:root {
  --c-primary: #2563eb;
  --c-primary-hover: #1d4ed8;
  --c-primary-light: #eff6ff;
  --c-secondary: #059669;
  --c-secondary-hover: #047857;
  --c-secondary-light: #ecfdf5;
  --c-accent: #3b82f6;
  --c-bg: #f5f7fa;
  --c-surface: #ffffff;
  --c-text: #0b1b33;
  --c-text-secondary: #475569;
  --c-text-muted: #94a3b8;
  --c-border: #e5e7eb;
  --c-border-light: #f3f4f6;
  --c-header-bg: rgba(15, 23, 42, 0.95);
  --c-header-text: #f1f5f9;
  --c-header-text-hover: #93c5fd;
  --c-header-active: #fff;
  --c-header-input-bg: rgba(255,255,255,.1);
  --c-header-input-border: rgba(255,255,255,.15);
  --c-header-input-focus-bg: rgba(255,255,255,.15);
  --c-header-overlay: rgba(255,255,255,.08);
  --c-header-muted: rgba(255,255,255,.4);
  --c-header-divider: rgba(255,255,255,.2);
  --c-header-avatar-border: rgba(255,255,255,.15);
  --c-code-bg: #1e293b;
  --c-code-text: #e2e8f0;
  --c-success: #10b981;
  --c-warning: #f59e0b;
  --c-danger: #ef4444;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.05);
  --shadow-md: 0 4px 12px rgba(0,0,0,.08);
  --shadow-lg: 0 10px 30px rgba(0,0,0,.1);
  --shadow-xl: 0 20px 50px rgba(0,0,0,.12);
  --font-base: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", "Fira Code", "Fira Mono", "Roboto Mono", Menlo, Courier, monospace;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 36px;
  --spacing-2xl: 48px;
  --container-max: 1240px;
  --header-h: 64px;

  /* Type scale (15px body base on 14px html) */
  --text-xs: .857rem;     /* 12px — badges, counters */
  --text-sm: .929rem;     /* 13px — meta, small */
  --text-base: 1.071rem;  /* 15px — body */
  --text-md: 1.286rem;    /* 18px — h3, section labels */
  --text-lg: 1.5rem;      /* 21px — h2 */
  --text-xl: 1.714rem;    /* 24px — h1 */
  --text-2xl: 2.143rem;   /* 30px — hero/title */
}

/* ─── Dark Mode ─────────────────────────── */
[data-theme="dark"]{
  --c-bg: #0f172a;
  --c-surface: #1e293b;
  --c-text: #e2e8f0;
  --c-text-secondary: #94a3b8;
  --c-text-muted: #64748b;
  --c-border: #334155;
  --c-border-light: #1e293b;
  --c-primary-light: #1e3a5f;
  --c-secondary-light: #064e3b;
  --c-header-bg: rgba(15, 23, 42, 0.98);
  --c-code-bg: #0f172a;
  --c-code-text: #e2e8f0;
  --shadow-sm: 0 1px 2px rgba(0,0,0,.2);
  --shadow-md: 0 4px 12px rgba(0,0,0,.3);
  --shadow-lg: 0 10px 30px rgba(0,0,0,.4);
  --shadow-xl: 0 20px 50px rgba(0,0,0,.5);
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:14px;scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{
  font-family:var(--font-base);
  font-size:var(--text-base);
  line-height:1.75;
  color:var(--c-text);
  background:var(--c-bg);
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}
img{max-width:100%;height:auto;display:block}
a{color:var(--c-primary);text-decoration:none;transition:color .2s}a:hover{color:var(--c-primary-hover)}
ul,ol{list-style:none}
h1{font-size:var(--text-xl);line-height:1.25;letter-spacing:-.02em}
h2{font-size:var(--text-lg);line-height:1.3;letter-spacing:-.01em}
h3{font-size:var(--text-md);line-height:1.35}
h4{font-size:var(--text-base);line-height:1.4}
h5{font-size:var(--text-sm);line-height:1.5}
h6{font-size:var(--text-xs);line-height:1.5}
h1,h2,h3,h4,h5,h6{font-weight:700;color:var(--c-text)}
.page-header h1{font-size:var(--text-xl);margin:var(--spacing-sm) 0 var(--spacing-xs)}
p{margin:0}
button{cursor:pointer;border:none;background:none;font:inherit}
input,textarea,select{font:inherit}
.container{max-width:var(--container-max);margin:0 auto;padding:0 var(--spacing-lg)}
@media(max-width:767px){.container{padding:0 var(--spacing-md)}}
.ad-slot{margin:var(--spacing-md) 0;text-align:center;overflow:hidden;line-height:0}
.ad-slot:empty{display:none}
.section-sidebar .ad-slot,.news-sidebar .ad-slot,.article-sidebar .ad-slot,.course-aside .ad-slot,.course-sidebar .ad-slot,.book-detail-sidebar .ad-slot{margin:0 0 var(--spacing-lg)}
.wrapper{width:100%}
.text-center{text-align:center}
.text-muted{color:var(--c-text-muted)}
.truncate{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}

.section{
  margin-top:var(--spacing-xl);
  background:var(--c-surface);
  border-radius:var(--radius-lg);
  box-shadow:var(--shadow-sm);
  overflow:hidden;
}
.section-heading{
  display:flex;
  align-items:center;
  justify-content:space-between;
  padding:16px 22px 0;
}
.section-heading h2{
  font-size:var(--text-md);
  font-weight:700;
  color:var(--c-text);
  position:relative;
  padding-left:14px;
}
.section-heading h2::before{
  content:'';
  position:absolute;
  left:0;
  top:4px;
  bottom:4px;
  width:5px;
  background:var(--c-primary);
  border-radius:3px;
}
.section-heading .more{
  font-size:var(--text-sm);
  color:var(--c-text-muted);
  transition:color .2s;
}
.section-heading .more:hover{color:var(--c-primary)}
.section-body{padding:20px 24px 24px}
@media(max-width:767px){
  .section-heading{padding:14px 16px 0}
  .section-body{padding:14px 16px 16px}
}

#topbar{
  position:sticky;
  top:0;
  z-index:1000;
  height:var(--header-h);
  background:var(--c-header-bg);
  backdrop-filter:saturate(180%) blur(20px);
  -webkit-backdrop-filter:saturate(180%) blur(20px);
  box-shadow:0 1px 3px rgba(0,0,0,.1);
}
#topbar .container{
  display:flex;
  align-items:center;
  height:100%;
}
#topbar .logo{
  display:flex;
  align-items:center;
  gap:10px;
  color:var(--c-header-text);
  font-size:var(--text-lg);
  font-weight:700;
  white-space:nowrap;
  margin-right:var(--spacing-xl);
}
#topbar .logo:hover{color:var(--c-header-text);opacity:.85}
#topbar .logo img{height:36px;border-radius:8px;flex-shrink:0}
#topbar .nav{display:flex;align-items:center;gap:2px;height:100%;flex:1}
#topbar .nav a{
  display:flex;
  align-items:center;
  height:100%;
  padding:0 14px;
  color:var(--c-header-text);
  font-size:var(--text-base);
  font-weight:500;
  position:relative;
  transition:color .2s,background .2s;
  border-radius:var(--radius-sm);
}
#topbar .nav a:hover{color:var(--c-header-text-hover);background:var(--c-header-overlay)}
#topbar .nav a.active{color:var(--c-header-active)}
#topbar .nav a.active::after{
  content:'';
  position:absolute;
  bottom:0;
  left:14px;
  right:14px;
  height:2px;
  background:var(--c-primary);
  border-radius:1px 1px 0 0;
}
#topbar .nav .new-badge{
  font-size:var(--text-xs);
  background:var(--c-danger);
  color:#fff;
  padding:0 4px;
  border-radius:3px;
  margin-left:4px;
  line-height:1.4;
}
#search{
  display:flex;
  align-items:center;
  margin-left:auto;
  flex-shrink:0;
}
#search .search-wrap{
  position:relative;
  display:flex;
  align-items:center;
}
#search .sinput{
  width:180px;
  height:36px;
  padding:0 36px 0 12px;
  border:1px solid var(--c-header-input-border);
  background:var(--c-header-input-bg);
  color:var(--c-header-text);
  border-radius:var(--radius-sm);
  outline:none;
  font-size:var(--text-sm);
  transition:border-color .2s,background .2s;
}
#search .sinput::placeholder{color:var(--c-header-muted)}
#search .sinput:focus{border-color:var(--c-primary);background:var(--c-header-input-focus-bg)}
#search .search-btn{
  position:absolute;
  right:0;
  top:0;
  display:flex;
  align-items:center;
  justify-content:center;
  width:36px;
  height:36px;
  background:none;
  border:none;
  color:var(--c-header-muted);
  cursor:pointer;
  transition:color .2s;
  border-radius:0 var(--radius-sm) var(--radius-sm) 0;
}
#search .search-btn:hover{color:var(--c-primary)}
.nav-toggle{display:none;color:var(--c-header-text);font-size:1.5rem;padding:8px;background:none;cursor:pointer}

/* ===== User Toolbar (Header) ===== */
#user-toolbar{display:flex;align-items:center;gap:0;margin-left:20px;flex-shrink:0}
.user-toolbar-link{font-size:13px;font-weight:500;color:var(--c-header-text);text-decoration:none;display:inline-flex;align-items:center;gap:6px;white-space:nowrap;transition:color .2s,background .2s;border-radius:var(--radius-sm);padding:6px 4px}
.user-toolbar-link:hover{color:var(--c-header-text-hover);background:var(--c-header-overlay)}
.user-toolbar-divider{color:var(--c-header-divider);font-size:12px;margin:0 2px;user-select:none}
.user-toolbar-avatar{width:26px;height:26px;border-radius:50%;object-fit:cover;border:2px solid var(--c-header-avatar-border);flex-shrink:0}
.user-toolbar-avatar-wrap{position:relative;display:inline-flex;flex-shrink:0}
.user-toolbar-vip-badge{
  position:absolute;top:-3px;right:-5px;
  min-width:14px;height:14px;
  padding:0 3px;
  font-size:9px;font-weight:700;line-height:14px;
  background:#f5a623;color:#fff;
  border-radius:7px;
  border:1.5px solid var(--c-header-bg);
  text-align:center;
}

/* ===== Theme Toggle (Header) ===== */
.theme-toggle-wrap{display:flex;align-items:center;gap:6px;margin-left:12px;flex-shrink:0}
.theme-toggle-btn{
  display:flex;align-items:center;justify-content:center;
  width:32px;height:32px;
  border-radius:var(--radius-sm);
  color:var(--c-header-text);
  transition:background .2s,color .2s;
}
.theme-toggle-btn:hover{background:var(--c-header-overlay);color:var(--c-header-text-hover)}
.theme-toggle-btn svg{width:18px;height:18px}
.theme-icon-sun,.theme-icon-moon{width:18px;height:18px}
.theme-icon-moon{display:none}
[data-theme="dark"] .theme-icon-sun{display:none}
[data-theme="dark"] .theme-icon-moon{display:block}

#mobile-avatar{display:none}
.mobile-search{display:none}
@media(max-width:1023px){
  #search .sinput{width:140px}
}
@media (min-width:1024px) and (max-width:1159px){
  #search .sinput{width:160px}
}
@media (min-width:768px) and (max-width:1023px){
  #topbar .logo{margin-right:var(--spacing-sm)}
  #topbar .nav{gap:0;min-width:0;overflow-x:auto;overflow-y:hidden;scrollbar-width:none}
  #topbar .nav::-webkit-scrollbar{display:none}
  #topbar .nav a{padding:0 10px;flex-shrink:0}
  #search{flex-shrink:1;min-width:0}
  #search .sinput{width:110px}
  #user-toolbar{margin-left:10px}
  .theme-toggle-wrap{margin-left:6px}
}
@media(max-width:767px){
  #topbar .container{position:relative;display:flex;align-items:center;justify-content:center;gap:12px}
  #mobile-avatar{display:flex;align-items:center;flex-shrink:0;position:absolute;left:var(--spacing-md);top:0;height:100%}
  .mobile-user-avatar{width:32px;height:32px;border-radius:50%;object-fit:cover}
  .mobile-login-icon{width:24px;height:24px;color:var(--c-header-text)}
  #topbar .logo{margin-right:0}
  #search{display:none}
  #user-toolbar .user-toolbar-link,
  #user-toolbar .user-toolbar-divider,
  #user-toolbar .user-toolbar-avatar-wrap{display:none}
  #user-toolbar{position:absolute;right:var(--spacing-md);top:0;height:100%;margin-left:0;justify-content:center}
  .theme-toggle-wrap{display:flex;margin-left:0}
  .nav-toggle{display:block}
  #topbar .nav{display:none;position:absolute;top:var(--header-h);left:0;right:0;flex-direction:column;background:var(--c-header-bg);padding:0 0 var(--spacing-sm);height:auto;backdrop-filter:saturate(180%) blur(20px);box-shadow:0 4px 20px rgba(0,0,0,.2)}
  #topbar .nav.open{display:flex}
  #topbar .nav a{height:44px;padding:0 var(--spacing-lg);justify-content:center}
  #topbar .nav a.active::after{display:none}
  #topbar .nav a.active{background:var(--c-header-overlay)}
  .mobile-search{display:flex;padding:10px var(--spacing-lg)}
  .mobile-search .search-wrap{flex:1;position:relative;display:flex;align-items:center}
  .mobile-search .sinput{width:100%;height:36px;padding:0 36px 0 12px;border:1px solid var(--c-header-input-border);background:var(--c-header-input-bg);color:var(--c-header-text);border-radius:var(--radius-sm);outline:none;font-size:var(--text-sm);box-sizing:border-box}
  .mobile-search .sinput::placeholder{color:var(--c-header-muted)}
  .mobile-search .search-btn{position:absolute;right:0;top:0;display:flex;align-items:center;justify-content:center;width:36px;height:36px;background:none;border:none;color:var(--c-header-muted);cursor:pointer;transition:color .2s;border-radius:0 var(--radius-sm) var(--radius-sm) 0}
  .mobile-search .search-btn:hover{color:var(--c-primary)}
}
@media(min-width:768px){.nav-toggle{display:none}}

#footer{
  margin-top:var(--spacing-2xl);
  background:var(--c-surface);
  border-top:1px solid var(--c-border);
}
#footer-inner{
  max-width:var(--container-max);
  margin:0 auto;
  padding:var(--spacing-xl) var(--spacing-lg);
  display:grid;
  grid-template-columns:2fr 1fr 1fr 1.5fr;
  gap:var(--spacing-xl);
}
#footer-inner h3{
  font-size:var(--text-sm);
  font-weight:700;
  margin-bottom:12px;
  color:var(--c-text);
}
#footer-inner p{font-size:var(--text-sm);color:var(--c-text-secondary);line-height:2}
#footer-inner a{color:var(--c-text-secondary)}
#footer-inner a:hover{color:var(--c-primary)}
.footer-desc{font-size:var(--text-sm);color:var(--c-text-muted);line-height:1.65;margin-bottom:12px}
.footer-social{display:flex;gap:var(--spacing-sm);margin-top:var(--spacing-md)}
.footer-social a{
  width:36px;height:36px;
  display:flex;align-items:center;justify-content:center;
  border-radius:50%;
  background:var(--c-bg);
  color:var(--c-text-secondary);
  font-size:var(--text-md);
  transition:background .2s,color .2s;
}
#footer-inner .footer-social a:hover{background:var(--c-primary);color:#fff}
.footer-text-icon{font-size:var(--text-md);font-weight:800;line-height:1;font-style:normal}
.footer-wechat img{width:100px;height:100px;border-radius:var(--radius-sm);margin-top:var(--spacing-sm)}
#copyright{
  border-top:1px solid var(--c-border);
  padding:var(--spacing-md) var(--spacing-lg);
  text-align:center;
  font-size:var(--text-sm);
  color:var(--c-text-muted);
}
#copyright a{color:var(--c-text-muted)}
#copyright a:hover{color:var(--c-primary)}
@media(max-width:767px){
  #footer-inner{grid-template-columns:1fr;gap:var(--spacing-lg)}
  #footer-inner > div:nth-child(n+2){display:none}
}

.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);border:0}
.thumb-img{object-fit:cover}

/* ─── Shared Component Patterns ────────────────── */
/* Sidebar card — 6 files */
.sidebar-card,.search-sidebar-card{
  background:var(--c-surface);
  border-radius:var(--radius-md);
  box-shadow:var(--shadow-sm);
  overflow:hidden;
  margin-bottom:var(--spacing-md);
}

/* Sidebar title — 5 files */
.sidebar-title{
  font-size:var(--text-sm);
  font-weight:700;
  padding:14px 16px;
  border-bottom:1px solid var(--c-border-light);
  display:flex;
  align-items:center;
  gap:8px;
}
.sidebar-title .ic-hot{color:var(--c-danger)}

/* Ranking list — 4 files */
.ranking-list{
  list-style:none;
  counter-reset:rank;
  padding:0;
  margin:0;
}
.ranking-list li{
  counter-increment:rank;
  display:flex;
  justify-content:space-between;
  align-items:center;
  padding:9px 16px;
  border-bottom:1px solid var(--c-border-light);
  gap:8px;
  transition:background .15s;
}
.ranking-list li:hover{background:var(--c-primary-light)}
.ranking-list li::before{
  content:counter(rank);
  width:20px;height:20px;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  border-radius:50%;
  font-size:var(--text-xs);
  font-weight:700;
  color:#fff;
  background:var(--c-border);
  flex-shrink:0;
}
.ranking-list li:nth-child(1)::before{background:#ef4444}
.ranking-list li:nth-child(2)::before{background:#f59e0b}
.ranking-list li:nth-child(3)::before{background:#10b981}
.ranking-list li a{
  flex:1;
  font-size:var(--text-sm);
  color:var(--c-text-secondary);
  overflow:hidden;
  white-space:nowrap;
  text-overflow:ellipsis;
}
.ranking-list li a:hover{color:var(--c-primary)}
.ranking-list li span{
  font-size:var(--text-xs);
  color:var(--c-text-muted);
  white-space:nowrap;
}
.ranking-list li span i{color:var(--c-danger)}

/* Tag pill — 3 files */
.article-tag,.cmd-tag,.distro-tag{
  display:inline-block;
  padding:3px 12px;
  font-size:var(--text-sm);
  color:var(--c-primary);
  background:var(--c-primary-light);
  border-radius:20px;
  transition:background .2s,color .2s;
}
.article-tag:hover,.cmd-tag:hover,.distro-tag:hover{
  background:var(--c-primary);
  color:#fff;
}

/* Breadcrumb — 6 files */
.article-breadcrumb,.cmd-breadcrumb,.course-breadcrumb,
.book-detail-breadcrumb,.distro-breadcrumb,.screenshot-breadcrumb{
  display:flex;
  align-items:center;
  gap:var(--spacing-sm);
  padding:var(--spacing-md) 0;
  font-size:var(--text-sm);
  color:var(--c-text-muted);
}
.article-breadcrumb a,.cmd-breadcrumb a,.course-breadcrumb a,
.book-detail-breadcrumb a,.distro-breadcrumb a,.screenshot-breadcrumb a{
  color:var(--c-text-muted);
  transition:color .2s;
}
.article-breadcrumb a:hover,.cmd-breadcrumb a:hover,.course-breadcrumb a:hover,
.book-detail-breadcrumb a:hover,.distro-breadcrumb a:hover,.screenshot-breadcrumb a:hover{
  color:var(--c-primary);
}
.article-breadcrumb .sep,.cmd-breadcrumb .sep,.course-breadcrumb .sep,
.book-detail-breadcrumb .sep,.distro-breadcrumb .sep,.screenshot-breadcrumb .sep{
  color:var(--c-border);
}
.article-breadcrumb .current,.cmd-breadcrumb .current,.course-breadcrumb .current,
.book-detail-breadcrumb .current,.distro-breadcrumb .current,.screenshot-breadcrumb .current{
  color:var(--c-text-secondary);
  overflow:hidden;
  text-overflow:ellipsis;
  white-space:nowrap;
}

/* Meta comment link — 2 files */
.cmd-meta-comment,.distro-meta-comment{
  display:flex;
  align-items:center;
  gap:4px;
  color:var(--c-text-muted);
  text-decoration:none;
}
.cmd-meta-comment:hover,.distro-meta-comment:hover{color:var(--c-primary)}

/* Filter tabs — 2 files */
.news-tab,.search-type-filter a{
  font-size:var(--text-sm);
  padding:6px 14px;
  border-radius:var(--radius-sm);
  color:var(--c-text-secondary);
  transition:background .15s,color .15s;
}
.news-tab:hover,.search-type-filter a:hover{
  background:var(--c-primary-light);
  color:var(--c-primary);
}
.news-tab.active,.search-type-filter a.active{
  background:var(--c-primary);
  color:#fff;
}

/* Icon jump animation (consolidated from 4 files) */
@keyframes icon-jump{
  0%{transform:translate(0)}
  10%{transform:translateY(8px) scaleX(1.2) scaleY(.8)}
  30%{transform:translateY(-5px) scaleX(1) scaleY(1) rotate(5deg)}
  50%{transform:translateY(3px) scale(1) rotate(0)}
  55%{transform:translateY(0) scaleX(1.1) scaleY(.9) rotate(0)}
  70%{transform:translateY(-5px) scaleX(1) scaleY(1) rotate(-2deg)}
  80%{transform:translateY(0) scaleX(1) scaleY(1) rotate(0)}
  85%{transform:translateY(0) scaleX(1.05) scaleY(.95) rotate(0)}
  100%{transform:translateY(0) scaleX(1) scaleY(1)}
}