');
+test_length_equals('calc(0px - clamp(30px, 100px, 20px))', '-30px');
+
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-values/minmax-angle-computed.html b/Tests/LibWeb/Text/input/wpt-import/css/css-values/minmax-angle-computed.html
new file mode 100644
index 00000000000..d3b837ff5a3
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-values/minmax-angle-computed.html
@@ -0,0 +1,57 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#comp-func">
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#angles">
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#calc-type-checking">
+<link rel="author" title="Xiaocheng Hu" href="mailto:xiaochengh@chromium.org">
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script src="../support/numeric-testcommon.js"></script>
+<div id="target"></div>
+<div id="reference"></div>
+<script>
+function test_angle_equals(value, expected) {
+  test_math_used(value, expected, {type: "angle"});
+}
+
+// Identity tests
+test_angle_equals('min(1deg)', '1deg');
+test_angle_equals('min(1grad)', '1grad');
+test_angle_equals('min(1rad)', '1rad');
+test_angle_equals('min(1turn)', '1turn');
+test_angle_equals('max(1deg)', '1deg');
+test_angle_equals('max(1grad)', '1grad');
+test_angle_equals('max(1rad)', '1rad');
+test_angle_equals('max(1turn)', '1turn');
+
+// Comparisons between same units
+test_angle_equals('min(1deg, 2deg)', '1deg');
+test_angle_equals('min(1grad, 2grad)', '1grad');
+test_angle_equals('min(1rad, 2rad)', '1rad');
+test_angle_equals('min(1turn, 2turn)', '1turn');
+test_angle_equals('max(1deg, 2deg)', '2deg');
+test_angle_equals('max(1grad, 2grad)', '2grad');
+test_angle_equals('max(1rad, 2rad)', '2rad');
+test_angle_equals('max(1turn, 2turn)', '2turn');
+
+// Comparisons between different units
+test_angle_equals('min(90deg, 0.26turn)', '90deg');
+test_angle_equals('min(1.57rad, 95deg)', '1.57rad');
+test_angle_equals('max(91deg, 0.25turn)', '91deg');
+test_angle_equals('max(1.58rad, 90deg)', '1.58rad');
+
+// Nestings
+test_angle_equals('min(270deg, max(0.25turn, 3.14rad))', '3.14rad');
+test_angle_equals('max(0.25turn, min(270deg, 3.14rad))', '3.14rad');
+
+// General calculations
+test_angle_equals('calc(min(90deg, 1.58rad) + 0.125turn)', '135deg');
+test_angle_equals('calc(min(90deg, 1.58rad) - 0.125turn)', '45deg');
+test_angle_equals('calc(min(90deg, 1.58rad) * 1.5', '135deg');
+test_angle_equals('calc(min(90deg, 1.58rad) / 2', '45deg');
+test_angle_equals('calc(max(90deg, 1.56rad) + 0.125turn', '135deg');
+test_angle_equals('calc(max(90deg, 1.56rad) - 0.125turn)', '45deg');
+test_angle_equals('calc(max(90deg, 1.56rad) * 1.5', '135deg');
+test_angle_equals('calc(max(90deg, 1.56rad) / 2', '45deg');
+test_angle_equals('calc(min(90deg, 1.58rad) + max(0.125turn, 49grad))', '135deg');
+test_angle_equals('calc(min(90deg, 1.58rad) - max(0.25turn, 99grad))', '0deg');
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-values/round-mod-rem-computed.html b/Tests/LibWeb/Text/input/wpt-import/css/css-values/round-mod-rem-computed.html
new file mode 100644
index 00000000000..c5a27961c14
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-values/round-mod-rem-computed.html
@@ -0,0 +1,218 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#round-func">
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#numbers">
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#calc-type-checking">
+<link rel="author" title="Apple Inc">
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script src="../support/numeric-testcommon.js"></script>
+<div style="width: 75px;">
+    <div id="target"></div>
+</div>
+<script>
+// Simple tests
+test_math_used('round(10,10)', '10', {type:'number'});
+test_math_used('mod(1,1)', '0', {type:'number'});
+test_math_used('rem(1,1)', '0', {type:'number'});
+
+// Test basic round
+test_math_used('calc(round(100,10))', '100', {type:'number'});
+test_math_used('calc(round(up, 101,10))', '110', {type:'number'});
+test_math_used('calc(round(down, 106,10))', '100', {type:'number'});
+test_math_used('calc(round(to-zero, 105, 10))', '100', {type:'number'});
+test_math_used('calc(round(to-zero, -105, 10))', '-100', {type:'number'});
+test_math_used('calc(round(-100, 10))', '-100', {type:'number'});
+test_math_used('calc(round(up, -103, 10))', '-100', {type:'number'});
+
+// Test round when first number is a multiple of the second number.
+for (let number of [0, 5, -5, 10, -10, 20, -20]) {
+    test_math_used(`round(up, ${number}, 5)`, `${number}`, {type:'number'});
+    test_math_used(`round(down, ${number}, 5)`, `${number}`, {type:'number'});
+    test_math_used(`round(nearest, ${number}, 5)`, `${number}`, {type:'number'});
+    test_math_used(`round(to-zero, ${number}, 5)`, `${number}`, {type:'number'});
+}
+
+// Test basic mod/rem
+test_math_used('mod(18,5)', '3', {type:'number'});
+test_math_used('rem(18,5)', '3', {type:'number'});
+test_math_used('mod(-140,-90)', '-50', {type:'number'});
+test_math_used('mod(-18,5)', '2', {type:'number'});
+test_math_used('rem(-18,5)', '-3', {type:'number'});
+test_math_used('mod(140,-90)', '-40', {type:'number'});
+test_math_used('rem(140,-90)', '50', {type:'number'});
+
+// Test basic calculations
+test_math_used('calc(round(round(100,10), 10))', '100', {type:'number'});
+test_math_used('calc(round(up, round(100,10) + 1,10))', '110', {type:'number'});
+test_math_used('calc(round(down, round(100,10) + 2 * 3,10))', '100', {type:'number'});
+test_math_used('calc(round(to-zero,round(100,10) * 2 - 95, 10))', '100', {type:'number'});
+test_math_used('calc(round(round(100,10)* -1,10))', '-100', {type:'number'});
+test_math_used('calc(round(up, -103 + -103 / -103 - 1,10))', '-100', {type:'number'});
+test_math_used('calc(mod(18,5) * 2 + mod(17,5))', '8', {type:'number'});
+test_math_used('calc(rem(mod(18,5),5))', '3', {type:'number'});
+test_math_used('calc(rem(mod(18,5),mod(17,5)))', '1', {type:'number'});
+test_math_used('calc(mod(-140,-90))', '-50', {type:'number'});
+test_math_used('calc(mod(rem(1,18)* -1,5))', '4', {type:'number'});
+
+// Type check
+test_math_used('round(10px,6px)', '12px');
+test_math_used('round(10cm,6cm)', '12cm');
+test_math_used('round(10mm,6mm)', '12mm');
+test_math_used('round(10Q, 6Q)', '12Q');
+test_math_used('round(10in,6in)', '12in');
+test_math_used('round(10pc,6pc)', '12pc');
+test_math_used('round(10pt,6pt)', '12pt');
+test_math_used('round(10em,6em)', '12em');
+test_math_used('round(10ex,6ex)', '12ex');
+test_math_used('round(10ch,6ch)', '12ch');
+test_math_used('round(10rem,6rem)', '12rem');
+test_math_used('round(10vh,6vh)', '12vh');
+test_math_used('round(10vw,6vw)', '12vw');
+test_math_used('round(10vmin,6vmin)', '12vmin');
+test_math_used('round(10vmax,6vmax)', '12vmax');
+test_math_used('round(10s,6s)', '12s', {type:'time'});
+test_math_used('round(10ms,6ms)', '12ms', {type:'time'});
+test_math_used('round(10deg,6deg)', '12deg', {type:'angle', approx:0.1});
+test_math_used('round(10grad,6grad)', '12grad', {type:'angle', approx:0.1});
+test_math_used('round(10rad,6rad)', '12rad',{type:'angle', approx:0.1});
+test_math_used('round(10turn,6turn)', '12turn',{type:'angle', approx:0.1});
+
+test_math_used('mod(10px,6px)', '4px');
+test_math_used('mod(10cm,6cm)', '4cm');
+test_math_used('mod(10mm,6mm)', '4mm');
+test_math_used('mod(10Q, 6Q)', '4Q');
+test_math_used('mod(10in,6in)', '4in');
+test_math_used('mod(10pc,6pc)', '4pc');
+test_math_used('mod(10em,6em)', '4em');
+test_math_used('mod(10ex,6ex)', '4ex');
+test_math_used('mod(10ch,6ch)', '4ch');
+test_math_used('mod(10rem,6rem)', '4rem');
+test_math_used('mod(10vh,6vh)', '4vh', {approx: 0.1});
+test_math_used('mod(10vw,6vw)', '4vw', {approx: 0.1});
+test_math_used('mod(10vmin,6vmin)', '4vmin', {approx: 0.1});
+test_math_used('mod(10vmax,6vmax)', '4vmax', {approx: 0.1});
+test_math_used('mod(10s,6s)', '4s', {type:'time'});
+test_math_used('mod(10ms,6ms)', '4ms', {type:'time'});
+test_math_used('mod(10deg,6deg)', '4deg', {type:'angle', approx:0.1});
+test_math_used('mod(10grad,6grad)', '4grad', {type:'angle', approx:0.1});
+test_math_used('mod(10rad,6rad)', '4rad',{type:'angle', approx:0.1});
+test_math_used('mod(10turn,6turn)', '4turn',{type:'angle', approx:0.1});
+
+test_math_used('rem(10px,6px)', '4px');
+test_math_used('rem(10cm,6cm)', '4cm');
+test_math_used('rem(10mm,6mm)', '4mm');
+test_math_used('rem(10Q, 6Q)', '4Q');
+test_math_used('rem(10in,6in)', '4in');
+test_math_used('rem(10pc,6pc)', '4pc');
+test_math_used('rem(10em,6em)', '4em');
+test_math_used('rem(10ex,6ex)', '4ex');
+test_math_used('rem(10ch,6ch)', '4ch');
+test_math_used('rem(10rem,6rem)', '4rem');
+test_math_used('rem(10vh,6vh)', '4vh', {approx: 0.1});
+test_math_used('rem(10vw,6vw)', '4vw', {approx: 0.1});
+test_math_used('rem(10vmin,6vmin)', '4vmin', {approx: 0.1});
+test_math_used('rem(10vmax,6vmax)', '4vmax', {approx: 0.1});
+test_math_used('rem(10s,6s)', '4s', {type:'time'});
+test_math_used('rem(10ms,6ms)', '4ms', {type:'time'});
+test_math_used('rem(10deg,6deg)', '4deg', {type:'angle', approx:0.1});
+test_math_used('rem(10grad,6grad)', '4grad', {type:'angle', approx:0.1});
+test_math_used('rem(10rad,6rad)', '4rad',{type:'angle', approx:0.1});
+test_math_used('rem(10turn,6turn)', '4turn',{type:'angle', approx:0.1});
+
+//Test percentage and mixed units
+test_math_used('round(10%,1px)', '8px');
+test_math_used('round(10%,5px)', '10px');
+test_math_used('round(2rem,5px)', '30px');
+test_math_used('round(100px,1rem)', '96px');
+test_math_used('round(10s,6000ms)', '12s', {type:'time'});
+test_math_used('round(10000ms,6s)', '12s', {type:'time'});
+
+test_math_used('mod(10%,1px)', '0.5px');
+test_math_used('mod(10%,5px)', '2.5px');
+test_math_used('mod(2rem,5px)', '2px');
+test_math_used('mod(100px,1rem)', '4px');
+test_math_used('mod(10s,6000ms)', '4s', {type:'time'});
+test_math_used('mod(10000ms,6s)', '4s', {type:'time'});
+test_math_used('mod(18px,100% / 15)', '3px', {approx: 0.1});
+test_math_used('mod(-18px,100% / 10)', '4.5px');
+test_math_used('mod(18%,5%)', '3%');
+test_math_used('mod(-19%,5%)', '1%');
+test_math_used('mod(18vw,5vw)', '3vw');
+test_math_used('mod(-18vw,5vw)', '2vw', {approx: 0.1});
+
+test_math_used('rem(10%,1px)', '0.5px');
+test_math_used('rem(10%,5px)', '2.5px');
+test_math_used('rem(2rem,5px)', '2px');
+test_math_used('rem(100px,1rem)', '4px');
+test_math_used('rem(10s,6000ms)', '4s', {type:'time'});
+test_math_used('rem(10000ms,6s)', '4s', {type:'time'});
+test_math_used('rem(18px,100% / 15)', '3px', {approx: 0.1});
+test_math_used('rem(-18px,100% / 15)', '-3px', {approx: 0.1});
+test_math_used('rem(18vw,5vw)', '3vw');
+test_math_used('rem(-18vw,5vw)', '-3vw');
+
+test_math_used('calc(round(1px + 0%, 1px + 0%))', '1px');
+test_math_used('calc(mod(3px + 0%, 2px + 0%))', '1px');
+test_math_used('calc(rem(3px + 0%, 2px + 0%))', '1px');
+
+test_math_used('round(1px + 0%, 1px)', '1px');
+test_math_used('mod(3px + 0%, 2px)', '1px');
+test_math_used('rem(3px + 0%, 2px)', '1px');
+
+// In round(A, B), if B is 0, the result is NaN. If A and B are both infinite, the result is NaN.
+// In mod(A, B) or rem(A, B), if B is 0, the result is NaN. If A is infinite, the result is NaN.
+for (let operator of ['round', 'mod', 'rem']) {
+    test_math_used(`${operator}(0, 0)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(-0, 0)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(Infinity, 0)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(-Infinity, 0)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(-4, 0)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(4, 0)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(Infinity, Infinity)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(-Infinity, -Infinity)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(Infinity, -Infinity)`, 'calc(NaN)', {type: 'number'});
+    test_math_used(`${operator}(-Infinity, Infinity)`, 'calc(NaN)', {type: 'number'});
+}
+
+// In round(A, B), if A is infinite but B is finite, the result is the same infinity.
+for (let roundingStrategy of ['up', 'down', 'nearest', 'to-zero']) {
+    test_math_used(`round(${roundingStrategy}, Infinity, 4)`, 'calc(Infinity)', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, -Infinity, 4)`, 'calc(-Infinity)', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, Infinity, -4)`, 'calc(Infinity)', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, -Infinity, -4)`, 'calc(-Infinity)', {type: 'number'});
+}
+
+// If A is finite but B is infinite, the result depends on the <rounding-strategy> and the sign of A:
+// nearest & to-zero: If A is positive or 0⁺, return 0⁺. Otherwise, return 0⁻.
+for (let roundingStrategy of ['nearest', 'to-zero']) {
+    test_math_used(`round(${roundingStrategy}, 0, Infinity)`, '0', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, 4, Infinity)`, '0', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, -0, Infinity)`, 'calc(-0)', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, -4, Infinity)`, 'calc(-0)', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, 0, -Infinity)`, '0', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, 4, -Infinity)`, '0', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, -0, -Infinity)`, 'calc(-0)', {type: 'number'});
+    test_math_used(`round(${roundingStrategy}, -4, -Infinity)`, 'calc(-0)', {type: 'number'});
+}
+
+// up: If A is positive (not zero), return +∞. If A is 0⁺, return 0⁺. Otherwise, return 0⁻.
+test_math_used('round(up, 1, Infinity)', 'calc(Infinity)', {type: 'number'});
+test_math_used('round(up, 0, Infinity)', '0', {type: 'number'});
+test_math_used('round(up, -1, Infinity)', 'calc(-0)', {type: 'number'});
+test_math_used('round(up, 1, -Infinity)', 'calc(Infinity)', {type: 'number'});
+test_math_used('round(up, 0, -Infinity)', '0', {type: 'number'});
+test_math_used('round(up, -1, -Infinity)', 'calc(-0)', {type: 'number'});
+// down: If A is negative (not zero), return −∞. If A is 0⁻, return 0⁻. Otherwise, return 0⁺.
+test_math_used('round(down, 1, Infinity)', 'calc(-0)', {type: 'number'});
+test_math_used('round(down, 0, Infinity)', '0', {type: 'number'});
+test_math_used('round(down, -1, Infinity)', 'calc(-Infinity)', {type: 'number'});
+test_math_used('round(down, 1, -Infinity)', 'calc(-0)', {type: 'number'});
+test_math_used('round(down, 0, -Infinity)', '0', {type: 'number'});
+test_math_used('round(down, -1, -Infinity)', 'calc(-Infinity)', {type: 'number'});
+
+// In mod(A, B) only, if B is infinite and A has opposite sign to B (including an oppositely-signed zero), the result is NaN.
+test_math_used('mod(-0, Infinity)', 'calc(NaN)', {type: 'number'});
+test_math_used('mod(0, -Infinity)', 'calc(NaN)', {type: 'number'});
+test_math_used('mod(-4, Infinity)', 'calc(NaN)', {type: 'number'});
+test_math_used('mod(4, -Infinity)', 'calc(NaN)', {type: 'number'});
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-values/signs-abs-computed.html b/Tests/LibWeb/Text/input/wpt-import/css/css-values/signs-abs-computed.html
new file mode 100644
index 00000000000..7de48927443
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-values/signs-abs-computed.html
@@ -0,0 +1,240 @@
+<!DOCTYPE html>
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#comp-func">
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#numbers">
+<link rel="help" href="https://drafts.csswg.org/css-values-4/#calc-type-checking">
+<link rel="author" title="Apple Inc">
+<script src="../../resources/testharness.js"></script>
+<script src="../../resources/testharnessreport.js"></script>
+<script src="../support/numeric-testcommon.js"></script>
+<div id="container" style="font-size: 20px; width: 100px">
+  <div id="target"></div>
+</div>
+<script>
+function test_zero(expression, { is_negative }) {
+  test_math_used(`calc(${expression})`, '0', {type:'integer'});
+  // to test zero sign, make it to negative infinity and clamp it between -1 and 1
+  test_math_used(`clamp(-1, calc( 1 / sign(${expression})), 1)`, (is_negative)? '-1' : '1', {type:'integer'});
+}
+
+function test_length_equals(value, expected, msgExtra) {
+  test_math_used(value, expected, {msgExtra, type: 'integer'});
+}
+
+// Identity tests
+test_math_used('abs(1)', '1', {type:'integer'});
+test_math_used('sign(1)', '1', {type:'integer'});
+test_math_used('abs(-1)', '1', {type:'integer'});
+test_math_used('sign(-1)', '-1', {type:'integer'});
+
+// Nestings
+test_math_used('abs(sign(1))', '1', {type:'integer'});
+test_math_used('abs(sign(sign(1)))', '1', {type:'integer'});
+test_math_used('sign(sign(sign(1) + sign(1)))', '1', {type:'integer'});
+
+// General calculations
+test_math_used('calc(abs(0.1 + 0.2) + 0.05)', '0.35', {type:'number', approx:0.1});
+test_math_used('calc(sign(0.1 + 0.2) - 0.05)', '0.95', {type:'number', approx:0.1});
+test_math_used('calc(abs(0.1 + 0.2) * 2)', '0.6', {type:'number', approx:0.1});
+test_math_used('calc(abs(sign(0.1) + 0.2) / 2)', '0.6', {type:'number', approx:0.1});
+test_math_used('calc(abs(0.1 + 0.2) * -2)', '-0.6', {type:'number', approx:0.1});
+test_math_used('calc(sign(0.1 - 0.2) - 0.05)', '-1.05', {type:'number', approx:0.1});
+test_math_used('calc(sign(1) + sign(1) - 0.05)', '1.95', {type:'number', approx:0.1});
+
+// Test with <length-percentage>
+test_math_used('abs(10px)', '10px', {type:'length'});
+test_math_used('abs(10%)', '10px', {type:'length'});
+test_math_used('abs(10px + 10%)', '20px', {type:'length'});
+test_math_used('calc(10px + abs(10%))', '20px', {type:'length'});
+test_math_used('abs(-10px)', '10px', {type:'length'});
+test_math_used('abs(-10%)', '10px', {type:'length'});
+// (20px + 1px) * (sign(20px - 10px - 10px) + 1)
+test_math_used('calc((1em + 1px) * (sign(1em - 10px - 10%) + 1))', '21px', {type:'length'});
+
+// Test sign for zero
+test_zero('calc(sign(-0))', {is_negative: true});
+test_zero('calc(sign(0))', {is_negative: false});
+
+// Test with NaN and inf
+test_math_used('abs(infinity)', 'calc(infinity)', {type:'number'});
+test_math_used('abs(-infinity)', 'calc(infinity)', {type:'number'});
+test_math_used('abs(NaN)', 'calc(NaN)', {type:'number'});
+
+// Test abs/sign with negate
+test_math_used('calc(20 - abs(-10))', '10', {type:'number'});
+test_math_used('calc(20 - abs(10))', '10', {type:'number'});
+test_math_used('calc(10 - abs(10 - abs(-30))', '-10', {type:'number'});
+test_math_used('calc(2 - sign(1))', '1', {type:'number'});
+test_math_used('calc(2 - sign(-1))', '3', {type:'number'});
+test_math_used('calc(2 - sign(1 - sign(-1)))', '1', {type:'number'});
+test_math_used('calc(10 - abs(20 - sign(2 - abs(-20))))', '-11', {type:'number'});
+
+// Type checking sign
+test_math_used('sign(1px)', '1', {type:'integer'});
+test_math_used('sign(1cm)', '1', {type:'integer'});
+test_math_used('sign(1mm)', '1', {type:'integer'});
+test_math_used('sign(1Q)', '1', {type:'integer'});
+test_math_used('sign(1in)', '1', {type:'integer'});
+test_math_used('sign(1pc)', '1', {type:'integer'});
+test_math_used('sign(1pt)', '1', {type:'integer'});
+test_math_used('sign(1em)', '1', {type:'integer'});
+test_math_used('sign(1ex)', '1', {type:'integer'});
+test_math_used('sign(1ch)', '1', {type:'integer'});
+test_math_used('sign(1rem)', '1', {type:'integer'});
+test_math_used('sign(1vh)', '1', {type:'integer'});
+test_math_used('sign(1vw)', '1', {type:'integer'});
+test_math_used('sign(1vmin)', '1', {type:'integer'});
+test_math_used('sign(1vmax)', '1', {type:'integer'});
+test_math_used('sign(-1px)', '-1', {type:'integer'});
+test_math_used('sign(-1cm)', '-1', {type:'integer'});
+test_math_used('sign(-1mm)', '-1', {type:'integer'});
+test_math_used('sign(-1Q)', '-1', {type:'integer'});
+test_math_used('sign(-1in)', '-1', {type:'integer'});
+test_math_used('sign(-1pc)', '-1', {type:'integer'});
+test_math_used('sign(-1pt)', '-1', {type:'integer'});
+test_math_used('sign(-1em)', '-1', {type:'integer'});
+test_math_used('sign(-1ex)', '-1', {type:'integer'});
+test_math_used('sign(-1ch)', '-1', {type:'integer'});
+test_math_used('sign(-1rem)', '-1', {type:'integer'});
+test_math_used('sign(-1vh)', '-1', {type:'integer'});
+test_math_used('sign(-1vw)', '-1', {type:'integer'});
+test_math_used('sign(-1vmin)', '-1', {type:'integer'});
+test_math_used('sign(-1vmax)', '-1', {type:'integer'});
+test_math_used('sign(1s)', '1', {type:'integer'});
+test_math_used('sign(1ms)', '1', {type:'integer'});
+test_math_used('sign(-1s)', '-1', {type:'integer'});
+test_math_used('sign(-1ms)', '-1', {type:'integer'});
+test_math_used('sign(1deg)', '1', {type:'integer'});
+test_math_used('sign(1grad)', '1', {type:'integer'});
+test_math_used('sign(1rad)', '1', {type:'integer'});
+test_math_used('sign(1turn)', '1', {type:'integer'});
+test_math_used('sign(-1deg)', '-1', {type:'integer'});
+test_math_used('sign(-1grad)', '-1', {type:'integer'});
+test_math_used('sign(-1rad)', '-1', {type:'integer'});
+test_math_used('sign(-1turn)', '-1', {type:'integer'});
+test_zero('sign(0px)', {is_negative: false});
+test_zero('sign(0cm)', {is_negative: false});
+test_zero('sign(0mm)', {is_negative: false});
+test_zero('sign(0Q)', {is_negative: false});
+test_zero('sign(0in)', {is_negative: false});
+test_zero('sign(0pc)', {is_negative: false});
+test_zero('sign(0pt)', {is_negative: false});
+test_zero('sign(0em)', {is_negative: false});
+test_zero('sign(0ex)', {is_negative: false});
+test_zero('sign(0ch)', {is_negative: false});
+test_zero('sign(0rem)', {is_negative: false});
+test_zero('sign(0vh)', {is_negative: false});
+test_zero('sign(0vw)', {is_negative: false});
+test_zero('sign(0vmin)', {is_negative: false});
+test_zero('sign(0vmax)', {is_negative: false});
+test_zero('sign(-0px)', {is_negative: true});
+test_zero('sign(-0cm)', {is_negative: true});
+test_zero('sign(-0mm)', {is_negative: true});
+test_zero('sign(-0Q)', {is_negative: true});
+test_zero('sign(-0in)', {is_negative: true});
+test_zero('sign(-0pc)', {is_negative: true});
+test_zero('sign(-0pt)', {is_negative: true});
+test_zero('sign(-0em)', {is_negative: true});
+test_zero('sign(-0ex)', {is_negative: true});
+test_zero('sign(-0ch)', {is_negative: true});
+test_zero('sign(-0rem)', {is_negative: true});
+test_zero('sign(-0vh)', {is_negative: true});
+test_zero('sign(-0vw)', {is_negative: true});
+test_zero('sign(-0vmin)', {is_negative: true});
+test_zero('sign(-0vmax)', {is_negative: true});
+test_zero('sign(0s)', {is_negative: false});
+test_zero('sign(0ms)', {is_negative: false});
+test_zero('sign(-0s)', {is_negative: true});
+test_zero('sign(-0ms)', {is_negative: true});
+test_zero('sign(0deg)', {is_negative: false});
+test_zero('sign(0grad)', {is_negative: false});
+test_zero('sign(0rad)', {is_negative: false});
+test_zero('sign(0turn)', {is_negative: false});
+test_zero('sign(-0deg)', {is_negative: true});
+test_zero('sign(-0grad)', {is_negative: true});
+test_zero('sign(-0rad)', {is_negative: true});
+test_zero('sign(-0turn)', {is_negative: true});
+
+// Type checking abs
+test_math_used('abs(1px)', '1px');
+test_math_used('abs(1cm)', '1cm');
+test_math_used('abs(1mm)', '1mm');
+test_math_used('abs(1Q)', '1Q');
+test_math_used('abs(1in)', '1in');
+test_math_used('abs(1pc)', '1pc');
+test_math_used('abs(1pt)', '1pt');
+test_math_used('abs(1em)', '1em');
+test_math_used('abs(1ex)', '1ex');
+test_math_used('abs(1ch)', '1ch');
+test_math_used('abs(1rem)', '1rem');
+test_math_used('abs(1vh)', '1vh');
+test_math_used('abs(1vw)', '1vw');
+test_math_used('abs(1vmin)', '1vmin');
+test_math_used('abs(1vmax)', '1vmax');
+test_math_used('abs(-1px)', '1px');
+test_math_used('abs(-1cm)', '1cm');
+test_math_used('abs(-1mm)', '1mm');
+test_math_used('abs(-1Q)', '1Q');
+test_math_used('abs(-1in)', '1in');
+test_math_used('abs(-1pc)', '1pc');
+test_math_used('abs(-1pt)', '1pt');
+test_math_used('abs(-1em)', '1em');
+test_math_used('abs(-1ex)', '1ex');
+test_math_used('abs(-1ch)', '1ch');
+test_math_used('abs(-1rem)', '1rem');
+test_math_used('abs(-1vh)', '1vh');
+test_math_used('abs(-1vw)', '1vw');
+test_math_used('abs(-1vmin)', '1vmin');
+test_math_used('abs(-1vmax)', '1vmax');
+test_math_used('abs(1s)', '1s', {type:'time'});
+test_math_used('abs(1ms)', '1ms', {type:'time'});
+test_math_used('abs(-1s)', '1s', {type:'time'});
+test_math_used('abs(-1ms)', '1ms', {type:'time'});
+test_math_used('abs(1deg)', '1deg', {type:'angle', approx:0.001});
+test_math_used('abs(1grad)', '1grad', {type:'angle', approx:0.001});
+test_math_used('abs(1rad)', '1rad', {type:'angle', approx:0.001});
+test_math_used('abs(1turn)', '1turn', {type:'angle', approx:0.001});
+test_math_used('abs(-1deg)', '1deg', {type:'angle', approx:0.001});
+test_math_used('abs(-1grad)', '1grad', {type:'angle', approx:0.001});
+test_math_used('abs(-1rad)', '1rad', {type:'angle', approx:0.001});
+test_math_used('abs(-1turn)', '1turn', {type:'angle', approx:0.001});
+
+// with relative length
+document.getElementById('container').style.fontSize = '10px';
+test_length_equals('sign(10px - 1em)', '0', 'fontSize=10px');
+test_length_equals('sign(10px - 2em)', '-1', 'fontSize=10px');
+document.getElementById('container').style.fontSize = '20px';
+
+test_math_used('calc(sign(10%) * 100px)', '100px');
+
+// Basic tests (just px and em) for sign() interaction with units not
+// otherwise used by the property.
+test_math_used('calc(2.5 - sign(41px - 2em) / 2)', '2', {type:'number'});
+test_math_used('calc(2.5 - sign(40px - 2em) / 2)', '2.5', {type:'number'});
+test_math_used('calc(2.5 - sign(39px - 2em) / 2)', '3', {type:'number'});
+test_math_used('calc(3 + sign(42px - 2em))', '4', {type:'integer'});
+test_math_used('calc(3 + sign(40px - 2em))', '3', {type:'integer'});
+test_math_used('calc(3 + sign(38px - 2em))', '2', {type:'integer'});
+test_math_used('calc(50px + 100px * sign(42px - 2em))', '150px', {type:'length'});
+test_math_used('calc(50px + 100px * sign(40px - 2em))', '50px', {type:'length'});
+test_math_used('calc(50px + 100px * sign(38px - 2em))', '-50px', {type:'length'});
+test_math_used('calc(90deg + 30deg * sign(42px - 2em))', '120deg', {type:'angle'});
+test_math_used('calc(90deg + 30deg * sign(40px - 2em))', '90deg', {type:'angle'});
+test_math_used('calc(90deg + 30deg * sign(38px - 2em))', '60deg', {type:'angle'});
+test_math_used('calc(5s + 15s * sign(42px - 2em))', '20s', {type:'time'});
+test_math_used('calc(5s + 15s * sign(40px - 2em))', '5s', {type:'time'});
+test_math_used('calc(5s + 15s * sign(38px - 2em))', '-10s', {type:'time'});
+test_math_used('calc(100dpi + 20dpi * sign(42px - 2em))', '120dpi', {type:'resolution'});
+test_math_used('calc(100dpi + 20dpi * sign(40px - 2em))', '100dpi', {type:'resolution'});
+test_math_used('calc(100dpi + 20dpi * sign(38px - 2em))', '80dpi', {type:'resolution'});
+test_math_used('calc(3fr + 1fr * sign(42px - 2em))', '4fr', {type:'flex'});
+test_math_used('calc(3fr + 1fr * sign(40px - 2em))', '3fr', {type:'flex'});
+test_math_used('calc(3fr + 1fr * sign(38px - 2em))', '2fr', {type:'flex'});
+// repeat a few with px and rem
+test_math_used('calc(2.5 - sign(33px - 2rem) / 2)', '2', {type:'number'});
+test_math_used('calc(2.5 - sign(32px - 2rem) / 2)', '2.5', {type:'number'});
+test_math_used('calc(2.5 - sign(31px - 2rem) / 2)', '3', {type:'number'});
+test_math_used('calc(50px + 100px * sign(34px - 2rem))', '150px', {type:'length'});
+test_math_used('calc(50px + 100px * sign(32px - 2rem))', '50px', {type:'length'});
+test_math_used('calc(50px + 100px * sign(30px - 2rem))', '-50px', {type:'length'});
+
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/support/numeric-testcommon.js b/Tests/LibWeb/Text/input/wpt-import/css/support/numeric-testcommon.js
new file mode 100644
index 00000000000..b11f5e90447
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/support/numeric-testcommon.js
@@ -0,0 +1,198 @@
+'use strict';
+
+/*
+Provides functions to help test that two numeric values are equivalent.
+These *do not* rely on you predicting what one value will serialize to;
+instead, they set and serialize *both* values,
+and just ensure that they serialize to the same thing.
+
+They rely on a #target element existing in the document,
+as this might rely on layout to resolve styles,
+and so it needs to be in the document.
+
+Three main functions are defined, with the same signatures:
+test_math_used() (for testing used values),
+test_math_computed() (for testing computed values),
+and test_math_specified() (for testing specified values).
+Signature for all is:
+
+test_math_X(
+    testString, // A numeric value; required.
+    expectedString, // A hopefully-equivalent numeric value; required.
+    { // all of these are optional
+        type, // "number", "length", etc. See impl for full list. Defaults to "length".
+        msg, // The message to display for the test; autogenned if not provided.
+        msgExtra, // Extra info to put after the auto-genned message.
+        prop, // If you want to override the automatic choice of tested property.
+        extraStyle, // Styles that need to be set at the same time to properly test the value.
+        approx, // The epsilon in order to compare numeric-ish values.
+                // Note that it'd use parseFloat in order to extract the
+                // values, so they can drop units or what not.
+    }
+);
+
+
+Additionally, five specialized functions are provided
+to test that a given value is ±∞, ±0, or NaN:
+
+* test_plus_infinity(testString)
+* test_minus_infinity(testString)
+* test_plus_zero(testString)
+* test_minus_zero(testString)
+* test_nan(testString)
+
+*/
+
+
+
+function test_math_used(testString, expectedString, {approx, msg, msgExtra, type, prop, extraStyle={}}={}) {
+    if(type === undefined) type = "length";
+    if(!prop) {
+        switch(type) {
+            case "number":     prop = "scale"; break;
+            case "integer":    prop = "z-index"; extraStyle.position="absolute"; break;
+            case "length":     prop = "margin-left"; break;
+            case "angle":      prop = "rotate"; break;
+            case "time":       prop = "transition-delay"; break;
+            case "resolution": prop = "image-resolution"; break;
+            case "flex":       prop = "grid-template-rows"; break;
+            default: throw Exception(`Value type '${type}' isn't capable of math.`);
+        }
+
+    }
+    _test_math({stage:'used', testString, expectedString, type, approx, msg, msgExtra, prop, extraStyle});
+}
+
+function test_math_computed(testString, expectedString, {approx, msg, msgExtra, type, prop, extraStyle={}}={}) {
+    if(type === undefined) type = "length";
+    if(!prop) {
+        switch(type) {
+            case "number":     prop = "scale"; break;
+            case "integer":    prop = "z-index"; extraStyle.position="absolute"; break;
+            case "length":     prop = "flex-basis"; break;
+            case "angle":      prop = "rotate"; break;
+            case "time":       prop = "transition-delay"; break;
+            case "resolution": prop = "image-resolution"; break;
+            case "flex":       prop = "grid-template-rows"; break;
+            default: throw Exception(`Value type '${type}' isn't capable of math.`);
+        }
+
+    }
+    _test_math({stage:'computed', testString, expectedString, type, approx, msg, msgExtra, prop, extraStyle});
+}
+
+function test_math_specified(testString, expectedString, {approx, msg, msgExtra, type, prop, extraStyle={}}={}) {
+    if(type === undefined) type = "length";
+    const stage = "specified";
+    if(!prop) {
+        switch(type) {
+            case "number":     prop = "scale"; break;
+            case "integer":    prop = "z-index"; extraStyle.position="absolute"; break;
+            case "length":     prop = "flex-basis"; break;
+            case "angle":      prop = "rotate"; break;
+            case "time":       prop = "transition-delay"; break;
+            case "resolution": prop = "image-resolution"; break;
+            case "flex":       prop = "grid-template-rows"; break;
+            default: throw Exception(`Value type '${type}' isn't capable of math.`);
+        }
+
+    }
+    // Find the test element
+    const testEl = document.getElementById('target');
+    if(testEl == null) throw "Couldn't find #target element to run tests on.";
+    // Then reset its styles
+    testEl.style = "";
+    for(const p in extraStyle) {
+        testEl.style[p] = extraStyle[p];
+    }
+    if(!msg) {
+        msg = `${testString} should be ${stage}-value-equivalent to ${expectedString}`;
+        if(msgExtra) msg += "; " + msgExtra;
+    }
+    let t = testString;
+    let e = expectedString;
+    test(()=>{
+        testEl.style[prop] = '';
+        testEl.style[prop] = t;
+        const usedValue = testEl.style[prop];
+        assert_not_equals(usedValue, '', `${testString} isn't valid in '${prop}'; got the default value instead.`);
+        testEl.style[prop] = '';
+        testEl.style[prop] = e;
+        const expectedValue = testEl.style[prop];
+        assert_not_equals(expectedValue, '', `${expectedString} isn't valid in '${prop}'; got the default value instead.`)
+        if (approx) {
+            let extractValue = function(value) {
+                if (value.startsWith("calc(")) {
+                    value = value.slice("calc(".length, -1);
+                }
+                return parseFloat(value);
+            };
+            let parsedUsed = extractValue(usedValue);
+            let parsedExpected = extractValue(expectedValue);
+            assert_approx_equals(parsedUsed, parsedExpected, approx, `${testString} and ${expectedString} ${approx} serialize to the same thing in ${stage} values.`);
+        } else {
+            assert_equals(usedValue, expectedValue, `${testString} and ${expectedString} serialize to the same thing in ${stage} values.`);
+        }
+    }, msg);
+}
+
+/*
+All of these expect the testString to evaluate to a <number>.
+*/
+function test_plus_infinity(testString) {
+    test_math_used(testString, "calc(infinity)", {type:"number"});
+}
+function test_minus_infinity(testString) {
+    test_math_used(testString, "calc(-infinity)", {type:"number"});
+}
+function test_plus_zero(testString) {
+    test_math_used(`calc(1 / ${testString})`, "calc(infinity)", {type:"number"});
+}
+function test_minus_zero(testString) {
+    test_math_used(`calc(1 / ${testString})`, "calc(-infinity)", {type:"number"});
+}
+function test_nan(testString) {
+    // Make sure that it's NaN, not an infinity,
+    // by making sure that it's the same value both pos and neg.
+    test_math_used(testString, "calc(NaN)", {type:"number"});
+    test_math_used(`calc(-1 * ${testString})`, "calc(NaN)", {type:"number"});
+}
+
+
+function _test_math({stage, testEl, testString, expectedString, type, approx, msg, msgExtra, prop, extraStyle}={}) {
+    // Find the test element
+    if(!testEl) testEl = document.getElementById('target');
+    if(testEl == null) throw "Couldn't find #target element to run tests on.";
+    // Then reset its styles
+    testEl.style = "";
+    for(const p in extraStyle) {
+        testEl.style[p] = extraStyle[p];
+    }
+    if(!msg) {
+        msg = `${testString} should be ${stage}-value-equivalent to ${expectedString}`;
+        if(msgExtra) msg += "; " + msgExtra;
+    }
+    let t = testString;
+    let e = expectedString;
+    test(()=>{
+        testEl.style[prop] = '';
+        const defaultValue = getComputedStyle(testEl)[prop];
+        testEl.style[prop] = t;
+        const usedValue = getComputedStyle(testEl)[prop];
+        assert_not_equals(usedValue, defaultValue, `${testString} isn't valid in '${prop}'; got the default value instead.`);
+        testEl.style[prop] = '';
+        testEl.style[prop] = e;
+        const expectedValue = getComputedStyle(testEl)[prop];
+        assert_not_equals(expectedValue, defaultValue, `${expectedString} isn't valid in '${prop}'; got the default value instead.`)
+        if (approx) {
+            let extractValue = function(value) {
+                return parseFloat(value);
+            };
+            let parsedUsed = extractValue(usedValue);
+            let parsedExpected = extractValue(expectedValue);
+            assert_approx_equals(parsedUsed, parsedExpected, approx, `${testString} and ${expectedString} ${approx} serialize to the same thing in ${stage} values.`);
+        } else {
+            assert_equals(usedValue, expectedValue, `${testString} and ${expectedString} serialize to the same thing in ${stage} values.`);
+        }
+    }, msg);
+}