Avoid deprecated sass default import warning

Use the namespace object for 'sass' fallback so sass-loader receives a proper implementation without triggering the 'import sass from "sass"' deprecation notice. Keeps 'sass-embedded' path unchanged

Author: PeterDaveHello

build.mjs

@@ -95,8 +95,9 @@ async function runWebpack(isWithoutKatex, isWithoutTiktoken, minimal, sourceBuil
     sassImpl = mod.default || mod
   } catch (e) {
     const mod = await import('sass')
-    // Ensure we pass the implementation object regardless of ESM/CJS interop
-    sassImpl = mod.default || mod
+    // Prefer namespace import style to avoid deprecated default import warning
+    // "import sass from 'sass'" is deprecated; use namespace instead
+    sassImpl = mod
   }
 
   const dirKey = path.basename(sourceBuildDir || outdir)