/* ==========================================
   Geek_log - 课程浏览系统样式
   设计参照：Warm Minimal / Anthropic 风格
   ========================================== */

/* ---- Google Fonts ---- */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@400;500;600;700&family=Lora:wght@400;500;600;700&family=Noto+Serif+SC:wght@400;600;700&display=swap');

/* ---- CSS Variables: Light Mode ---- */
:root {
  /* Surface hierarchy */
  --surface-0: #faf9f5;
  --surface-1: #ffffff;
  --surface-2: #f2f1ec;
  --surface-3: #eae8e1;
  --surface-4: #dddbd3;

  /* Brand */
  --brand-dark: #141413;
  --brand-orange: #d97757;
  --brand-orange-hover: #e08a6e;
  --brand-blue: #6a9bcc;
  --brand-green: #788c5d;

  /* Text hierarchy */
  --text-primary: #141413;
  --text-secondary: #5c5b56;
  --text-tertiary: #9c9a91;

  /* Borders (semi-transparent) */
  --border-color: rgba(20,20,19,.1);
  --border-subtle: rgba(20,20,19,.05);

  /* Semantic */
  --risk-warn: #c4912e;
  --risk-danger: #c05a3c;

  /* Hover / Active */
  --hover-overlay: rgba(20,20,19,.04);
  --active-orange-bg: rgba(217,119,87,.08);

  /* Shadows (very light) */
  --shadow-sm: 0 1px 3px rgba(0,0,0,.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,.07);
  --shadow-lg: 0 12px 32px rgba(0,0,0,.08);

  /* Layout */
  --radius-sm: 6px;
  --radius: 10px;
  --radius-lg: 14px;
  --header-h: 60px;
  --sidebar-w: 260px;

  /* Fonts */
  --font-heading: 'Poppins', Arial, 'PingFang SC', sans-serif;
  --font-body: 'Lora', Georgia, 'Noto Serif SC', serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Fira Mono', Menlo, Consolas, monospace;
}

/* ---- CSS Variables: Dark Mode ---- */
[data-theme="dark"] {
  --surface-0: #141413;
  --surface-1: #1a1a19;
  --surface-2: #222221;
  --surface-3: #2c2c2a;
  --surface-4: #383835;

  --text-primary: #faf9f5;
  --text-secondary: #b0aea5;
  --text-tertiary: #6e6d66;

  --border-color: rgba(250,249,245,.08);
  --border-subtle: rgba(250,249,245,.04);

  --hover-overlay: rgba(250,249,245,.04);
  --active-orange-bg: rgba(217,119,87,.12);

  --brand-orange-hover: #e8a08a;
  --risk-warn: #d9a757;
  --risk-danger: #d97757;

  --shadow-sm: 0 1px 2px rgba(0,0,0,.35);
  --shadow-md: 0 4px 12px rgba(0,0,0,.40);
  --shadow-lg: 0 12px 32px rgba(0,0,0,.45);
}

/* ---- Reset ---- */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* ---- Base ---- */
body {
  font-family: var(--font-body);
  background: var(--surface-0);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  transition: background .25s, color .25s;
}

::selection {
  background: rgba(217,119,87,.25);
  color: var(--text-primary);
}

a {
  color: var(--brand-orange);
  text-decoration: none;
  transition: color .15s;
}

a:hover {
  color: var(--brand-orange-hover);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  line-height: 1.25;
}

/* ---- Header (Frosted Glass) ---- */
.header {
  height: var(--header-h);
  background: rgba(250,249,245,.88);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  padding: 0 24px;
}

[data-theme="dark"] .header {
  background: rgba(20,20,19,.88);
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.logo {
  font-family: var(--font-heading);
  font-size: 20px;
  font-weight: 700;
  color: var(--text-primary);
  white-space: nowrap;
}

.logo a {
  color: inherit;
  text-decoration: none;
}

.logo span {
  color: var(--brand-orange);
}

/* ---- Search Box ---- */
.search-box {
  flex: 1;
  max-width: 400px;
  position: relative;
}

.search-box .search-icon {
  position: absolute;
  left: 12px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-tertiary);
  pointer-events: none;
}

.search-box input {
  width: 100%;
  padding: 8px 12px 8px 38px;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-size: 0.88rem;
  font-family: var(--font-body);
  background: var(--surface-2);
  color: var(--text-primary);
  outline: none;
  transition: border-color .2s, box-shadow .2s;
}

.search-box input:focus {
  border-color: var(--brand-orange);
  box-shadow: 0 0 0 2px rgba(217,119,87,.12);
}

.search-box input::placeholder {
  color: var(--text-tertiary);
}

/* ---- Header Actions ---- */
.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  cursor: pointer;
  color: var(--text-secondary);
  transition: background .15s, border-color .2s;
}

.theme-toggle:hover {
  background: var(--hover-overlay);
  border-color: var(--brand-orange);
}

.theme-toggle svg {
  display: block;
}

.stats {
  font-family: var(--font-heading);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--text-tertiary);
  white-space: nowrap;
}

/* ---- Breadcrumb ---- */
.breadcrumb {
  max-width: 1200px;
  margin: 16px auto 0;
  padding: 0 24px;
  font-family: var(--font-heading);
  font-size: 0.78rem;
  color: var(--text-tertiary);
}

.breadcrumb a {
  color: var(--text-tertiary);
}

.breadcrumb a:hover {
  color: var(--brand-orange);
}

.breadcrumb .sep {
  margin: 0 6px;
  opacity: 0.5;
}

/* ---- Main Content ---- */
.main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 28px 32px;
}

/* ---- fadeUp Animation ---- */
@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.main > *:nth-child(1) { animation: fadeUp .4s ease both; animation-delay: 0s; }
.main > *:nth-child(2) { animation: fadeUp .4s ease both; animation-delay: .06s; }
.main > *:nth-child(3) { animation: fadeUp .4s ease both; animation-delay: .12s; }
.main > *:nth-child(4) { animation: fadeUp .4s ease both; animation-delay: .18s; }
.main > *:nth-child(5) { animation: fadeUp .4s ease both; animation-delay: .24s; }

/* ---- Category Tabs ---- */
.category-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 24px;
}

.category-tab {
  padding: 5px 14px;
  border: 1px solid var(--border-color);
  border-radius: 20px;
  font-family: var(--font-heading);
  font-size: 0.78rem;
  font-weight: 500;
  cursor: pointer;
  background: var(--surface-1);
  color: var(--text-secondary);
  transition: background .15s, border-color .2s, color .15s;
  white-space: nowrap;
  user-select: none;
}

.category-tab:hover {
  border-color: rgba(217,119,87,.3);
  color: var(--brand-orange);
}

.category-tab.active {
  background: var(--brand-orange);
  color: var(--brand-dark);
  border-color: var(--brand-orange);
  font-weight: 600;
}

.category-tab .count {
  font-size: 0.68rem;
  opacity: 0.6;
  margin-left: 4px;
}

/* ---- Course Grid ---- */
.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 16px;
}

/* ---- Course Card ---- */
.course-card {
  background: var(--surface-1);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 22px;
  cursor: pointer;
  transition: border-color .2s;
  display: flex;
  flex-direction: column;
}

.course-card:hover {
  border-color: rgba(217,119,87,.2);
}

.course-card-title {
  font-family: var(--font-heading);
  font-size: 0.92rem;
  font-weight: 600;
  margin-bottom: 10px;
  color: var(--text-primary);
  line-height: 1.35;
  word-break: break-all;
}

.course-card-meta {
  font-family: var(--font-heading);
  font-size: 0.68rem;
  font-weight: 500;
  color: var(--text-tertiary);
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: auto;
  letter-spacing: 0.04em;
}

/* ---- Badges ---- */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: 4px;
  font-family: var(--font-heading);
  font-size: 0.62rem;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.badge-category {
  background: rgba(217,119,87,.1);
  color: var(--brand-orange);
}

.badge-unfinished {
  background: rgba(196,145,46,.1);
  color: var(--risk-warn);
}

.badge-complete {
  background: rgba(120,140,93,.1);
  color: var(--brand-green);
}

/* ---- Course Detail Page ---- */
.course-header {
  background: var(--surface-1);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 24px;
}

.course-title {
  font-family: var(--font-heading);
  font-size: 1.45rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.course-info {
  font-family: var(--font-heading);
  font-size: 0.84rem;
  color: var(--text-secondary);
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
}

.lesson-list {
  list-style: none;
}

.lesson-item {
  background: var(--surface-1);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 6px;
  transition: border-color .2s, background .15s;
}

.lesson-item:hover {
  border-color: rgba(217,119,87,.2);
  background: var(--hover-overlay);
}

.lesson-link {
  display: flex;
  align-items: center;
  padding: 11px 14px;
  color: var(--text-primary);
  text-decoration: none;
  gap: 12px;
  transition: color .15s;
}

.lesson-link:hover {
  color: var(--brand-orange);
}

.lesson-num {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-tertiary);
  min-width: 32px;
}

.lesson-title {
  font-family: var(--font-body);
  font-size: 0.88rem;
  flex: 1;
  color: var(--text-secondary);
}

.lesson-link:hover .lesson-title {
  color: var(--brand-orange);
}

/* ---- Reader Layout ---- */
.reader-layout {
  display: flex;
  gap: 24px;
  max-width: 1200px;
  margin: 0 auto;
  padding: 24px;
}

/* ---- Reader Sidebar ---- */
.reader-sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  position: sticky;
  top: calc(var(--header-h) + 16px);
  max-height: calc(100vh - var(--header-h) - 32px);
  overflow-y: auto;
  background: var(--surface-1);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 12px;
}

.reader-sidebar .sidebar-title {
  font-family: var(--font-heading);
  font-size: 0.84rem;
  font-weight: 600;
  padding: 8px;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 8px;
  color: var(--text-primary);
}

.reader-sidebar .sidebar-title a {
  color: inherit;
  text-decoration: none;
}

.reader-sidebar .sidebar-title a:hover {
  color: var(--brand-orange);
}

.reader-sidebar .sidebar-item {
  display: block;
  padding: 7px 10px;
  font-family: var(--font-heading);
  font-size: 0.76rem;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  text-decoration: none;
  line-height: 1.4;
  transition: background .15s, color .15s;
  border-left: 3px solid transparent;
}

.reader-sidebar .sidebar-item:hover {
  background: var(--hover-overlay);
  color: var(--brand-orange);
}

.reader-sidebar .sidebar-item.active {
  background: var(--active-orange-bg);
  color: var(--brand-orange);
  font-weight: 600;
  border-left-color: var(--brand-orange);
}

/* ---- Reader Content ---- */
.reader-content {
  flex: 1;
  min-width: 0;
  background: var(--surface-1);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 32px;
  animation: fadeUp .4s ease both;
}

.article-title {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 2px solid var(--brand-orange);
  line-height: 1.35;
  color: var(--text-primary);
}

.reader-content .article-body p {
  margin-bottom: 16px;
  line-height: 1.8;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

.reader-content .article-body h1,
.reader-content .article-body h2,
.reader-content .article-body h3 {
  margin: 28px 0 12px;
  color: var(--text-primary);
}

.reader-content .article-body h2 {
  font-size: 1.15rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.reader-content .article-body h3 {
  font-size: 1rem;
  font-weight: 600;
}

.reader-content .article-body img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
  margin: 16px 0;
}

.reader-content .article-body code {
  background: var(--surface-2);
  padding: 2px 6px;
  border-radius: 3px;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--brand-orange);
}

.reader-content .article-body pre {
  background: #1e1e1e;
  color: #d4d4d4;
  padding: 18px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin: 18px 0;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  line-height: 1.6;
}

[data-theme="dark"] .reader-content .article-body pre {
  background: #0d0d0d;
}

.reader-content .article-body pre code {
  background: none;
  padding: 0;
  color: inherit;
}

.reader-content .article-body ul,
.reader-content .article-body ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.reader-content .article-body li {
  margin-bottom: 8px;
  line-height: 1.7;
  font-size: 0.94rem;
  color: var(--text-secondary);
}

.reader-content .article-body blockquote {
  border-left: 3px solid var(--brand-orange);
  padding: 10px 18px;
  margin: 18px 0;
  background: var(--active-orange-bg);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-secondary);
}

.reader-content .article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 18px 0;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  overflow: hidden;
}

.reader-content .article-body th,
.reader-content .article-body td {
  border-bottom: 1px solid var(--border-subtle);
  padding: 11px 14px;
  text-align: left;
  font-size: 0.88rem;
}

.reader-content .article-body th {
  background: var(--surface-2);
  font-family: var(--font-heading);
  font-size: 0.68rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
  text-transform: uppercase;
}

.reader-content .article-body td {
  color: var(--text-secondary);
}

/* ---- Reader Nav ---- */
.reader-nav {
  display: flex;
  justify-content: space-between;
  margin-top: 32px;
  padding-top: 16px;
  border-top: 1px solid var(--border-color);
}

.reader-nav a {
  font-family: var(--font-heading);
  padding: 9px 18px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text-secondary);
  transition: background .15s, border-color .2s, color .15s;
}

.reader-nav a:hover {
  background: var(--active-orange-bg);
  border-color: rgba(217,119,87,.2);
  color: var(--brand-orange);
  text-decoration: none;
}

/* ---- Empty / Loading States ---- */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--text-tertiary);
}

.empty-state p {
  font-family: var(--font-heading);
  font-size: 0.92rem;
}

.loading {
  text-align: center;
  padding: 40px;
  color: var(--text-tertiary);
  font-family: var(--font-heading);
  font-size: 0.84rem;
}

/* ---- Special Content Classes ---- */
.orange {
  color: var(--brand-orange);
  font-weight: 600;
}

/* ---- Scrollbar ---- */
::-webkit-scrollbar {
  width: 5px;
  height: 5px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--surface-4);
  border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-tertiary);
}

/* ---- Responsive: Tablet ---- */
@media (max-width: 1024px) {
  .course-grid {
    grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  }
}

/* ---- Responsive: Mobile ---- */
@media (max-width: 768px) {
  .header {
    padding: 0 14px;
  }

  .header-inner {
    flex-wrap: wrap;
  }

  .search-box {
    order: 3;
    max-width: 100%;
    flex-basis: 100%;
    margin-top: 8px;
  }

  .main {
    padding: 16px 12px;
  }

  .course-grid {
    grid-template-columns: 1fr;
  }

  .reader-layout {
    flex-direction: column;
    padding: 12px;
  }

  .reader-sidebar {
    width: 100%;
    position: static;
    max-height: 280px;
  }

  .reader-content {
    padding: 18px;
  }

  .category-tabs {
    overflow-x: auto;
    flex-wrap: nowrap;
    -webkit-overflow-scrolling: touch;
    padding-bottom: 8px;
  }

  .course-card {
    padding: 16px;
  }

  .article-title {
    font-size: 1.15rem;
  }

  .breadcrumb {
    padding: 0 12px;
  }
}

@media (max-width: 480px) {
  .stats {
    display: none;
  }

  .course-grid {
    gap: 10px;
  }
}