/* =========================================================
   凤凰体育平台 / 凤凰竞技
   全站共享样式 site.css
   设计母题：赛事直播信号条 · 红黑对决 · 非对称双栏
   ========================================================= */

/* ---------- 1. 设计令牌 ---------- */
:root {
  --obsidian: #0B0D11;
  --flame: #E84B22;
  --gold: #C9A55C;
  --charcoal: #1A1C23;
  --bone: #F4F5F7;
  --silver: #A0A4B0;
  --ember: #B3301A;
  --warm-white: #FAF6EF;
  --red-glow: rgba(232, 75, 34, 0.15);

  --font-heading: "PingFang SC Heavy", "Noto Sans CJK SC Black", "Source Han Sans SC Heavy", "Microsoft YaHei UI Bold", "Microsoft YaHei", sans-serif;
  --font-body: "PingFang SC Regular", "Noto Sans CJK SC", "Source Han Sans SC", "Microsoft YaHei UI", "Microsoft YaHei", sans-serif;
  --font-mono: "SF Mono", "Cascadia Code", "Roboto Mono", Consolas, monospace;

  --container-w: 1360px;
  --container-pad: 24px;
  --header-h: 70px;
  --radius: 8px;
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --transition: 220ms var(--ease);
}

/* ---------- 2. Reset 与基础 ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

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

body {
  min-height: 100vh;
  overflow-x: hidden;
  background:
    radial-gradient(1100px 420px at 85% -100px, rgba(232, 75, 34, 0.08), transparent 62%),
    var(--obsidian);
  color: var(--bone);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}

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

input,
button,
textarea,
select {
  font: inherit;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  line-height: 1.2;
  text-wrap: balance;
}

p {
  text-wrap: pretty;
}

a {
  color: var(--flame);
  text-decoration: none;
}

ul,
ol {
  list-style: none;
}

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

#main-content:focus {
  outline: none;
}

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

#main-content {
  scroll-margin-top: calc(var(--header-h) + 10px);
}

::selection {
  background: rgba(232, 75, 34, 0.75);
  color: #fff;
}

/* ---------- 3. 排版 ---------- */
.site-title {
  font-family: var(--font-heading);
  font-size: clamp(34px, 5vw, 58px);
  font-weight: 900;
  letter-spacing: 0.02em;
  line-height: 1.08;
  color: var(--warm-white);
}

.site-title--light {
  color: var(--obsidian);
}

.page-subtitle {
  font-size: 18px;
  color: var(--silver);
  margin-top: 12px;
}

.text-muted {
  color: var(--silver);
}

.text-gold {
  color: var(--gold);
}

.text-flame {
  color: var(--flame);
}

/* ---------- 4. 容器与布局 ---------- */
.container {
  width: min(100% - 48px, var(--container-w));
  margin-inline: auto;
}

.container--narrow {
  width: min(100% - 48px, 920px);
  margin-inline: auto;
}

.main-layout {
  padding-block: 44px 80px;
}

.section {
  padding-block: 64px;
}

.section--compact {
  padding-block: 32px;
}

.section--light {
  background: var(--warm-white);
  color: var(--obsidian);
}

.section--light h1,
.section--light h2,
.section--light h3,
.section--light h4,
.section--light h5,
.section--light h6 {
  color: var(--obsidian);
}

.layout-split {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 0.7fr);
  gap: 48px;
  align-items: start;
}

.layout-split__main {
  min-width: 0;
}

.layout-split__aside {
  position: sticky;
  top: calc(var(--header-h) + 28px);
  background: var(--charcoal);
  border: 1px solid rgba(160, 164, 176, 0.12);
  border-radius: var(--radius);
  padding: 28px;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}

@media (max-width: 980px) {
  .layout-split {
    grid-template-columns: 1fr;
    gap: 28px;
  }

  .layout-split__aside {
    position: static;
  }
}

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

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 24px;
}

@media (max-width: 900px) {
  .grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  }
}

/* ---------- 5. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(11, 13, 17, 0.92);
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid rgba(232, 75, 34, 0.3);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.35);
}

.site-header::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--flame) 0%, var(--gold) 30%, var(--gold) 70%, var(--flame) 100%);
  opacity: 0.9;
}

.site-header::after {
  content: "";
  position: absolute;
  top: 2px;
  left: 0;
  width: 100%;
  height: 26px;
  background: linear-gradient(180deg, rgba(232, 75, 34, 0.08), transparent);
  pointer-events: none;
}

.header-shell {
  display: flex;
  align-items: center;
  gap: 14px;
  min-height: var(--header-h);
  position: relative;
}

.skip-link {
  position: absolute;
  top: -100%;
  left: 16px;
  z-index: 999;
  padding: 10px 20px;
  background: var(--flame);
  color: #fff;
  font-weight: 700;
  font-size: 14px;
  letter-spacing: 0.06em;
  border-radius: 0 0 8px 8px;
  transition: top 200ms var(--ease);
}

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

.brand-lockup {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  margin-right: auto;
  padding: 8px 0;
  flex-shrink: 0;
}

.brand-lockup:hover .brand-mark {
  filter: drop-shadow(0 0 14px rgba(232, 75, 34, 0.7));
}

.brand-mark {
  position: relative;
  flex-shrink: 0;
  display: block;
  width: 28px;
  height: 36px;
  background: linear-gradient(180deg, var(--gold) 0%, var(--flame) 56%, var(--ember) 100%);
  border-radius: 50% 50% 48% 48% / 62% 62% 38% 38%;
  transform: rotate(-6deg);
  box-shadow: 0 0 14px rgba(232, 75, 34, 0.45);
  transition: filter var(--transition);
}

.brand-mark::before {
  content: "";
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.35);
  filter: blur(2px);
}

.brand-name {
  font-family: var(--font-heading);
  font-size: 20px;
  font-weight: 900;
  color: var(--warm-white);
  letter-spacing: 0.08em;
  line-height: 1.2;
  white-space: nowrap;
}

/* ---------- 6. 导航 ---------- */
.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 10px;
  background: transparent;
  border: 1px solid rgba(160, 164, 176, 0.25);
  border-radius: 6px;
  cursor: pointer;
  transition: border-color var(--transition), background var(--transition);
}

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

.nav-toggle__bar {
  display: block;
  width: 100%;
  height: 2px;
  border-radius: 2px;
  background: var(--bone);
  transition: transform 300ms var(--ease), opacity 200ms var(--ease);
}

.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);
}

.site-nav {
  position: absolute;
  top: 100%;
  left: 0;
  right: 0;
  background: rgba(11, 13, 17, 0.98);
  border-bottom: 1px solid rgba(232, 75, 34, 0.4);
  max-height: 0;
  overflow: hidden;
  visibility: hidden;
  opacity: 0;
  transition: max-height 400ms var(--ease), opacity 300ms var(--ease), visibility 0s linear 400ms;
}

.site-nav[data-open] {
  max-height: min(480px, calc(100vh - var(--header-h)));
  overflow-y: auto;
  visibility: visible;
  opacity: 1;
  transition: max-height 400ms var(--ease), opacity 300ms var(--ease), visibility 0s;
}

.nav-list {
  display: flex;
  flex-direction: column;
  padding: 12px 24px 20px;
}

.nav-list__link {
  display: block;
  position: relative;
  padding: 13px 4px;
  color: var(--bone);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.04em;
  border-bottom: 1px solid rgba(160, 164, 176, 0.1);
  transition: color var(--transition);
}

.nav-list__link:hover {
  color: var(--flame);
}

.nav-list__link::after {
  content: "";
  position: absolute;
  left: 4px;
  bottom: 0;
  width: 28px;
  height: 2px;
  background: linear-gradient(90deg, var(--flame), var(--gold));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 300ms var(--ease);
}

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

.nav-list__link[aria-current="page"] {
  color: var(--flame);
  font-weight: 700;
}

@media (min-width: 901px) {
  .nav-toggle {
    display: none;
  }

  .site-nav {
    position: static;
    margin-left: auto;
    max-height: none;
    overflow: visible;
    visibility: visible;
    opacity: 1;
    background: none;
    border-bottom: none;
    transition: none;
  }

  .nav-list {
    flex-direction: row;
    align-items: center;
    gap: 2px;
    padding: 0;
  }

  .nav-list__link {
    padding: 10px 14px;
    border-bottom: none;
  }

  .nav-list__link::after {
    left: 14px;
    right: 14px;
    width: auto;
  }
}

/* ---------- 7. CTA 与按钮 ---------- */
.cta-btn {
  position: relative;
  z-index: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  flex-shrink: 0;
  padding: 12px 26px 12px 30px;
  color: #fff;
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.08em;
  border-radius: 3px;
  text-decoration: none;
  transition: transform var(--transition), box-shadow var(--transition);
}

.cta-btn::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background: linear-gradient(120deg, var(--flame) 0%, var(--ember) 100%);
  clip-path: polygon(10px 0, calc(100% - 10px) 0, 100% 50%, calc(100% - 10px) 100%, 10px 100%, 0 50%);
  box-shadow: 0 4px 18px rgba(232, 75, 34, 0.35);
  transition: filter var(--transition), box-shadow var(--transition);
}

.cta-btn:hover {
  transform: translateY(-2px);
}

.cta-btn:hover::before {
  filter: brightness(1.08);
  box-shadow: 0 8px 28px rgba(232, 75, 34, 0.5);
}

.cta-btn:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 4px;
}

.cta-btn__arrow {
  font-size: 18px;
  line-height: 1;
  transition: transform var(--transition);
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  min-height: 46px;
  padding: 10px 24px;
  border: 2px solid transparent;
  border-radius: 4px;
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-decoration: none;
  cursor: pointer;
  transition: transform var(--transition), background var(--transition), border-color var(--transition), box-shadow var(--transition), color var(--transition);
}

.btn--primary {
  background: linear-gradient(120deg, var(--flame), var(--ember));
  color: #fff;
  box-shadow: 0 4px 16px rgba(232, 75, 34, 0.35);
}

.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(232, 75, 34, 0.5);
}

.btn--outline {
  border-color: rgba(232, 75, 34, 0.55);
  color: var(--flame);
  background: transparent;
}

.btn--outline:hover {
  background: var(--red-glow);
  border-color: var(--flame);
}

.btn--light {
  background: var(--warm-white);
  color: var(--obsidian);
}

.btn--light:hover {
  background: #fff;
  transform: translateY(-2px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
}

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: 80px;
  background: var(--obsidian);
  border-top: 1px solid rgba(232, 75, 34, 0.25);
}

.site-footer::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, transparent 0%, var(--flame) 25%, var(--gold) 50%, var(--flame) 75%, transparent 100%);
  opacity: 0.7;
}

.site-footer::after {
  content: "";
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 720px;
  height: 280px;
  background: radial-gradient(closest-side, rgba(232, 75, 34, 0.1), transparent);
  pointer-events: none;
}

.footer-shell {
  position: relative;
  padding-block: 56px 40px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr 1.2fr;
  gap: 48px;
}

@media (max-width: 900px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 34px;
  }

  .site-footer {
    margin-top: 56px;
  }
}

.footer-brand {
  max-width: 42ch;
}

.footer-logo {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 16px;
  text-decoration: none;
}

.footer-logo__mark {
  display: block;
  width: 22px;
  height: 28px;
  background: linear-gradient(180deg, var(--gold), var(--flame));
  border-radius: 50% 50% 48% 48% / 62% 62% 38% 38%;
  box-shadow: 0 0 10px rgba(232, 75, 34, 0.4);
}

.footer-logo__text {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 900;
  color: var(--warm-white);
  letter-spacing: 0.06em;
}

.footer-slogan {
  font-family: var(--font-heading);
  font-size: 24px;
  font-weight: 800;
  letter-spacing: 0.1em;
  color: var(--gold);
  margin-bottom: 12px;
}

.footer-trust {
  font-size: 14px;
  line-height: 1.8;
  color: var(--silver);
}

.footer-nav {
  display: flex;
  flex-direction: column;
}

.footer-title {
  position: relative;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--gold);
  padding-bottom: 10px;
  margin-bottom: 18px;
}

.footer-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 28px;
  height: 2px;
  background: var(--flame);
  transform: skewX(-30deg);
}

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

.footer-links a {
  display: inline-block;
  color: var(--silver);
  font-size: 15px;
  transition: color var(--transition), padding-left var(--transition);
}

.footer-links a:hover {
  color: var(--flame);
  padding-left: 6px;
}

.footer-contact__line {
  font-size: 14px;
  line-height: 1.8;
  color: var(--silver);
  margin-bottom: 6px;
}

.footer-contact__note {
  font-size: 13px;
  color: var(--gold);
  margin-top: 12px;
  letter-spacing: 0.03em;
}

.footer-bottom {
  position: relative;
  background: rgba(0, 0, 0, 0.35);
  border-top: 1px solid rgba(160, 164, 176, 0.1);
  padding: 16px 0;
}

.footer-bottom__inner {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 8px 24px;
}

.footer-copy,
.footer-icp {
  font-size: 13px;
  color: var(--silver);
}

/* ---------- 9. 通用组件 ---------- */
.section-label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-heading);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--gold);
}

.section-label::before {
  content: "";
  width: 22px;
  height: 2px;
  background: var(--flame);
  transform: skewX(-32deg);
}

.section-label--light {
  color: var(--ember);
}

.breadcrumbs {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  row-gap: 6px;
  margin-bottom: 20px;
  font-size: 14px;
  color: var(--silver);
}

.breadcrumbs a {
  color: var(--silver);
  text-decoration: none;
  transition: color var(--transition);
}

.breadcrumbs a:hover {
  color: var(--flame);
}

.breadcrumbs [aria-current="page"] {
  color: var(--warm-white);
}

.breadcrumbs__sep {
  margin: 0 8px;
  color: var(--ember);
  font-family: var(--font-mono);
}

.card {
  background: var(--charcoal);
  border: 1px solid rgba(160, 164, 176, 0.1);
  border-radius: var(--radius);
  padding: 28px;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(232, 75, 34, 0.35);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.3);
}

.card__title {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 800;
  color: var(--warm-white);
  margin-bottom: 10px;
}

.card__text {
  font-size: 15px;
  color: var(--silver);
}

.tag {
  display: inline-flex;
  align-items: center;
  padding: 3px 12px;
  background: var(--red-glow);
  border: 1px solid rgba(232, 75, 34, 0.3);
  border-radius: 999px;
  color: var(--flame);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.tag--gold {
  background: rgba(201, 165, 92, 0.1);
  border-color: rgba(201, 165, 92, 0.35);
  color: var(--gold);
}

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 2px;
  border-bottom: 2px solid rgba(160, 164, 176, 0.18);
}

.tab {
  position: relative;
  padding: 12px 20px;
  background: none;
  border: none;
  color: var(--silver);
  font-family: var(--font-heading);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: color var(--transition);
}

.tab::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 2px;
  background: linear-gradient(90deg, var(--flame), var(--gold));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 300ms var(--ease);
}

.tab:hover {
  color: var(--warm-white);
}

.tab[aria-selected="true"] {
  color: var(--flame);
}

.tab[aria-selected="true"]::after {
  transform: scaleX(1);
}

.tab-panel {
  padding: 28px 0 8px;
}

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

.timeline {
  position: relative;
  padding-left: 30px;
}

.timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 4px;
  bottom: 4px;
  width: 2px;
  background: linear-gradient(180deg, var(--flame), var(--gold));
  opacity: 0.6;
}

.timeline__item {
  position: relative;
  margin-bottom: 24px;
}

.timeline__item::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--obsidian);
  border: 2px solid var(--flame);
  box-shadow: 0 0 0 3px rgba(232, 75, 34, 0.2);
}

.timeline__meta {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--gold);
}

.timeline__title {
  font-family: var(--font-heading);
  font-size: 18px;
  font-weight: 800;
  color: var(--warm-white);
  margin: 4px 0 6px;
}

.timeline__text {
  font-size: 15px;
  color: var(--silver);
}

.prose {
  max-width: 72ch;
}

.prose h2 {
  font-family: var(--font-heading);
  font-size: 24px;
  font-weight: 800;
  color: var(--warm-white);
  margin: 40px 0 14px;
}

.prose h3 {
  font-family: var(--font-heading);
  font-size: 19px;
  font-weight: 700;
  color: var(--warm-white);
  margin: 28px 0 10px;
}

.prose p {
  margin-bottom: 16px;
  color: var(--bone);
}

.prose a {
  color: var(--flame);
  text-decoration: underline;
  text-underline-offset: 4px;
}

.prose a:hover {
  color: var(--ember);
}

.prose ul,
.prose ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.prose ul li {
  list-style: square;
  margin-bottom: 8px;
  color: var(--bone);
}

.prose ol li {
  list-style: decimal;
  margin-bottom: 8px;
  color: var(--bone);
}

.prose blockquote {
  margin: 24px 0;
  padding: 12px 20px;
  border-left: 3px solid var(--flame);
  background: var(--red-glow);
  color: var(--silver);
  font-style: italic;
}

.prose strong {
  color: var(--warm-white);
  font-weight: 700;
}

.prose--light h2,
.prose--light h3,
.prose--light strong {
  color: var(--obsidian);
}

/* ---------- 10. 图片容器 ---------- */
.image-frame {
  position: relative;
  overflow: hidden;
  border-radius: 10px;
  background: var(--charcoal);
  width: 100%;
}

.image-frame::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: radial-gradient(closest-side at 70% 20%, rgba(232, 75, 34, 0.12), transparent 80%);
  pointer-events: none;
}

.image-frame--16-9 {
  aspect-ratio: 16 / 9;
}

.image-frame--4-3 {
  aspect-ratio: 4 / 3;
}

.image-frame--wide {
  aspect-ratio: 21 / 9;
}

.image-frame img,
.image-frame__placeholder {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: transform 520ms var(--ease);
}

.image-frame:hover img,
.image-frame:hover .image-frame__placeholder {
  transform: scale(1.04);
}

.image-frame__placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  background: linear-gradient(140deg, var(--charcoal), #11141B);
  color: var(--silver);
  font-size: 14px;
  letter-spacing: 0.14em;
  z-index: 0;
}

.figure {
  margin: 24px 0;
}

.figure__caption {
  font-size: 13px;
  color: var(--silver);
  margin-top: 8px;
}

/* ---------- 11. 索引与分隔 ---------- */
.index-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.index-list a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 12px;
  color: var(--silver);
  font-size: 15px;
  text-decoration: none;
  border-left: 2px solid transparent;
  transition: color var(--transition), border-color var(--transition), background var(--transition);
}

.index-list a:hover {
  color: var(--warm-white);
  border-left-color: var(--flame);
  background: var(--red-glow);
}

.index-list a[aria-current="page"] {
  color: var(--flame);
  border-left-color: var(--flame);
  font-weight: 600;
}

.index-list__num {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--gold);
  flex-shrink: 0;
}

.rule {
  height: 1px;
  border: none;
  margin: 32px 0;
  background: linear-gradient(90deg, var(--red-glow), rgba(232, 75, 34, 0.04), transparent);
}

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

/* ---------- 12. 动效组件 ---------- */
.scroll-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 100%;
  height: 3px;
  background: linear-gradient(90deg, var(--flame), var(--gold));
  transform: scaleX(0);
  transform-origin: 0 50%;
  z-index: 5;
  pointer-events: none;
}

.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 80;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border: none;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--flame), var(--ember));
  color: #fff;
  font-size: 20px;
  cursor: pointer;
  box-shadow: 0 6px 20px rgba(232, 75, 34, 0.45);
  opacity: 0;
  visibility: hidden;
  transform: translateY(16px);
  transition: opacity var(--transition), transform var(--transition), visibility var(--transition), filter var(--transition);
}

.back-to-top.is-visible {
  opacity: 1;
  visibility: visible;
  transform: none;
}

.back-to-top:hover {
  filter: brightness(1.1);
}

.back-to-top__icon {
  line-height: 1;
  transform: translateY(-1px);
}

[data-reveal] {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 700ms cubic-bezier(0.22, 1, 0.36, 1), transform 700ms cubic-bezier(0.22, 1, 0.36, 1);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

[data-reveal-delay="1"] {
  transition-delay: 100ms;
}

[data-reveal-delay="2"] {
  transition-delay: 200ms;
}

[data-reveal-delay="3"] {
  transition-delay: 300ms;
}

[data-reveal-delay="4"] {
  transition-delay: 400ms;
}

/* ---------- 13. 响应式微调 ---------- */
@media (max-width: 900px) {
  :root {
    --header-h: 64px;
  }

  .main-layout {
    padding-block: 32px 60px;
  }

  .section {
    padding-block: 44px;
  }

  .footer-shell {
    padding-block: 40px 32px;
  }
}

@media (max-width: 480px) {
  .header-shell {
    gap: 8px;
  }

  .brand-lockup {
    gap: 8px;
  }

  .brand-mark {
    width: 24px;
    height: 32px;
  }

  .brand-name {
    font-size: 16px;
    letter-spacing: 0.04em;
  }

  .nav-toggle {
    width: 40px;
    height: 40px;
    padding: 8px;
  }

  .cta-btn {
    padding: 9px 14px 9px 18px;
    font-size: 14px;
    gap: 6px;
  }

  .cta-btn__arrow {
    display: none;
  }

  .back-to-top {
    right: 16px;
    bottom: 16px;
    width: 42px;
    height: 42px;
  }
}

/* ---------- 14. 无障碍偏好 ---------- */
@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;
    transition-delay: 0ms !important;
  }

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

  .back-to-top {
    transition: none !important;
  }
}