/* ==========================================================================
   新利看台 · /assets/site.css
   共享外壳：reset / 变量 / 中文排版 / 页头 / 页脚 / 按钮 / 网格 / 基础组件
   ========================================================================== */

/* ---------- 1. Reset ---------- */
*,
*::before,
*::after { box-sizing: border-box; }

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

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

ul, ol { padding: 0; list-style: none; }

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

button { font: inherit; color: inherit; background: none; border: 0; padding: 0; cursor: pointer; }

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

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

/* ---------- 2. 变量 ---------- */
:root {
  --ink: #0A1F1A;
  --ink-deep: #071411;
  --moss: #1E4D3E;
  --slate: #2E3A36;
  --paper: #F2EFE6;
  --paper-dim: #DFD9C9;
  --cyan: #29E0C2;
  --cyan-deep: #12A38D;
  --amber: #EBA83C;
  --clay: #B0603F;

  --tone-epl: #8F2E3C;
  --tone-laliga: #EBA83C;
  --tone-seriea: #27528C;
  --tone-bundesliga: #4C7A3F;
  --tone-ligue1: #4A6E75;

  --glass: rgba(242, 239, 230, 0.08);
  --line: rgba(242, 239, 230, 0.14);
  --line-strong: rgba(242, 239, 230, 0.28);
  --text: rgba(242, 239, 230, 0.78);
  --text-dim: rgba(242, 239, 230, 0.56);

  --font-sans: "Source Han Sans SC", "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", system-ui, sans-serif;
  --font-serif: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "SimSun", serif;
  --font-mono: "JetBrains Mono", "Roboto Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --shell: 1320px;
  --gutter: clamp(16px, 4vw, 40px);
  --radius: 12px;
  --radius-sm: 8px;
  --ease: cubic-bezier(0.2, 0.7, 0.3, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background: var(--ink);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  letter-spacing: 0.01em;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--cyan); color: #06231E; }

h1, h2, h3, h4 {
  font-family: var(--font-sans);
  font-weight: 900;
  color: var(--paper);
  line-height: 1.2;
  letter-spacing: 0.01em;
}

strong { color: var(--paper); font-weight: 700; }

main:focus { outline: none; }

/* ---------- 4. 布局壳 ---------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.grid { display: grid; gap: var(--grid-gap, 24px); }
.grid--12 { grid-template-columns: repeat(12, minmax(0, 1fr)); }
.grid--auto { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }

.span-3 { grid-column: span 3; }
.span-4 { grid-column: span 4; }
.span-6 { grid-column: span 6; }
.span-8 { grid-column: span 8; }
.span-9 { grid-column: span 9; }
.span-12 { grid-column: span 12; }

@media (max-width: 900px) {
  .span-3, .span-4 { grid-column: span 6; }
  .span-6, .span-8, .span-9 { grid-column: span 12; }
}

@media (max-width: 560px) {
  .span-3, .span-4, .span-6 { grid-column: span 12; }
}

/* ---------- 5. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 200;
  transform: translateY(-240%);
  background: var(--cyan);
  color: #06231E;
  font-weight: 700;
  font-size: 14px;
  padding: 12px 18px;
  border-radius: var(--radius-sm);
  transition: transform 0.18s var(--ease);
}

.skip-link:focus,
.skip-link:focus-visible { transform: translateY(0); }

/* ---------- 6. 页头 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: linear-gradient(180deg, rgba(10, 31, 26, 0.99) 0%, rgba(10, 31, 26, 0.94) 100%);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

/* 6.1 联赛赛程带 */
.league-strip {
  background: var(--moss);
  border-bottom: 1px solid rgba(7, 20, 17, 0.55);
}

.league-strip__inner {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 48px;
  overflow-x: auto;
  overflow-y: hidden;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

.league-strip__inner::-webkit-scrollbar { display: none; }

.league-strip__label {
  flex: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  color: var(--cyan);
  text-transform: uppercase;
}

.league-strip__list {
  display: flex;
  align-items: center;
  gap: 6px;
  flex: none;
}

.league-strip__meta {
  flex: none;
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--amber);
  white-space: nowrap;
}

.league-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 32px;
  padding: 4px 11px;
  border: 1px solid rgba(242, 239, 230, 0.18);
  border-radius: 999px;
  font-size: 13px;
  line-height: 1;
  white-space: nowrap;
  color: rgba(242, 239, 230, 0.72);
  transition: background 0.18s var(--ease), border-color 0.18s var(--ease), color 0.18s var(--ease);
}

.league-chip:hover {
  color: var(--paper);
  border-color: var(--line-strong);
  background: rgba(242, 239, 230, 0.06);
}

.league-chip[aria-pressed="true"] {
  color: var(--paper);
  border-color: var(--cyan);
  background: rgba(41, 224, 194, 0.14);
}

.league-chip__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--tone, var(--slate));
  box-shadow: 0 0 0 2px rgba(7, 20, 17, 0.55);
}

.league-chip__round {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.04em;
  color: var(--text-dim);
}

.league-chip[aria-pressed="true"] .league-chip__round { color: var(--cyan); }

/* 联赛识别色 */
.tone-epl { --tone: var(--tone-epl); }
.tone-laliga { --tone: var(--tone-laliga); }
.tone-seriea { --tone: var(--tone-seriea); }
.tone-bundesliga { --tone: var(--tone-bundesliga); }
.tone-ligue1 { --tone: var(--tone-ligue1); }

/* 6.2 报头 */
.masthead { position: relative; }

.masthead__inner {
  display: flex;
  align-items: center;
  gap: clamp(16px, 2vw, 32px);
  min-height: 74px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: none;
}

.brand__mark {
  width: 36px;
  height: 36px;
  flex: none;
  display: grid;
  place-items: center;
  border-radius: 5px;
  background: linear-gradient(160deg, var(--cyan) 0%, var(--cyan-deep) 100%);
  box-shadow: 0 0 0 1px rgba(7, 20, 17, 0.4);
}

.brand__mark span {
  width: 20px;
  height: 15px;
  background-image:
    linear-gradient(var(--ink-deep), var(--ink-deep)),
    linear-gradient(var(--ink-deep), var(--ink-deep)),
    linear-gradient(var(--ink-deep), var(--ink-deep));
  background-repeat: no-repeat;
  background-size: 100% 3px, 68% 3px, 100% 3px;
  background-position: 0 0, 0 50%, 0 100%;
}

.brand__text { display: flex; flex-direction: column; gap: 2px; }

.brand__name {
  font-family: var(--font-sans);
  font-weight: 900;
  font-size: 20px;
  letter-spacing: 0.08em;
  color: var(--paper);
  line-height: 1.1;
}

.brand__tagline {
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--text-dim);
  line-height: 1.1;
}

.masthead__actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: none;
  margin-left: auto;
}

/* 6.3 命令栏导航 */
.command-bar {
  display: flex;
  align-items: center;
  margin-left: auto;
}

.command-bar__list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.command-bar__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 10px 12px;
  border-radius: 6px;
  font-size: 14px;
  letter-spacing: 0.02em;
  color: rgba(242, 239, 230, 0.72);
  transition: color 0.18s var(--ease), background 0.18s var(--ease);
}

.command-bar__link:hover {
  color: var(--paper);
  background: rgba(242, 239, 230, 0.07);
}

.command-bar__index {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.06em;
  color: rgba(41, 224, 194, 0.62);
}

.command-bar__link[aria-current="page"] { color: var(--paper); }

.command-bar__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 12px;
  right: 12px;
  bottom: 4px;
  height: 2px;
  border-radius: 2px;
  background: var(--cyan);
}

.command-bar__link[aria-current="page"] .command-bar__index { color: var(--cyan); }

.command-bar__foot { display: none; }

.command-bar__note {
  font-size: 12px;
  line-height: 1.5;
  color: var(--text-dim);
  margin-bottom: 12px;
}

/* 6.4 移动端菜单按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  min-height: 44px;
  min-width: 44px;
  padding: 0 12px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  color: var(--paper);
  transition: border-color 0.18s var(--ease), color 0.18s var(--ease);
}

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

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: background 0.18s var(--ease);
}

.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 18px;
  height: 2px;
  background: currentColor;
  transition: transform 0.2s var(--ease);
}

.nav-toggle__bars::before { top: -6px; }
.nav-toggle__bars::after { top: 6px; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars { background: var(--cyan); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after { transform: translateY(-6px) rotate(-45deg); }

.nav-toggle__text {
  font-size: 13px;
  letter-spacing: 0.1em;
  line-height: 1;
}

/* 6.5 滚动进度 */
.scroll-progress {
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 2px;
  background: rgba(242, 239, 230, 0.1);
  pointer-events: none;
}

.scroll-progress__bar {
  display: block;
  height: 100%;
  transform-origin: 0 50%;
  transform: scaleX(var(--scroll-progress, 0));
  background: linear-gradient(90deg, var(--cyan) 0%, var(--amber) 100%);
}

/* 6.6 页头响应式 */
@media (max-width: 1200px) {
  .command-bar__link { padding: 10px 9px; font-size: 13px; }
  .masthead__inner { gap: 16px; }
}

@media (max-width: 1024px) {
  .masthead__inner { min-height: 62px; }

  .nav-toggle { display: inline-flex; }

  .command-bar {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: block;
    margin-left: 0;
    padding: 8px var(--gutter) 22px;
    background: rgba(8, 24, 20, 0.99);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 48px rgba(0, 0, 0, 0.45);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-8px);
    pointer-events: none;
    transition: opacity 0.2s var(--ease), transform 0.2s var(--ease), visibility 0.2s var(--ease);
  }

  .command-bar[data-open] {
    visibility: visible;
    opacity: 1;
    transform: none;
    pointer-events: auto;
  }

  .command-bar__list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .command-bar__link {
    min-height: 48px;
    padding: 12px 8px;
    border-radius: 0;
    border-bottom: 1px solid rgba(242, 239, 230, 0.08);
    font-size: 15px;
  }

  .command-bar__link[aria-current="page"]::after {
    left: 0;
    right: auto;
    top: 12px;
    bottom: 12px;
    width: 3px;
    height: auto;
  }

  .command-bar__foot {
    display: block;
    margin-top: 18px;
  }

  .league-strip__meta { display: none; }
}

@media (max-width: 640px) {
  .masthead__actions .btn--primary { display: none; }
  .brand__name { font-size: 18px; }
  .brand__tagline { font-size: 10px; letter-spacing: 0.12em; }
  .brand__mark { width: 32px; height: 32px; }
  .brand__mark span { width: 17px; height: 13px; }
  .league-chip { min-height: 44px; padding-inline: 12px; }
  .league-strip__inner { min-height: 58px; }
}

/* ---------- 7. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 0 18px;
  border: 1px solid transparent;
  border-radius: var(--radius-sm);
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1;
  text-align: center;
  transition: background 0.18s var(--ease), color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.btn--primary { background: var(--cyan); color: #06231E; }
.btn--primary:hover { background: #5CECD4; }

.btn--ghost {
  background: transparent;
  border-color: var(--line-strong);
  color: var(--paper);
}
.btn--ghost:hover { border-color: var(--cyan); color: var(--cyan); }

.btn--amber { background: var(--amber); color: #241503; }
.btn--amber:hover { background: #F3BC5E; }

.btn--clay {
  background: transparent;
  border-color: var(--clay);
  color: #DFA184;
}
.btn--clay:hover { background: rgba(176, 96, 63, 0.16); }

.btn--block { width: 100%; }

/* ---------- 8. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 8vw, 104px);
  background: linear-gradient(180deg, #081814 0%, var(--ink) 70%);
  border-top: 1px solid var(--line);
  color: var(--text);
}

.footer-beam {
  height: 4px;
  background:
    linear-gradient(90deg,
      var(--cyan) 0 16%,
      var(--amber) 16% 28%,
      rgba(242, 239, 230, 0.16) 28% 100%);
}

.footer__inner {
  display: grid;
  grid-template-columns: minmax(0, 1.05fr) minmax(0, 2fr);
  gap: clamp(28px, 4vw, 64px);
  padding-block: clamp(32px, 5vw, 56px) clamp(20px, 3vw, 36px);
}

.footer__brand { display: flex; flex-direction: column; align-items: flex-start; gap: 16px; }

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

.footer__pitch {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text-dim);
  max-width: 22em;
}

.footer__cta { margin-top: 4px; }

.footer__nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: clamp(16px, 3vw, 32px);
}

.footer__col { min-width: 0; }

.footer__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 14px;
}

.footer__list li + li { margin-top: 10px; }

.footer__list a {
  display: inline-block;
  font-size: 14px;
  line-height: 1.4;
  color: rgba(242, 239, 230, 0.76);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.footer__list a:hover {
  color: var(--paper);
  border-bottom-color: var(--cyan);
}

.footer__contact {
  display: grid;
  gap: 12px;
  margin-top: clamp(4px, 1vw, 12px);
  padding-top: clamp(20px, 3vw, 32px);
  border-top: 1px solid var(--line);
}

.footer__contact-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 10px 24px;
}

.footer__contact-list li { display: flex; flex-wrap: wrap; align-items: baseline; gap: 4px 10px; }

.footer__contact-key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan);
  flex: none;
}

.footer__contact-value {
  font-size: 14px;
  line-height: 1.5;
  color: rgba(242, 239, 230, 0.8);
  overflow-wrap: anywhere;
}

.footer__note {
  font-size: 12px;
  line-height: 1.6;
  color: var(--text-dim);
  max-width: 46em;
}

.footer__legend {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 20px;
  margin-top: clamp(20px, 3vw, 32px);
  padding-block: 20px 32px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  color: var(--text-dim);
}

.footer__spectrum {
  display: flex;
  gap: 3px;
  flex: 1 1 140px;
  max-width: 220px;
}

.footer__bar {
  flex: 1 1 0;
  height: 6px;
  border-radius: 2px;
  background: var(--tone, var(--slate));
}

.footer__legal {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--text-dim);
}

.footer__copyright {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--text-dim);
  margin-left: auto;
}

@media (max-width: 900px) {
  .footer__inner { grid-template-columns: minmax(0, 1fr); }
  .footer__copyright { margin-left: 0; }
}

@media (max-width: 700px) {
  .footer__nav { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

/* ---------- 9. 章节与内容层 ---------- */
.section { padding-block: clamp(32px, 5vw, 64px); }

.section__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 10px 20px;
  margin-bottom: clamp(16px, 2.5vw, 28px);
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--cyan);
}

.section__title {
  font-size: clamp(22px, 3vw, 32px);
  font-weight: 900;
  letter-spacing: 0.01em;
}

.lede {
  font-family: var(--font-serif);
  font-size: clamp(16px, 1.6vw, 20px);
  line-height: 1.7;
  color: inherit;
  opacity: 0.84;
  max-width: 34em;
}

.paper {
  background: var(--paper);
  color: #17251F;
  border-radius: var(--radius);
  padding: clamp(20px, 3vw, 40px);
  box-shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
}

.prose {
  max-width: 38em;
  font-size: 16px;
  line-height: 1.7;
  color: #1B2B25;
}

.prose > * + * { margin-top: 1em; }

.prose h2,
.prose h3 { color: #0A1F1A; }

.prose h2 { font-size: clamp(20px, 2.4vw, 26px); }

.prose h3 { font-size: clamp(17px, 2vw, 20px); }

.prose ul,
.prose ol { list-style: disc; padding-left: 1.3em; }

.prose ol { list-style: decimal; }

.prose li + li { margin-top: 0.4em; }

.prose a {
  color: #12796A;
  border-bottom: 1px solid rgba(18, 121, 106, 0.4);
}

.prose a:hover { border-bottom-color: #12796A; }

.prose code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: rgba(10, 31, 26, 0.08);
  padding: 1px 5px;
  border-radius: 4px;
}

/* ---------- 10. 数据与图形组件 ---------- */
.data-figure { display: flex; flex-direction: column; gap: 6px; }

.data-figure__value {
  font-family: var(--font-mono);
  font-weight: 700;
  font-size: clamp(36px, 6vw, 64px);
  line-height: 0.95;
  letter-spacing: -0.02em;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

.data-figure__unit {
  font-size: 0.38em;
  vertical-align: super;
  margin-left: 3px;
  color: var(--cyan);
  letter-spacing: 0;
}

.data-figure__label {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--text-dim);
}

.glass-panel {
  background: var(--glass);
  border: 1px solid rgba(242, 239, 230, 0.16);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  border-radius: var(--radius);
  padding: clamp(14px, 2vw, 22px);
}

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 26px;
  padding: 2px 10px;
  border: 1px solid rgba(176, 96, 63, 0.5);
  border-radius: 999px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: #DFA184;
  line-height: 1.2;
}

.figure-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background: var(--slate);
  aspect-ratio: 16 / 9;
}

.figure-frame--wide { aspect-ratio: 21 / 9; }
.figure-frame--portrait { aspect-ratio: 4 / 5; }

.figure-frame img,
.figure-frame picture,
.figure-frame svg {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.figure-frame__glass {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: clamp(12px, 2vw, 20px);
  background: linear-gradient(0deg, rgba(7, 20, 17, 0.92) 0%, rgba(7, 20, 17, 0) 100%);
  color: var(--paper);
}

.figure-frame__caption {
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: 0.02em;
  color: rgba(242, 239, 230, 0.8);
}

@media (max-width: 560px) {
  .figure-frame { aspect-ratio: 4 / 3; }
  .figure-frame--wide { aspect-ratio: 16 / 9; }
}

/* ---------- 11. 面包屑 ---------- */
.breadcrumb { padding-block: 16px 0; }

.breadcrumb__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--text-dim);
}

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

.breadcrumb__item + .breadcrumb__item::before {
  content: "/";
  color: rgba(242, 239, 230, 0.32);
}

.breadcrumb__link {
  color: var(--text-dim);
  border-bottom: 1px solid transparent;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease);
}

.breadcrumb__link:hover { color: var(--cyan); border-bottom-color: var(--cyan); }

/* ---------- 12. 显现与返回顶部 ---------- */
:root.has-reveal [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity 0.5s var(--ease), transform 0.5s var(--ease);
}

:root.has-reveal [data-reveal][data-reveal-in] {
  opacity: 1;
  transform: none;
}

.back-to-top {
  position: fixed;
  right: 16px;
  bottom: 16px;
  z-index: 70;
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--cyan);
  color: #06231E;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.45);
  transition: opacity 0.2s var(--ease), transform 0.2s var(--ease), visibility 0.2s var(--ease), background 0.18s var(--ease);
}

.back-to-top::before {
  content: "";
  width: 12px;
  height: 12px;
  border-left: 2px solid currentColor;
  border-top: 2px solid currentColor;
  transform: translateY(3px) rotate(45deg);
}

.back-to-top:hover { background: #5CECD4; }

.back-to-top[data-visible] {
  opacity: 1;
  visibility: visible;
  transform: none;
}

@media (min-width: 1024px) {
  .back-to-top { right: 28px; bottom: 28px; }
}

/* ---------- 13. 平滑滚动与减弱动效 ---------- */
@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

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

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  :root.has-reveal [data-reveal] {
    opacity: 1;
    transform: none;
  }

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