/* ============================================================
   K1赛事 · 共享样式表 /assets/site.css
   头部左侧竖向数据面板 / 顶部冷光青细线 / 页脚编辑部索引
   ============================================================ */

/* ---------- 01 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  background-color: #062B23;
}

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

ul, ol { list-style: none; }

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

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

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

table { border-collapse: collapse; width: 100%; }

[hidden] { display: none !important; }

/* ---------- 02 设计令牌 ---------- */
:root {
  --ink-900: #062B23;
  --ink-800: #0B4034;
  --ink-700: #10161A;
  --cyan-500: #12E0B0;
  --cyan-300: #6BFFD0;
  --orange-500: #FF5A1F;
  --gold-400: #FFC24D;
  --gray-500: #5C6B66;
  --mist: #E8EFEA;
  --white: #FFFFFF;

  --font-sans: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Hiragino Sans GB",
    "Microsoft YaHei", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, "SFMono-Regular",
    Menlo, Consolas, "Courier New", monospace;

  --rail-w: 236px;
  --rail-narrow: 96px;

  --ease: cubic-bezier(.2, .8, .2, 1);
  --line: rgba(107, 255, 208, .22);
  --line-soft: rgba(107, 255, 208, .14);
  --panel: rgba(255, 255, 255, .06);
  --panel-2: rgba(255, 255, 255, .10);
  --shell-max: 1280px;
  --gutter: clamp(18px, 3.4vw, 48px);
}

@media (max-width: 900px) {
  :root { --rail-w: 0px; }
}

@media (min-width: 901px) {
  html[data-rail="narrow"] { --rail-w: var(--rail-narrow); }
}

/* ---------- 03 基础排版 ---------- */
body {
  font-family: var(--font-sans);
  font-size: 17px;
  font-weight: 400;
  line-height: 1.85;
  color: var(--mist);
  background-color: var(--ink-900);
  background-image:
    linear-gradient(rgba(107, 255, 208, .045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(107, 255, 208, .045) 1px, transparent 1px),
    radial-gradient(1200px 620px at 78% -8%, rgba(18, 224, 176, .16), transparent 62%),
    radial-gradient(900px 520px at 6% 104%, rgba(255, 90, 31, .10), transparent 66%);
  background-size: 72px 72px, 72px 72px, auto, auto;
  background-attachment: fixed;
  min-height: 100vh;
  padding-left: var(--rail-w);
  overflow-x: hidden;
  transition: padding-left .42s var(--ease);
}

::selection { background: var(--cyan-500); color: #04241D; }

#main-content { display: block; }

p { text-wrap: pretty; }

.t-display {
  font-size: clamp(2.6rem, 6.4vw, 4rem);
  line-height: 1.04;
  font-weight: 900;
  letter-spacing: -.02em;
  color: var(--white);
}

.t-h1 {
  font-size: clamp(2rem, 4.4vw, 3rem);
  line-height: 1.12;
  font-weight: 800;
  letter-spacing: -.02em;
  color: var(--white);
}

.t-h2 {
  font-size: clamp(1.5rem, 3vw, 2.125rem);
  line-height: 1.2;
  font-weight: 800;
  letter-spacing: -.02em;
  color: var(--white);
}

.t-h3 {
  font-size: clamp(1.15rem, 2.2vw, 1.6rem);
  line-height: 1.32;
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--white);
}

.t-lead {
  font-size: clamp(1.02rem, 1.6vw, 1.18rem);
  line-height: 1.8;
  color: var(--mist);
}

.t-body {
  font-size: 17px;
  line-height: 1.85;
  color: rgba(232, 239, 234, .86);
  max-width: 38em;
}

.t-mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  letter-spacing: .02em;
}

.t-label {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--gray-500);
}

.t-note {
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.7;
  letter-spacing: .02em;
  color: var(--gray-500);
}

.t-accent { color: var(--cyan-500); }
.t-data { color: var(--orange-500); }
.text-gold { color: var(--gold-400); }

.u-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;
}

/* ---------- 04 布局工具 ---------- */
.container {
  width: 100%;
  max-width: var(--shell-max);
  margin-inline: auto;
  padding-inline: var(--gutter);
}

.section { padding-block: clamp(44px, 6vw, 88px); }
.section--tight { padding-block: clamp(26px, 4vw, 52px); }

.section__head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 14px 28px;
  margin-bottom: clamp(20px, 3vw, 34px);
}

.grid { display: grid; gap: clamp(16px, 2.4vw, 28px); }
.grid--7-5 { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }
.grid--8-4 { grid-template-columns: minmax(0, 8fr) minmax(0, 4fr); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }

@media (max-width: 980px) {
  .grid--7-5, .grid--8-4, .grid--3, .grid--2 { grid-template-columns: minmax(0, 1fr); }
}

/* ---------- 05 跳过链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: calc(var(--rail-w) + 14px);
  z-index: 200;
  transform: translateY(-180%);
  padding: 10px 18px;
  background: var(--cyan-500);
  color: #04241D;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .08em;
  border-radius: 2px;
  transition: transform .25s var(--ease);
}

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

/* ---------- 06 头部：左侧竖向数据面板 ---------- */
.site-header {
  position: fixed;
  top: 0; left: 0; bottom: 0;
  z-index: 60;
  width: var(--rail-w);
  display: flex;
  flex-direction: column;
  gap: 22px;
  padding: 26px 20px 24px 22px;
  background: linear-gradient(180deg,
    rgba(6, 43, 35, .99) 0%,
    rgba(6, 43, 35, .95) 52%,
    rgba(16, 22, 26, .99) 100%);
  border-right: 1px solid var(--line);
  overflow-y: auto;
  overscroll-behavior: contain;
  transition: width .42s var(--ease), padding .42s var(--ease);
}

.site-header::-webkit-scrollbar { width: 6px; }
.site-header::-webkit-scrollbar-thumb { background: rgba(107, 255, 208, .28); }

.site-header__rule {
  position: fixed;
  top: 0;
  left: var(--rail-w);
  right: 0;
  height: 1px;
  z-index: 59;
  background: linear-gradient(90deg,
    rgba(107, 255, 208, .55),
    rgba(18, 224, 176, .18) 55%,
    rgba(18, 224, 176, 0) 100%);
  pointer-events: none;
  transition: left .42s var(--ease);
}

.site-header__progress {
  display: block;
  height: 1px;
  width: 0;
  background: var(--cyan-500);
  box-shadow: 0 0 12px rgba(18, 224, 176, .85);
  transition: width .12s linear;
}

.site-header__brand { flex: 0 0 auto; }

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.brand__mark {
  display: inline-grid;
  place-items: center;
  width: 40px;
  height: 40px;
  flex: none;
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .02em;
  color: #04241D;
  background: var(--cyan-500);
  clip-path: polygon(0 0, 100% 0, 100% 74%, 74% 100%, 0 100%);
}

.brand__text {
  display: flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  overflow: hidden;
}

.brand__line {
  font-size: 13.5px;
  font-weight: 700;
  letter-spacing: .01em;
  color: var(--white);
  white-space: nowrap;
}

.brand__sig {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: .16em;
  color: var(--gray-500);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 9px;
  padding: 8px 13px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(255, 255, 255, .05);
  color: var(--mist);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
}

.nav-toggle:hover { border-color: var(--cyan-300); color: var(--white); }

.nav-toggle__bars {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 16px;
  flex: none;
}

.nav-toggle__bars i {
  display: block;
  height: 1.5px;
  background: var(--cyan-300);
  transition: transform .25s var(--ease);
}

.site-header[data-open] .nav-toggle__bars i:first-child {
  transform: translateY(2.75px) rotate(45deg);
}

.site-header[data-open] .nav-toggle__bars i:last-child {
  transform: translateY(-2.75px) rotate(-45deg);
}

.site-nav {
  display: flex;
  flex-direction: column;
  gap: 16px;
  flex: 1 1 auto;
  min-height: 0;
}

.site-nav__eyebrow {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--gray-500);
}

.site-nav__eyebrow-en { color: var(--cyan-500); }

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

.site-nav__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 10px 8px 10px 6px;
  border-left: 2px solid transparent;
  color: rgba(232, 239, 234, .82);
  transition: color .22s var(--ease), border-color .22s var(--ease), background .22s var(--ease);
}

.site-nav__link:hover {
  color: var(--white);
  border-left-color: var(--cyan-300);
  background: rgba(107, 255, 208, .06);
}

.site-nav__link[aria-current="page"] {
  color: var(--cyan-500);
  border-left-color: var(--cyan-500);
  background: rgba(18, 224, 176, .10);
}

.site-nav__num {
  font-family: var(--font-mono);
  font-size: 12.5px;
  font-variant-numeric: tabular-nums;
  letter-spacing: .06em;
  color: var(--gray-500);
  transition: color .22s var(--ease);
}

.site-nav__link:hover .site-nav__num { color: var(--cyan-300); }
.site-nav__link[aria-current="page"] .site-nav__num { color: var(--cyan-500); }

.site-nav__label {
  font-size: 15px;
  font-weight: 500;
  letter-spacing: .01em;
}

.site-nav__foot {
  margin-top: auto;
  padding-top: 18px;
  border-top: 1px solid rgba(107, 255, 208, .18);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.site-nav__round {
  display: flex;
  align-items: baseline;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--gray-500);
}

.site-nav__round-val { color: var(--gold-400); }

.site-nav__util {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
}

.site-nav__util a {
  color: rgba(232, 239, 234, .58);
  transition: color .2s var(--ease);
}

.site-nav__util a:hover { color: var(--cyan-300); }

.site-nav__cta { align-self: flex-start; }

/* ---------- 07 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: .5em;
  padding: .72em 1.25em;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: rgba(255, 255, 255, .04);
  color: var(--mist);
  font-family: var(--font-sans);
  font-size: 13.5px;
  font-weight: 500;
  letter-spacing: .06em;
  text-transform: uppercase;
  line-height: 1.2;
  transition: background .22s var(--ease), border-color .22s var(--ease),
    color .22s var(--ease), transform .22s var(--ease);
}

.btn:hover {
  border-color: var(--cyan-300);
  color: var(--white);
  transform: translateY(-1px);
}

.btn--primary {
  background: var(--cyan-500);
  border-color: var(--cyan-500);
  color: #04241D;
  font-weight: 700;
}

.btn--primary:hover {
  background: var(--cyan-300);
  border-color: var(--cyan-300);
  color: #04241D;
}

.btn--data {
  background: var(--orange-500);
  border-color: var(--orange-500);
  color: var(--white);
  font-weight: 700;
}

.btn--data:hover {
  background: #FF7A45;
  border-color: #FF7A45;
  color: var(--white);
}

.btn--ghost {
  background: transparent;
  border-color: rgba(107, 255, 208, .45);
  color: var(--cyan-300);
}

.btn--ghost:hover {
  background: rgba(107, 255, 208, .1);
  color: var(--white);
}

/* ---------- 08 面包屑 ---------- */
.breadcrumb {
  padding-top: 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--gray-500);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .5em;
}

.breadcrumb li + li::before {
  content: "/";
  margin-right: .5em;
  color: rgba(107, 255, 208, .4);
}

.breadcrumb a {
  color: rgba(232, 239, 234, .68);
  transition: color .2s var(--ease);
}

.breadcrumb a:hover { color: var(--cyan-300); }

.breadcrumb [aria-current="page"] { color: var(--cyan-500); }

/* ---------- 09 章节编号 ---------- */
.chapter {
  display: flex;
  align-items: flex-start;
  gap: clamp(12px, 2vw, 26px);
  margin-bottom: clamp(18px, 2.6vw, 34px);
}

.chapter__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: clamp(2.6rem, 6vw, 4rem);
  font-weight: 700;
  line-height: .9;
  letter-spacing: -.02em;
  color: var(--cyan-500);
  font-variant-numeric: tabular-nums;
}

.chapter__meta { padding-top: .3em; }

.chapter__kicker {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--gray-500);
}

.chapter__title {
  margin-top: 4px;
  font-size: clamp(1.25rem, 2.4vw, 1.75rem);
  font-weight: 800;
  line-height: 1.26;
  letter-spacing: -.01em;
  color: var(--white);
}

/* ---------- 10 斜切分割 ---------- */
.slash {
  height: 12px;
  border: 0;
  background: linear-gradient(90deg,
    var(--cyan-500) 0 34%,
    rgba(18, 224, 176, .22) 34% 100%);
  clip-path: polygon(0 0, 100% 0, calc(100% - 20px) 100%, 0 100%);
  opacity: .85;
}

.slash--data {
  background: linear-gradient(90deg,
    var(--orange-500) 0 22%,
    rgba(255, 90, 31, .22) 22% 100%);
}

/* ---------- 11 卡片 ---------- */
.card {
  position: relative;
  padding: clamp(18px, 2.2vw, 26px);
  background: linear-gradient(160deg, rgba(255, 255, 255, .085), rgba(255, 255, 255, .035));
  border: 1px solid var(--line);
  border-radius: 3px;
  transition: border-color .25s var(--ease), transform .35s var(--ease), background .25s var(--ease);
}

.card::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 44px;
  height: 2px;
  background: var(--cyan-300);
  opacity: .85;
}

.card:hover {
  border-color: rgba(107, 255, 208, .5);
  background: linear-gradient(160deg, rgba(255, 255, 255, .12), rgba(255, 255, 255, .05));
  transform: translateY(-3px);
}

.card--data::before { background: var(--orange-500); }
.card--flat:hover { transform: none; }

.card__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 14px;
}

.card__title {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.4;
  color: var(--white);
}

.card__text {
  font-size: 15px;
  line-height: 1.8;
  color: rgba(232, 239, 234, .78);
}

/* ---------- 12 标签 ---------- */
.pill {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(18, 224, 176, .07);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--cyan-300);
}

.pill--data {
  color: var(--orange-500);
  border-color: rgba(255, 90, 31, .42);
  background: rgba(255, 90, 31, .09);
}

.pill--gold {
  color: var(--gold-400);
  border-color: rgba(255, 194, 77, .4);
  background: rgba(255, 194, 77, .08);
}

/* ---------- 13 数据三联 ---------- */
.stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.stat__num {
  font-family: var(--font-mono);
  font-size: clamp(1.7rem, 3.4vw, 2.5rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.01em;
  color: var(--white);
  font-variant-numeric: tabular-nums;
}

.stat__num--data { color: var(--orange-500); }
.stat__num--gold { color: var(--gold-400); }

.stat__label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--gray-500);
}

/* ---------- 14 旁注 ---------- */
.aside-note {
  border-left: 2px solid rgba(107, 255, 208, .35);
  padding-left: 14px;
}

.aside-note__title {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--cyan-300);
  margin-bottom: 6px;
}

/* ---------- 15 折叠旁注 ---------- */
.fold {
  border: 1px solid var(--line);
  border-radius: 3px;
  background: rgba(255, 255, 255, .03);
}

.fold__btn {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 16px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--gray-500);
  text-align: left;
  transition: color .2s var(--ease);
}

.fold__btn:hover { color: var(--cyan-300); }

.fold__mark {
  flex: none;
  color: var(--cyan-500);
  transition: transform .25s var(--ease);
}

.fold__btn[aria-expanded="true"] .fold__mark { transform: rotate(45deg); }

.fold__panel {
  padding: 0 16px 16px;
  font-size: 14px;
  line-height: 1.8;
  color: rgba(232, 239, 234, .78);
}

/* ---------- 16 表格 ---------- */
.table-wrap {
  width: 100%;
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: 3px;
}

.table {
  font-family: var(--font-mono);
  font-size: 13.5px;
  font-variant-numeric: tabular-nums;
  min-width: 520px;
}

.table caption {
  padding: 12px 16px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--gray-500);
}

.table th, .table td {
  padding: 11px 16px;
  text-align: left;
  border-bottom: 1px solid var(--line-soft);
}

.table thead th {
  background: var(--ink-700);
  color: var(--cyan-300);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.table tbody tr {
  transition: background .2s var(--ease);
}

.table tbody tr:nth-child(even) { background: rgba(255, 255, 255, .025); }
.table tbody tr:hover { background: rgba(107, 255, 208, .07); }
.table tbody tr:last-child td { border-bottom: 0; }

.table .is-num {
  text-align: right;
  color: var(--orange-500);
}

/* ---------- 17 图片容器 ---------- */
.media {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: linear-gradient(155deg, var(--ink-800), var(--ink-700));
}

.media > img,
.media > picture > img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}

.media::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 1;
  background: linear-gradient(180deg, rgba(6, 43, 35, 0) 38%, rgba(6, 43, 35, .82) 100%);
  pointer-events: none;
}

.media__caption {
  position: relative;
  z-index: 2;
  margin-top: auto;
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.65;
  letter-spacing: .06em;
  color: var(--mist);
}

.media--with-caption { display: flex; flex-direction: column; justify-content: flex-end; }
.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--3x4 { aspect-ratio: 3 / 4; }
.media--square { aspect-ratio: 1 / 1; }

.media--empty::before {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 0;
  background-image:
    repeating-linear-gradient(45deg,
      rgba(107, 255, 208, .07) 0 1px,
      transparent 1px 14px);
}

/* ---------- 18 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 7vw, 96px);
  background: linear-gradient(180deg, var(--ink-700) 0%, #0A1216 100%);
  border-top: 1px solid var(--line);
  color: var(--mist);
}

.site-footer::before {
  content: "";
  display: block;
  height: 8px;
  background: linear-gradient(90deg,
    var(--cyan-500) 0 52%,
    var(--gold-400) 52% 64%,
    rgba(107, 255, 208, .18) 64% 100%);
}

.site-footer__inner {
  max-width: var(--shell-max);
  margin-inline: auto;
  padding: clamp(36px, 5vw, 62px) var(--gutter) clamp(22px, 3vw, 34px);
}

.site-footer__grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(3, minmax(0, 1fr));
  gap: clamp(22px, 3vw, 44px);
}

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

.site-footer__mark {
  font-family: var(--font-mono);
  font-size: 2.5rem;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--cyan-500);
}

.site-footer__name {
  margin-top: 10px;
  font-size: 15px;
  font-weight: 700;
  color: var(--white);
}

.site-footer__meta {
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--gray-500);
}

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

.site-footer__title {
  margin-bottom: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--gray-500);
}

.site-footer__links {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.site-footer__links a {
  display: inline-block;
  font-size: 14.5px;
  color: rgba(232, 239, 234, .78);
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.site-footer__links a:hover {
  color: var(--cyan-300);
  border-bottom-color: rgba(107, 255, 208, .5);
}

.site-footer__contact {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 28px;
  margin-top: clamp(28px, 4vw, 48px);
  padding-top: clamp(20px, 3vw, 30px);
  border-top: 1px solid rgba(107, 255, 208, .16);
}

.site-footer__contact-item {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .03em;
  color: var(--mist);
}

.site-footer__contact-item b {
  margin-right: 6px;
  font-weight: 500;
  color: var(--cyan-300);
}

.site-footer__note {
  width: 100%;
  max-width: 68ch;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.75;
  color: var(--gray-500);
}

.site-footer__legal {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 24px;
  margin-top: clamp(22px, 3vw, 34px);
  padding-top: 16px;
  border-top: 1px solid rgba(107, 255, 208, .16);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .04em;
  color: var(--gray-500);
}

/* ---------- 19 动效 ---------- */
html[data-js="on"] [data-reveal] {
  opacity: 0;
  transform: translateY(12px);
  transition: opacity .42s var(--ease), transform .42s var(--ease);
}

html[data-js="on"] [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 20 焦点与减弱动效 ---------- */
:focus-visible {
  outline: 2px solid var(--cyan-300);
  outline-offset: 3px;
  border-radius: 2px;
}

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

  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
  }

  html[data-js="on"] [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .site-header__progress { transition: none; }
}

/* ---------- 21 移动端与平板 ---------- */
@media (max-width: 900px) {
  body {
    padding-left: 0;
    padding-top: 62px;
    font-size: 16.5px;
  }

  .skip-link { left: 12px; }

  .site-header {
    inset: 0 0 auto 0;
    width: auto;
    height: 62px;
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 0 16px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    overflow: visible;
  }

  .site-header__rule { display: none; }
  .site-header__brand { margin-bottom: 0; min-width: 0; }
  .brand__line { font-size: 12.5px; }
  .brand__sig { display: none; }
  .nav-toggle { display: inline-flex; }

  .site-nav {
    position: fixed;
    inset: auto 0 0 0;
    z-index: 70;
    max-height: 78vh;
    overflow-y: auto;
    gap: 18px;
    padding: 20px 18px calc(24px + env(safe-area-inset-bottom, 0px));
    background: linear-gradient(180deg, rgba(6, 43, 35, .99) 0%, rgba(16, 22, 26, .99) 100%);
    border-top: 2px solid var(--cyan-500);
    border-radius: 14px 14px 0 0;
    transform: translateY(102%);
    visibility: hidden;
    transition: transform .38s var(--ease), visibility .38s var(--ease);
  }

  .site-header[data-open] .site-nav,
  .site-nav[data-open] {
    transform: translateY(0);
    visibility: visible;
  }

  .site-nav__list {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 6px;
  }

  .site-nav__item { flex: 1 1 calc(50% - 6px); }

  .site-nav__link {
    border-left: 0;
    border-bottom: 2px solid transparent;
    padding: 11px 10px;
    background: rgba(255, 255, 255, .04);
    border-radius: 2px;
  }

  .site-nav__link:hover,
  .site-nav__link[aria-current="page"] {
    border-left: 0;
    border-bottom-color: var(--cyan-500);
  }

  .site-nav__foot { margin-top: 8px; }

  .site-nav__util {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 16px;
  }

  .site-nav__cta { align-self: stretch; width: 100%; }

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

@media (max-width: 560px) {
  .site-footer__grid { grid-template-columns: minmax(0, 1fr); gap: 26px; }
  .site-footer__contact { flex-direction: column; gap: 8px; }
  .chapter { flex-direction: column; gap: 8px; }
  .chapter__num { font-size: 2.6rem; }
  .btn { width: 100%; }
  .site-nav__cta { width: 100%; }
}

@media (min-width: 901px) {
  html[data-rail="narrow"] .site-header {
    padding-left: 16px;
    padding-right: 16px;
    align-items: flex-start;
  }

  html[data-rail="narrow"] .brand__text,
  html[data-rail="narrow"] .site-nav__eyebrow,
  html[data-rail="narrow"] .site-nav__label,
  html[data-rail="narrow"] .site-nav__util,
  html[data-rail="narrow"] .site-nav__cta,
  html[data-rail="narrow"] .site-nav__round-key {
    display: none;
  }

  html[data-rail="narrow"] .site-nav__link {
    justify-content: center;
    padding-inline: 4px;
  }
}