Fix: Optimized the table of contents style and homepage card layout #3221 (#9993)

### What problem does this PR solve?

Fix: Optimized the table of contents style and homepage card layout
#3221

- Added background color, text color, and shadow styles to the Markdown
table of contents
- Optimized the date display style in the HomeCard component to prevent
overflow
- Standardized the translation of "dataset" to "knowledge base" to
improve terminology consistency

### Type of change

- [x] Bug Fix (non-breaking change which fixes an issue)

web/src/pages/home/datasets.tsx

@@ -30,7 +30,7 @@ export function Datasets() {
             <CardSkeleton />
           </div>
         ) : (
-          <div className="grid gap-6 sm:grid-cols-1 md:grid-cols-2 lg:grid-cols-4 xl:grid-cols-6 2xl:grid-cols-8 max-h-[78vh] overflow-auto">
+          <div className="grid gap-6 grid-cols-1 md:grid-cols-2 lg:grid-cols-4 xl:grid-cols-5 2xl:grid-cols-6 3xl:grid-cols-7 max-h-[78vh] overflow-auto">
             {kbs
               ?.slice(0, 6)
               .map((dataset) => (