Reject non-finite hsl()/hsla() components in parse_css

Found while testing crates/color/src/lib.rs:~173-180 (parse_css, hsl/hsla arm)

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/color/src/lib.rs

@@ -180,6 +180,9 @@ impl Color {
             let h = parts.first()?.trim_end_matches("deg").parse::<f32>().ok()?;
             let s = parts.get(1)?.trim_end_matches('%').parse::<f32>().ok()? / 100.0;
             let l = parts.get(2)?.trim_end_matches('%').parse::<f32>().ok()? / 100.0;
+            if !(h.is_finite() && s.is_finite() && l.is_finite()) {
+                return None;
+            }
             let alpha = match parts.get(3) {
                 Some(a) => parse_alpha(a)?,
                 None => 1.0,
@@ -286,7 +289,8 @@ fn css_hue(p: &str) -> Option<f32> {
 }
 
 fn parse_alpha(a: &str) -> Option<f32> {
-    if let Some(pc) = a.strip_suffix('%') { pc.parse::<f32>().ok().map(|v| v / 100.0) } else { a.parse::<f32>().ok() }
+    let v = if let Some(pc) = a.strip_suffix('%') { pc.parse::<f32>().ok().map(|v| v / 100.0) } else { a.parse::<f32>().ok() }?;
+    v.is_finite().then_some(v)
 }
 
 /// One colour stop of a gradient.

crates/color/src/tests.rs

@@ -141,3 +141,10 @@ fn to_css_round_trips_every_alpha() {
         assert_eq!(Color::parse_css(&c.to_css()).unwrap().to_rgba8(), c.to_rgba8(), "alpha {a}: {}", c.to_css());
     }
 }
+
+#[test]
+fn css_hsl_rejects_non_finite() {
+    for s in ["hsl(nan,50%,50%)", "hsl(inf,50%,50%)", "hsl(0,inf%,50%)", "hsl(0,50%,infinity%)", "hsla(120,50%,50%,nan)"] {
+        assert_eq!(Color::parse_css(s), None, "{s}");
+    }
+}