/* ============================================
   b体育中国官网 · Site Kit /assets/site.css
   深空球场 · 矿物编辑部
   ============================================ */

/* ---------- 1. Reset & Variables ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  /* 矿物色系统 */
  --color-abyss: #161C24;
  --color-space: #121A29;
  --color-deepblue: #0B1524;
  --color-paper: #F2EDE4;
  --color-paper-dim: #E8E2D6;
  --color-stone: #9C9A93;
  --color-moss: #4C5B3D;
  --color-moss-dark: #2E3B24;
  --color-terra: #C36B49;
  --color-lime: #C8FF00;
  --color-orange: #FF6A3C;
  --color-gold: #D9B36A;
  --color-warmgray: #C4BDB3;

  /* 线条 */
  --line-dark: rgba(255,255,255,0.08);
  --line-dark-strong: rgba(255,255,255,0.16);
  --line-light: rgba(22,28,36,0.12);

  /* 字体 */
  --font-display: 'Noto Serif SC', 'Source Han Serif SC', serif;
  --font-body: 'Noto Sans SC', 'Source Han Sans SC', sans-serif;
  --font-mono: 'IBM Plex Mono', monospace;

  /* 圆角 */
  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-pill: 999px;

  /* 布局 */
  --content-max: 1280px;
  --header-h: 76px;
  --topbar-h: 36px;
  --space-section: 120px;

  /* 动效 */
  --ease-out: cubic-bezier(0.22, 1, 0.36, 1);
  --motion-fast: 180ms;
  --motion-base: 400ms;

  /* 阴影 */
  --shadow-card: 0 8px 32px rgba(0,0,0,0.28);
  --shadow-floating: 0 16px 48px rgba(0,0,0,0.5);
}

/* ---------- 2. Base ---------- */
html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  background: var(--color-abyss);
  color: var(--color-warmgray);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img,
picture,
video,
canvas {
  display: block;
  max-width: 100%;
}

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

ul,
ol {
  list-style: none;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  cursor: pointer;
}

::selection {
  background: var(--color-lime);
  color: var(--color-abyss);
}

:focus-visible {
  outline: 3px solid var(--color-lime);
  outline-offset: 3px;
  border-radius: 4px;
}

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

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

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

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

/* ---------- 3. Layout ---------- */
.container {
  max-width: var(--content-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 32px;
  padding-right: 32px;
}

.site-main {
  flex: 1 0 auto;
  background: var(--color-abyss);
  min-height: 70vh;
}

.section {
  padding: var(--space-section) 0;
}

.section--dark {
  background: var(--color-deepblue);
}

.section--paper {
  background: var(--color-paper);
  color: var(--color-abyss);
}

.section--paper .section-title {
  color: var(--color-abyss);
}

.section--paper .section-desc {
  color: var(--color-moss-dark);
}

.section--paper .section-eyebrow {
  color: var(--color-terra);
}

.section--paper .section-eyebrow::before {
  background: var(--color-terra);
}

.section--paper .chapter-num {
  -webkit-text-stroke: 1px rgba(22,28,36,0.18);
}

.section-head {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 48px;
}

.section-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--color-lime);
  text-transform: uppercase;
}

.section-eyebrow::before {
  content: '';
  width: 28px;
  height: 2px;
  background: var(--color-orange);
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(30px, 4vw, 40px);
  font-weight: 800;
  line-height: 1.25;
  color: var(--color-paper);
  margin: 0;
}

.section-desc {
  font-size: 16px;
  line-height: 1.7;
  color: var(--color-warmgray);
  max-width: 60ch;
}

.chapter-num {
  font-family: var(--font-display);
  font-size: clamp(64px, 10vw, 120px);
  font-weight: 900;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px var(--line-dark-strong);
  user-select: none;
  pointer-events: none;
}

/* ---------- 4. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--radius-pill);
  font-family: var(--font-body);
  font-size: 15px;
  font-weight: 700;
  border: 2px solid transparent;
  cursor: pointer;
  transition:
    transform var(--motion-fast) var(--ease-out),
    box-shadow var(--motion-fast),
    background var(--motion-fast),
    border-color var(--motion-fast),
    color var(--motion-fast);
}

.btn--primary,
.btn--download {
  background: var(--color-orange);
  border-color: var(--color-orange);
  color: var(--color-abyss);
}

.btn--primary:hover,
.btn--download:hover {
  background: var(--color-lime);
  border-color: var(--color-lime);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(200,255,0,0.18);
}

.btn--ghost {
  background: transparent;
  border: 2px solid var(--line-dark-strong);
  color: var(--color-warmgray);
}

.btn--ghost:hover {
  border-color: var(--color-lime);
  color: var(--color-lime);
  transform: translateY(-2px);
}

.btn__arrow {
  display: inline-block;
  transition: transform var(--motion-fast) var(--ease-out);
}

.btn:hover .btn__arrow {
  transform: translateX(4px);
}

/* ---------- 5. Skip Link ---------- */
.skip-link {
  position: fixed;
  top: -60px;
  left: 20px;
  z-index: 3000;
  background: var(--color-lime);
  color: var(--color-abyss);
  font-weight: 700;
  font-size: 14px;
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  text-decoration: none;
  transition: top 0.2s ease;
}

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

/* ---------- 6. Topbar ---------- */
.topbar {
  position: relative;
  background: var(--color-moss-dark);
  border-bottom: 1px solid rgba(200,255,0,0.12);
  font-size: 13px;
  z-index: 100;
}

.topbar__inner {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: var(--topbar-h);
  padding-top: 6px;
  padding-bottom: 6px;
}

.topbar__signal {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-lime);
  box-shadow: 0 0 0 4px rgba(200,255,0,0.15);
  animation: signal-pulse 2.4s ease-in-out infinite;
}

@keyframes signal-pulse {
  0% {
    box-shadow: 0 0 0 0 rgba(200,255,0,0.4);
  }
  70% {
    box-shadow: 0 0 0 10px rgba(200,255,0,0);
  }
  100% {
    box-shadow: 0 0 0 0 rgba(200,255,0,0);
  }
}

.topbar__text {
  font-size: 13px;
  color: var(--color-warmgray);
  line-height: 1.4;
}

.topbar__code {
  font-family: var(--font-mono);
  color: var(--color-lime);
  background: rgba(200,255,0,0.08);
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 12px;
  margin-left: 4px;
}

/* ---------- 7. Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background: linear-gradient(180deg, rgba(15,21,30,0.92), rgba(9,15,24,0.98));
  border-bottom: 1px solid var(--line-dark);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.reading-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 3px;
  background: transparent;
  z-index: 2;
}

.reading-progress span {
  display: block;
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--color-lime), var(--color-orange));
  border-radius: 0 3px 3px 0;
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: 28px;
  min-height: var(--header-h);
  padding-top: 12px;
  padding-bottom: 12px;
}

/* ---------- 8. Brand ---------- */
.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.brand__mark {
  position: relative;
  width: 44px;
  height: 44px;
  border-radius: 14px;
  background: linear-gradient(135deg, var(--color-orange), var(--color-terra));
  transform: rotate(-8deg);
  transition: transform var(--motion-base) var(--ease-out);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.brand__mark::before {
  content: 'B';
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 900;
  line-height: 1;
  color: var(--color-abyss);
  transform: rotate(8deg);
}

.brand__mark::after {
  content: '';
  position: absolute;
  right: -5px;
  bottom: -5px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--color-lime);
  border: 3px solid var(--color-abyss);
}

.brand:hover .brand__mark {
  transform: rotate(0deg) scale(1.04);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 900;
  color: var(--color-paper);
  line-height: 1.2;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.brand__tagline {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-stone);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  white-space: nowrap;
}

/* ---------- 9. Navigation ---------- */
.main-nav {
  margin-left: auto;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item {
  position: relative;
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 10px 16px;
  border-radius: var(--radius-pill);
  color: var(--color-warmgray);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.01em;
  transition:
    color var(--motion-fast) var(--ease-out),
    background var(--motion-fast),
    transform var(--motion-fast);
}

.nav-link::after {
  content: '';
  position: absolute;
  left: 16px;
  right: 16px;
  bottom: 4px;
  height: 2px;
  background: var(--color-lime);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--motion-base) var(--ease-out);
}

.nav-link:hover {
  color: var(--color-paper);
}

.nav-link:hover::after,
.nav-link[aria-current="page"]::after {
  transform: scaleX(1);
}

.nav-link[aria-current="page"] {
  color: var(--color-paper);
  background: rgba(200,255,0,0.06);
}

.nav-index {
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  color: var(--color-terra);
  transition: color var(--motion-fast);
}

.nav-link:hover .nav-index,
.nav-link[aria-current="page"] .nav-index {
  color: var(--color-lime);
}

.nav-label {
  white-space: nowrap;
}

/* ---------- 10. Nav Toggle ---------- */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  border: 1px solid var(--line-dark-strong);
  border-radius: 50%;
  background: transparent;
  cursor: pointer;
  padding: 10px;
  transition: border-color var(--motion-fast), background var(--motion-fast);
}

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

.nav-toggle__bar {
  display: block;
  height: 2px;
  width: 100%;
  border-radius: 2px;
  background: var(--color-paper);
  transition: transform 0.3s var(--ease-out), opacity 0.2s;
}

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

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

.nav-toggle[aria-expanded="true"] .nav-toggle__bar:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ---------- 11. Footer ---------- */
.site-footer {
  position: relative;
  background: linear-gradient(160deg, var(--color-abyss) 0%, var(--color-deepblue) 70%, #080E16 100%);
  color: var(--color-warmgray);
  flex-shrink: 0;
  overflow: hidden;
}

.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 24px;
  background: linear-gradient(90deg, var(--color-orange), var(--color-terra));
  clip-path: polygon(0 0, calc(100% - 160px) 0, 100% 100%, 0 100%);
  z-index: 2;
}

.site-footer::after {
  content: '';
  position: absolute;
  right: -80px;
  top: 120px;
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, rgba(200,255,0,0.06), transparent 70%);
  pointer-events: none;
}

.site-footer__inner {
  position: relative;
  padding-top: 72px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.7fr 0.7fr 1.3fr;
  gap: 48px;
  padding-bottom: 56px;
  border-bottom: 1px solid var(--line-dark);
}

.footer-brand {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.footer-logo {
  font-family: var(--font-display);
  font-size: 30px;
  font-weight: 900;
  color: var(--color-paper);
  line-height: 1.2;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.footer-logo::before {
  content: 'B';
  width: 40px;
  height: 40px;
  background: linear-gradient(135deg, var(--color-orange), var(--color-terra));
  border-radius: 12px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  font-weight: 900;
  color: var(--color-abyss);
  transform: rotate(-6deg);
  flex-shrink: 0;
}

.footer-about {
  font-size: 15px;
  line-height: 1.7;
  color: var(--color-stone);
  max-width: 32ch;
  margin-top: 16px;
}

.footer-version {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-gold);
  background: rgba(217,179,106,0.06);
  border: 1px solid rgba(217,179,106,0.2);
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  margin-top: 20px;
}

.footer-version::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-lime);
}

.footer-heading {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-stone);
  margin-bottom: 16px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--line-dark);
  display: flex;
  align-items: center;
  gap: 8px;
}

.footer-heading::before {
  content: '/';
  color: var(--color-orange);
  font-weight: 700;
}

.footer-link-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.footer-link-list a {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 7px 0;
  color: var(--color-warmgray);
  font-size: 14px;
  transition:
    color var(--motion-fast),
    padding-left var(--motion-base) var(--ease-out);
}

.footer-link-list a::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-terra);
  opacity: 0.4;
  flex-shrink: 0;
  transition:
    background var(--motion-fast),
    opacity var(--motion-fast);
}

.footer-link-list a:hover {
  color: var(--color-paper);
  padding-left: 8px;
}

.footer-link-list a:hover::before {
  background: var(--color-lime);
  opacity: 1;
}

.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.contact-item {
  display: grid;
  grid-template-columns: 48px 1fr;
  align-items: center;
  gap: 10px;
}

.contact-label {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--color-stone);
  letter-spacing: 0.08em;
}

.contact-value {
  font-size: 14px;
  color: var(--color-warmgray);
  overflow-wrap: anywhere;
}

.copy-btn {
  grid-column: 2;
  justify-self: start;
  background: transparent;
  border: 1px solid var(--line-dark-strong);
  color: var(--color-stone);
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1;
  padding: 6px 14px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition:
    color var(--motion-fast),
    border-color var(--motion-fast),
    background var(--motion-fast);
}

.copy-btn:hover {
  color: var(--color-lime);
  border-color: rgba(200,255,0,0.4);
}

.copy-btn.is-copied {
  color: var(--color-lime);
  border-color: var(--color-lime);
  background: rgba(200,255,0,0.08);
}

.contact-note {
  font-size: 12px;
  line-height: 1.6;
  color: var(--color-stone);
  margin-top: 16px;
  max-width: 34ch;
  border-left: 3px solid var(--color-terra);
  padding-left: 12px;
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 24px;
  padding: 20px 0 28px;
}

.footer-trust {
  font-size: 13px;
  color: var(--color-stone);
  max-width: 60ch;
  line-height: 1.5;
}

.footer-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-stone);
}

/* ---------- 12. Mobile Toolbar ---------- */
.mobile-toolbar {
  display: none;
}

@media (max-width: 700px) {
  body {
    padding-bottom: 80px;
  }

  .mobile-toolbar {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    position: fixed;
    left: 12px;
    right: 12px;
    bottom: 12px;
    z-index: 1100;
    background: rgba(15,21,30,0.92);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid var(--line-dark-strong);
    border-radius: 20px;
    box-shadow: var(--shadow-floating);
    padding: 6px;
  }

  .mobile-toolbar__btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    padding: 8px 4px;
    background: transparent;
    border: none;
    border-radius: 14px;
    color: var(--color-stone);
    font-family: var(--font-body);
    font-size: 11px;
    cursor: pointer;
    text-decoration: none;
    transition:
      background var(--motion-fast),
      color var(--motion-fast);
  }

  .mobile-toolbar__btn:hover,
  .mobile-toolbar__btn:focus-visible {
    background: rgba(200,255,0,0.08);
    color: var(--color-lime);
    outline: none;
  }

  .mobile-toolbar__icon {
    font-size: 18px;
    line-height: 1;
  }

  .mobile-toolbar__label {
    font-size: 10px;
    color: inherit;
  }
}

/* ---------- 13. Shared Components ---------- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 600;
  line-height: 1.4;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  background: var(--color-moss-dark);
  color: var(--color-warmgray);
}

.badge--live {
  background: rgba(255,106,60,0.14);
  color: var(--color-orange);
  border: 1px solid rgba(255,106,60,0.3);
}

.badge--live::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-orange);
}

.badge--sync {
  background: rgba(200,255,0,0.08);
  color: var(--color-lime);
  border: 1px solid rgba(200,255,0,0.24);
}

.badge--sync::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--color-lime);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--color-moss-dark);
  border: 1px solid var(--line-dark-strong);
  border-radius: 10px;
  transform: skewX(-6deg);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-lime);
  transition:
    transform var(--motion-base) var(--ease-out),
    border-color var(--motion-fast);
}

.tag > * {
  transform: skewX(6deg);
}

.tag:hover {
  transform: skewX(-3deg);
  border-color: var(--color-lime);
}

.card {
  background: linear-gradient(180deg, rgba(22,28,36,0.7), rgba(15,21,30,0.9));
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-lg);
  padding: 24px;
  box-shadow: var(--shadow-card);
  transition:
    border-color var(--motion-fast),
    transform var(--motion-base) var(--ease-out);
}

.card:hover {
  border-color: var(--color-terra);
  transform: translateX(2px);
}

.card--media {
  padding: 0;
  overflow: hidden;
}

.card--media .card__body {
  padding: 24px;
}

.card__body {
  padding: 0;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 24px;
}

.media {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-moss-dark), var(--color-abyss));
  aspect-ratio: 4 / 3;
}

.media--wide {
  aspect-ratio: 16 / 9;
}

.media--portrait {
  aspect-ratio: 3 / 4;
}

.media > img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.media__placeholder {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: linear-gradient(135deg, var(--color-moss-dark), var(--color-abyss));
  color: var(--color-stone);
  font-family: var(--font-mono);
  font-size: 13px;
}

.split-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  align-items: center;
}

.item-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.item-list li {
  position: relative;
  padding: 12px 16px 12px 44px;
  border: 1px solid var(--line-dark);
  border-radius: var(--radius-md);
  transition:
    border-color var(--motion-fast),
    background var(--motion-fast);
}

.item-list li::before {
  content: '';
  position: absolute;
  left: 18px;
  top: 50%;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--color-terra);
  transform: translateY(-50%);
}

.item-list li:hover {
  border-color: var(--color-terra);
  background: rgba(255,106,60,0.04);
}

.stat-block {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.stat-block__num {
  font-family: var(--font-display);
  font-size: clamp(40px, 5vw, 64px);
  font-weight: 900;
  color: var(--color-orange);
  line-height: 1;
}

.stat-block__label {
  font-size: 14px;
  color: var(--color-stone);
  margin-top: 8px;
}

/* ---------- 14. Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--color-stone);
  padding: 16px 0;
}

.breadcrumb a {
  color: var(--color-warmgray);
  transition: color var(--motion-fast);
}

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

.breadcrumb__sep {
  color: var(--color-stone);
  opacity: 0.6;
}

.breadcrumb [aria-current="page"] {
  color: var(--color-paper);
  font-weight: 600;
}

/* ---------- 15. Page Hero ---------- */
.page-hero {
  padding: 72px 0 48px;
  background: linear-gradient(160deg, var(--color-abyss), var(--color-deepblue));
  position: relative;
  overflow: hidden;
}

.page-hero::after {
  content: '';
  position: absolute;
  right: 0;
  top: 0;
  bottom: 0;
  width: 30%;
  background: linear-gradient(120deg, transparent, rgba(255,106,60,0.06));
  clip-path: polygon(20% 0, 100% 0, 100% 100%, 0 100%);
  pointer-events: none;
}

.page-hero__inner {
  position: relative;
  z-index: 1;
}

.page-hero__title {
  font-family: var(--font-display);
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 900;
  line-height: 1.2;
  color: var(--color-paper);
  max-width: 16ch;
}

.page-hero__sub {
  font-size: 17px;
  color: var(--color-warmgray);
  margin-top: 16px;
  max-width: 50ch;
}

/* ---------- 16. Utils ---------- */
.text-muted {
  color: var(--color-stone);
}

[data-chapter],
section[id] {
  scroll-margin-top: calc(var(--header-h) + 20px);
}

/* ---------- 17. Responsive ---------- */
@media (max-width: 1080px) {
  .nav-link {
    padding: 8px 10px;
    font-size: 13px;
  }

  .brand__tagline {
    display: none;
  }

  .site-header__inner {
    gap: 16px;
  }
}

@media (max-width: 900px) {
  .nav-toggle {
    display: inline-flex;
  }

  .btn--download {
    display: none;
  }

  .main-nav {
    position: absolute;
    top: calc(100% + 8px);
    left: 12px;
    right: 12px;
    width: auto;
    max-height: calc(100vh - var(--header-h) - 100px);
    border-radius: 20px;
    overflow-y: auto;
    padding: 24px;
    background: var(--color-space);
    border: 1px solid var(--line-dark-strong);
    box-shadow: var(--shadow-floating);
    transform: translateY(-8px);
    opacity: 0;
    visibility: hidden;
    transition:
      transform 0.35s var(--ease-out),
      opacity 0.25s,
      visibility 0.25s;
    margin-left: 0;
  }

  .main-nav[data-open] {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 6px;
  }

  .nav-link {
    padding: 16px 20px;
    font-size: 17px;
    border-radius: var(--radius-md);
    justify-content: flex-start;
  }

  .nav-link::after {
    left: 20px;
    right: auto;
    width: 24px;
    bottom: 10px;
  }

  .nav-index {
    font-size: 12px;
    width: 28px;
  }

  .split-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-grid {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 768px) {
  .container {
    padding-left: 20px;
    padding-right: 20px;
  }

  .section {
    padding: 64px 0;
  }

  .section-head {
    margin-bottom: 32px;
  }

  .brand__name {
    font-size: 20px;
  }

  .program__header {
    gap: 12px;
  }

  .page-hero {
    padding: 48px 0 32px;
  }

  .stat-block {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 600px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .footer-bottom {
    flex-direction: column;
    align-items: flex-start;
  }

  .stat-block {
    grid-template-columns: 1fr;
  }

  .brand__mark {
    width: 40px;
    height: 40px;
    border-radius: 12px;
  }

  .brand__name {
    font-size: 18px;
  }

  .site-header__inner {
    min-height: 64px;
  }
}

/* ---------- 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;
  }

  html {
    scroll-behavior: auto;
  }

  .topbar__signal {
    animation: none;
  }

  .card:hover {
    transform: none;
  }

  .btn:hover {
    transform: none;
  }

  .tag {
    transform: none;
  }
}