fix(docs): add missing hero section styles for homepage

Homepage used custom classes (home-header, home-intro-row, home-stats,
quick-start, command-block, etc.) that had no CSS definitions, causing
all elements to render unstyled and stacked in a single block.

Added styles for:
- .home-header: flex row layout with bottom border separator
- .home-logo: 48×48 gradient rounded square
- .home-title / .home-subtitle: stacked title typography
- .home-nav: inline link group
- .home-intro-row: two-column intro + language tags row
- .home-stats span: pill-style language badges
- .quick-start / .command-block: styled code command block
- Responsive breakpoint at 768px for mobile stacking

Applies to both zh/ and en/ index pages.

Generated with [Devin](https://cli.devin.ai/docs)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

Author: LessUp

docs/.vitepress/theme/styles/vars.css

@@ -626,6 +626,160 @@
   color: var(--ck-slate-400);
 }
 
+/* === Homepage Hero Section === */
+.home-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  padding: 48px 0 24px;
+  border-bottom: 1px solid var(--vp-c-border);
+  margin-bottom: 32px;
+}
+
+.home-header-left {
+  display: flex;
+  align-items: center;
+  gap: 16px;
+}
+
+.home-logo {
+  width: 48px;
+  height: 48px;
+  background: var(--ck-gradient-primary);
+  color: #fff;
+  border-radius: 12px;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  font-size: 14px;
+  font-weight: 700;
+  letter-spacing: 0.5px;
+  flex-shrink: 0;
+}
+
+.home-title {
+  display: block;
+  font-size: 22px;
+  font-weight: 700;
+  color: var(--vp-c-text-1);
+  line-height: 1.2;
+}
+
+.home-subtitle {
+  display: block;
+  font-size: 13px;
+  color: var(--vp-c-text-3);
+  margin-top: 2px;
+}
+
+.home-nav {
+  display: flex;
+  align-items: center;
+  gap: 24px;
+}
+
+.home-nav a {
+  font-size: 14px;
+  font-weight: 500;
+  color: var(--vp-c-brand-1);
+  text-decoration: none;
+  transition: opacity 150ms ease;
+  border-bottom: none;
+}
+
+.home-nav a:hover {
+  opacity: 0.75;
+}
+
+.home-intro-row {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  gap: 32px;
+  padding: 24px 0 32px;
+}
+
+.home-intro {
+  font-size: 15px;
+  line-height: 1.7;
+  color: var(--vp-c-text-2);
+  max-width: 680px;
+}
+
+.home-stats {
+  display: flex;
+  align-items: center;
+  gap: 8px;
+  flex-shrink: 0;
+}
+
+.home-stats span {
+  font-size: 12px;
+  font-weight: 600;
+  color: var(--vp-c-text-2);
+  padding: 4px 10px;
+  background: var(--vp-c-bg-soft);
+  border: 1px solid var(--vp-c-border);
+  border-radius: 20px;
+}
+
+.quick-start {
+  margin-top: 48px;
+  padding: 24px 0 48px;
+  border-top: 1px solid var(--vp-c-border);
+}
+
+.quick-start-title {
+  font-size: 16px;
+  font-weight: 600;
+  color: var(--vp-c-text-1);
+  margin-bottom: 12px;
+}
+
+.quick-start-content {
+  display: flex;
+  align-items: center;
+}
+
+.command-block {
+  background: var(--vp-c-bg-soft);
+  border: 1px solid var(--vp-c-border);
+  border-radius: 8px;
+  padding: 12px 16px;
+  font-family: var(--ck-font-mono);
+  font-size: 13px;
+  color: var(--vp-c-brand-1);
+  overflow-x: auto;
+  width: 100%;
+}
+
+.command-block code {
+  background: transparent;
+  padding: 0;
+  border-radius: 0;
+  font-size: 13px;
+  color: inherit;
+}
+
+@media (max-width: 768px) {
+  .home-header {
+    flex-direction: column;
+    align-items: flex-start;
+    gap: 16px;
+    padding: 32px 0 20px;
+  }
+
+  .home-intro-row {
+    flex-direction: column;
+    align-items: flex-start;
+    gap: 16px;
+  }
+
+  .home-stats {
+    flex-wrap: wrap;
+  }
+}
+
 /* === Homepage Feature Cards === */
 .feature-map {
   display: grid;