/* ============================================================
   江南赛场 · 共享样式表 /assets/site.css
   水墨江南 × 数据赛场
   ============================================================ */

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

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

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

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

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

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

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

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

hr { border: 0; }

/* ---------- 2. 令牌 ---------- */
:root {
  /* 色 */
  --dai: #2E4A52;     /* 黛青 */
  --yue: #F5F7F6;     /* 月白 */
  --ou: #D9C7D6;      /* 藕荷 */
  --mo: #1A1F1E;      /* 墨色 */
  --qing: #8FA3A6;    /* 青灰 */
  --dan: #E3ECEA;     /* 淡青 */
  --zhu: #C13A2E;     /* 朱砂红 */
  --jin: #C9A96A;     /* 鎏金 */
  --xuan: #FDFCF8;    /* 宣纸白 */

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

  /* 尺寸 */
  --rail-w: 92px;
  --top-h: 72px;
  --maxw: 1180px;
  --gutter: clamp(20px, 4vw, 56px);
  --radius: 28px;
  --radius-sm: 20px;
  --radius-lg: 40px;

  /* 缓动 */
  --ease: cubic-bezier(.22, .61, .36, 1);
  --ease-soft: cubic-bezier(.4, .1, .2, 1);
}

/* ---------- 3. 基础排版 ---------- */
body {
  margin: 0;
  padding-left: var(--rail-w);
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.75;
  color: var(--mo);
  background-color: var(--yue);
  background-image:
    radial-gradient(900px 460px at 10% -6%, rgba(46, 74, 82, .085), transparent 66%),
    radial-gradient(720px 400px at 92% 3%, rgba(217, 199, 214, .30), transparent 68%),
    radial-gradient(640px 520px at 70% 98%, rgba(227, 236, 234, .55), transparent 70%);
  background-repeat: no-repeat;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: padding-left .32s var(--ease);
}

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  font-weight: 400;
  line-height: 1.22;
  letter-spacing: .012em;
  color: var(--dai);
}

h1 { font-size: clamp(2.5rem, 6vw, 5rem); font-weight: 300; }
h2 { font-size: clamp(1.7rem, 3.6vw, 2.6rem); font-weight: 300; }
h3 { font-size: clamp(1.15rem, 1.9vw, 1.42rem); }

strong { font-weight: 600; }

code, kbd, samp, .mono {
  font-family: var(--font-mono);
  font-size: .92em;
}

::selection { background: rgba(193, 58, 46, .18); color: var(--mo); }

/* ---------- 4. 可访问性 ---------- */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  white-space: nowrap;
  border: 0;
}

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

.skip-link {
  position: absolute;
  left: var(--rail-w);
  top: -120px;
  z-index: 300;
  padding: 12px 22px;
  background: var(--mo);
  color: var(--xuan);
  font-size: .84rem;
  letter-spacing: .12em;
  border-radius: 0 0 14px 0;
  transition: top .22s var(--ease);
}
.skip-link:focus { top: 0; }

/* ---------- 5. 顶栏 ---------- */
.topbar {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(245, 247, 246, .88);
  -webkit-backdrop-filter: saturate(1.4) blur(14px);
  backdrop-filter: saturate(1.4) blur(14px);
  border-bottom: 1px solid rgba(46, 74, 82, .10);
}

.topbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  max-width: 1440px;
  margin-inline: auto;
  min-height: var(--top-h);
  padding: 10px clamp(18px, 3.4vw, 44px);
}

.scroll-meter {
  position: absolute;
  left: 0; right: 0; bottom: -1px;
  height: 2px;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--zhu), var(--jin));
  pointer-events: none;
}

/* ---------- 6. 品牌 ---------- */
.brand {
  display: flex;
  align-items: center;
  gap: 14px;
  min-width: 0;
}

.brand__mark {
  flex: 0 0 auto;
  width: 42px; height: 42px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  background: var(--dai);
  color: var(--xuan);
  font-family: var(--font-serif);
  font-size: 1.06rem;
  line-height: 1;
  box-shadow: inset 0 0 0 1px rgba(201, 169, 106, .6),
              0 6px 18px rgba(46, 74, 82, .22);
  transition: background-color .28s var(--ease), box-shadow .28s var(--ease);
}
.brand:hover .brand__mark {
  background: #25404a;
  box-shadow: inset 0 0 0 1px rgba(201, 169, 106, .9),
              0 8px 22px rgba(46, 74, 82, .3);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  line-height: 1.24;
}

.brand__line {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(.94rem, 1.5vw, 1.08rem);
  letter-spacing: .03em;
  color: var(--dai);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.brand__tagline {
  font-size: .7rem;
  letter-spacing: .34em;
  color: var(--qing);
  white-space: nowrap;
}

/* ---------- 7. 顶栏辅助信息 ---------- */
.topbar__meta {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-left: auto;
}

.topbar__mail {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 8px 16px;
  border: 1px solid rgba(143, 163, 166, .48);
  border-radius: 999px;
  font-family: var(--font-mono);
  font-size: .76rem;
  letter-spacing: .03em;
  color: var(--dai);
  white-space: nowrap;
  transition: border-color .26s var(--ease), background-color .26s var(--ease);
}
.topbar__mail::before {
  content: "";
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--zhu);
  flex: 0 0 auto;
}
.topbar__mail:hover {
  border-color: var(--dai);
  background: rgba(46, 74, 82, .05);
}

/* ---------- 8. 移动菜单按钮 ---------- */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 10px 18px;
  border: 1px solid rgba(46, 74, 82, .28);
  border-radius: 999px;
  color: var(--dai);
  font-size: .82rem;
  letter-spacing: .16em;
  transition: border-color .26s var(--ease), background-color .26s var(--ease);
}
.nav-toggle:hover {
  border-color: var(--dai);
  background: rgba(46, 74, 82, .06);
}

.nav-toggle__bars {
  position: relative;
  display: block;
  width: 20px; height: 10px;
  flex: 0 0 auto;
}
.nav-toggle__bars::before,
.nav-toggle__bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 20px; height: 1.5px;
  background: currentColor;
  transition: transform .26s var(--ease);
}
.nav-toggle__bars::before { top: 0; }
.nav-toggle__bars::after { bottom: 0; }

.nav-toggle[aria-expanded="true"] .nav-toggle__bars::before {
  transform: translateY(4.25px) rotate(45deg);
}
.nav-toggle[aria-expanded="true"] .nav-toggle__bars::after {
  transform: translateY(-4.25px) rotate(-45deg);
}

.nav-toggle__text { line-height: 1; }

/* ---------- 9. 侧边轨道导航 ---------- */
.rail {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 90;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 22px 0 26px;
  background: var(--dai);
  color: var(--yue);
  overflow: hidden;
}

.rail::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(26, 31, 30, .38), transparent 34%),
    radial-gradient(150px 340px at 50% 0%, rgba(201, 169, 106, .20), transparent 72%),
    radial-gradient(120px 260px at 50% 100%, rgba(217, 199, 214, .14), transparent 74%);
}

.rail::after {
  content: "";
  position: absolute;
  top: 0; bottom: 0; right: 0;
  width: 1px;
  background: linear-gradient(180deg, transparent, rgba(201, 169, 106, .45), transparent);
  pointer-events: none;
}

.rail__hint {
  display: none;
  align-self: stretch;
  font-size: .72rem;
  letter-spacing: .16em;
  color: rgba(245, 247, 246, .55);
}

.rail__list {
  position: relative;
  z-index: 1;
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
  padding-block: 6px;
  overflow-y: auto;
  overflow-x: hidden;
  scrollbar-width: none;
}
.rail__list::-webkit-scrollbar { display: none; }

.rail__item { display: flex; }

.rail__link {
  position: relative;
  display: block;
  padding: 15px 12px;
  border-radius: 999px;
  writing-mode: vertical-rl;
  text-orientation: upright;
  font-size: .78rem;
  line-height: 1;
  letter-spacing: .24em;
  color: rgba(245, 247, 246, .64);
  transition: color .26s var(--ease), background-color .26s var(--ease);
}

.rail__link:hover {
  color: var(--xuan);
  background: rgba(245, 247, 246, .09);
}

.rail__link[aria-current="page"] {
  color: var(--xuan);
  background: rgba(245, 247, 246, .11);
}

.rail__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 50%; bottom: 3px;
  width: 5px; height: 5px;
  margin-left: -2.5px;
  border-radius: 50%;
  background: var(--zhu);
  box-shadow: 0 0 0 4px rgba(193, 58, 46, .18);
}

.rail__foot {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
}

.rail__pulse {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--jin);
  animation: rail-pulse 3s var(--ease) infinite;
}

@keyframes rail-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(201, 169, 106, .55); }
  50%      { box-shadow: 0 0 0 7px rgba(201, 169, 106, 0); }
}

.rail__foot-text {
  writing-mode: vertical-rl;
  text-orientation: upright;
  font-size: .62rem;
  letter-spacing: .3em;
  line-height: 1;
  color: rgba(245, 247, 246, .48);
}

/* ---------- 10. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(64px, 10vw, 140px);
  padding: clamp(52px, 7vw, 96px) 0 34px;
  background: var(--dai);
  color: rgba(245, 247, 246, .8);
  overflow: hidden;
}

.site-footer::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(680px 340px at 84% -12%, rgba(201, 169, 106, .16), transparent 70%),
    radial-gradient(560px 300px at 6% 112%, rgba(217, 199, 214, .14), transparent 72%),
    linear-gradient(180deg, rgba(26, 31, 30, .28), transparent 42%);
}

.site-footer::after {
  content: "";
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(201, 169, 106, .7), transparent);
}

.footer__inner {
  position: relative;
  z-index: 1;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.footer__lead {
  display: grid;
  gap: 14px;
  max-width: 660px;
}

.footer__eyebrow {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .26em;
  color: var(--jin);
}

.footer__title {
  font-family: var(--font-serif);
  font-weight: 300;
  font-size: clamp(2.1rem, 5.4vw, 3.6rem);
  line-height: 1.12;
  letter-spacing: .06em;
  color: var(--xuan);
}

.footer__sub {
  font-size: .92rem;
  line-height: 1.85;
  color: rgba(245, 247, 246, .64);
  max-width: 52ch;
}

.footer__grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr 0.85fr;
  gap: clamp(30px, 5vw, 72px);
  margin-top: clamp(38px, 6vw, 72px);
  padding-top: clamp(28px, 4vw, 46px);
  border-top: 1px solid rgba(245, 247, 246, .14);
}

.footer__col-title {
  font-family: var(--font-sans);
  font-size: .72rem;
  font-weight: 400;
  letter-spacing: .32em;
  color: var(--jin);
  margin-bottom: 16px;
}

.footer__list {
  display: grid;
  gap: 9px;
}

.footer__link {
  position: relative;
  display: inline-block;
  padding-bottom: 2px;
  font-size: .9rem;
  color: rgba(245, 247, 246, .74);
  transition: color .24s var(--ease);
}
.footer__link::after {
  content: "";
  position: absolute;
  left: 0; bottom: 0;
  width: 100%; height: 1px;
  background: currentColor;
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform .3s var(--ease);
}
.footer__link:hover { color: var(--xuan); }
.footer__link:hover::after { transform: scaleX(1); }

.footer__contact {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .82rem;
  line-height: 1.8;
  color: rgba(245, 247, 246, .78);
  word-break: break-word;
}

.footer__contact--addr {
  font-family: var(--font-sans);
  font-size: .88rem;
  line-height: 1.8;
  color: rgba(245, 247, 246, .66);
  max-width: 30ch;
  word-break: normal;
}

.footer__base {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px 28px;
  margin-top: clamp(30px, 5vw, 56px);
  padding-top: 22px;
  border-top: 1px solid rgba(245, 247, 246, .12);
  font-size: .76rem;
  color: rgba(245, 247, 246, .52);
}

.footer__copy { letter-spacing: .04em; }

.footer__icp {
  font-family: var(--font-mono);
  letter-spacing: .04em;
}

.footer__note {
  flex: 1 1 320px;
  text-align: right;
  line-height: 1.75;
}

/* ---------- 11. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 14px 28px;
  border: 1px solid transparent;
  border-radius: 999px;
  font-family: var(--font-sans);
  font-size: .9rem;
  letter-spacing: .1em;
  line-height: 1.2;
  cursor: pointer;
  transition: background-color .26s var(--ease),
              border-color .26s var(--ease),
              color .26s var(--ease),
              transform .26s var(--ease),
              box-shadow .26s var(--ease);
}
.btn:hover { transform: translateY(-2px); }
.btn:active { transform: translateY(0); }

.btn--primary {
  background: var(--zhu);
  color: var(--xuan);
  box-shadow: 0 8px 20px rgba(193, 58, 46, .22);
}
.btn--primary:hover {
  background: #a92f24;
  box-shadow: 0 10px 24px rgba(193, 58, 46, .3);
}

.btn--ghost {
  border-color: rgba(46, 74, 82, .32);
  color: var(--dai);
}
.btn--ghost:hover {
  border-color: var(--dai);
  background: rgba(46, 74, 82, .06);
}

.btn--gold {
  background: var(--jin);
  color: #2b2417;
  box-shadow: 0 8px 20px rgba(201, 169, 106, .26);
}
.btn--gold:hover { background: #bd9b57; }

/* ---------- 12. 面包屑 ---------- */
.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: 20px;
  font-size: .76rem;
  letter-spacing: .1em;
  color: var(--qing);
}
.breadcrumb a {
  color: var(--qing);
  transition: color .22s var(--ease);
}
.breadcrumb a:hover { color: var(--zhu); }
.breadcrumb__sep { color: var(--ou); }
.breadcrumb [aria-current="page"] { color: var(--dai); }

/* ---------- 13. 正文容器 ---------- */
.prose {
  max-width: 68ch;
  font-size: 1rem;
  line-height: 1.9;
  color: #33403f;
}
.prose > * + * { margin-top: 1.05em; }
.prose h2 {
  font-family: var(--font-serif);
  font-weight: 400;
  font-size: clamp(1.5rem, 3vw, 2.05rem);
  line-height: 1.3;
  color: var(--dai);
  margin-top: 2.2em;
}
.prose h3 {
  font-family: var(--font-serif);
  font-weight: 400;
  font-size: clamp(1.12rem, 1.9vw, 1.34rem);
  color: var(--dai);
  margin-top: 1.8em;
}
.prose ul,
.prose ol {
  display: grid;
  gap: .55em;
}
.prose li {
  position: relative;
  padding-left: 1.15em;
}
.prose li::before {
  content: "";
  position: absolute;
  left: 0; top: .8em;
  width: 5px; height: 5px;
  border-radius: 50%;
  background: var(--ou);
}
.prose strong { color: var(--dai); font-weight: 600; }
.prose a {
  color: var(--zhu);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: color .22s var(--ease);
}
.prose a:hover { color: var(--dai); }
.prose blockquote {
  padding-left: 22px;
  border-left: 2px solid var(--ou);
  font-family: var(--font-serif);
  color: var(--dai);
}

/* ---------- 14. 布局工具 ---------- */
.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(48px, 7vw, 96px); }
.section--tight { padding-block: clamp(28px, 4vw, 52px); }

.section__head {
  display: grid;
  gap: 12px;
  max-width: 66ch;
  margin-bottom: clamp(24px, 3.4vw, 46px);
}

.section__title {
  font-family: var(--font-serif);
  font-weight: 300;
  font-size: clamp(1.7rem, 3.6vw, 2.6rem);
  line-height: 1.2;
  letter-spacing: .02em;
  color: var(--dai);
}

.section__note {
  font-size: .92rem;
  line-height: 1.8;
  color: var(--qing);
  max-width: 54ch;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .26em;
  text-transform: uppercase;
  color: var(--zhu);
}
.eyebrow::before {
  content: "";
  display: inline-block;
  width: 22px; height: 1px;
  background: currentColor;
}

.rule {
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, rgba(46, 74, 82, .26), rgba(46, 74, 82, 0));
}

/* ---------- 15. 网格 ---------- */
.grid {
  display: grid;
  gap: clamp(18px, 2.4vw, 28px);
  grid-template-columns: repeat(auto-fit, minmax(min(260px, 100%), 1fr));
}
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }

/* ---------- 16. 标签 / 数据 / 状态 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 13px;
  border: 1px solid rgba(46, 74, 82, .12);
  border-radius: 999px;
  background: var(--dan);
  color: var(--dai);
  font-size: .72rem;
  letter-spacing: .14em;
  line-height: 1.7;
  transition: border-color .24s var(--ease), background-color .24s var(--ease);
}
.tag--hot {
  background: rgba(193, 58, 46, .1);
  border-color: rgba(193, 58, 46, .24);
  color: var(--zhu);
}
.tag--gold {
  background: rgba(201, 169, 106, .16);
  border-color: rgba(201, 169, 106, .38);
  color: #8a6f34;
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.stat__value {
  font-family: var(--font-mono);
  font-size: clamp(1.25rem, 2.4vw, 1.75rem);
  font-weight: 400;
  line-height: 1.3;
  letter-spacing: -.01em;
  color: var(--dai);
}
.stat__label {
  font-size: .72rem;
  letter-spacing: .2em;
  color: var(--qing);
}

.status-dot {
  display: inline-block;
  flex: 0 0 auto;
  width: 7px; height: 7px;
  border-radius: 50%;
  background: var(--zhu);
}

/* ---------- 17. 图像容器 ---------- */
.media-frame {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius);
  background-image: linear-gradient(140deg, var(--dan) 0%, var(--ou) 100%);
  background-color: var(--dan);
  isolation: isolate;
}
.media-frame img,
.media-frame > picture > img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(180deg, rgba(46, 74, 82, .07), rgba(26, 31, 30, .22));
}
.media-frame--wide { aspect-ratio: 16 / 9; }
.media-frame--tall { aspect-ratio: 3 / 4; }
.media-frame--square { aspect-ratio: 1 / 1; }
.media-frame--panel { aspect-ratio: 4 / 3; }
.media-frame--inset { border-radius: var(--radius-sm); }
.media-frame--flat::after { display: none; }

.media-caption {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  font-size: .74rem;
  letter-spacing: .1em;
  color: var(--qing);
}
.media-caption::before {
  content: "";
  display: block;
  width: 16px; height: 1px;
  background: var(--ou);
}

/* ---------- 18. 手风琴 ---------- */
.accordion {
  border-top: 1px solid rgba(46, 74, 82, .14);
}
.accordion__item {
  border-bottom: 1px solid rgba(46, 74, 82, .14);
}
.accordion__trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 20px 4px;
  text-align: left;
  font-family: var(--font-serif);
  font-size: clamp(1rem, 1.6vw, 1.16rem);
  font-weight: 400;
  line-height: 1.5;
  color: var(--dai);
  transition: color .22s var(--ease);
}
.accordion__trigger:hover { color: var(--zhu); }

.accordion__sign {
  position: relative;
  flex: 0 0 auto;
  width: 14px; height: 14px;
}
.accordion__sign::before,
.accordion__sign::after {
  content: "";
  position: absolute;
  background: currentColor;
  transition: transform .2s var(--ease), opacity .2s var(--ease);
}
.accordion__sign::before {
  left: 0; top: 6.25px;
  width: 14px; height: 1.5px;
}
.accordion__sign::after {
  left: 6.25px; top: 0;
  width: 1.5px; height: 14px;
}
.accordion__trigger[aria-expanded="true"] .accordion__sign::after {
  transform: scaleY(0);
  opacity: 0;
}

.accordion__panel {
  max-height: 0;
  overflow: hidden;
  transition: max-height .2s var(--ease);
}
.accordion__panel[data-open] { max-height: 42rem; }
.accordion__panel > div {
  padding: 0 4px 22px;
  font-size: .94rem;
  line-height: 1.85;
  color: #4a5755;
}

/* ---------- 19. 响应式 ---------- */
@media (max-width: 1180px) {
  .footer__grid { grid-template-columns: 1.2fr 1fr 0.8fr; }
}

@media (max-width: 1023px) {
  :root { --rail-w: 0px; --top-h: 66px; }

  .topbar__mail { display: none; }
  .nav-toggle { display: inline-flex; }

  .brand__tagline { display: none; }

  .skip-link { left: 0; }

  .rail {
    width: min(80vw, 320px);
    align-items: stretch;
    gap: 12px;
    padding: 24px 0 26px;
    transform: translateX(-102%);
    transition: transform .32s var(--ease);
    box-shadow: 26px 0 64px rgba(26, 31, 30, .3);
    overflow-y: auto;
  }
  .rail[data-open] { transform: translateX(0); }

  .rail__hint {
    display: block;
    order: -1;
    padding: 0 26px 14px;
    border-bottom: 1px solid rgba(245, 247, 246, .14);
  }

  .rail__list {
    flex: 0 0 auto;
    align-items: stretch;
    gap: 4px;
    padding: 0 20px;
    overflow: visible;
  }

  .rail__item { display: block; }

  .rail__link {
    display: flex;
    align-items: center;
    padding: 14px 18px;
    border-radius: 14px;
    writing-mode: horizontal-tb;
    text-orientation: mixed;
    font-size: .96rem;
    letter-spacing: .14em;
    line-height: 1.4;
  }

  .rail__link[aria-current="page"] {
    background: rgba(245, 247, 246, .12);
    box-shadow: inset 3px 0 0 0 var(--zhu);
  }
  .rail__link[aria-current="page"]::after { display: none; }

  .rail__foot {
    margin-top: auto;
    padding: 18px 26px 0;
    flex-direction: row;
    align-items: center;
    justify-content: flex-start;
    gap: 10px;
    border-top: 1px solid rgba(245, 247, 246, .14);
    margin-inline: 20px;
  }
  .rail__foot-text {
    writing-mode: horizontal-tb;
    text-orientation: mixed;
    letter-spacing: .2em;
  }

  .grid--3,
  .grid--4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 860px) {
  .footer__grid { grid-template-columns: 1fr 1fr; }
  .footer__col:first-child { grid-column: 1 / -1; }
}

@media (max-width: 640px) {
  body { line-height: 1.72; }

  .topbar__inner { gap: 12px; padding-inline: 18px; }

  .brand__mark { width: 36px; height: 36px; font-size: .94rem; }
  .brand__line { font-size: .88rem; max-width: 46vw; }

  .nav-toggle { padding: 9px 14px; gap: 8px; }
  .nav-toggle__text { display: none; }

  .footer__grid { grid-template-columns: 1fr; gap: 30px; }
  .footer__base { flex-direction: column; align-items: flex-start; gap: 8px; }
  .footer__note { text-align: left; flex: 1 1 auto; }

  .grid--2,
  .grid--3,
  .grid--4 { grid-template-columns: 1fr; }

  .media-frame { border-radius: var(--radius-sm); }
}

@media (max-width: 400px) {
  .brand__line { font-size: .82rem; max-width: 42vw; }
}

/* ---------- 20. 降低动效 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *,
  *::before,
  *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
  .btn:hover { transform: none; }
  .rail__pulse { animation: none; }
}