/* ═══════════════════════════════════════════════════════
   Kuaisou MMS — Design System v2
   Glass Morphism · Light/Dark · Six-Color Palette
   Engineered by Claude (Anthropic) for Kuaisou MMS
   ═══════════════════════════════════════════════════════ */

:root {
  --mms-font: -apple-system, 'SF Pro Display', BlinkMacSystemFont, 'PingFang SC', 'Noto Sans SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
  --mms-mono: 'SF Mono', 'Fira Code', Consolas, monospace;
  --mms-blue: #1a73e8;
  --mms-blue-soft: rgba(26,115,232,.08);
  --mms-blue-glow: rgba(26,115,232,.18);
  --mms-red: #e53935;
  --mms-green: #00897b;
  --mms-radius-s: 10px;
  --mms-radius-m: 14px;
  --mms-radius-l: 22px;
  --mms-ease: cubic-bezier(.4,0,.2,1);
  --mms-t: .25s var(--mms-ease);

  /* Light theme (default) */
  --bg: #f5f5f5;
  --bg-card: rgba(255,255,255,.78);
  --bg-card-hover: rgba(255,255,255,.92);
  --bg-card-solid: #fff;
  --border: rgba(0,0,0,.07);
  --border-hover: rgba(0,0,0,.14);
  --text-1: #1a1a1a;
  --text-2: #555;
  --text-3: #999;
  --text-4: #ccc;
  --shine: linear-gradient(135deg, rgba(255,255,255,.95) 0%, transparent 60%);
  --shadow-s: 0 1px 3px rgba(0,0,0,.04);
  --shadow-m: 0 2px 12px rgba(0,0,0,.06);
  --shadow-l: 0 8px 32px rgba(0,0,0,.08);
  --blur: 32px;
}

[data-theme="dark"] {
  --bg: #1a1a1a;
  --bg-card: rgba(255,255,255,.04);
  --bg-card-hover: rgba(255,255,255,.07);
  --bg-card-solid: #1a1a1a;
  --border: rgba(255,255,255,.07);
  --border-hover: rgba(255,255,255,.14);
  --text-1: rgba(255,255,255,.92);
  --text-2: rgba(255,255,255,.58);
  --text-3: rgba(255,255,255,.32);
  --text-4: rgba(255,255,255,.14);
  --shine: linear-gradient(135deg, rgba(255,255,255,.04) 0%, transparent 60%);
  --shadow-s: 0 1px 3px rgba(0,0,0,.3);
  --shadow-m: 0 2px 12px rgba(0,0,0,.4);
  --shadow-l: 0 8px 32px rgba(0,0,0,.5);
  --mms-blue: #5b9cf6;
  --mms-blue-soft: rgba(91,156,246,.12);
  --mms-blue-glow: rgba(91,156,246,.22);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0 }
html { scroll-behavior: smooth }
body {
  font-family: var(--mms-font);
  line-height: 1.75;
  color: var(--text-1);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -webkit-text-size-adjust: 100%;
  transition: background .4s, color .4s;
}
a { color: var(--mms-blue); text-decoration: none; transition: color var(--mms-t) }
a:hover { opacity: .85 }
::selection { background: var(--mms-blue-soft); color: var(--text-1) }

/* ═══ Layout ═══ */
.container { max-width: 780px; margin: 0 auto; padding: 0 24px }

/* ═══ Header ═══ */
.site-header {
  position: sticky; top: 0; z-index: 90;
  display: flex; justify-content: space-between; align-items: center;
  padding: 14px 0; margin-bottom: 36px;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  transition: background .4s;
}
.site-header .logo {
  font-size: 16px; font-weight: 800; color: var(--text-1);
  text-decoration: none; letter-spacing: -.4px;
  transition: color var(--mms-t);
}
.site-header .logo:hover { color: var(--mms-blue) }
.header-right { display: flex; align-items: center; gap: 12px }

/* Theme toggle */
.theme-toggle {
  width: 36px; height: 36px; border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-card);
  color: var(--text-3);
  cursor: pointer; display: flex; align-items: center; justify-content: center;
  font-size: 16px; transition: all var(--mms-t);
}
.theme-toggle:hover {
  border-color: var(--border-hover);
  color: var(--text-1);
  background: var(--bg-card-hover);
}

/* ═══ Search — First-class citizen ═══ */
.search-box { position: relative }
.search-box input {
  width: 200px; padding: 9px 16px 9px 38px;
  font-size: 14px; font-family: var(--mms-font);
  color: var(--text-1);
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--mms-radius-l);
  outline: none;
  backdrop-filter: blur(var(--blur));
  -webkit-backdrop-filter: blur(var(--blur));
  transition: all .35s var(--mms-ease);
}
.search-box input::placeholder { color: var(--text-4) }
.search-box input:focus {
  width: 300px;
  border-color: var(--mms-blue);
  background: var(--bg-card-hover);
  box-shadow: 0 0 0 3px var(--mms-blue-glow);
}
.search-box::before {
  content: '\f002';
  font-family: 'Font Awesome 5 Free'; font-weight: 900;
  position: absolute; left: 14px; top: 50%; transform: translateY(-50%);
  font-size: 12px; color: var(--text-4); pointer-events: none;
  z-index: 1;
}

/* Search results dropdown */
.search-results {
  position: absolute; top: calc(100% + 8px); right: 0;
  width: 440px;
  background: var(--bg-card-solid);
  border: 1px solid var(--border);
  border-radius: var(--mms-radius-m);
  box-shadow: var(--shadow-l);
  display: none; z-index: 100;
  max-height: 480px; overflow-y: auto;
  animation: fadeSlide .2s var(--mms-ease);
}
@keyframes fadeSlide { from { opacity: 0; transform: translateY(-6px) } to { opacity: 1; transform: translateY(0) } }
.sr-ai { padding: 16px 18px; background: var(--mms-blue-soft); border-bottom: 2px solid var(--mms-blue) }
.sr-ai-label { font-size: 10px; font-weight: 700; color: var(--mms-blue); letter-spacing: .8px; text-transform: uppercase; margin-bottom: 8px }
.sr-ai-body { font-size: 14px; color: var(--text-2); line-height: 1.75 }
.sr-divider { padding: 6px 18px; font-size: 10px; font-weight: 600; color: var(--text-4); background: var(--bg); letter-spacing: .3px }
.sr-item { padding: 12px 18px; border-bottom: 1px solid var(--border); cursor: pointer; transition: background var(--mms-t) }
.sr-item:last-child { border-bottom: none }
.sr-item:hover { background: var(--bg-card) }
.sr-item h4 { font-size: 14px; font-weight: 600; color: var(--text-1); margin-bottom: 3px }
.sr-item p { font-size: 12px; color: var(--text-3); display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden }
.sr-empty { padding: 28px; text-align: center; color: var(--text-4); font-size: 14px }
.sr-loading { padding: 28px; text-align: center; color: var(--mms-blue); font-size: 14px }

/* ═══ Breadcrumb ═══ */
nav.bc { font-size: 14px; color: var(--text-4); margin-bottom: 20px }
nav.bc a { color: var(--text-3) }
nav.bc a:hover { color: var(--mms-blue) }

/* ═══ Footer ═══ */
.site-footer {
  margin-top: 56px; padding: 28px 0;
  border-top: 1px solid var(--border);
  text-align: center; font-size: 12px; color: var(--text-4);
}
.site-footer a { color: var(--text-4); margin: 0 8px }
.site-footer a:hover { color: var(--mms-blue) }

/* ═══ Tags ═══ */
.tag-link {
  display: inline-block; padding: 5px 14px; margin: 3px;
  background: var(--bg-card); color: var(--mms-blue);
  border: 1px solid var(--border); border-radius: var(--mms-radius-l);
  font-size: 14px; font-weight: 500;
  transition: all var(--mms-t);
}
.tag-link:hover { background: var(--mms-blue); color: #fff; border-color: var(--mms-blue); box-shadow: 0 2px 8px var(--mms-blue-glow); text-decoration: none }

.tag-module {
  margin-top: 24px; padding: 18px 20px;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--mms-radius-m);
  position: relative; overflow: hidden;
  backdrop-filter: blur(var(--blur)); -webkit-backdrop-filter: blur(var(--blur));
}
.tag-module::before { content: ''; position: absolute; inset: 0; background: var(--shine); pointer-events: none }
.tag-module h3 { font-size: 14px; font-weight: 700; color: var(--text-2); margin-bottom: 10px; letter-spacing: .2px }
.tag-module a {
  display: inline-block; padding: 4px 12px; margin: 3px;
  background: var(--bg-card-solid); color: var(--mms-blue);
  border: 1px solid var(--border); border-radius: 8px;
  font-size: 14px; transition: all var(--mms-t);
}
.tag-module a:hover { background: var(--mms-blue-soft); border-color: var(--mms-blue); text-decoration: none }
.tag-module .count { color: var(--text-4); font-size: 10px }

/* ═══ Meta info ═══ */
.meta-info { color: var(--text-3); font-size: 14px; margin-bottom: 28px; padding-bottom: 16px; border-bottom: 1px solid var(--border) }
.meta-info span { margin-right: 16px }

/* ═══ Search highlight ═══ */
mark { background: var(--mms-blue-soft); color: var(--mms-blue); padding: 1px 2px; border-radius: 3px }

/* ═══ Responsive ═══ */
@media (max-width: 640px) {
  .container { padding: 0 16px }
  .search-box input { width: 44px; padding: 9px 0 9px 38px; border-color: transparent; background: transparent }
  .search-box input:focus { width: 200px; padding: 9px 16px 9px 38px; border-color: var(--mms-blue); background: var(--bg-card) }
  .search-box input::placeholder { opacity: 0 }
  .search-box input:focus::placeholder { opacity: 1 }
  .search-results { width: calc(100vw - 32px); right: -16px }
  .site-header { padding: 12px 0; margin-bottom: 24px }
}