diff --git a/Libraries/LibWeb/CSS/Parser/Parser.cpp b/Libraries/LibWeb/CSS/Parser/Parser.cpp
index 8c35548e0e4..9f5b3bcc91a 100644
--- a/Libraries/LibWeb/CSS/Parser/Parser.cpp
+++ b/Libraries/LibWeb/CSS/Parser/Parser.cpp
@@ -1783,6 +1783,8 @@ bool Parser::has_ignored_vendor_prefix(StringView string)
         return false;
     if (string.starts_with("-libweb-"sv))
         return false;
+    if (string.count('-') == 1)
+        return false;
     return true;
 }
 
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/test_font_family_parsing.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/test_font_family_parsing.txt
index 1f3080359a1..b11bebf3c8e 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/test_font_family_parsing.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/test_font_family_parsing.txt
@@ -2,8 +2,7 @@ Harness status: OK
 
 Found 2232 tests
 
-2180 Pass
-52 Fail
+2232 Pass
 Pass	font-family: simple
 Pass	font-family: simple (setter)
 Pass	font: 16px simple
@@ -90,32 +89,32 @@ Pass	font: bolder oblique 16px "simple"
 Pass	font: bolder oblique 16px "simple" (setter)
 Pass	font-family: -simple
 Pass	font-family: -simple (setter)
-Fail	font: 16px -simple
-Fail	font: 16px -simple (setter)
-Fail	font: 900px -simple
-Fail	font: 900px -simple (setter)
-Fail	font: 900em -simple
-Fail	font: 900em -simple (setter)
-Fail	font: 35% -simple
-Fail	font: 35% -simple (setter)
-Fail	font: 7832.3% -simple
-Fail	font: 7832.3% -simple (setter)
-Fail	font: xx-large -simple
-Fail	font: xx-large -simple (setter)
-Fail	font: lighter larger -simple
-Fail	font: lighter larger -simple (setter)
-Fail	font: italic 16px -simple
-Fail	font: italic 16px -simple (setter)
-Fail	font: italic bold 16px -simple
-Fail	font: italic bold 16px -simple (setter)
-Fail	font: normal smaller -simple
-Fail	font: normal smaller -simple (setter)
-Fail	font: normal normal 16px -simple
-Fail	font: normal normal 16px -simple (setter)
-Fail	font: 400 normal 16px -simple
-Fail	font: 400 normal 16px -simple (setter)
-Fail	font: bolder oblique 16px -simple
-Fail	font: bolder oblique 16px -simple (setter)
+Pass	font: 16px -simple
+Pass	font: 16px -simple (setter)
+Pass	font: 900px -simple
+Pass	font: 900px -simple (setter)
+Pass	font: 900em -simple
+Pass	font: 900em -simple (setter)
+Pass	font: 35% -simple
+Pass	font: 35% -simple (setter)
+Pass	font: 7832.3% -simple
+Pass	font: 7832.3% -simple (setter)
+Pass	font: xx-large -simple
+Pass	font: xx-large -simple (setter)
+Pass	font: lighter larger -simple
+Pass	font: lighter larger -simple (setter)
+Pass	font: italic 16px -simple
+Pass	font: italic 16px -simple (setter)
+Pass	font: italic bold 16px -simple
+Pass	font: italic bold 16px -simple (setter)
+Pass	font: normal smaller -simple
+Pass	font: normal smaller -simple (setter)
+Pass	font: normal normal 16px -simple
+Pass	font: normal normal 16px -simple (setter)
+Pass	font: 400 normal 16px -simple
+Pass	font: 400 normal 16px -simple (setter)
+Pass	font: bolder oblique 16px -simple
+Pass	font: bolder oblique 16px -simple (setter)
 Pass	font-family: _simple
 Pass	font-family: _simple (setter)
 Pass	font: 16px _simple
@@ -202,32 +201,32 @@ Pass	font: bolder oblique 16px quite _simple
 Pass	font: bolder oblique 16px quite _simple (setter)
 Pass	font-family: quite -simple
 Pass	font-family: quite -simple (setter)
-Fail	font: 16px quite -simple
-Fail	font: 16px quite -simple (setter)
-Fail	font: 900px quite -simple
-Fail	font: 900px quite -simple (setter)
-Fail	font: 900em quite -simple
-Fail	font: 900em quite -simple (setter)
-Fail	font: 35% quite -simple
-Fail	font: 35% quite -simple (setter)
-Fail	font: 7832.3% quite -simple
-Fail	font: 7832.3% quite -simple (setter)
-Fail	font: xx-large quite -simple
-Fail	font: xx-large quite -simple (setter)
-Fail	font: lighter larger quite -simple
-Fail	font: lighter larger quite -simple (setter)
-Fail	font: italic 16px quite -simple
-Fail	font: italic 16px quite -simple (setter)
-Fail	font: italic bold 16px quite -simple
-Fail	font: italic bold 16px quite -simple (setter)
-Fail	font: normal smaller quite -simple
-Fail	font: normal smaller quite -simple (setter)
-Fail	font: normal normal 16px quite -simple
-Fail	font: normal normal 16px quite -simple (setter)
-Fail	font: 400 normal 16px quite -simple
-Fail	font: 400 normal 16px quite -simple (setter)
-Fail	font: bolder oblique 16px quite -simple
-Fail	font: bolder oblique 16px quite -simple (setter)
+Pass	font: 16px quite -simple
+Pass	font: 16px quite -simple (setter)
+Pass	font: 900px quite -simple
+Pass	font: 900px quite -simple (setter)
+Pass	font: 900em quite -simple
+Pass	font: 900em quite -simple (setter)
+Pass	font: 35% quite -simple
+Pass	font: 35% quite -simple (setter)
+Pass	font: 7832.3% quite -simple
+Pass	font: 7832.3% quite -simple (setter)
+Pass	font: xx-large quite -simple
+Pass	font: xx-large quite -simple (setter)
+Pass	font: lighter larger quite -simple
+Pass	font: lighter larger quite -simple (setter)
+Pass	font: italic 16px quite -simple
+Pass	font: italic 16px quite -simple (setter)
+Pass	font: italic bold 16px quite -simple
+Pass	font: italic bold 16px quite -simple (setter)
+Pass	font: normal smaller quite -simple
+Pass	font: normal smaller quite -simple (setter)
+Pass	font: normal normal 16px quite -simple
+Pass	font: normal normal 16px quite -simple (setter)
+Pass	font: 400 normal 16px quite -simple
+Pass	font: 400 normal 16px quite -simple (setter)
+Pass	font: bolder oblique 16px quite -simple
+Pass	font: bolder oblique 16px quite -simple (setter)
 Pass	font-family: 0simple
 Pass	font-family: 0simple (setter)
 Pass	font: 16px 0simple
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-computed.txt
index 7ac687aaff5..d39ff100ee2 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-computed.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-computed.txt
@@ -2,22 +2,22 @@ Harness status: OK
 
 Found 30 tests
 
-14 Pass
-16 Fail
+18 Pass
+12 Fail
 Pass	Property grid-area value 'auto / auto / auto / auto'
 Pass	Property grid-row value 'auto / auto'
 Pass	Property grid-column-end value 'auto'
-Fail	Property grid-row value '-zπ'
+Pass	Property grid-row value '-zπ'
 Pass	Property grid-row-start value 'AZ'
-Fail	Property grid-column-start value '-_π'
+Pass	Property grid-column-start value '-_π'
 Pass	Property grid-row-end value '_9'
 Fail	Property grid-area value '1 / 90 -a- / auto / auto'
 Pass	Property grid-row value '2 az / auto'
 Pass	Property grid-column value '9 / -19 zA'
 Pass	Property grid-row-start value '-19'
-Fail	Property grid-row-start value '9 -Z_'
+Pass	Property grid-row-start value '9 -Z_'
 Pass	Property grid-column-start value '-44 Z'
-Fail	Property grid-row-end value '1 -πA'
+Pass	Property grid-row-end value '1 -πA'
 Pass	Property grid-column-end value '5 π_'
 Fail	Property grid-area value 'span 2 i / auto / auto / auto'
 Pass	Property grid-row value 'span 2 / auto'
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-valid.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-valid.txt
index a712f742fcd..83c02e5c139 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-valid.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-grid/parsing/grid-area-valid.txt
@@ -2,8 +2,8 @@ Harness status: OK
 
 Found 57 tests
 
-24 Pass
-33 Fail
+30 Pass
+27 Fail
 Pass	e.style['grid-area'] = "auto" should set the property value
 Pass	e.style['grid-area'] = "auto / auto" should set the property value
 Pass	e.style['grid-area'] = "auto / auto / auto" should set the property value
@@ -13,23 +13,23 @@ Pass	e.style['grid-row'] = "auto" should set the property value
 Pass	e.style['grid-row'] = "auto/auto" should set the property value
 Pass	e.style['grid-column-end'] = "AuTo" should set the property value
 Fail	e.style['grid-area'] = "--a" should set the property value
-Fail	e.style['grid-row'] = "-zπ" should set the property value
-Fail	e.style['grid-row'] = "-zπ/-zπ" should set the property value
+Pass	e.style['grid-row'] = "-zπ" should set the property value
+Pass	e.style['grid-row'] = "-zπ/-zπ" should set the property value
 Pass	e.style['grid-row'] = "i / i" should set the property value
 Pass	e.style['grid-row-start'] = "AZ" should set the property value
-Fail	e.style['grid-column-start'] = "-_π" should set the property value
+Pass	e.style['grid-column-start'] = "-_π" should set the property value
 Pass	e.style['grid-row-end'] = "_9" should set the property value
 Fail	e.style['grid-area'] = "1" should set the property value
 Fail	e.style['grid-area'] = "+90 -a-" should set the property value
 Pass	e.style['grid-row'] = "az 2" should set the property value
 Pass	e.style['grid-column'] = "9" should set the property value
 Pass	e.style['grid-column'] = "-19 zA" should set the property value
-Fail	e.style['grid-column'] = "-A0 33" should set the property value
+Pass	e.style['grid-column'] = "-A0 33" should set the property value
 Pass	e.style['grid-row-start'] = "-19" should set the property value
-Fail	e.style['grid-row-start'] = "9 -Z_" should set the property value
+Pass	e.style['grid-row-start'] = "9 -Z_" should set the property value
 Pass	e.style['grid-column-start'] = "+90" should set the property value
 Pass	e.style['grid-column-start'] = "Z -44" should set the property value
-Fail	e.style['grid-row-end'] = "1 -πA" should set the property value
+Pass	e.style['grid-row-end'] = "1 -πA" should set the property value
 Pass	e.style['grid-column-end'] = "π_ +5" should set the property value
 Fail	e.style['grid-area'] = "span 2 i" should set the property value
 Fail	e.style['grid-area'] = "i 2 SpAn" should set the property value