add scrollarea

crates/theme/src/colors.rs

@@ -33,8 +33,10 @@ pub struct ColorTokens {
     pub input: Hsla,
     pub ring: Hsla,
     pub selection: Hsla,
-    /// The scrim behind modal layers; translucent in every theme.
+    /// The scrim behind modal layers, translucent in every theme.
     pub overlay: Hsla,
+    /// The overlay scrollbar thumb, translucent over scrolling content.
+    pub scrollbar_thumb: Hsla,
 }
 
 impl ColorTokens {
@@ -60,6 +62,8 @@ impl ColorTokens {
             ring: hex(0x93c5fd),
             selection: hex(0xdbeafe),
             overlay: scrim(0.25),
+            // macOS light overlay thumbs are translucent black.
+            scrollbar_thumb: hsla(0., 0., 0., 0.25),
         }
     }
 
@@ -85,6 +89,8 @@ impl ColorTokens {
             ring: hex(0x1d4ed8),
             selection: hex(0x1e3a8a),
             overlay: scrim(0.45),
+            // macOS dark overlay thumbs are translucent light gray.
+            scrollbar_thumb: hsla(0., 0., 1., 0.3),
         }
     }
 }