/* ============================================================
   火博体育HB 中文站 — 全局共享样式 /assets/site.css
   约定：堆叠画板 / 热力数据场 / 印刷标签
   ============================================================ */

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

[hidden] {
  display: none !important;
}

:root {
  /* 色彩体系 */
  --c-primary: #E6342A;
  --c-primary-light: #FF6B60;
  --c-gold: #F7B500;
  --c-gold-light: #FFD966;
  --c-bg: #1A1A1A;
  --c-bg-alt: #2A2A2A;
  --c-bg-deep: #141414;
  --c-text: #F5F5F5;
  --c-text-alt: #8C8C8C;

  /* 字体协议 */
  --font-display: "Arial Narrow", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --font-mono: "SF Mono", "Menlo", "Consolas", monospace;

  /* 布局 */
  --container-w: 1240px;
  --container-pad: 24px;
  --header-h: 72px;
  --radius: 12px;
  --transition: 240ms ease;
  --shadow-card: 0 2px 12px rgba(0, 0, 0, 0.35);
}

@media (max-width: 640px) {
  :root {
    --container-pad: 16px;
  }
}

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

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  color: var(--c-text);
  background-color: var(--c-bg);
  background-image:
    radial-gradient(circle at 12% 8%, rgba(230, 52, 42, 0.1), transparent 42%),
    radial-gradient(circle at 88% 24%, rgba(247, 181, 0, 0.07), transparent 35%),
    radial-gradient(circle at 50% 100%, rgba(230, 52, 42, 0.05), transparent 50%);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

@media (min-width: 1024px) {
  body {
    background-attachment: fixed;
  }
}

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

img,
svg {
  display: block;
  max-width: 100%;
}

ul,
ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 900;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

p {
  margin-bottom: 1em;
}

::selection {
  background: var(--c-primary);
  color: #fff;
}

:focus-visible {
  outline: 2px solid var(--c-gold);
  outline-offset: 3px;
}

/* 滚动条 */
::-webkit-scrollbar {
  width: 10px;
  height: 10px;
}
::-webkit-scrollbar-track {
  background: var(--c-bg-deep);
}
::-webkit-scrollbar-thumb {
  background: #3a3a3a;
  border-radius: 5px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--c-primary);
}

/* ---------- 3. Utilities ---------- */
.container {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: -64px;
  left: 16px;
  z-index: 300;
  padding: 10px 20px;
  background: var(--c-gold);
  color: var(--c-bg);
  font-size: 14px;
  font-weight: 700;
  border-radius: 0 0 8px 8px;
  transition: top 180ms ease;
}

.skip-link:focus-visible {
  top: 0;
}

.main-content {
  display: block;
  padding-top: var(--header-h);
  min-height: 60vh;
}

/* ---------- 4. Header ---------- */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 200;
  height: var(--header-h);
  background: rgba(26, 26, 26, 0.82);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(245, 245, 245, 0.07);
  transition: background 240ms ease, box-shadow 240ms ease;
}

.site-header.is-scrolled {
  background: rgba(20, 20, 20, 0.94);
  box-shadow: 0 8px 28px rgba(0, 0, 0, 0.32);
}

.site-header__inner {
  position: relative;
  max-width: var(--container-w);
  height: 100%;
  margin: 0 auto;
  padding: 0 var(--container-pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

/* 顶部滚动进度条 */
.scroll-progress {
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: linear-gradient(90deg, var(--c-primary), var(--c-gold));
  z-index: 5;
  pointer-events: none;
}

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

.brand__mark {
  position: relative;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--c-primary) 0%, var(--c-gold) 130%);
  box-shadow:
    0 6px 16px rgba(230, 52, 42, 0.35),
    inset 0 1px 0 rgba(255, 255, 255, 0.25);
  transform: rotate(-2deg);
}

.brand__mark::after {
  content: '';
  position: absolute;
  inset: 3px;
  border: 1px solid rgba(26, 26, 26, 0.3);
  border-radius: 9px;
}

.brand__mark-core {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 18px;
  color: var(--c-bg);
  letter-spacing: -0.02em;
  position: relative;
  z-index: 1;
}

.brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.15;
}

.brand__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 20px;
  color: var(--c-text);
  letter-spacing: 0.06em;
}

.brand__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--c-gold);
  letter-spacing: 0.14em;
  margin-top: 2px;
}

/* 主导航 */
.site-nav__list {
  display: flex;
  align-items: center;
  gap: 4px;
}

.site-nav__link {
  display: inline-flex;
  align-items: center;
  position: relative;
  padding: 10px 14px;
  font-size: 15px;
  font-weight: 600;
  color: var(--c-text);
  letter-spacing: 0.02em;
  border-radius: 6px;
  transition: color 240ms ease, background 240ms ease;
}

.site-nav__link::after {
  content: '';
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 2px;
  height: 2px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-gold));
  border-radius: 1px;
  transform: scaleX(0);
  transform-origin: 0 50%;
  transition: transform 240ms ease;
}

.site-nav__link:hover {
  color: var(--c-text);
  background: rgba(245, 245, 245, 0.04);
}

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

.site-nav__item:has(.site-nav__link[aria-current="page"]) .site-nav__link {
  color: var(--c-gold);
}

/* 汉堡按钮 */
.nav-toggle {
  display: none;
  width: 46px;
  height: 46px;
  padding: 0 12px;
  background: rgba(245, 245, 245, 0.04);
  border: 1px solid rgba(245, 245, 245, 0.12);
  border-radius: 10px;
  cursor: pointer;
  flex-direction: column;
  align-items: stretch;
  justify-content: center;
  gap: 6px;
  transition: border-color 240ms ease, background 240ms ease;
}

.nav-toggle:hover {
  background: rgba(245, 245, 245, 0.08);
  border-color: rgba(247, 181, 0, 0.4);
}

.nav-toggle__line {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--c-text);
  border-radius: 1px;
  transition: transform 300ms ease, opacity 300ms ease;
}

.nav-toggle.is-active .nav-toggle__line:nth-child(1) {
  transform: translateY(8px) rotate(45deg);
}

.nav-toggle.is-active .nav-toggle__line:nth-child(2) {
  opacity: 0;
}

.nav-toggle.is-active .nav-toggle__line:nth-child(3) {
  transform: translateY(-8px) rotate(-45deg);
}

/* 移动端导航状态 */
@media (max-width: 880px) {
  .site-header__inner {
    gap: 12px;
  }

  .nav-toggle {
    display: flex;
  }

  .site-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    background: rgba(20, 20, 20, 0.97);
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(247, 181, 0, 0.15);
    box-shadow: 0 20px 32px rgba(0, 0, 0, 0.5);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity 280ms ease, transform 280ms ease, visibility 280ms ease;
    overflow-y: auto;
    max-height: calc(100vh - var(--header-h));
  }

  .site-nav.is-open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .site-nav__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 12px var(--container-pad) 20px;
  }

  .site-nav__item {
    border-bottom: 1px solid rgba(245, 245, 245, 0.05);
  }

  .site-nav__item:last-child {
    border-bottom: none;
  }

  .site-nav__link {
    display: block;
    padding: 16px 8px 16px 16px;
    font-size: 16px;
    border-left: 2px solid transparent;
  }

  .site-nav__link::after {
    display: none;
  }

  .site-nav__link:hover {
    background: rgba(245, 245, 245, 0.04);
  }

  .site-nav__link[aria-current="page"] {
    color: var(--c-gold);
    background: rgba(247, 181, 0, 0.06);
    border-left-color: var(--c-gold);
  }
}

/* ---------- 5. Footer ---------- */
.site-footer {
  position: relative;
  margin-top: auto;
  background: var(--c-bg-deep);
  color: var(--c-text-alt);
}

.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  height: 3px;
  width: 100%;
  background: linear-gradient(90deg, var(--c-primary) 0%, var(--c-gold) 30%, transparent 80%);
}

.site-footer__inner {
  max-width: var(--container-w);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

.site-footer__top {
  display: grid;
  grid-template-columns: 1.4fr 0.7fr 0.7fr 1.1fr;
  gap: 48px;
  padding: 56px 0 44px;
}

.site-footer__brand-row {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 20px;
  transition: opacity 240ms ease;
}

.site-footer__brand-row:hover {
  opacity: 0.88;
}

.brand__mark--footer {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  box-shadow: 0 4px 14px rgba(230, 52, 42, 0.28);
}

.brand__name--footer {
  font-size: 22px;
}

.site-footer__tagline {
  font-family: var(--font-display);
  font-size: 15px;
  letter-spacing: 0.08em;
  color: var(--c-text);
  margin-bottom: 12px;
}

.site-footer__trust {
  font-size: 13px;
  line-height: 1.8;
  border-left: 2px solid var(--c-gold);
  padding-left: 14px;
}

.site-footer__col {
  min-width: 0;
}

.site-footer__heading {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 14px;
  color: var(--c-text);
  letter-spacing: 0.1em;
  margin-bottom: 20px;
}

.site-footer__heading::after {
  content: '';
  width: 24px;
  height: 2px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-gold));
  border-radius: 1px;
}

.site-footer__list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 14px;
  color: var(--c-text-alt);
  transition: color 240ms ease;
}

.footer-link::before {
  content: '';
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 4px 0 4px 6px;
  border-color: transparent transparent transparent var(--c-primary);
  transition: border-color 240ms ease, transform 240ms ease;
}

.footer-link:hover {
  color: var(--c-gold);
}

.footer-link:hover::before {
  border-left-color: var(--c-gold);
  transform: translateX(2px);
}

.site-footer__contact-list {
  gap: 14px;
}

.site-footer__contact-line {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 12px;
  font-size: 13px;
  line-height: 1.6;
  min-width: 0;
  word-break: break-all;
}

.site-footer__contact-k {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--c-gold);
  background: rgba(247, 181, 0, 0.08);
  border: 1px solid rgba(247, 181, 0, 0.18);
  border-radius: 4px;
  text-align: center;
  padding: 3px 0;
  align-self: start;
}

.site-footer__bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-top: 1px solid rgba(245, 245, 245, 0.07);
  padding: 20px 0 24px;
  font-size: 13px;
}

.site-footer__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.site-footer__icp {
  color: var(--c-text-alt);
}

.site-footer__legal {
  display: flex;
  align-items: center;
  gap: 10px;
}

.footer-link--inline {
  color: var(--c-text-alt);
  font-size: 13px;
  transition: color 240ms ease;
}

.footer-link--inline::before {
  display: none;
}

.footer-link--inline:hover {
  color: var(--c-gold);
}

.site-footer__sep {
  color: rgba(245, 245, 245, 0.2);
  font-family: var(--font-mono);
  font-size: 12px;
}

@media (max-width: 1024px) {
  .site-footer__top {
    grid-template-columns: 1fr 1fr;
    gap: 40px;
  }
}

@media (max-width: 600px) {
  .site-footer__top {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .site-footer__bottom {
    flex-direction: column;
    align-items: flex-start;
  }
}

/* ---------- 6. Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border-radius: 999px;
  font-family: var(--font-sans);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.03em;
  line-height: 1;
  border: 1px solid transparent;
  cursor: pointer;
  transition: transform 240ms ease, box-shadow 240ms ease, background 240ms ease, color 240ms ease;
}

.btn--primary {
  background: linear-gradient(135deg, var(--c-primary) 0%, #FF8A5B 120%);
  color: #fff;
  box-shadow: 0 6px 18px rgba(230, 52, 42, 0.3);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 28px rgba(230, 52, 42, 0.4);
}

.btn--ghost {
  background: transparent;
  border-color: rgba(245, 245, 245, 0.22);
  color: var(--c-text);
}

.btn--ghost:hover {
  border-color: var(--c-gold);
  color: var(--c-gold);
}

/* ---------- 7. Breadcrumb ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding: 20px 0;
  font-size: 13px;
  color: var(--c-text-alt);
}

.breadcrumb a {
  color: var(--c-text-alt);
  transition: color 240ms ease;
}

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

.breadcrumb__sep {
  color: var(--c-primary);
  font-family: var(--font-mono);
  font-size: 12px;
}

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

/* ---------- 8. Section & Layout ---------- */
.section {
  padding: clamp(64px, 8vw, 112px) 0;
  position: relative;
}

.section--alt {
  background: var(--c-bg-alt);
}

.section__header {
  margin-bottom: 40px;
  max-width: 720px;
}

.section__header--center {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.section-title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 4vw, 48px);
  line-height: 1.1;
  letter-spacing: -0.01em;
  color: var(--c-text);
}

.section-description {
  font-size: 15px;
  color: var(--c-text-alt);
  max-width: 600px;
  margin-top: 12px;
}

.grid {
  display: grid;
  gap: 24px;
}

.grid--2 {
  grid-template-columns: repeat(2, 1fr);
}

.grid--3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid--4 {
  grid-template-columns: repeat(4, 1fr);
}

@media (max-width: 1024px) {
  .grid--4 {
    grid-template-columns: repeat(2, 1fr);
  }

  .grid--3 {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 640px) {
  .grid--2,
  .grid--3,
  .grid--4 {
    grid-template-columns: 1fr;
  }
}

/* ---------- 9. Components ---------- */
/* 章节索引标签 */
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--c-gold);
  margin-bottom: 16px;
}

.eyebrow::before {
  content: '';
  width: 28px;
  height: 1px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-gold));
}

/* 纸张叠层面板 */
.stack-panel {
  position: relative;
  background: var(--c-bg-alt);
  border: 1px solid rgba(245, 245, 245, 0.06);
  border-radius: var(--radius);
  padding: clamp(28px, 5vw, 56px);
  box-shadow:
    10px 10px 0 rgba(230, 52, 42, 0.06),
    10px 10px 0 1px rgba(247, 181, 0, 0.04);
}

/* 标签 */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 12px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  line-height: 1.7;
  white-space: nowrap;
}

.tag--red {
  background: rgba(230, 52, 42, 0.15);
  border: 1px solid rgba(230, 52, 42, 0.32);
  color: var(--c-primary-light);
}

.tag--gold {
  background: rgba(247, 181, 0, 0.14);
  border: 1px solid rgba(247, 181, 0, 0.3);
  color: var(--c-gold);
}

/* 数据表 */
.data-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--c-text);
  background: var(--c-bg-alt);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid rgba(245, 245, 245, 0.06);
}

.data-table th {
  padding: 12px 16px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--c-text-alt);
  text-align: left;
  background: rgba(245, 245, 245, 0.04);
  border-bottom: 1px solid rgba(245, 245, 245, 0.08);
  font-family: var(--font-mono);
}

.data-table td {
  padding: 14px 16px;
  border-bottom: 1px solid rgba(245, 245, 245, 0.04);
}

.data-table tbody tr:last-child td {
  border-bottom: none;
}

.data-table tbody tr {
  transition: background 240ms ease;
}

.data-table tbody tr:hover {
  background: rgba(230, 52, 42, 0.05);
}

.data-table .num {
  font-family: var(--font-mono);
  text-align: right;
}

.data-table .num--hl {
  color: var(--c-gold);
  font-weight: 700;
}

/* 指标卡 */
.stat-card {
  background: var(--c-bg-alt);
  border: 1px solid rgba(245, 245, 245, 0.06);
  border-radius: var(--radius);
  padding: 24px 28px;
  position: relative;
  box-shadow: var(--shadow-card);
  overflow: hidden;
}

.stat-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 48px;
  height: 2px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-gold));
}

.stat-card__value {
  font-family: var(--font-mono);
  font-size: clamp(32px, 4vw, 44px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--c-text);
  letter-spacing: -0.02em;
}

.stat-card__value--gold {
  color: var(--c-gold);
}

.stat-card__label {
  margin-top: 8px;
  font-size: 13px;
  color: var(--c-text-alt);
}

/* 数据条 */
.gauge-bar {
  height: 6px;
  border-radius: 999px;
  background: rgba(245, 245, 245, 0.08);
  overflow: hidden;
}

.gauge-bar__fill {
  display: block;
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-gold));
}

/* 时间轴 */
.timeline {
  position: relative;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 7px;
  top: 4px;
  bottom: 12px;
  width: 2px;
  background: linear-gradient(180deg, var(--c-primary), var(--c-gold) 40%, transparent 90%);
}

.timeline__item {
  position: relative;
  padding-left: 32px;
  padding-bottom: 28px;
}

.timeline__item:last-child {
  padding-bottom: 0;
}

.timeline__item::before {
  content: '';
  position: absolute;
  left: 3px;
  top: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--c-bg);
  border: 2px solid var(--c-gold);
  box-shadow: 0 0 0 3px rgba(247, 181, 0, 0.15);
}

/* 标签页 */
.tabs {
  width: 100%;
}

.tabs__list {
  display: flex;
  gap: 6px;
  border-bottom: 1px solid rgba(245, 245, 245, 0.1);
  padding-bottom: 10px;
  overflow-x: auto;
  scrollbar-width: none;
}

.tabs__list::-webkit-scrollbar {
  display: none;
}

.tab-button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 20px;
  border: none;
  border-radius: 8px;
  background: transparent;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 600;
  color: var(--c-text-alt);
  white-space: nowrap;
  cursor: pointer;
  transition: all 240ms ease;
}

.tab-button:hover {
  color: var(--c-text);
  background: rgba(245, 245, 245, 0.06);
}

.tab-button[aria-selected="true"],
.tab-button.is-active {
  color: var(--c-bg);
  background: linear-gradient(135deg, var(--c-primary), var(--c-gold));
}

.tab-panel[hidden] {
  display: none;
}

/* 图片容器 */
.stage-media {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background: var(--c-bg-alt);
  aspect-ratio: 16 / 9;
  min-height: 160px;
}

.stage-media::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    linear-gradient(135deg, rgba(230, 52, 42, 0.2), transparent 45%),
    linear-gradient(315deg, rgba(247, 181, 0, 0.12), transparent 40%),
    repeating-linear-gradient(45deg, transparent 0 12px, rgba(255, 255, 255, 0.02) 12px 14px);
}

.stage-media__caption {
  position: absolute;
  left: 12px;
  bottom: 12px;
  z-index: 1;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--c-text);
  background: rgba(20, 20, 20, 0.8);
  padding: 4px 12px;
  border-radius: 4px;
  border-left: 2px solid var(--c-gold);
}

/* 首屏章节预览索引 */
.chapter-index {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.chapter-index__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--c-bg-alt);
  border: 1px solid rgba(245, 245, 245, 0.08);
  border-radius: 999px;
  font-size: 13px;
  color: var(--c-text-alt);
  transition: all 240ms ease;
}

.chapter-index__item:hover {
  border-color: var(--c-gold);
  color: var(--c-gold);
  transform: translateY(-2px);
}

.chapter-index__num {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--c-primary);
}

/* ---------- 10. Motion & Reduced Motion ---------- */
[data-reveal] {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.7s cubic-bezier(0.2, 0.6, 0.2, 1), transform 0.7s cubic-bezier(0.2, 0.6, 0.2, 1);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }

  [data-reveal] {
    opacity: 1 !important;
    transform: none !important;
  }

  .scroll-progress {
    display: none;
  }
}