/* ========== 1. Root & Reset ========== */
:root {
  --color-bg: #0f1e3c;
  --color-bg-deep: #0a1428;
  --color-panel: #1a2a4a;
  --color-glass: rgba(255, 255, 255, 0.08);
  --color-accent: #39ff14;
  --color-accent-dim: rgba(57, 255, 20, 0.15);
  --color-accent-glow: rgba(57, 255, 20, 0.5);
  --color-orange: #ff6b35;
  --color-blue-gray: #b0c4de;
  --color-muted: #6c86a6;
  --color-line: #2e4a6b;
  --color-white: #ffffff;
  --color-ok: #00ff88;
  --color-warn: #ffcc00;
  --font-title: 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-body: 'Noto Sans SC', 'Source Han Sans', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'Roboto Mono', 'Consolas', 'Menlo', monospace;
  --track-w: 280px;
  --content-max: 1200px;
  --content-pad: clamp(20px, 4vw, 48px);
  --radius: 14px;
  --radius-lg: 18px;
  --radius-sm: 8px;
  --shadow-panel: 0 12px 40px rgba(0, 0, 0, 0.35);
  --shadow-lift: 0 16px 44px rgba(0, 0, 0, 0.45);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body,
h1,
h2,
h3,
h4,
h5,
h6,
p,
ul,
ol,
dl,
dd,
figure,
blockquote {
  margin: 0;
  padding: 0;
}

body {
  background: var(--color-bg);
  color: var(--color-white);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

h1,
h2,
h3,
h4 {
  font-family: var(--font-title);
  font-weight: 800;
  color: var(--color-white);
  line-height: 1.2;
  margin: 0 0 0.5em;
}

h1 { font-size: clamp(34px, 5vw, 48px); }
h2 { font-size: clamp(26px, 3.4vw, 32px); }
h3 { font-size: 24px; }
h4 { font-size: 18px; }

a {
  color: var(--color-accent);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--color-white);
}

ul,
ol {
  list-style: none;
}

/* ========== 2. Focus & Selection & Scrollbar ========== */
:focus {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 2px;
}

::selection {
  background: var(--color-accent);
  color: #0f1e3c;
}

::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg-deep);
}

::-webkit-scrollbar-thumb {
  background: var(--color-line);
  border-radius: 5px;
  border: 2px solid var(--color-bg-deep);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-accent);
}

/* ========== 3. Skip Link ========== */
.skip-link {
  position: fixed;
  top: -100px;
  left: 16px;
  z-index: 5000;
  padding: 10px 18px;
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #0f1e3c;
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 800;
  text-decoration: none;
  box-shadow: 0 8px 30px rgba(57, 255, 20, 0.4);
  transition: top 0.25s var(--ease);
}

.skip-link:focus-visible {
  top: 16px;
}

/* ========== 4. Buttons ========== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 999px;
  border: 1px solid var(--color-line);
  background: var(--color-panel);
  color: var(--color-blue-gray);
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 700;
  line-height: 1.4;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
}

.btn:hover {
  border-color: rgba(57, 255, 20, 0.45);
  color: var(--color-accent);
  transform: translateY(-2px);
}

.btn-primary {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #0f1e3c;
  box-shadow: 0 6px 26px rgba(57, 255, 20, 0.3);
}

.btn-primary:hover {
  background: #54ff35;
  border-color: #54ff35;
  color: #0f1e3c;
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
}

.btn-sm {
  padding: 7px 14px;
  font-size: 13px;
}

/* ========== 5. Header / Brand Track ========== */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--track-w);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  background:
    linear-gradient(180deg, rgba(57, 255, 20, 0.05), transparent 28%),
    var(--color-bg-deep);
  border-right: 1px solid var(--color-line);
}

.brand-track {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 28px 20px 20px;
  overflow-y: auto;
  scrollbar-width: thin;
  scrollbar-color: var(--color-line) transparent;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  color: var(--color-white);
  text-decoration: none;
  transition: opacity 0.2s ease;
}

.brand:hover {
  opacity: 0.88;
  color: var(--color-white);
}

.brand-box {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--color-accent), #00d4ff);
  color: #0f1e3c;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 800;
  box-shadow: 0 0 22px rgba(57, 255, 20, 0.3);
  overflow: hidden;
  flex: none;
}

.brand-box::before {
  content: "";
  position: absolute;
  inset: 3px;
  border: 1px solid rgba(15, 30, 60, 0.3);
  border-radius: 7px;
}

.brand-box::after {
  content: "";
  position: absolute;
  width: 14px;
  height: 14px;
  background: rgba(255, 255, 255, 0.5);
  top: -8px;
  left: -8px;
  transform: rotate(45deg);
}

.brand-copy {
  display: flex;
  flex-direction: column;
  min-width: 0;
}

.brand-title {
  font-family: var(--font-title);
  font-size: 20px;
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: 0.02em;
  color: var(--color-white);
}

.brand-sub {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-muted);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  line-height: 1.4;
}

/* Navigation */
.site-nav {
  margin-top: 40px;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 16px;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font-title);
  font-size: 15px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--color-blue-gray);
  text-decoration: none;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
}

.nav-link::before {
  content: "";
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--color-line);
  flex: none;
  transition: background 0.2s ease, box-shadow 0.2s ease;
}

.nav-link:hover {
  color: var(--color-accent);
  background: var(--color-accent-dim);
  border-color: rgba(57, 255, 20, 0.25);
}

.nav-link:hover::before {
  background: var(--color-accent);
  box-shadow: 0 0 10px rgba(57, 255, 20, 0.7);
}

.nav-link[aria-current="page"] {
  color: #0f1e3c;
  background: var(--color-accent);
  border-color: var(--color-accent);
  box-shadow: 0 4px 24px rgba(57, 255, 20, 0.35);
}

.nav-link[aria-current="page"]::before {
  background: #0f1e3c;
  box-shadow: none;
}

/* Mobile nav toggle */
.nav-toggle {
  display: none;
}

/* Track panel */
.track-panel {
  margin-top: auto;
  border-top: 1px solid var(--color-line);
  padding-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.track-stats {
  display: grid;
  gap: 10px;
}

.track-stat {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  font-size: 12px;
}

.track-stat dt {
  color: var(--color-muted);
  letter-spacing: 0.04em;
}

.track-stat dd {
  color: var(--color-blue-gray);
  font-size: 12px;
}

.track-live {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--color-ok);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.live-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-ok);
  box-shadow: 0 0 10px var(--color-ok);
  animation: live-pulse 2s ease-in-out infinite;
}

@keyframes live-pulse {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.85); }
}

/* Scroll progress bar */
.rail-progress {
  position: absolute;
  top: 0;
  right: -1px;
  width: 2px;
  height: 100%;
  background: rgba(57, 255, 20, 0.12);
  overflow: hidden;
  z-index: 10;
  pointer-events: none;
}

.rail-progress::before {
  content: "";
  display: block;
  width: 100%;
  height: 100%;
  background: var(--color-accent);
  box-shadow: 0 0 12px var(--color-accent);
  opacity: 0.9;
  transform: scaleY(var(--scroll-pct, 0));
  transform-origin: top;
}

/* ========== 6. Main Content ========== */
.main-content {
  margin-left: var(--track-w);
  min-height: 100vh;
  position: relative;
  background-color: var(--color-bg);
  background-image:
    radial-gradient(1100px 440px at 75% -80px, rgba(57, 255, 20, 0.10), transparent 65%),
    linear-gradient(rgba(46, 74, 107, 0.12) 1px, transparent 1px),
    linear-gradient(90deg, rgba(46, 74, 107, 0.12) 1px, transparent 1px);
  background-size: auto, 56px 56px, 56px 56px;
  background-repeat: no-repeat, repeat, repeat;
}

#main-content {
  outline: none;
  scroll-margin-top: 80px;
}

#main-content:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: -2px;
}

.content-shell {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 48px var(--content-pad) 88px;
}

/* ========== 7. Page Intro & Breadcrumb ========== */
.page-intro {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
  gap: 32px;
  align-items: end;
  padding-bottom: 40px;
  margin-bottom: 44px;
  border-bottom: 1px solid var(--color-line);
  position: relative;
}

.page-intro::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 72px;
  height: 3px;
  background: var(--color-accent);
  border-radius: 2px;
}

.page-title {
  font-size: clamp(36px, 5vw, 52px);
  line-height: 1.12;
  margin: 0 0 12px;
  letter-spacing: -0.02em;
}

.page-intro-meta {
  display: grid;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-muted);
  border-left: 1px solid var(--color-line);
  padding-left: 20px;
}

.page-intro-meta strong {
  color: var(--color-blue-gray);
  font-weight: 600;
}

.section-kicker {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 8px;
}

.breadcrumbs {
  margin-bottom: 28px;
}

.breadcrumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--color-muted);
}

.breadcrumb-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.breadcrumb-item + .breadcrumb-item::before {
  content: "/";
  color: var(--color-line);
}

.breadcrumb-link {
  color: var(--color-blue-gray);
  text-decoration: none;
  transition: color 0.2s ease;
}

.breadcrumb-link:hover {
  color: var(--color-accent);
}

.breadcrumb-item[aria-current="page"] {
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 12px;
}

.lead {
  font-size: 18px;
  line-height: 1.85;
  color: var(--color-blue-gray);
  max-width: 720px;
  margin-bottom: 24px;
}

.h-sep {
  border: 0;
  height: 1px;
  background: linear-gradient(90deg, var(--color-line), transparent);
  margin: 44px 0;
}

/* ========== 8. Section Heading ========== */
.section-head {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 56px 0 20px;
}

.section-index {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  color: var(--color-accent);
  background: var(--color-accent-dim);
  border: 1px solid rgba(57, 255, 20, 0.25);
  border-radius: var(--radius-sm);
  padding: 2px 8px;
  white-space: nowrap;
}

.section-title {
  margin: 0;
  font-size: 28px;
}

.section-desc {
  color: var(--color-muted);
  font-size: 14px;
  max-width: 640px;
  margin: 0 0 20px;
}

/* ========== 9. Grids & Cards ========== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 20px;
}

.col-3 { grid-column: span 3; }
.col-4 { grid-column: span 4; }
.col-5 { grid-column: span 5; }
.col-6 { grid-column: span 6; }
.col-7 { grid-column: span 7; }
.col-8 { grid-column: span 8; }
.col-12 { grid-column: span 12; }

.panel-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 22px;
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.25s var(--ease), border-color 0.25s var(--ease), box-shadow 0.25s var(--ease);
}

.panel-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 3px;
  height: 100%;
  background: linear-gradient(180deg, transparent, var(--color-accent), transparent);
  opacity: 0;
  transition: opacity 0.25s ease;
}

.panel-card:hover {
  transform: translateY(-4px);
  border-color: rgba(57, 255, 20, 0.6);
  box-shadow: var(--shadow-lift);
}

.panel-card:hover::before {
  opacity: 1;
}

.panel-card-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
}

.panel-card-title {
  font-family: var(--font-title);
  font-size: 18px;
  font-weight: 800;
  color: var(--color-white);
  line-height: 1.3;
  margin: 0;
}

.panel-card-index {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-muted);
  padding: 3px 8px;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  white-space: nowrap;
}

.panel-card-body {
  color: var(--color-blue-gray);
  font-size: 14px;
  line-height: 1.7;
  flex: 1;
}

.panel-card-action {
  margin-top: auto;
  padding-top: 12px;
}

.metric-card {
  position: relative;
  overflow: hidden;
  background: linear-gradient(160deg, var(--color-panel), var(--color-bg-deep));
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
  padding: 22px;
  transition: border-color 0.25s ease, transform 0.25s var(--ease), box-shadow 0.25s ease;
}

.metric-card:hover {
  border-color: rgba(57, 255, 20, 0.45);
  transform: translateY(-4px);
  box-shadow: var(--shadow-panel);
}

.metric-card::after {
  content: "";
  position: absolute;
  right: -40px;
  top: -40px;
  width: 120px;
  height: 120px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(57, 255, 20, 0.16), transparent 70%);
  pointer-events: none;
}

.metric-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--color-blue-gray);
  font-size: 13px;
  margin-bottom: 10px;
  position: relative;
  z-index: 1;
}

.metric-value {
  display: block;
  font-family: var(--font-mono);
  font-size: 44px;
  font-weight: 700;
  line-height: 1.1;
  color: var(--color-white);
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  position: relative;
  z-index: 1;
}

.metric-value.accent {
  color: var(--color-accent);
  text-shadow: 0 0 30px rgba(57, 255, 20, 0.35);
}

.metric-value.orange {
  color: var(--color-orange);
  text-shadow: 0 0 30px rgba(255, 107, 53, 0.3);
}

.metric-trend {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  padding: 3px 10px;
  border-radius: 999px;
}

.metric-trend.up {
  color: var(--color-ok);
  background: rgba(0, 255, 136, 0.12);
}

.metric-trend.down {
  color: var(--color-orange);
  background: rgba(255, 107, 53, 0.14);
}

.metric-foot {
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--color-line);
  font-size: 12px;
  color: var(--color-muted);
  position: relative;
  z-index: 1;
}

/* ========== 10. Data Lines, Badges, Chips ========== */
.mono-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.01em;
}

.data-line {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding: 11px 0;
  border-bottom: 1px dashed var(--color-line);
  font-size: 14px;
}

.data-line .k {
  color: var(--color-blue-gray);
}

.data-line .v {
  font-family: var(--font-mono);
  color: var(--color-white);
  font-variant-numeric: tabular-nums;
}

.data-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 44px;
  height: 26px;
  padding: 0 12px;
  border-radius: 7px;
  background: var(--color-accent-dim);
  border: 1px solid rgba(57, 255, 20, 0.35);
  color: var(--color-accent);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.data-badge.alert {
  background: rgba(255, 107, 53, 0.16);
  border-color: rgba(255, 107, 53, 0.4);
  color: var(--color-orange);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: 999px;
  background: var(--color-glass);
  border: 1px solid var(--color-line);
  color: var(--color-blue-gray);
  font-size: 13px;
  font-weight: 600;
  white-space: nowrap;
}

.chip.accent {
  background: var(--color-accent-dim);
  border-color: rgba(57, 255, 20, 0.35);
  color: var(--color-accent);
}

.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.stat-array {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 12px;
}

.stat-cell {
  background: var(--color-glass);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 14px 18px;
  transition: border-color 0.2s ease;
}

.stat-cell:hover {
  border-color: rgba(57, 255, 20, 0.35);
}

.stat-cell dt {
  font-size: 12px;
  color: var(--color-muted);
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}

.stat-cell dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 24px;
  font-weight: 700;
  color: var(--color-white);
  font-variant-numeric: tabular-nums;
}

/* ========== 11. Image Frame ========== */
.img-frame {
  position: relative;
  display: block;
  overflow: hidden;
  background: linear-gradient(145deg, var(--color-panel), var(--color-bg-deep));
  border: 1px solid var(--color-line);
  border-radius: var(--radius);
}

.img-frame::before {
  content: "";
  display: block;
  padding-top: 56.25%;
}

.img-frame.is-4-3::before {
  padding-top: 75%;
}

.img-frame.is-1-1::before {
  padding-top: 100%;
}

.img-frame img,
.img-frame .img-fill {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.img-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(15, 30, 60, 0.7), transparent 55%);
  pointer-events: none;
}

.img-caption {
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 12px;
  z-index: 2;
  color: var(--color-white);
  font-weight: 700;
  font-size: 15px;
  line-height: 1.4;
  text-shadow: 0 2px 12px rgba(0, 0, 0, 0.7);
}

/* ========== 12. Visual Screen & Research Board ========== */
.visual-screen {
  position: relative;
  overflow: hidden;
  background:
    linear-gradient(180deg, rgba(57, 255, 20, 0.05), transparent 35%),
    var(--color-bg-deep);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-lg);
  padding: 24px;
}

.visual-screen::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-accent), transparent);
}

.board-abstract {
  position: relative;
  background: linear-gradient(135deg, rgba(57, 255, 20, 0.07), rgba(255, 255, 255, 0.02));
  border: 1px solid var(--color-line);
  border-left: 3px solid var(--color-accent);
  border-radius: var(--radius);
  padding: 24px;
  color: var(--color-blue-gray);
  line-height: 1.85;
  font-size: 15px;
}

.board-abstract strong {
  color: var(--color-white);
}

.evidence-card {
  position: relative;
  background: var(--color-panel);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 18px 20px 18px 54px;
}

.evidence-card + .evidence-card {
  margin-top: 12px;
}

.evidence-num {
  position: absolute;
  left: 18px;
  top: 18px;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  color: var(--color-accent);
}

.term-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 12px;
}

.term-item {
  background: var(--color-glass);
  border: 1px solid var(--color-line);
  border-radius: var(--radius-sm);
  padding: 14px 16px;
}

.term-item dt {
  font-family: var(--font-title);
  font-weight: 800;
  color: var(--color-accent);
  font-size: 14px;
  margin-bottom: 4px;
}

.term-item dd {
  color: var(--color-blue-gray);
  font-size: 13px;
  line-height: 1.6;
}

.reading-list {
  display: grid;
  gap: 8px;
}

.reading-list a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  background: var(--color-glass);
  border: 1px solid transparent;
  color: var(--color-blue-gray);
  font-size: 14px;
  text-decoration: none;
  transition: border-color 0.2s ease, color 0.2s ease, background 0.2s ease;
}

.reading-list a::before {
  content: "→";
  flex: none;
  color: var(--color-accent);
  font-family: var(--font-mono);
}

.reading-list a:hover {
  border-color: rgba(57, 255, 20, 0.35);
  color: var(--color-white);
  background: var(--color-accent-dim);
}

/* ========== 13. Accordion ========== */
.accordion {
  border: 1px solid var(--color-line);
  background: var(--color-panel);
  border-radius: var(--radius);
  overflow: hidden;
  transition: border-color 0.2s ease;
}

.accordion + .accordion {
  margin-top: 12px;
}

.accordion[open] {
  border-color: rgba(57, 255, 20, 0.35);
}

.accordion-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 20px;
  cursor: pointer;
  font-family: var(--font-title);
  font-size: 16px;
  font-weight: 700;
  color: var(--color-white);
  list-style: none;
}

.accordion-btn::-webkit-details-marker {
  display: none;
}

.accordion-btn::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 22px;
  color: var(--color-accent);
  flex: none;
  transition: transform 0.25s var(--ease);
}

.accordion[open] .accordion-btn::after {
  transform: rotate(45deg);
}

.accordion-panel {
  padding: 0 20px 18px;
  color: var(--color-blue-gray);
  font-size: 15px;
  line-height: 1.8;
}

.accordion[open] .accordion-panel {
  border-top: 1px dashed var(--color-line);
  padding-top: 14px;
}

/* ========== 14. Tabs ========== */
.tab-board {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 20px;
}

.tab-btn {
  appearance: none;
  -webkit-appearance: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 16px;
  border-radius: 999px;
  border: 1px solid var(--color-line);
  background: var(--color-panel);
  color: var(--color-blue-gray);
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 700;
  line-height: 1.3;
  cursor: pointer;
  transition: background 0.2s ease, border-color 0.2s ease, color 0.2s ease, box-shadow 0.2s ease;
}

.tab-btn:hover {
  border-color: rgba(57, 255, 20, 0.45);
  color: var(--color-accent);
}

.tab-btn.is-active {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #0f1e3c;
  box-shadow: 0 4px 20px rgba(57, 255, 20, 0.35);
}

.tab-panel.is-active {
  animation: fade-slide-in 0.3s var(--ease);
}

@keyframes fade-slide-in {
  from {
    opacity: 0;
    transform: translateX(14px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

[hidden] {
  display: none !important;
}

/* ========== 15. Reveal ========== */
.js-enabled .reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.6s var(--ease), transform 0.6s var(--ease);
}

.js-enabled .reveal.is-in {
  opacity: 1;
  transform: none;
}

/* ========== 16. Footer ========== */
.site-footer {
  margin-left: var(--track-w);
  background: var(--color-bg-deep);
  border-top: 1px solid var(--color-line);
  padding: 64px var(--content-pad) 28px;
  color: var(--color-blue-gray);
  font-size: 14px;
}

.footer-grid {
  max-width: var(--content-max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1.6fr;
  gap: 48px 40px;
}

.footer-intro .brand {
  margin-bottom: 16px;
}

.footer-note {
  max-width: 420px;
  color: var(--color-muted);
  font-size: 14px;
  line-height: 1.9;
  margin-bottom: 18px;
}

.footer-trust {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
}

.trust-item {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--color-blue-gray);
  font-size: 13px;
}

.trust-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-accent);
  box-shadow: 0 0 8px rgba(57, 255, 20, 0.6);
}

.footer-head {
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.08em;
  color: var(--color-white);
  margin: 0 0 14px;
  text-transform: uppercase;
}

.footer-list,
.contact-list {
  display: grid;
  gap: 10px;
}

.footer-list a,
.contact-link {
  color: var(--color-blue-gray);
  text-decoration: none;
  font-size: 14px;
  transition: color 0.2s ease, padding-left 0.2s ease;
}

.footer-list a:hover,
.contact-link:hover {
  color: var(--color-accent);
  padding-left: 4px;
}

.contact-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  line-height: 1.5;
}

.contact-label {
  font-size: 12px;
  color: var(--color-muted);
  letter-spacing: 0.06em;
}

.contact-list .mono-num {
  color: var(--color-white);
  font-size: 15px;
}

.footer-cta {
  margin-top: 16px;
}

.footer-bar {
  max-width: var(--content-max);
  margin: 48px auto 0;
  padding-top: 20px;
  border-top: 1px solid var(--color-line);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 24px;
  font-size: 13px;
  color: var(--color-muted);
}

.copyright {
  font-family: var(--font-mono);
  color: var(--color-blue-gray);
}

.legacy-link {
  color: var(--color-muted);
  font-size: 12px;
  text-decoration: none;
  border: 1px solid var(--color-line);
  border-radius: 999px;
  padding: 3px 12px;
  transition: color 0.2s ease, border-color 0.2s ease;
}

.legacy-link:hover {
  color: var(--color-warn);
  border-color: rgba(255, 204, 0, 0.45);
}

.footer-slogan {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--color-muted);
}

/* ========== 17. Responsive ========== */
@media (max-width: 960px) {
  body {
    padding-top: 64px;
  }

  .site-header {
    width: 100%;
    height: 64px;
    bottom: auto;
    border-right: none;
    border-bottom: 1px solid var(--color-line);
    background: rgba(10, 20, 40, 0.92);
    -webkit-backdrop-filter: blur(16px);
    backdrop-filter: blur(16px);
  }

  .brand-track {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    padding: 0 14px;
    overflow: visible;
  }

  .site-nav {
    position: fixed;
    top: 64px;
    left: 12px;
    right: 12px;
    margin: 0;
    z-index: 999;
    background: rgba(13, 26, 50, 0.98);
    border: 1px solid var(--color-line);
    border-radius: var(--radius);
    box-shadow: var(--shadow-panel);
    padding: 12px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0s linear 0.25s;
  }

  .site-nav[data-open] {
    opacity: 1;
    visibility: visible;
    transform: none;
    transition: opacity 0.25s var(--ease), transform 0.25s var(--ease);
  }

  .nav-toggle {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 14px;
    background: var(--color-panel);
    border: 1px solid var(--color-line);
    border-radius: 999px;
    color: var(--color-blue-gray);
    font-family: var(--font-title);
    font-size: 13px;
    font-weight: 700;
    cursor: pointer;
    transition: border-color 0.2s ease, color 0.2s ease;
  }

  .nav-toggle:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
  }

  .nav-toggle-icon {
    display: inline-flex;
    flex-direction: column;
    gap: 4px;
    width: 18px;
  }

  .nav-toggle-icon .bar {
    display: block;
    width: 100%;
    height: 2px;
    background: currentColor;
    border-radius: 2px;
    transition: transform 0.25s var(--ease), opacity 0.2s ease;
  }

  .nav-toggle[aria-expanded="true"] .bar:nth-child(1) {
    transform: translateY(6px) rotate(45deg);
  }

  .nav-toggle[aria-expanded="true"] .bar:nth-child(2) {
    opacity: 0;
  }

  .nav-toggle[aria-expanded="true"] .bar:nth-child(3) {
    transform: translateY(-6px) rotate(-45deg);
  }

  .track-panel {
    display: none;
  }

  .rail-progress {
    right: 0;
    top: auto;
    bottom: -1px;
    width: 100%;
    height: 2px;
  }

  .rail-progress::before {
    transform: scaleX(var(--scroll-pct, 0));
    transform-origin: left;
  }

  .main-content,
  .site-footer {
    margin-left: 0;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 36px 24px;
  }

  .footer-intro {
    grid-column: span 2;
  }
}

@media (max-width: 760px) {
  .page-intro {
    grid-template-columns: 1fr;
    gap: 20px;
    padding-bottom: 28px;
    margin-bottom: 32px;
  }

  .page-intro-meta {
    border-left: 0;
    padding-left: 0;
    border-top: 1px solid var(--color-line);
    padding-top: 16px;
  }

  .card-grid {
    gap: 14px;
  }

  .col-3,
  .col-4,
  .col-5,
  .col-6,
  .col-7,
  .col-8 {
    grid-column: span 12;
  }
}

@media (max-width: 600px) {
  .site-footer {
    padding: 48px 20px 24px;
  }

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

  .footer-intro {
    grid-column: auto;
  }

  .footer-slogan {
    margin-left: 0;
    width: 100%;
  }
}

@media (max-width: 380px) {
  .brand-sub {
    display: none;
  }

  .brand-box {
    width: 32px;
    height: 32px;
    font-size: 16px;
    border-radius: 7px;
  }

  .brand-title {
    font-size: 16px;
  }

  .nav-toggle-label {
    display: none;
  }
}

/* ========== 18. Reduced Motion ========== */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }

  .site-nav {
    transition-delay: 0s !important;
  }

  .js-enabled .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }
}