Like CSS Grid, Servo's `Preferences::default()` ships
`layout_variable_fonts_enabled: false`. `Servo::new` forwards it to Stylo
(`layout.variable_fonts.enabled`), and with the gate off Stylo ignores
`font-variation-settings` and variable weight/width axes: a variable font
renders only its default instance, so every requested weight looks
identical. Modern sites lean on variable fonts (Inter, Roboto Flex,
system New York/SF), so text rendered at the wrong weight versus Chrome.
servo-fonts already drives variations through HarfBuzz, so enabling the
pref is the real fix. Verified with a `@font-face` page using a variable
font at `font-variation-settings: "wght" 200` vs `"wght" 900`: identical
weight before, distinctly light vs black after.
runtime.rs 473 lines (<500). fmt/audit/clippy clean; software_host real-
Servo test passes.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
ZacharyZhang-NYandClaude Opus 4.8
d150da5bd0