From 56c4e8199bff9e82a3050e49b1a3fc67182136c3 Mon Sep 17 00:00:00 2001
From: Callum Law <callumlaw1709@outlook.com>
Date: Fri, 22 Aug 2025 03:50:16 +1200
Subject: [PATCH] LibWeb: Clamp negative font-size when loading font

`font-size` can end up with a negative value - either due to `calc`
being resolved using the old method which doesn't clamp the value, or
interpolation - in this case we should clamp negative values to zero.

Gains us 36 new WPT passes and fixes crashes in the three imported
tests.
---
 Libraries/LibWeb/CSS/StyleComputer.cpp        |   4 +
 .../font-size-interpolation-001.txt           | 146 ++++++++++++++++++
 .../font-size-interpolation-002.txt           |  34 ++++
 .../font-size-interpolation-003.txt           |  34 ++++
 .../css/css-fonts/parsing/font-computed.txt   |  72 ++++-----
 .../css-fonts/parsing/font-size-computed.txt  |   7 +-
 .../font-size-interpolation-001.html          | 103 ++++++++++++
 .../font-size-interpolation-002.html          |  49 ++++++
 .../font-size-interpolation-003.html          |  47 ++++++
 9 files changed, 456 insertions(+), 40 deletions(-)
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-001.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-002.txt
 create mode 100644 Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-003.txt
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-001.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-002.html
 create mode 100644 Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-003.html

diff --git a/Libraries/LibWeb/CSS/StyleComputer.cpp b/Libraries/LibWeb/CSS/StyleComputer.cpp
index df9f83e4fd8..cbd5deb39c5 100644
--- a/Libraries/LibWeb/CSS/StyleComputer.cpp
+++ b/Libraries/LibWeb/CSS/StyleComputer.cpp
@@ -1989,6 +1989,10 @@ RefPtr<Gfx::FontCascadeList const> StyleComputer::compute_font_for_style_values(
         }
     }
 
+    // FIXME: Font size can end up being negative due to interpolation - we can remove this once we correctly handle interpolation clamping.
+    if (font_size_in_px < 0)
+        font_size_in_px = 0;
+
     auto slope = font_style.to_font_slope();
 
     // FIXME: Implement the full font-matching algorithm: https://www.w3.org/TR/css-fonts-4/#font-matching-algorithm
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-001.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-001.txt
new file mode 100644
index 00000000000..c6acfd2bf18
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-001.txt
@@ -0,0 +1,146 @@
+Harness status: OK
+
+Found 140 tests
+
+110 Pass
+30 Fail
+Fail	CSS Transitions: property <font-size> from neutral to [20px] at (-2) should be [0px]
+Pass	CSS Transitions: property <font-size> from neutral to [20px] at (-0.3) should be [7px]
+Pass	CSS Transitions: property <font-size> from neutral to [20px] at (0) should be [10px]
+Pass	CSS Transitions: property <font-size> from neutral to [20px] at (0.3) should be [13px]
+Pass	CSS Transitions: property <font-size> from neutral to [20px] at (0.6) should be [16px]
+Pass	CSS Transitions: property <font-size> from neutral to [20px] at (1) should be [20px]
+Pass	CSS Transitions: property <font-size> from neutral to [20px] at (1.5) should be [25px]
+Fail	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (-2) should be [0px]
+Pass	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (-0.3) should be [7px]
+Pass	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (0) should be [10px]
+Pass	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (0.3) should be [13px]
+Pass	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (0.6) should be [16px]
+Pass	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (1) should be [20px]
+Pass	CSS Transitions with transition: all: property <font-size> from neutral to [20px] at (1.5) should be [25px]
+Fail	CSS Animations: property <font-size> from neutral to [20px] at (-2) should be [0px]
+Fail	CSS Animations: property <font-size> from neutral to [20px] at (-0.3) should be [7px]
+Pass	CSS Animations: property <font-size> from neutral to [20px] at (0) should be [10px]
+Fail	CSS Animations: property <font-size> from neutral to [20px] at (0.3) should be [13px]
+Fail	CSS Animations: property <font-size> from neutral to [20px] at (0.6) should be [16px]
+Pass	CSS Animations: property <font-size> from neutral to [20px] at (1) should be [20px]
+Fail	CSS Animations: property <font-size> from neutral to [20px] at (1.5) should be [25px]
+Fail	Web Animations: property <font-size> from neutral to [20px] at (-2) should be [0px]
+Fail	Web Animations: property <font-size> from neutral to [20px] at (-0.3) should be [7px]
+Pass	Web Animations: property <font-size> from neutral to [20px] at (0) should be [10px]
+Fail	Web Animations: property <font-size> from neutral to [20px] at (0.3) should be [13px]
+Fail	Web Animations: property <font-size> from neutral to [20px] at (0.6) should be [16px]
+Pass	Web Animations: property <font-size> from neutral to [20px] at (1) should be [20px]
+Fail	Web Animations: property <font-size> from neutral to [20px] at (1.5) should be [25px]
+Pass	CSS Transitions: property <font-size> from [initial] to [20px] at (-2) should be [8px]
+Pass	CSS Transitions: property <font-size> from [initial] to [20px] at (-0.3) should be [14.8px]
+Pass	CSS Transitions: property <font-size> from [initial] to [20px] at (0) should be [16px]
+Pass	CSS Transitions: property <font-size> from [initial] to [20px] at (0.3) should be [17.2px]
+Fail	CSS Transitions: property <font-size> from [initial] to [20px] at (0.6) should be [18.4px]
+Pass	CSS Transitions: property <font-size> from [initial] to [20px] at (1) should be [20px]
+Pass	CSS Transitions: property <font-size> from [initial] to [20px] at (1.5) should be [22px]
+Pass	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (-2) should be [8px]
+Pass	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (-0.3) should be [14.8px]
+Pass	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (0) should be [16px]
+Pass	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (0.3) should be [17.2px]
+Fail	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (0.6) should be [18.4px]
+Pass	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (1) should be [20px]
+Pass	CSS Transitions with transition: all: property <font-size> from [initial] to [20px] at (1.5) should be [22px]
+Fail	CSS Animations: property <font-size> from [initial] to [20px] at (-2) should be [8px]
+Fail	CSS Animations: property <font-size> from [initial] to [20px] at (-0.3) should be [14.8px]
+Fail	CSS Animations: property <font-size> from [initial] to [20px] at (0) should be [16px]
+Fail	CSS Animations: property <font-size> from [initial] to [20px] at (0.3) should be [17.2px]
+Fail	CSS Animations: property <font-size> from [initial] to [20px] at (0.6) should be [18.4px]
+Pass	CSS Animations: property <font-size> from [initial] to [20px] at (1) should be [20px]
+Fail	CSS Animations: property <font-size> from [initial] to [20px] at (1.5) should be [22px]
+Fail	Web Animations: property <font-size> from [initial] to [20px] at (-2) should be [8px]
+Fail	Web Animations: property <font-size> from [initial] to [20px] at (-0.3) should be [14.8px]
+Fail	Web Animations: property <font-size> from [initial] to [20px] at (0) should be [16px]
+Fail	Web Animations: property <font-size> from [initial] to [20px] at (0.3) should be [17.2px]
+Fail	Web Animations: property <font-size> from [initial] to [20px] at (0.6) should be [18.4px]
+Pass	Web Animations: property <font-size> from [initial] to [20px] at (1) should be [20px]
+Fail	Web Animations: property <font-size> from [initial] to [20px] at (1.5) should be [22px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (-2) should be [50px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (-0.3) should be [33px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (0) should be [30px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (0.3) should be [27px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (0.6) should be [24px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (1) should be [20px]
+Pass	CSS Transitions: property <font-size> from [inherit] to [20px] at (1.5) should be [15px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (-2) should be [50px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (-0.3) should be [33px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (0) should be [30px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (0.3) should be [27px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (0.6) should be [24px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (1) should be [20px]
+Pass	CSS Transitions with transition: all: property <font-size> from [inherit] to [20px] at (1.5) should be [15px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (-2) should be [50px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (-0.3) should be [33px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (0) should be [30px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (0.3) should be [27px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (0.6) should be [24px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (1) should be [20px]
+Pass	CSS Animations: property <font-size> from [inherit] to [20px] at (1.5) should be [15px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (-2) should be [50px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (-0.3) should be [33px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (0) should be [30px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (0.3) should be [27px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (0.6) should be [24px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (1) should be [20px]
+Pass	Web Animations: property <font-size> from [inherit] to [20px] at (1.5) should be [15px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (-2) should be [50px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (-0.3) should be [33px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (0) should be [30px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (0.3) should be [27px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (0.6) should be [24px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (1.5) should be [15px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (-2) should be [50px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (-0.3) should be [33px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (0) should be [30px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (0.3) should be [27px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (0.6) should be [24px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (1.5) should be [15px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (-2) should be [50px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (-0.3) should be [33px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (0) should be [30px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (0.3) should be [27px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (0.6) should be [24px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (1.5) should be [15px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (-2) should be [50px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (-0.3) should be [33px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (0) should be [30px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (0.3) should be [27px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (0.6) should be [24px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (1.5) should be [15px]
+Fail	CSS Transitions: property <font-size> from [4px] to [14px] at (-2) should be [0px]
+Pass	CSS Transitions: property <font-size> from [4px] to [14px] at (-0.3) should be [1px]
+Pass	CSS Transitions: property <font-size> from [4px] to [14px] at (0) should be [4px]
+Pass	CSS Transitions: property <font-size> from [4px] to [14px] at (0.3) should be [7px]
+Pass	CSS Transitions: property <font-size> from [4px] to [14px] at (0.6) should be [10px]
+Pass	CSS Transitions: property <font-size> from [4px] to [14px] at (1) should be [14px]
+Pass	CSS Transitions: property <font-size> from [4px] to [14px] at (1.5) should be [19px]
+Fail	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (-2) should be [0px]
+Pass	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (-0.3) should be [1px]
+Pass	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (0) should be [4px]
+Pass	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (0.3) should be [7px]
+Pass	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (0.6) should be [10px]
+Pass	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (1) should be [14px]
+Pass	CSS Transitions with transition: all: property <font-size> from [4px] to [14px] at (1.5) should be [19px]
+Fail	CSS Animations: property <font-size> from [4px] to [14px] at (-2) should be [0px]
+Pass	CSS Animations: property <font-size> from [4px] to [14px] at (-0.3) should be [1px]
+Pass	CSS Animations: property <font-size> from [4px] to [14px] at (0) should be [4px]
+Pass	CSS Animations: property <font-size> from [4px] to [14px] at (0.3) should be [7px]
+Pass	CSS Animations: property <font-size> from [4px] to [14px] at (0.6) should be [10px]
+Pass	CSS Animations: property <font-size> from [4px] to [14px] at (1) should be [14px]
+Pass	CSS Animations: property <font-size> from [4px] to [14px] at (1.5) should be [19px]
+Fail	Web Animations: property <font-size> from [4px] to [14px] at (-2) should be [0px]
+Pass	Web Animations: property <font-size> from [4px] to [14px] at (-0.3) should be [1px]
+Pass	Web Animations: property <font-size> from [4px] to [14px] at (0) should be [4px]
+Pass	Web Animations: property <font-size> from [4px] to [14px] at (0.3) should be [7px]
+Pass	Web Animations: property <font-size> from [4px] to [14px] at (0.6) should be [10px]
+Pass	Web Animations: property <font-size> from [4px] to [14px] at (1) should be [14px]
+Pass	Web Animations: property <font-size> from [4px] to [14px] at (1.5) should be [19px]
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-002.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-002.txt
new file mode 100644
index 00000000000..d6263b9c24d
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-002.txt
@@ -0,0 +1,34 @@
+Harness status: OK
+
+Found 28 tests
+
+24 Pass
+4 Fail
+Fail	CSS Transitions: property <font-size> from [unset] to [20px] at (-2) should be [0px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (-0.3) should be [7px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (0) should be [10px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (0.3) should be [13px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (0.6) should be [16px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	CSS Transitions: property <font-size> from [unset] to [20px] at (1.5) should be [25px]
+Fail	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (-2) should be [0px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (-0.3) should be [7px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (0) should be [10px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (0.3) should be [13px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (0.6) should be [16px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	CSS Transitions with transition: all: property <font-size> from [unset] to [20px] at (1.5) should be [25px]
+Fail	CSS Animations: property <font-size> from [unset] to [20px] at (-2) should be [0px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (-0.3) should be [7px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (0) should be [10px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (0.3) should be [13px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (0.6) should be [16px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	CSS Animations: property <font-size> from [unset] to [20px] at (1.5) should be [25px]
+Fail	Web Animations: property <font-size> from [unset] to [20px] at (-2) should be [0px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (-0.3) should be [7px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (0) should be [10px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (0.3) should be [13px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (0.6) should be [16px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (1) should be [20px]
+Pass	Web Animations: property <font-size> from [unset] to [20px] at (1.5) should be [25px]
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-003.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-003.txt
new file mode 100644
index 00000000000..5d9cb74bc7f
--- /dev/null
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/animations/font-size-interpolation-003.txt
@@ -0,0 +1,34 @@
+Harness status: OK
+
+Found 28 tests
+
+24 Pass
+4 Fail
+Fail	CSS Transitions: property <font-size> from [10px] to [20px] at (-2) should be [0px]
+Pass	CSS Transitions: property <font-size> from [10px] to [20px] at (-0.3) should be [7px]
+Pass	CSS Transitions: property <font-size> from [10px] to [20px] at (0) should be [10px]
+Pass	CSS Transitions: property <font-size> from [10px] to [20px] at (0.3) should be [13px]
+Pass	CSS Transitions: property <font-size> from [10px] to [20px] at (0.6) should be [16px]
+Pass	CSS Transitions: property <font-size> from [10px] to [20px] at (1) should be [20px]
+Pass	CSS Transitions: property <font-size> from [10px] to [20px] at (1.5) should be [25px]
+Fail	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (-2) should be [0px]
+Pass	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (-0.3) should be [7px]
+Pass	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (0) should be [10px]
+Pass	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (0.3) should be [13px]
+Pass	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (0.6) should be [16px]
+Pass	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (1) should be [20px]
+Pass	CSS Transitions with transition: all: property <font-size> from [10px] to [20px] at (1.5) should be [25px]
+Fail	CSS Animations: property <font-size> from [10px] to [20px] at (-2) should be [0px]
+Pass	CSS Animations: property <font-size> from [10px] to [20px] at (-0.3) should be [7px]
+Pass	CSS Animations: property <font-size> from [10px] to [20px] at (0) should be [10px]
+Pass	CSS Animations: property <font-size> from [10px] to [20px] at (0.3) should be [13px]
+Pass	CSS Animations: property <font-size> from [10px] to [20px] at (0.6) should be [16px]
+Pass	CSS Animations: property <font-size> from [10px] to [20px] at (1) should be [20px]
+Pass	CSS Animations: property <font-size> from [10px] to [20px] at (1.5) should be [25px]
+Fail	Web Animations: property <font-size> from [10px] to [20px] at (-2) should be [0px]
+Pass	Web Animations: property <font-size> from [10px] to [20px] at (-0.3) should be [7px]
+Pass	Web Animations: property <font-size> from [10px] to [20px] at (0) should be [10px]
+Pass	Web Animations: property <font-size> from [10px] to [20px] at (0.3) should be [13px]
+Pass	Web Animations: property <font-size> from [10px] to [20px] at (0.6) should be [16px]
+Pass	Web Animations: property <font-size> from [10px] to [20px] at (1) should be [20px]
+Pass	Web Animations: property <font-size> from [10px] to [20px] at (1.5) should be [25px]
\ No newline at end of file
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-computed.txt
index 32592e070f8..18db5864058 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-computed.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-computed.txt
@@ -2,8 +2,8 @@ Harness status: OK
 
 Found 315 tests
 
-244 Pass
-71 Fail
+278 Pass
+37 Fail
 Pass	caption should be a supported system font.
 Pass	icon should be a supported system font.
 Pass	menu should be a supported system font.
@@ -17,7 +17,7 @@ Pass	Property font value 'normal normal normal larger/calc(120% + 1.2em) fantasy
 Pass	Property font value 'normal normal normal normal smaller monospace'
 Pass	Property font value 'normal normal normal italic 10px/normal Menu'
 Pass	Property font value 'normal normal normal small-caps 20%/1.2 "Non-Generic Example Family Name"'
-Fail	Property font value 'normal normal normal bold calc(30% - 40px)/calc(120% + 1.2em) serif'
+Pass	Property font value 'normal normal normal bold calc(30% - 40px)/calc(120% + 1.2em) serif'
 Pass	Property font value 'normal normal normal ultra-condensed xx-small sans-serif'
 Pass	Property font value 'normal normal italic medium/normal cursive'
 Pass	Property font value 'normal normal italic normal xx-large/1.2 fantasy'
@@ -25,7 +25,7 @@ Pass	Property font value 'normal normal italic small-caps larger/calc(120% + 1.2
 Pass	Property font value 'normal normal italic bolder smaller Menu'
 Pass	Property font value 'normal normal italic extra-condensed 10px/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'normal normal small-caps 20%/1.2 serif'
-Fail	Property font value 'normal normal small-caps normal calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
+Pass	Property font value 'normal normal small-caps normal calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
 Pass	Property font value 'normal normal small-caps italic xx-small cursive'
 Fail	Property font value 'normal normal small-caps lighter medium/normal fantasy'
 Pass	Property font value 'normal normal small-caps condensed xx-large/1.2 monospace'
@@ -41,7 +41,7 @@ Pass	Property font value 'normal normal ultra-expanded small-caps larger/calc(12
 Pass	Property font value 'normal normal ultra-condensed 100 smaller serif'
 Pass	Property font value 'normal italic 10px/normal sans-serif'
 Pass	Property font value 'normal italic normal 20%/1.2 cursive'
-Fail	Property font value 'normal italic normal normal calc(30% - 40px)/calc(120% + 1.2em) fantasy'
+Pass	Property font value 'normal italic normal normal calc(30% - 40px)/calc(120% + 1.2em) fantasy'
 Pass	Property font value 'normal italic normal small-caps xx-small monospace'
 Pass	Property font value 'normal italic normal 900 medium/normal Menu'
 Pass	Property font value 'normal italic normal extra-condensed xx-large/1.2 "Non-Generic Example Family Name"'
@@ -49,7 +49,7 @@ Pass	Property font value 'normal italic small-caps larger/calc(120% + 1.2em) ser
 Pass	Property font value 'normal italic small-caps normal smaller sans-serif'
 Pass	Property font value 'normal italic small-caps bold 10px/normal cursive'
 Pass	Property font value 'normal italic small-caps condensed 20%/1.2 fantasy'
-Fail	Property font value 'normal italic bolder calc(30% - 40px)/calc(120% + 1.2em) monospace'
+Pass	Property font value 'normal italic bolder calc(30% - 40px)/calc(120% + 1.2em) monospace'
 Fail	Property font value 'normal italic lighter normal xx-small Menu'
 Pass	Property font value 'normal italic 100 small-caps medium/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'normal italic 900 semi-condensed xx-large/1.2 serif'
@@ -57,7 +57,7 @@ Pass	Property font value 'normal italic semi-expanded larger/calc(120% + 1.2em)
 Pass	Property font value 'normal italic expanded normal smaller cursive'
 Pass	Property font value 'normal italic extra-expanded small-caps 10px/normal fantasy'
 Pass	Property font value 'normal italic ultra-expanded bold 20%/1.2 monospace'
-Fail	Property font value 'normal small-caps calc(30% - 40px)/calc(120% + 1.2em) Menu'
+Pass	Property font value 'normal small-caps calc(30% - 40px)/calc(120% + 1.2em) Menu'
 Pass	Property font value 'normal small-caps normal xx-small "Non-Generic Example Family Name"'
 Pass	Property font value 'normal small-caps normal normal medium/normal serif'
 Pass	Property font value 'normal small-caps normal italic xx-large/1.2 sans-serif'
@@ -73,7 +73,7 @@ Pass	Property font value 'normal small-caps bold italic larger/calc(120% + 1.2em
 Pass	Property font value 'normal small-caps bolder condensed smaller monospace'
 Pass	Property font value 'normal small-caps semi-condensed 10px/normal Menu'
 Pass	Property font value 'normal small-caps semi-expanded normal 20%/1.2 "Non-Generic Example Family Name"'
-Fail	Property font value 'normal small-caps expanded italic calc(30% - 40px)/calc(120% + 1.2em) serif'
+Pass	Property font value 'normal small-caps expanded italic calc(30% - 40px)/calc(120% + 1.2em) serif'
 Fail	Property font value 'normal small-caps extra-expanded lighter xx-small sans-serif'
 Pass	Property font value 'normal 100 medium/normal cursive'
 Pass	Property font value 'normal 900 normal xx-large/1.2 fantasy'
@@ -81,7 +81,7 @@ Pass	Property font value 'normal bold normal normal larger/calc(120% + 1.2em) mo
 Pass	Property font value 'normal bolder normal italic smaller Menu'
 Fail	Property font value 'normal lighter normal small-caps 10px/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'normal 100 normal ultra-expanded 20%/1.2 serif'
-Fail	Property font value 'normal 900 italic calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
+Pass	Property font value 'normal 900 italic calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
 Pass	Property font value 'normal bold italic normal xx-small cursive'
 Pass	Property font value 'normal bolder italic small-caps medium/normal fantasy'
 Fail	Property font value 'normal lighter italic ultra-condensed xx-large/1.2 monospace'
@@ -97,7 +97,7 @@ Pass	Property font value 'normal extra-expanded larger/calc(120% + 1.2em) "Non-G
 Pass	Property font value 'normal ultra-expanded normal smaller serif'
 Pass	Property font value 'normal ultra-condensed normal normal 10px/normal sans-serif'
 Pass	Property font value 'normal extra-condensed normal italic 20%/1.2 cursive'
-Fail	Property font value 'normal condensed normal small-caps calc(30% - 40px)/calc(120% + 1.2em) fantasy'
+Pass	Property font value 'normal condensed normal small-caps calc(30% - 40px)/calc(120% + 1.2em) fantasy'
 Pass	Property font value 'normal semi-condensed normal bolder xx-small monospace'
 Pass	Property font value 'normal semi-expanded italic medium/normal Menu'
 Pass	Property font value 'normal expanded italic normal xx-large/1.2 "Non-Generic Example Family Name"'
@@ -105,7 +105,7 @@ Pass	Property font value 'normal extra-expanded italic small-caps larger/calc(12
 Fail	Property font value 'normal ultra-expanded italic lighter smaller sans-serif'
 Pass	Property font value 'normal ultra-condensed small-caps 10px/normal cursive'
 Pass	Property font value 'normal extra-condensed small-caps normal 20%/1.2 fantasy'
-Fail	Property font value 'normal condensed small-caps italic calc(30% - 40px)/calc(120% + 1.2em) monospace'
+Pass	Property font value 'normal condensed small-caps italic calc(30% - 40px)/calc(120% + 1.2em) monospace'
 Pass	Property font value 'normal semi-condensed small-caps 100 xx-small Menu'
 Pass	Property font value 'normal semi-expanded 900 medium/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'normal expanded bold normal xx-large/1.2 serif'
@@ -113,7 +113,7 @@ Pass	Property font value 'normal extra-expanded bolder italic larger/calc(120% +
 Fail	Property font value 'normal ultra-expanded lighter small-caps smaller cursive'
 Pass	Property font value 'italic 10px/normal fantasy'
 Pass	Property font value 'italic normal 20%/1.2 monospace'
-Fail	Property font value 'italic normal normal calc(30% - 40px)/calc(120% + 1.2em) Menu'
+Pass	Property font value 'italic normal normal calc(30% - 40px)/calc(120% + 1.2em) Menu'
 Pass	Property font value 'italic normal normal normal xx-small "Non-Generic Example Family Name"'
 Pass	Property font value 'italic normal normal small-caps medium/normal serif'
 Pass	Property font value 'italic normal normal 100 xx-large/1.2 sans-serif'
@@ -121,7 +121,7 @@ Pass	Property font value 'italic normal normal ultra-condensed larger/calc(120%
 Pass	Property font value 'italic normal small-caps smaller fantasy'
 Pass	Property font value 'italic normal small-caps normal 10px/normal monospace'
 Pass	Property font value 'italic normal small-caps 900 20%/1.2 Menu'
-Fail	Property font value 'italic normal small-caps extra-condensed calc(30% - 40px)/calc(120% + 1.2em) "Non-Generic Example Family Name"'
+Pass	Property font value 'italic normal small-caps extra-condensed calc(30% - 40px)/calc(120% + 1.2em) "Non-Generic Example Family Name"'
 Pass	Property font value 'italic normal bold xx-small serif'
 Pass	Property font value 'italic normal bolder normal medium/normal sans-serif'
 Fail	Property font value 'italic normal lighter small-caps xx-large/1.2 cursive'
@@ -129,7 +129,7 @@ Pass	Property font value 'italic normal 100 condensed larger/calc(120% + 1.2em)
 Pass	Property font value 'italic normal semi-condensed smaller monospace'
 Pass	Property font value 'italic normal semi-expanded normal 10px/normal Menu'
 Pass	Property font value 'italic normal expanded small-caps 20%/1.2 "Non-Generic Example Family Name"'
-Fail	Property font value 'italic normal extra-expanded 900 calc(30% - 40px)/calc(120% + 1.2em) serif'
+Pass	Property font value 'italic normal extra-expanded 900 calc(30% - 40px)/calc(120% + 1.2em) serif'
 Pass	Property font value 'italic small-caps xx-small sans-serif'
 Pass	Property font value 'italic small-caps normal medium/normal cursive'
 Pass	Property font value 'italic small-caps normal normal xx-large/1.2 fantasy'
@@ -137,7 +137,7 @@ Pass	Property font value 'italic small-caps normal bold larger/calc(120% + 1.2em
 Pass	Property font value 'italic small-caps normal ultra-expanded smaller Menu'
 Pass	Property font value 'italic small-caps bolder 10px/normal "Non-Generic Example Family Name"'
 Fail	Property font value 'italic small-caps lighter normal 20%/1.2 serif'
-Fail	Property font value 'italic small-caps 100 ultra-condensed calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
+Pass	Property font value 'italic small-caps 100 ultra-condensed calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
 Pass	Property font value 'italic small-caps extra-condensed xx-small cursive'
 Pass	Property font value 'italic small-caps condensed normal medium/normal fantasy'
 Pass	Property font value 'italic small-caps semi-condensed 900 xx-large/1.2 monospace'
@@ -145,7 +145,7 @@ Pass	Property font value 'italic bold larger/calc(120% + 1.2em) Menu'
 Pass	Property font value 'italic bolder normal smaller "Non-Generic Example Family Name"'
 Fail	Property font value 'italic lighter normal normal 10px/normal serif'
 Pass	Property font value 'italic 100 normal small-caps 20%/1.2 sans-serif'
-Fail	Property font value 'italic 900 normal semi-expanded calc(30% - 40px)/calc(120% + 1.2em) cursive'
+Pass	Property font value 'italic 900 normal semi-expanded calc(30% - 40px)/calc(120% + 1.2em) cursive'
 Pass	Property font value 'italic bold small-caps xx-small fantasy'
 Pass	Property font value 'italic bolder small-caps normal medium/normal monospace'
 Fail	Property font value 'italic lighter small-caps expanded xx-large/1.2 Menu'
@@ -153,7 +153,7 @@ Pass	Property font value 'italic 100 extra-expanded larger/calc(120% + 1.2em) "N
 Pass	Property font value 'italic 900 ultra-expanded normal smaller serif'
 Pass	Property font value 'italic bold ultra-condensed small-caps 10px/normal sans-serif'
 Pass	Property font value 'italic extra-condensed 20%/1.2 cursive'
-Fail	Property font value 'italic condensed normal calc(30% - 40px)/calc(120% + 1.2em) fantasy'
+Pass	Property font value 'italic condensed normal calc(30% - 40px)/calc(120% + 1.2em) fantasy'
 Pass	Property font value 'italic semi-condensed normal normal xx-small monospace'
 Pass	Property font value 'italic semi-expanded normal small-caps medium/normal Menu'
 Pass	Property font value 'italic expanded normal bolder xx-large/1.2 "Non-Generic Example Family Name"'
@@ -161,7 +161,7 @@ Pass	Property font value 'italic extra-expanded small-caps larger/calc(120% + 1.
 Pass	Property font value 'italic ultra-expanded small-caps normal smaller sans-serif'
 Fail	Property font value 'italic ultra-condensed small-caps lighter 10px/normal cursive'
 Pass	Property font value 'italic extra-condensed 100 20%/1.2 fantasy'
-Fail	Property font value 'italic condensed 900 normal calc(30% - 40px)/calc(120% + 1.2em) monospace'
+Pass	Property font value 'italic condensed 900 normal calc(30% - 40px)/calc(120% + 1.2em) monospace'
 Pass	Property font value 'italic semi-condensed bold small-caps xx-small Menu'
 Pass	Property font value 'small-caps medium/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'small-caps normal xx-large/1.2 serif'
@@ -169,7 +169,7 @@ Pass	Property font value 'small-caps normal normal larger/calc(120% + 1.2em) san
 Pass	Property font value 'small-caps normal normal normal smaller cursive'
 Pass	Property font value 'small-caps normal normal italic 10px/normal fantasy'
 Pass	Property font value 'small-caps normal normal bolder 20%/1.2 monospace'
-Fail	Property font value 'small-caps normal normal semi-expanded calc(30% - 40px)/calc(120% + 1.2em) Menu'
+Pass	Property font value 'small-caps normal normal semi-expanded calc(30% - 40px)/calc(120% + 1.2em) Menu'
 Pass	Property font value 'small-caps normal italic xx-small "Non-Generic Example Family Name"'
 Pass	Property font value 'small-caps normal italic normal medium/normal serif'
 Fail	Property font value 'small-caps normal italic lighter xx-large/1.2 sans-serif'
@@ -177,7 +177,7 @@ Pass	Property font value 'small-caps normal italic expanded larger/calc(120% + 1
 Pass	Property font value 'small-caps normal 100 smaller fantasy'
 Pass	Property font value 'small-caps normal 900 normal 10px/normal monospace'
 Pass	Property font value 'small-caps normal bold italic 20%/1.2 Menu'
-Fail	Property font value 'small-caps normal bolder extra-expanded calc(30% - 40px)/calc(120% + 1.2em) "Non-Generic Example Family Name"'
+Pass	Property font value 'small-caps normal bolder extra-expanded calc(30% - 40px)/calc(120% + 1.2em) "Non-Generic Example Family Name"'
 Pass	Property font value 'small-caps normal ultra-expanded xx-small serif'
 Pass	Property font value 'small-caps normal ultra-condensed normal medium/normal sans-serif'
 Pass	Property font value 'small-caps normal extra-condensed italic xx-large/1.2 cursive'
@@ -185,7 +185,7 @@ Fail	Property font value 'small-caps normal condensed lighter larger/calc(120% +
 Pass	Property font value 'small-caps italic smaller monospace'
 Pass	Property font value 'small-caps italic normal 10px/normal Menu'
 Pass	Property font value 'small-caps italic normal normal 20%/1.2 "Non-Generic Example Family Name"'
-Fail	Property font value 'small-caps italic normal 100 calc(30% - 40px)/calc(120% + 1.2em) serif'
+Pass	Property font value 'small-caps italic normal 100 calc(30% - 40px)/calc(120% + 1.2em) serif'
 Pass	Property font value 'small-caps italic normal semi-condensed xx-small sans-serif'
 Pass	Property font value 'small-caps italic 900 medium/normal cursive'
 Pass	Property font value 'small-caps italic bold normal xx-large/1.2 fantasy'
@@ -193,7 +193,7 @@ Pass	Property font value 'small-caps italic bolder semi-expanded larger/calc(120
 Pass	Property font value 'small-caps italic expanded smaller Menu'
 Pass	Property font value 'small-caps italic extra-expanded normal 10px/normal "Non-Generic Example Family Name"'
 Fail	Property font value 'small-caps italic ultra-expanded lighter 20%/1.2 serif'
-Fail	Property font value 'small-caps 100 calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
+Pass	Property font value 'small-caps 100 calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
 Pass	Property font value 'small-caps 900 normal xx-small cursive'
 Pass	Property font value 'small-caps bold normal normal medium/normal fantasy'
 Pass	Property font value 'small-caps bolder normal italic xx-large/1.2 monospace'
@@ -201,7 +201,7 @@ Fail	Property font value 'small-caps lighter normal ultra-condensed larger/calc(
 Pass	Property font value 'small-caps 100 italic smaller "Non-Generic Example Family Name"'
 Pass	Property font value 'small-caps 900 italic normal 10px/normal serif'
 Pass	Property font value 'small-caps bold italic extra-condensed 20%/1.2 sans-serif'
-Fail	Property font value 'small-caps bolder condensed calc(30% - 40px)/calc(120% + 1.2em) cursive'
+Pass	Property font value 'small-caps bolder condensed calc(30% - 40px)/calc(120% + 1.2em) cursive'
 Fail	Property font value 'small-caps lighter semi-condensed normal xx-small fantasy'
 Pass	Property font value 'small-caps 100 semi-expanded italic medium/normal monospace'
 Pass	Property font value 'small-caps expanded xx-large/1.2 Menu'
@@ -209,7 +209,7 @@ Pass	Property font value 'small-caps extra-expanded normal larger/calc(120% + 1.
 Pass	Property font value 'small-caps ultra-expanded normal normal smaller serif'
 Pass	Property font value 'small-caps ultra-condensed normal italic 10px/normal sans-serif'
 Pass	Property font value 'small-caps extra-condensed normal 900 20%/1.2 cursive'
-Fail	Property font value 'small-caps condensed italic calc(30% - 40px)/calc(120% + 1.2em) fantasy'
+Pass	Property font value 'small-caps condensed italic calc(30% - 40px)/calc(120% + 1.2em) fantasy'
 Pass	Property font value 'small-caps semi-condensed italic normal xx-small monospace'
 Pass	Property font value 'small-caps semi-expanded italic bold medium/normal Menu'
 Pass	Property font value 'small-caps expanded bolder xx-large/1.2 "Non-Generic Example Family Name"'
@@ -217,7 +217,7 @@ Fail	Property font value 'small-caps extra-expanded lighter normal larger/calc(1
 Pass	Property font value 'small-caps ultra-expanded 100 italic smaller sans-serif'
 Pass	Property font value '900 10px/normal cursive'
 Pass	Property font value 'bold normal 20%/1.2 fantasy'
-Fail	Property font value 'bolder normal normal calc(30% - 40px)/calc(120% + 1.2em) monospace'
+Pass	Property font value 'bolder normal normal calc(30% - 40px)/calc(120% + 1.2em) monospace'
 Fail	Property font value 'lighter normal normal normal xx-small Menu'
 Pass	Property font value '100 normal normal italic medium/normal "Non-Generic Example Family Name"'
 Pass	Property font value '900 normal normal small-caps xx-large/1.2 serif'
@@ -225,7 +225,7 @@ Pass	Property font value 'bold normal normal ultra-condensed larger/calc(120% +
 Pass	Property font value 'bolder normal italic smaller cursive'
 Fail	Property font value 'lighter normal italic normal 10px/normal fantasy'
 Pass	Property font value '100 normal italic small-caps 20%/1.2 monospace'
-Fail	Property font value '900 normal italic extra-condensed calc(30% - 40px)/calc(120% + 1.2em) Menu'
+Pass	Property font value '900 normal italic extra-condensed calc(30% - 40px)/calc(120% + 1.2em) Menu'
 Pass	Property font value 'bold normal small-caps xx-small "Non-Generic Example Family Name"'
 Pass	Property font value 'bolder normal small-caps normal medium/normal serif'
 Fail	Property font value 'lighter normal small-caps italic xx-large/1.2 sans-serif'
@@ -241,7 +241,7 @@ Pass	Property font value 'bolder italic normal small-caps larger/calc(120% + 1.2
 Fail	Property font value 'lighter italic normal ultra-expanded smaller monospace'
 Pass	Property font value '100 italic small-caps 10px/normal Menu'
 Pass	Property font value '900 italic small-caps normal 20%/1.2 "Non-Generic Example Family Name"'
-Fail	Property font value 'bold italic small-caps ultra-condensed calc(30% - 40px)/calc(120% + 1.2em) serif'
+Pass	Property font value 'bold italic small-caps ultra-condensed calc(30% - 40px)/calc(120% + 1.2em) serif'
 Pass	Property font value 'bolder italic extra-condensed xx-small sans-serif'
 Fail	Property font value 'lighter italic condensed normal medium/normal cursive'
 Pass	Property font value '100 italic semi-condensed small-caps xx-large/1.2 fantasy'
@@ -249,7 +249,7 @@ Pass	Property font value '900 small-caps larger/calc(120% + 1.2em) monospace'
 Pass	Property font value 'bold small-caps normal smaller Menu'
 Pass	Property font value 'bolder small-caps normal normal 10px/normal "Non-Generic Example Family Name"'
 Fail	Property font value 'lighter small-caps normal italic 20%/1.2 serif'
-Fail	Property font value '100 small-caps normal semi-expanded calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
+Pass	Property font value '100 small-caps normal semi-expanded calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
 Pass	Property font value '900 small-caps italic xx-small cursive'
 Pass	Property font value 'bold small-caps italic normal medium/normal fantasy'
 Pass	Property font value 'bolder small-caps italic expanded xx-large/1.2 monospace'
@@ -257,7 +257,7 @@ Fail	Property font value 'lighter small-caps extra-expanded larger/calc(120% + 1
 Pass	Property font value '100 small-caps ultra-expanded normal smaller "Non-Generic Example Family Name"'
 Pass	Property font value '900 small-caps ultra-condensed italic 10px/normal serif'
 Pass	Property font value 'bold extra-condensed 20%/1.2 sans-serif'
-Fail	Property font value 'bolder condensed normal calc(30% - 40px)/calc(120% + 1.2em) cursive'
+Pass	Property font value 'bolder condensed normal calc(30% - 40px)/calc(120% + 1.2em) cursive'
 Fail	Property font value 'lighter semi-condensed normal normal xx-small fantasy'
 Pass	Property font value '100 semi-expanded normal italic medium/normal monospace'
 Pass	Property font value '900 expanded normal small-caps xx-large/1.2 Menu'
@@ -265,7 +265,7 @@ Pass	Property font value 'bold extra-expanded italic larger/calc(120% + 1.2em) "
 Pass	Property font value 'bolder ultra-expanded italic normal smaller serif'
 Fail	Property font value 'lighter ultra-condensed italic small-caps 10px/normal sans-serif'
 Pass	Property font value '100 extra-condensed small-caps 20%/1.2 cursive'
-Fail	Property font value '900 condensed small-caps normal calc(30% - 40px)/calc(120% + 1.2em) fantasy'
+Pass	Property font value '900 condensed small-caps normal calc(30% - 40px)/calc(120% + 1.2em) fantasy'
 Pass	Property font value 'bold semi-condensed small-caps italic xx-small monospace'
 Pass	Property font value 'semi-expanded medium/normal Menu'
 Pass	Property font value 'expanded normal xx-large/1.2 "Non-Generic Example Family Name"'
@@ -273,7 +273,7 @@ Pass	Property font value 'extra-expanded normal normal larger/calc(120% + 1.2em)
 Pass	Property font value 'ultra-expanded normal normal normal smaller sans-serif'
 Pass	Property font value 'ultra-condensed normal normal italic 10px/normal cursive'
 Pass	Property font value 'extra-condensed normal normal small-caps 20%/1.2 fantasy'
-Fail	Property font value 'condensed normal normal bolder calc(30% - 40px)/calc(120% + 1.2em) monospace'
+Pass	Property font value 'condensed normal normal bolder calc(30% - 40px)/calc(120% + 1.2em) monospace'
 Pass	Property font value 'semi-condensed normal italic xx-small Menu'
 Pass	Property font value 'semi-expanded normal italic normal medium/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'expanded normal italic small-caps xx-large/1.2 serif'
@@ -281,7 +281,7 @@ Fail	Property font value 'extra-expanded normal italic lighter larger/calc(120%
 Pass	Property font value 'ultra-expanded normal small-caps smaller cursive'
 Pass	Property font value 'ultra-condensed normal small-caps normal 10px/normal fantasy'
 Pass	Property font value 'extra-condensed normal small-caps italic 20%/1.2 monospace'
-Fail	Property font value 'condensed normal small-caps 100 calc(30% - 40px)/calc(120% + 1.2em) Menu'
+Pass	Property font value 'condensed normal small-caps 100 calc(30% - 40px)/calc(120% + 1.2em) Menu'
 Pass	Property font value 'semi-condensed normal 900 xx-small "Non-Generic Example Family Name"'
 Pass	Property font value 'semi-expanded normal bold normal medium/normal serif'
 Pass	Property font value 'expanded normal bolder italic xx-large/1.2 sans-serif'
@@ -289,7 +289,7 @@ Fail	Property font value 'extra-expanded normal lighter small-caps larger/calc(1
 Pass	Property font value 'ultra-expanded italic smaller fantasy'
 Pass	Property font value 'ultra-condensed italic normal 10px/normal monospace'
 Pass	Property font value 'extra-condensed italic normal normal 20%/1.2 Menu'
-Fail	Property font value 'condensed italic normal small-caps calc(30% - 40px)/calc(120% + 1.2em) "Non-Generic Example Family Name"'
+Pass	Property font value 'condensed italic normal small-caps calc(30% - 40px)/calc(120% + 1.2em) "Non-Generic Example Family Name"'
 Pass	Property font value 'semi-condensed italic normal 100 xx-small serif'
 Pass	Property font value 'semi-expanded italic small-caps medium/normal sans-serif'
 Pass	Property font value 'expanded italic small-caps normal xx-large/1.2 cursive'
@@ -297,7 +297,7 @@ Pass	Property font value 'extra-expanded italic small-caps 900 larger/calc(120%
 Pass	Property font value 'ultra-expanded italic bold smaller monospace'
 Pass	Property font value 'ultra-condensed italic bolder normal 10px/normal Menu'
 Fail	Property font value 'extra-condensed italic lighter small-caps 20%/1.2 "Non-Generic Example Family Name"'
-Fail	Property font value 'condensed small-caps calc(30% - 40px)/calc(120% + 1.2em) serif'
+Pass	Property font value 'condensed small-caps calc(30% - 40px)/calc(120% + 1.2em) serif'
 Pass	Property font value 'semi-condensed small-caps normal xx-small sans-serif'
 Pass	Property font value 'semi-expanded small-caps normal normal medium/normal cursive'
 Pass	Property font value 'expanded small-caps normal italic xx-large/1.2 fantasy'
@@ -305,7 +305,7 @@ Pass	Property font value 'extra-expanded small-caps normal 100 larger/calc(120%
 Pass	Property font value 'ultra-expanded small-caps italic smaller Menu'
 Pass	Property font value 'ultra-condensed small-caps italic normal 10px/normal "Non-Generic Example Family Name"'
 Pass	Property font value 'extra-condensed small-caps italic 900 20%/1.2 serif'
-Fail	Property font value 'condensed small-caps bold calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
+Pass	Property font value 'condensed small-caps bold calc(30% - 40px)/calc(120% + 1.2em) sans-serif'
 Pass	Property font value 'semi-condensed small-caps bolder normal xx-small cursive'
 Fail	Property font value 'semi-expanded small-caps lighter italic medium/normal fantasy'
 Pass	Property font value 'expanded 100 xx-large/1.2 monospace'
@@ -313,7 +313,7 @@ Pass	Property font value 'extra-expanded 900 normal larger/calc(120% + 1.2em) Me
 Pass	Property font value 'ultra-expanded bold normal normal smaller "Non-Generic Example Family Name"'
 Pass	Property font value 'ultra-condensed bolder normal italic 10px/normal serif'
 Fail	Property font value 'extra-condensed lighter normal small-caps 20%/1.2 sans-serif'
-Fail	Property font value 'condensed 100 italic calc(30% - 40px)/calc(120% + 1.2em) cursive'
+Pass	Property font value 'condensed 100 italic calc(30% - 40px)/calc(120% + 1.2em) cursive'
 Pass	Property font value 'semi-condensed 900 italic normal xx-small fantasy'
 Pass	Property font value 'semi-expanded bold italic small-caps medium/normal monospace'
 Pass	Property font value 'expanded bolder small-caps xx-large/1.2 Menu'
diff --git a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-size-computed.txt b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-size-computed.txt
index 195c100b17e..fb9bb6d8ff4 100644
--- a/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-size-computed.txt
+++ b/Tests/LibWeb/Text/expected/wpt-import/css/css-fonts/parsing/font-size-computed.txt
@@ -2,8 +2,7 @@ Harness status: OK
 
 Found 21 tests
 
-19 Pass
-2 Fail
+21 Pass
 Pass	xx-small <= x-small
 Pass	x-small <= small
 Pass	small <= medium
@@ -15,9 +14,9 @@ Pass	inherit <= larger
 Pass	smaller <= inherit
 Pass	Property font-size value '10px'
 Pass	Property font-size value '20%'
-Fail	Property font-size value 'calc(30% - 40px)'
+Pass	Property font-size value 'calc(30% - 40px)'
 Pass	Property font-size value 'calc(30% + 40px)'
-Fail	Property font-size value 'calc(10px - 0.5em)'
+Pass	Property font-size value 'calc(10px - 0.5em)'
 Pass	Property font-size value 'calc(10px + 0.5em)'
 Pass	<font size="2"> is font-size: small
 Pass	<font size="3"> is font-size: medium
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-001.html b/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-001.html
new file mode 100644
index 00000000000..75648db0ead
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-001.html
@@ -0,0 +1,103 @@
+<!DOCTYPE html>
+<meta charset="UTF-8">
+<title>font-size interpolation</title>
+<link rel="help" href="https://drafts.csswg.org/css-fonts-3/#propdef-font-size">
+<meta name="assert" content="font-size supports animation as length">
+
+<script src="../../../resources/testharness.js"></script>
+<script src="../../../resources/testharnessreport.js"></script>
+<script src="../../../css/support/interpolation-testcommon.js"></script>
+
+<style>
+.parent {
+  font-size: 30px;
+}
+.target {
+  display: inline-block;
+  font: 10px sans-serif;
+}
+.expected {
+  color: green;
+  margin-right: 30px;
+}
+</style>
+
+<body>
+<template id="target-template">
+  <span>
+    <div class="target">Test Text</div>
+  </span>
+</template>
+</body>
+
+<script>
+test_interpolation({
+  property: 'font-size',
+  from: neutralKeyframe,
+  to: '20px',
+}, [
+  {at: -2, expect: '0px'},
+  {at: -0.3, expect: '7px'},
+  {at: 0, expect: '10px'},
+  {at: 0.3, expect: '13px'},
+  {at: 0.6, expect: '16px'},
+  {at: 1, expect: '20px'},
+  {at: 1.5, expect: '25px'},
+]);
+
+test_interpolation({
+  property: 'font-size',
+  from: 'initial',
+  to: '20px',
+}, [
+  {at: -2, expect: '8px'},
+  {at: -0.3, expect: '14.8px'},
+  {at: 0, expect: '16px'},
+  {at: 0.3, expect: '17.2px'},
+  {at: 0.6, expect: '18.4px'},
+  {at: 1, expect: '20px'},
+  {at: 1.5, expect: '22px'},
+]);
+
+test_interpolation({
+  property: 'font-size',
+  from: 'inherit',
+  to: '20px',
+}, [
+  {at: -2, expect: '50px'},
+  {at: -0.3, expect: '33px'},
+  {at: 0, expect: '30px'},
+  {at: 0.3, expect: '27px'},
+  {at: 0.6, expect: '24px'},
+  {at: 1, expect: '20px'},
+  {at: 1.5, expect: '15px'},
+]);
+
+test_interpolation({
+  property: 'font-size',
+  from: 'unset',
+  to: '20px',
+}, [
+  {at: -2, expect: '50px'},
+  {at: -0.3, expect: '33px'},
+  {at: 0, expect: '30px'},
+  {at: 0.3, expect: '27px'},
+  {at: 0.6, expect: '24px'},
+  {at: 1, expect: '20px'},
+  {at: 1.5, expect: '15px'},
+]);
+
+test_interpolation({
+  property: 'font-size',
+  from: '4px',
+  to: '14px'
+}, [
+  {at: -2, expect: '0px'},  // CSS font-size can't be negative.
+  {at: -0.3, expect: '1px'},
+  {at: 0, expect: '4px'},
+  {at: 0.3, expect: '7px'},
+  {at: 0.6, expect: '10px'},
+  {at: 1, expect: '14px'},
+  {at: 1.5, expect: '19px'},
+]);
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-002.html b/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-002.html
new file mode 100644
index 00000000000..db08e4eb688
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-002.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<meta charset="UTF-8">
+<title>font-size interpolation</title>
+<link rel="help" href="https://drafts.csswg.org/css-fonts-3/#propdef-font-size">
+<meta name="assert" content="font-size supports animation as length">
+
+<script src="../../../resources/testharness.js"></script>
+<script src="../../../resources/testharnessreport.js"></script>
+<script src="../../../css/support/interpolation-testcommon.js"></script>
+
+<style>
+.container {
+  font-size: 10px;
+}
+.target {
+  display: inline-block;
+  font: 100px sans-serif;
+  font-size: 20px;
+}
+.expected {
+  color: green;
+  margin-right: 30px;
+}
+</style>
+
+<body>
+<template id="target-template">
+  <span class="container">
+    <div class="target">TT</div>
+  </span>
+</template>
+</body>
+
+<script>
+// Test the 'unset' case.
+test_interpolation({
+  property: 'font-size',
+  from: 'unset',
+  to: '20px'
+}, [
+  {at: -2, expect: '0px'},  // CSS font-size can't be negative.
+  {at: -0.3, expect: '7px'},
+  {at: 0, expect: '10px'},
+  {at: 0.3, expect: '13px'},
+  {at: 0.6, expect: '16px'},
+  {at: 1, expect: '20px'},
+  {at: 1.5, expect: '25px'},
+]);
+</script>
diff --git a/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-003.html b/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-003.html
new file mode 100644
index 00000000000..2d31ad91c4b
--- /dev/null
+++ b/Tests/LibWeb/Text/input/wpt-import/css/css-fonts/animations/font-size-interpolation-003.html
@@ -0,0 +1,47 @@
+<!DOCTYPE html>
+<meta charset="UTF-8">
+<title>font-size interpolation with zoom</title>
+<link rel="help" href="https://drafts.csswg.org/css-fonts-3/#propdef-font-size">
+<meta name="assert" content="font-size supports animation as a length, respecting zoom">
+
+<script src="../../../resources/testharness.js"></script>
+<script src="../../../resources/testharnessreport.js"></script>
+<script src="../../../css/support/interpolation-testcommon.js"></script>
+
+<style>
+.container {
+  zoom: 2;
+}
+.target {
+  display: inline-block;
+}
+.expected {
+  color: green;
+  margin-right: 30px;
+}
+</style>
+
+<body>
+<template id="target-template">
+  <span class="container">
+    <div class="target">TT</div>
+  </span>
+</template>
+</body>
+
+<script>
+// The container has zoom: 2 applied to it.
+test_interpolation({
+  property: 'font-size',
+  from: '10px',
+  to: '20px'
+}, [
+  {at: -2, expect: '0px'}, // CSS font-size can't be negative.
+  {at: -0.3, expect: '7px'},
+  {at: 0, expect: '10px'},
+  {at: 0.3, expect: '13px'},
+  {at: 0.6, expect: '16px'},
+  {at: 1, expect: '20px'},
+  {at: 1.5, expect: '25px'},
+]);
+</script>