Unify CSS feature query truth

crates/obscura-js/src/ops.rs

@@ -2457,6 +2457,7 @@ pub fn build_extension() -> Extension {
         ops.push(op_image_metadata());
         ops.push(op_layout_geometry());
         ops.push(op_computed_style());
+        ops.push(op_css_supports());
         ops.push(op_layout_metrics());
         ops.push(op_scroll_offset());
         ops.push(op_scroll_to());
@@ -2703,6 +2704,15 @@ fn op_computed_style(state: &OpState, #[string] nid_str: String) -> String {
     serde_json::Value::Object(object).to_string()
 }
 
+/// Use the renderer's declaration parser as the single feature-query source
+/// of truth. Keeping this bridge synchronous and state-free makes the common
+/// two-argument `CSS.supports()` overload a single native call.
+#[cfg(feature = "render")]
+#[op2(fast)]
+fn op_css_supports(#[string] name: &str, #[string] value: &str) -> bool {
+    obscura_render::style::supports_declaration(name, value)
+}
+
 /// Root scrolling overflow in CSS pixels. The JS CSSOM probes this op only in
 /// render builds; default scraping builds retain their deliberately unbounded
 /// synthetic scrolling behavior.

crates/obscura-js/src/runtime.rs

@@ -3086,13 +3086,19 @@ mod tests {
                     CSS.supports("color", "light-dark(rgb(1, 2, 3), color-mix(in srgb, white 50%, black))"),
                     CSS.supports("(color:light-dark(red, light-dark(white, black)))"),
                     CSS.supports("color", "light-dark(red)"),
-                    CSS.supports("color", "light-dark(red, rgb(1, 2, 3)")
+                    CSS.supports("color", "light-dark(red, rgb(1, 2, 3)"),
+                    CSS.supports("border", "2px dashed red"),
+                    CSS.supports("border-width", "10%"),
+                    CSS.supports("word-break", "break-all"),
+                    CSS.supports("filter", "blur(2px)"),
+                    CSS.supports("content", "attr(data-label)"),
+                    CSS.supports("display", "grid;")
                 ])"#,
             )
             .unwrap();
         assert_eq!(
             result,
-            serde_json::json!("[false,false,false,true,false,true,true,true,false,false,false,true,false,true,true,false,false]")
+            serde_json::json!("[false,false,false,false,false,true,true,true,false,false,false,true,false,true,true,false,false,true,false,true,false,true,false]")
         );
     }