/* ============================================================
   AI 学习路线 - 公共样式
   ============================================================ */

/* ----- CSS Variables ----- */
:root {
  --primary:        #6366f1;
  --primary-light:  #818cf8;
  --primary-dark:   #4338ca;
  --secondary:      #0ea5e9;
  --success:        #10b981;
  --warning:        #f59e0b;
  --danger:         #ef4444;
  --purple:         #8b5cf6;

  --dark-bg:        #0f172a;
  --card-bg:        #1e293b;
  --card-bg-hover:  #263347;
  --card-border:    #334155;
  --card-border-hover: #6366f1;

  --text-main:      #f1f5f9;
  --text-sub:       #94a3b8;
  --text-muted:     #64748b;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--dark-bg);
  color: var(--text-main);
  font-family: 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
  min-height: 100vh;
  line-height: 1.6;
}

a { color: var(--primary-light); text-decoration: none; transition: color 0.2s; }
a:hover { color: #fff; }

img { max-width: 100%; }

/* ----- Scrollbar ----- */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: var(--dark-bg); }
::-webkit-scrollbar-thumb { background: #334155; border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary); }

/* ============================================================
   HEADER / NAV
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  background: rgba(15, 23, 42, 0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--card-border);
}
.site-header .inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  height: 58px;
  gap: 8px;
}
.site-logo {
  font-size: 1rem;
  font-weight: 700;
  background: linear-gradient(90deg, var(--primary-light), var(--secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
  margin-right: 8px;
}
.site-logo span { -webkit-text-fill-color: var(--text-sub); font-weight: 400; font-size: 0.8rem; margin-left: 6px; }
.header-nav { display: flex; align-items: center; gap: 2px; flex-wrap: wrap; }
.header-nav a {
  color: var(--text-sub);
  font-size: 0.83rem;
  padding: 6px 12px;
  border-radius: 6px;
  transition: color 0.2s, background 0.2s;
  white-space: nowrap;
}
.header-nav a:hover, .header-nav a.active {
  color: var(--primary-light);
  background: rgba(99, 102, 241, 0.1);
}
.header-spacer { flex: 1; }
.header-badge {
  font-size: 0.72rem;
  padding: 3px 10px;
  border-radius: 12px;
  background: rgba(99, 102, 241, 0.15);
  border: 1px solid rgba(99, 102, 241, 0.35);
  color: var(--primary-light);
  white-space: nowrap;
}

/* ============================================================
   HERO
   ============================================================ */
.hero {
  background: linear-gradient(135deg, #0f172a 0%, #1e1b4b 50%, #0c1445 100%);
  padding: 80px 24px 60px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  width: 700px; height: 700px;
  background: radial-gradient(circle, rgba(99,102,241,0.12) 0%, transparent 70%);
  top: -250px; right: -150px;
  border-radius: 50%;
  pointer-events: none;
}
.hero::after {
  content: '';
  position: absolute;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(14,165,233,0.08) 0%, transparent 70%);
  bottom: -150px; left: -100px;
  border-radius: 50%;
  pointer-events: none;
}
.hero-inner {
  max-width: 1200px;
  margin: 0 auto;
  position: relative;
  z-index: 1;
}
.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(99,102,241,0.15);
  border: 1px solid rgba(99,102,241,0.35);
  color: var(--primary-light);
  padding: 5px 14px;
  border-radius: 20px;
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  margin-bottom: 20px;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.2rem);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 16px;
  background: linear-gradient(120deg, #fff 0%, var(--primary-light) 50%, var(--secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-desc {
  font-size: 1.05rem;
  color: var(--text-sub);
  max-width: 640px;
  line-height: 1.8;
}
.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-top: 28px;
}

/* ============================================================
   BUTTONS
   ============================================================ */
.btn-primary-custom {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  color: #fff;
  border: none;
  padding: 10px 22px;
  border-radius: 8px;
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  transition: opacity 0.2s, transform 0.2s;
  text-decoration: none;
}
.btn-primary-custom:hover { opacity: 0.88; transform: translateY(-1px); color: #fff; }

.btn-outline-custom {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: transparent;
  color: var(--text-sub);
  border: 1px solid var(--card-border);
  padding: 10px 22px;
  border-radius: 8px;
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  transition: border-color 0.2s, color 0.2s;
  text-decoration: none;
}
.btn-outline-custom:hover { border-color: var(--primary-light); color: var(--primary-light); }

/* ============================================================
   CONTAINER
   ============================================================ */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ============================================================
   SECTION
   ============================================================ */
.section { padding: 64px 0; }
.section-sm { padding: 40px 0; }

.section-header { margin-bottom: 40px; }
.section-eyebrow {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--primary-light);
  margin-bottom: 8px;
}
.section-title {
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 700;
  margin-bottom: 10px;
}
.section-desc {
  color: var(--text-sub);
  font-size: 0.95rem;
  max-width: 600px;
}
.section-line {
  width: 40px; height: 3px;
  background: linear-gradient(90deg, var(--primary), var(--secondary));
  border-radius: 2px;
  margin-bottom: 12px;
}

hr.divider {
  border: none;
  border-top: 1px solid var(--card-border);
  margin: 0;
}

/* ============================================================
   CARDS
   ============================================================ */
.card-grid { display: grid; gap: 20px; }
.card-grid-2 { grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); }
.card-grid-3 { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
.card-grid-4 { grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); }

.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  padding: 24px;
  transition: transform 0.22s, border-color 0.22s, box-shadow 0.22s;
  position: relative;
  overflow: hidden;
}
.card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
}
.card:hover {
  transform: translateY(-4px);
  border-color: var(--primary);
  box-shadow: 0 12px 40px rgba(99,102,241,0.18);
}

/* accent top border variants */
.card-accent-indigo::before { background: linear-gradient(90deg, #6366f1, #818cf8); }
.card-accent-blue::before   { background: linear-gradient(90deg, #0ea5e9, #38bdf8); }
.card-accent-green::before  { background: linear-gradient(90deg, #10b981, #34d399); }
.card-accent-yellow::before { background: linear-gradient(90deg, #f59e0b, #fbbf24); }
.card-accent-red::before    { background: linear-gradient(90deg, #ef4444, #f87171); }
.card-accent-purple::before { background: linear-gradient(90deg, #8b5cf6, #a78bfa); }
.card-accent-cyan::before   { background: linear-gradient(90deg, #06b6d4, #67e8f9); }
.card-accent-rose::before   { background: linear-gradient(90deg, #f43f5e, #fb7185); }

/* stage overview cards (index page) */
.stage-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: transform 0.22s, border-color 0.22s, box-shadow 0.22s;
  position: relative;
  overflow: hidden;
  text-decoration: none;
  color: inherit;
}
.stage-card::after {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(99,102,241,0.04), transparent);
  opacity: 0;
  transition: opacity 0.3s;
}
.stage-card:hover {
  transform: translateY(-6px);
  border-color: var(--primary);
  box-shadow: 0 16px 48px rgba(99,102,241,0.22);
  color: inherit;
}
.stage-card:hover::after { opacity: 1; }

.stage-num {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: 10px;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  width: fit-content;
}
.stage-icon {
  font-size: 2.4rem;
  line-height: 1;
}
.stage-title {
  font-size: 1.2rem;
  font-weight: 700;
}
.stage-desc {
  font-size: 0.85rem;
  color: var(--text-sub);
  line-height: 1.7;
}
.stage-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 4px; }
.stage-arrow {
  margin-top: auto;
  color: var(--text-muted);
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: color 0.2s, gap 0.2s;
}
.stage-card:hover .stage-arrow { color: var(--primary-light); gap: 8px; }

/* ============================================================
   TAGS / BADGES
   ============================================================ */
.tag {
  display: inline-block;
  font-size: 0.72rem;
  padding: 3px 9px;
  border-radius: 8px;
  font-weight: 500;
  background: rgba(99,102,241,0.12);
  border: 1px solid rgba(99,102,241,0.25);
  color: #a5b4fc;
}
.tag-green  { background: rgba(16,185,129,0.1);  border-color: rgba(16,185,129,0.25);  color: #6ee7b7; }
.tag-blue   { background: rgba(14,165,233,0.1);  border-color: rgba(14,165,233,0.25);  color: #7dd3fc; }
.tag-yellow { background: rgba(245,158,11,0.1);  border-color: rgba(245,158,11,0.25);  color: #fcd34d; }
.tag-red    { background: rgba(239,68,68,0.1);   border-color: rgba(239,68,68,0.25);   color: #fca5a5; }
.tag-purple { background: rgba(139,92,246,0.1);  border-color: rgba(139,92,246,0.25);  color: #c4b5fd; }
.tag-cyan   { background: rgba(6,182,212,0.1);   border-color: rgba(6,182,212,0.25);   color: #67e8f9; }

.phase-badge {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 10px;
  border-radius: 12px;
  display: inline-block;
}
.phase-1 { background: rgba(16,185,129,0.15);  color: #34d399; border: 1px solid rgba(16,185,129,0.3); }
.phase-2 { background: rgba(99,102,241,0.15);  color: #a5b4fc; border: 1px solid rgba(99,102,241,0.3); }
.phase-3 { background: rgba(14,165,233,0.15);  color: #7dd3fc; border: 1px solid rgba(14,165,233,0.3); }
.phase-4 { background: rgba(245,158,11,0.15);  color: #fbbf24; border: 1px solid rgba(245,158,11,0.3); }

/* ============================================================
   ICON BOX
   ============================================================ */
.icon-box {
  width: 44px; height: 44px;
  border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.25rem;
  flex-shrink: 0;
}
.icon-indigo { background: rgba(99,102,241,0.15); }
.icon-blue   { background: rgba(14,165,233,0.15); }
.icon-green  { background: rgba(16,185,129,0.15); }
.icon-yellow { background: rgba(245,158,11,0.15); }
.icon-red    { background: rgba(239,68,68,0.15);  }
.icon-purple { background: rgba(139,92,246,0.15); }
.icon-cyan   { background: rgba(6,182,212,0.15);  }

/* ============================================================
   TIMELINE
   ============================================================ */
.timeline { position: relative; padding-left: 28px; }
.timeline::before {
  content: '';
  position: absolute;
  left: 7px; top: 6px; bottom: 6px;
  width: 2px;
  background: linear-gradient(180deg, var(--primary) 0%, var(--secondary) 60%, transparent 100%);
}
.timeline-item { position: relative; margin-bottom: 28px; }
.timeline-item:last-child { margin-bottom: 0; }
.timeline-dot {
  position: absolute;
  left: -22px; top: 5px;
  width: 14px; height: 14px;
  border-radius: 50%;
  border: 2px solid var(--primary);
  background: var(--dark-bg);
  transition: background 0.2s;
}
.timeline-dot.filled { background: var(--primary); }
.timeline-dot.yellow { border-color: var(--warning); }
.timeline-dot.green  { border-color: var(--success); background: var(--success); }
.timeline-label {
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 2px;
}
.timeline-title { font-size: 0.95rem; font-weight: 600; margin-bottom: 4px; }
.timeline-desc { font-size: 0.82rem; color: var(--text-sub); line-height: 1.65; }

/* ============================================================
   ACCORDION
   ============================================================ */
.accord-list { display: flex; flex-direction: column; gap: 10px; }
.accord-item {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  overflow: hidden;
}
.accord-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 18px;
  cursor: pointer;
  user-select: none;
  gap: 12px;
  transition: background 0.2s;
}
.accord-header:hover { background: rgba(99,102,241,0.06); }
.accord-header-left { display: flex; align-items: center; gap: 10px; }
.accord-icon { font-size: 1rem; }
.accord-title { font-size: 0.93rem; font-weight: 600; }
.accord-arrow {
  color: var(--text-sub);
  font-size: 0.75rem;
  transition: transform 0.3s;
  flex-shrink: 0;
}
.accord-item.open .accord-arrow { transform: rotate(180deg); }
.accord-body { max-height: 0; overflow: hidden; transition: max-height 0.4s ease; }
.accord-body-inner {
  padding: 4px 18px 18px 18px;
  font-size: 0.85rem;
  color: var(--text-sub);
  line-height: 1.8;
  border-top: 1px solid var(--card-border);
}

/* ============================================================
   RESOURCE LINKS
   ============================================================ */
.res-list { display: flex; flex-direction: column; gap: 10px; }
.res-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 14px 16px;
  transition: border-color 0.2s, background 0.2s;
  text-decoration: none;
  color: inherit;
}
.res-item:hover {
  border-color: var(--primary);
  background: var(--card-bg-hover);
  color: inherit;
}
.res-icon { font-size: 1.5rem; flex-shrink: 0; line-height: 1; margin-top: 2px; }
.res-title { font-size: 0.9rem; font-weight: 600; margin-bottom: 3px; color: var(--text-main); }
.res-desc { font-size: 0.78rem; color: var(--text-sub); line-height: 1.55; }
.res-meta { display: flex; align-items: center; gap: 8px; margin-top: 5px; flex-wrap: wrap; }
.res-arrow { margin-left: auto; color: var(--text-muted); font-size: 0.8rem; flex-shrink: 0; align-self: center; transition: color 0.2s; }
.res-item:hover .res-arrow { color: var(--primary-light); }

/* ============================================================
   SKILL BARS
   ============================================================ */
.skill-list { display: flex; flex-direction: column; gap: 14px; }
.skill-item {}
.skill-label { display: flex; justify-content: space-between; font-size: 0.82rem; margin-bottom: 5px; }
.skill-val { font-weight: 600; }
.skill-track {
  height: 6px;
  border-radius: 3px;
  background: rgba(255,255,255,0.06);
  overflow: hidden;
}
.skill-fill {
  height: 100%;
  border-radius: 3px;
  width: 0;
  transition: width 1.3s cubic-bezier(0.4,0,0.2,1);
}
.fill-green  { background: linear-gradient(90deg, #10b981, #34d399); }
.fill-indigo { background: linear-gradient(90deg, #6366f1, #818cf8); }
.fill-blue   { background: linear-gradient(90deg, #0ea5e9, #38bdf8); }
.fill-yellow { background: linear-gradient(90deg, #f59e0b, #fbbf24); }
.fill-red    { background: linear-gradient(90deg, #ef4444, #f87171); }

/* ============================================================
   TIP / CALLOUT BOXES
   ============================================================ */
.callout {
  border-left: 3px solid var(--primary);
  border-radius: 0 10px 10px 0;
  background: rgba(99,102,241,0.07);
  padding: 14px 18px;
  font-size: 0.85rem;
  color: var(--text-sub);
  line-height: 1.75;
}
.callout strong, .callout b { color: var(--primary-light); }
.callout-green  { border-color: var(--success);  background: rgba(16,185,129,0.07); }
.callout-green strong { color: #34d399; }
.callout-yellow { border-color: var(--warning);  background: rgba(245,158,11,0.07); }
.callout-yellow strong { color: #fbbf24; }
.callout-red    { border-color: var(--danger);   background: rgba(239,68,68,0.07); }
.callout-red strong { color: #f87171; }

/* ============================================================
   INFO GRID (key concepts)
   ============================================================ */
.info-grid { display: grid; gap: 12px; }
.info-grid-2 { grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); }
.info-grid-3 { grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }

.info-tile {
  background: rgba(255,255,255,0.025);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 14px 16px;
}
.info-tile-title { font-size: 0.85rem; font-weight: 600; margin-bottom: 5px; }
.info-tile-desc  { font-size: 0.78rem; color: var(--text-sub); line-height: 1.6; }

/* ============================================================
   BREADCRUMB
   ============================================================ */
.breadcrumb-bar {
  background: rgba(255,255,255,0.025);
  border-bottom: 1px solid var(--card-border);
  padding: 10px 0;
}
.breadcrumb-bar .container { display: flex; align-items: center; gap: 8px; font-size: 0.8rem; color: var(--text-muted); }
.breadcrumb-bar a { color: var(--text-muted); transition: color 0.2s; }
.breadcrumb-bar a:hover { color: var(--primary-light); }
.breadcrumb-bar .sep { opacity: 0.4; }
.breadcrumb-bar .current { color: var(--text-sub); }

/* ============================================================
   PAGE PREV / NEXT
   ============================================================ */
.page-nav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}
.page-nav-btn {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 16px 20px;
  text-decoration: none;
  color: var(--text-sub);
  transition: border-color 0.2s, color 0.2s;
  flex: 1;
  min-width: 160px;
}
.page-nav-btn:hover { border-color: var(--primary); color: var(--primary-light); }
.page-nav-btn.next { justify-content: flex-end; text-align: right; }
.page-nav-label { font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); margin-bottom: 3px; }
.page-nav-title { font-size: 0.9rem; font-weight: 600; color: var(--text-main); }

/* ============================================================
   EXPANDABLE NOTES (user extension area)
   ============================================================ */
.notes-section {
  background: rgba(255,255,255,0.018);
  border: 1px dashed var(--card-border);
  border-radius: 14px;
  padding: 28px;
}
.notes-section-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.notes-placeholder {
  font-size: 0.83rem;
  color: var(--text-muted);
  font-style: italic;
  padding: 20px 0;
  text-align: center;
  border: 1px dashed rgba(255,255,255,0.06);
  border-radius: 8px;
}

/* ============================================================
   FOOTER
   ============================================================ */
.site-footer {
  background: var(--card-bg);
  border-top: 1px solid var(--card-border);
  padding: 32px 24px;
  text-align: center;
}
.site-footer p { font-size: 0.82rem; color: var(--text-muted); line-height: 2; }
.site-footer a { color: var(--text-sub); }
.site-footer a:hover { color: var(--primary-light); }

/* ============================================================
   UTILITIES
   ============================================================ */
.flex        { display: flex; }
.flex-wrap   { flex-wrap: wrap; }
.items-center{ align-items: center; }
.items-start { align-items: flex-start; }
.gap-8       { gap: 8px; }
.gap-12      { gap: 12px; }
.gap-16      { gap: 16px; }
.gap-20      { gap: 20px; }
.gap-24      { gap: 24px; }
.mt-8        { margin-top: 8px; }
.mt-12       { margin-top: 12px; }
.mt-16       { margin-top: 16px; }
.mt-20       { margin-top: 20px; }
.mt-24       { margin-top: 24px; }
.mt-32       { margin-top: 32px; }
.mt-48       { margin-top: 48px; }
.mb-8        { margin-bottom: 8px; }
.mb-12       { margin-bottom: 12px; }
.mb-16       { margin-bottom: 16px; }
.mb-20       { margin-bottom: 20px; }
.mb-24       { margin-bottom: 24px; }
.text-sub    { color: var(--text-sub); }
.text-muted  { color: var(--text-muted); }
.text-sm     { font-size: 0.82rem; }

/* ============================================================
   MODAL (弹窗)
   ============================================================ */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
}
.modal-content {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  max-width: 500px;
  width: 100%;
  max-height: 80vh;
  overflow: hidden;
  animation: modalFadeIn 0.2s ease;
}
@keyframes modalFadeIn {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}
.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--card-border);
}
.modal-title {
  font-size: 1rem;
  font-weight: 600;
}
.modal-close {
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--text-muted);
  transition: color 0.2s;
  padding: 4px;
  line-height: 1;
}
.modal-close:hover { color: var(--text-main); }
.modal-body {
  padding: 20px;
  max-height: calc(80vh - 80px);
  overflow-y: auto;
}
.update-item {
  margin-bottom: 16px;
}
.update-item:last-child { margin-bottom: 0; }
.update-date {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--primary-light);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
  display: block;
}
.update-content strong {
  font-size: 0.95rem;
  color: var(--text-main);
  display: block;
  margin-bottom: 8px;
}
.update-content ul {
  padding-left: 20px;
  font-size: 0.82rem;
  color: var(--text-sub);
  line-height: 1.8;
}

/* ============================================================
   RESPONSIVE (响应式)
   ============================================================ */
@media (max-width: 768px) {
  /* Header */
  .site-header .inner {
    padding: 0 16px;
    height: 54px;
    flex-wrap: wrap;
    gap: 6px;
  }
  .header-nav {
    flex-wrap: wrap;
    gap: 2px;
    margin-left: auto;
  }
  .header-nav a {
    font-size: 0.78rem;
    padding: 5px 10px;
  }
  .site-logo span { display: none; }
  .header-badge { display: none; }
  
  /* Hero */
  .hero {
    padding: 60px 16px 40px;
  }
  .hero h1 {
    font-size: clamp(1.6rem, 4vw, 2.2rem);
  }
  .hero-desc {
    font-size: 0.95rem;
  }
  .hero-actions {
    flex-direction: column;
  }
  .btn-primary-custom, .btn-outline-custom {
    width: 100%;
    justify-content: center;
  }
  
  /* Cards */
  .card-grid-2 {
    grid-template-columns: 1fr !important;
  }
  .card-grid-3 {
    grid-template-columns: 1fr !important;
  }
  
  /* Info Grid */
  .info-grid-2 {
    grid-template-columns: 1fr !important;
  }
  
  /* Page Nav */
  .page-nav {
    flex-direction: column;
  }
  .page-nav-btn {
    justify-content: center !important;
    text-align: center;
  }
  
  /* Breadcrumb */
  .breadcrumb-bar {
    padding: 8px 0;
  }
  .breadcrumb-bar .container {
    font-size: 0.72rem;
  }
  
  /* Container */
  .container {
    padding: 0 16px;
  }
  
  /* Section Header */
  .section-header {
    margin-bottom: 24px;
  }
  .section-title {
    font-size: 1.3rem !important;
  }
  
  /* Notes Section */
  .notes-section {
    padding: 20px 16px;
  }
  
  /* Timeline */
  .timeline {
    padding-left: 20px;
  }
  .timeline-dot {
    width: 12px;
    height: 12px;
    left: -17px;
  }
  
  /* Accordion */
  .accord-header {
    padding: 12px 14px;
  }
  .accord-title {
    font-size: 0.88rem;
  }
}

@media (max-width: 480px) {
  /* Hero */
  .hero {
    padding: 48px 12px 32px;
  }
  .hero-eyebrow {
    font-size: 0.72rem;
    padding: 4px 10px;
  }
  .hero-desc {
    font-size: 0.88rem;
    line-height: 1.7;
  }
  
  /* Cards */
  .card {
    padding: 16px;
  }
  
  /* Stage Card */
  .stage-card {
    padding: 20px 16px !important;
  }
  .stage-tags {
    gap: 4px !important;
  }
  .stage-tags .tag {
    font-size: 0.66rem;
    padding: 3px 8px;
  }
  
  /* Modal */
  .modal-content {
    margin: 10px;
    border-radius: 12px;
  }
  .modal-body {
    padding: 16px;
  }
}
.text-xs     { font-size: 0.72rem; }
.font-600    { font-weight: 600; }
.font-700    { font-weight: 700; }

/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
  .hero { padding: 56px 20px 44px; }
  .section { padding: 48px 0; }
  .card-grid-4 { grid-template-columns: repeat(auto-fill, minmax(180px, 1fr)); }
  .card-grid-2, .card-grid-3 { grid-template-columns: 1fr; }
  .page-nav { flex-direction: column; }
}
@media (max-width: 520px) {
  .container { padding: 0 16px; }
  .card { padding: 18px; }
  .stage-card { padding: 22px 18px; }
}