refactor(docs): move sidebar styles to css file and remove cache busting

Clean up styles by moving them from config to dedicated CSS file
Remove unnecessary cache busting parameter from style import

docs/.vitepress/config.mjs

@@ -6,34 +6,7 @@ export default defineConfig({
   description: 'Easy-Vibe 中文实战课 - 零基础学会用 AI 干实际工作',
   head: [
     ['link', { rel: 'icon', href: '/logo.png' }],
-    ['style', {}, `
-      :root {
-        --vp-sidebar-nav-section-gap: 4px;
-        --vp-sidebar-item-line-height: 16px !important;
-        --vp-sidebar-item-padding-bottom: 0px !important;
-        --vp-sidebar-item-padding-top: 0px !important;
-      }
-      .VPSidebarItem .item,
-      .VPSidebarItem .VPLink,
-      .VPSidebarItem .link,
-      .VPSidebarItem .text {
-        padding-top: 1px !important;
-        padding-bottom: 1px !important;
-        min-height: unset !important;
-        line-height: 1.2 !important;
-        font-size: 13px !important;
-      }
-      .VPSidebarItem.level-0 { padding-bottom: 4px !important; }
-      .VPSidebarItem.level-0 > .item { padding-top: 3px !important; padding-bottom: 3px !important; }
-      .VPSidebarItem.level-0 > .item .text { font-weight: 600 !important; font-size: 14px !important; }
-      .VPSidebarItem.level-1 .item,
-      .VPSidebarItem.level-2 .item,
-      .VPSidebarItem.level-3 .item,
-      .VPSidebarItem.level-4 .item { padding-top: 0px !important; padding-bottom: 0px !important; }
-      .VPSidebarItem .VPLink { display: flex !important; align-items: center !important; min-height: 20px !important; }
-      .VPSidebarGroup { padding-top: 2px !important; padding-bottom: 2px !important; }
-      .VPSidebarItem .indicator { height: 10px !important; width: 3px !important; top: 50% !important; transform: translateY(-50%) !important; }
-    `]
+    ['link', { rel: 'stylesheet', href: '/style.css' }]
   ],
   themeConfig: {
     logo: '/logo.png',