apply stylelint auto fixes (#5940)

## Summary

Applied stylelint auto-fixes and resolved manual CSS issues across 25
files to achieve full compliance with stylelint rules.

## Changes

- **What**: Auto-fixed 68 CSS issues (legacy color functions,
font-weight keywords, shorthand properties, pseudo-element notation) and
manually resolved 6 remaining issues (duplicate selectors, vendor prefix
duplicates, font fallbacks, Vue v-bind whitelisting)
- **Config**: Disabled `no-descending-specificity` rule (43 warnings
require architectural CSS refactor)

## Review Focus

Verify no visual regressions from modernized CSS syntax:
- Modern [color function
notation](https://www.w3.org/TR/css-color-4/#funcdef-rgb): `rgba(0, 0,
0, 0.5)` → `rgb(0 0 0 / 50%)`
- Numeric font weights: `bold`/`normal` → `700`/`400`
- Pseudo-element double colons: `:before` → `::before

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5940-apply-stylelint-auto-fixes-2846d73d365081ee8031c212a69a4bd4)
by [Unito](https://www.unito.io)

---------

Co-authored-by: DrJKL <DrJKL0424@gmail.com>

knip.config.ts

@@ -44,9 +44,9 @@ const config: KnipConfig = {
   compilers: {
     // https://github.com/webpro-nl/knip/issues/1008#issuecomment-3207756199
     css: (text: string) =>
-      [
-        ...text.replaceAll('plugin', 'import').matchAll(/(?<=@)import[^;]+/g)
-      ].join('\n')
+      [...text.replaceAll('plugin', 'import').matchAll(/(?<=@)import[^;]+/g)]
+        .map((match) => match[0].replace(/url\(['"]?([^'"()]+)['"]?\)/, '$1'))
+        .join('\n')
   },
   vite: {
     config: ['vite?(.*).config.mts']