fix web build

crates/theme/src/platform_kind.rs

@@ -3,6 +3,7 @@ pub enum PlatformKind {
     Mac,
     Linux,
     Windows,
+    Web,
 }
 
 impl PlatformKind {
@@ -11,22 +12,21 @@ impl PlatformKind {
             Self::Linux
         } else if cfg!(target_os = "windows") {
             Self::Windows
-        } else {
+        } else if cfg!(target_os = "macos") {
             Self::Mac
+        } else {
+            Self::Web
         }
     }
 
-    #[allow(dead_code)]
     pub fn is_linux(&self) -> bool {
         matches!(self, Self::Linux)
     }
 
-    #[allow(dead_code)]
     pub fn is_windows(&self) -> bool {
         matches!(self, Self::Windows)
     }
 
-    #[allow(dead_code)]
     pub fn is_mac(&self) -> bool {
         matches!(self, Self::Mac)
     }