/* ==========================================================================
   爱体育 · 共享样式表 /assets/site.css
   纸张叠层 + 印刷边框 + 对角线速度感
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 20px);
}

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

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

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

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

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

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

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

hr { border: 0; }

/* ---------- 2. 设计变量 ---------- */
:root {
  --ink-900: #0A0E1A;
  --ink-700: #1A2135;
  --paper-050: #F7F3EC;
  --paper-100: #EDE6DA;
  --rule-300: #C6BEB0;
  --brand-orange: #FF5A1F;
  --orange-200: #FFD9C7;
  --volt-400: #C8FF3D;
  --signal-blue: #2E5BFF;
  --amber-500: #FFB020;
  --muted-600: #5C6579;

  --font-display: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-body: system-ui, -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", "Courier New", monospace;

  --shell: 1320px;
  --gutter: 24px;
  --header-h: 76px;

  --ease: cubic-bezier(.22, .7, .24, 1);
  --t-fast: 160ms;
  --t-mid: 240ms;
  --t-slow: 420ms;

  --shadow-card: 4px 4px 0 rgba(10, 14, 26, .10);
  --shadow-card-hover: 7px 7px 0 rgba(10, 14, 26, .16);
}

/* ---------- 3. 基础排版 ---------- */
body {
  background-color: var(--paper-050);
  color: var(--ink-900);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.75;
  letter-spacing: .008em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.12;
  letter-spacing: -.02em;
}

h1 { font-size: clamp(34px, 5.4vw, 60px); }
h2 { font-size: clamp(26px, 3.4vw, 40px); }
h3 { font-size: clamp(20px, 2.1vw, 26px); line-height: 1.3; }

strong { font-weight: 800; }

::selection {
  background: var(--brand-orange);
  color: var(--ink-900);
}

.mono {
  font-family: var(--font-mono);
  letter-spacing: .04em;
  font-variant-numeric: tabular-nums;
}

.muted { color: var(--muted-600); }

.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(--brand-orange);
  outline-offset: 3px;
}

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

.section { padding-block: clamp(48px, 7vw, 96px); }
.section--tight { padding-block: clamp(28px, 4vw, 52px); }
.section--ink { background-color: var(--ink-900); color: var(--paper-050); }
.section--ink .section-lead { color: rgba(247, 243, 236, .70); }
.section--paper { background-color: var(--paper-100); }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 16px 32px;
  margin-bottom: clamp(24px, 3vw, 40px);
}

.section-index {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--brand-orange);
  margin-bottom: 10px;
}

.section-title {
  display: inline-block;
  padding-bottom: 16px;
  background-image: linear-gradient(var(--brand-orange), var(--brand-orange));
  background-repeat: no-repeat;
  background-position: 0 100%;
  background-size: 64px 5px;
}

.section-lead {
  max-width: 46em;
  font-size: 17px;
  line-height: 1.78;
  color: var(--muted-600);
}

/* 12 栅格非对称双栏：主 8 / 索引 3 / 空 1 */
.layout-split {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: 36px 32px;
  align-items: start;
}

.layout-split__main { grid-column: 1 / span 8; min-width: 0; }
.layout-split__rail { grid-column: 10 / span 3; min-width: 0; }

/* 等距网格 */
.grid { display: grid; gap: 24px; }
.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)); }

/* 斜切分隔带 */
.divider-slant {
  display: block;
  height: 14px;
  border: 0;
  background: repeating-linear-gradient(
    115deg,
    var(--brand-orange) 0 12px,
    transparent 12px 30px
  );
  opacity: .55;
  clip-path: polygon(0 0, 100% 0, 100% 60%, 0 100%);
}

/* 速度线装饰条 */
.speed-strip {
  display: block;
  height: 6px;
  background: repeating-linear-gradient(
    100deg,
    var(--brand-orange) 0 22px,
    transparent 22px 44px
  );
  opacity: .85;
}

/* ---------- 5. 跳转链接 ---------- */
.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 400;
  padding: 11px 20px;
  background-color: var(--brand-orange);
  color: var(--ink-900);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 14px;
  letter-spacing: .1em;
  border: 2px solid var(--ink-900);
  transform: translateY(-180%);
  transition: transform var(--t-fast) var(--ease);
}

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

/* ---------- 6. 头部 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 120;
  min-height: var(--header-h);
  color: var(--paper-050);
  background-image: linear-gradient(
    180deg,
    rgba(10, 14, 26, .86) 0%,
    rgba(10, 14, 26, .46) 62%,
    rgba(10, 14, 26, .18) 100%
  );
  -webkit-backdrop-filter: blur(10px) saturate(130%);
  backdrop-filter: blur(10px) saturate(130%);
  transition:
    background-color var(--t-fast) linear,
    background-image 120ms linear,
    box-shadow var(--t-fast) linear;
}

.site-header[data-scrolled] {
  background-color: var(--ink-900);
  background-image: none;
  box-shadow:
    0 18px 34px -26px rgba(10, 14, 26, .95),
    inset 0 -1px 0 rgba(255, 90, 31, .3);
}

.header-inner {
  position: relative;
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  min-height: var(--header-h);
  padding: 12px var(--gutter);
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 20px;
}

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

.brand-mark {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  flex: 0 0 auto;
  background-color: var(--brand-orange);
  color: var(--ink-900);
  font-family: var(--font-display);
  font-size: 21px;
  font-weight: 800;
  line-height: 1;
  clip-path: polygon(0 0, 100% 0, 100% 74%, 74% 100%, 0 100%);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.16;
  min-width: 0;
}

.brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  letter-spacing: .06em;
  color: var(--paper-050);
}

.brand-tag {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .16em;
  color: rgba(247, 243, 236, .62);
  white-space: nowrap;
}

/* 主导航 */
.primary-nav {
  display: flex;
  justify-content: center;
  min-width: 0;
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 2px;
}

.nav-link {
  position: relative;
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 11px 13px;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: .02em;
  color: rgba(247, 243, 236, .76);
  transition: color var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease);
}

.nav-idx {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .04em;
  color: var(--brand-orange);
  opacity: .8;
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 13px;
  right: 13px;
  bottom: 3px;
  height: 2px;
  background-color: var(--brand-orange);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform var(--t-mid) var(--ease);
}

.nav-link:hover { color: var(--paper-050); }
.nav-link:hover::after { transform: scaleX(1); }

.nav-link[aria-current="page"] { color: var(--paper-050); }
.nav-link[aria-current="page"]::after { transform: scaleX(1); }
.nav-link[aria-current="page"] .nav-idx { opacity: 1; }

/* 右侧工具 */
.header-tools {
  display: flex;
  align-items: center;
  gap: 10px;
  justify-self: end;
}

.icon-btn {
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  border: 1px solid rgba(247, 243, 236, .3);
  color: var(--paper-050);
  transition: border-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease);
}

.icon-btn:hover,
.icon-btn[aria-expanded="true"] {
  border-color: var(--brand-orange);
  color: var(--brand-orange);
}

.icon-search { display: block; }

.btn-login {
  display: inline-flex;
  align-items: center;
  padding: 11px 20px;
  border: 1px solid var(--brand-orange);
  color: var(--brand-orange);
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .1em;
  white-space: nowrap;
  transition: background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.btn-login:hover {
  background-color: var(--brand-orange);
  color: var(--ink-900);
}

/* 移动导航按钮 */
.nav-toggle {
  display: none;
  align-items: center;
  gap: 10px;
  padding: 11px 14px;
  border: 1px solid rgba(247, 243, 236, .32);
  color: var(--paper-050);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  transition: border-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.nav-toggle-bars {
  display: grid;
  gap: 4px;
  width: 18px;
}

.nav-toggle-bars span {
  display: block;
  height: 2px;
  background-color: var(--brand-orange);
  transition: transform var(--t-mid) var(--ease);
}

.site-header[data-open] .nav-toggle {
  border-color: var(--brand-orange);
  color: var(--brand-orange);
}

.site-header[data-open] .nav-toggle-bars span:first-child {
  transform: translateY(3px) rotate(45deg);
}

.site-header[data-open] .nav-toggle-bars span:last-child {
  transform: translateY(-3px) rotate(-45deg);
}

/* 搜索浮层 */
.search-panel {
  position: absolute;
  top: 100%;
  right: var(--gutter);
  z-index: 130;
  width: min(420px, calc(100vw - 2 * var(--gutter)));
  padding: 20px;
  background-color: var(--ink-900);
  border: 1px solid rgba(255, 90, 31, .45);
  box-shadow: 6px 6px 0 rgba(10, 14, 26, .22);
}

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

.search-label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--brand-orange);
  margin-bottom: 10px;
}

.search-input {
  width: 100%;
  padding: 12px 14px;
  background-color: var(--ink-700);
  border: 1px solid rgba(198, 190, 176, .35);
  color: var(--paper-050);
  font-size: 15px;
  transition: border-color var(--t-fast) var(--ease);
}

.search-input::placeholder { color: rgba(247, 243, 236, .42); }
.search-input:focus { border-color: var(--brand-orange); }

.search-hint {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(247, 243, 236, .62);
}

.search-go {
  display: inline-block;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--volt-400);
  border-bottom: 1px solid transparent;
  transition: border-color var(--t-fast) var(--ease);
}

.search-go:hover { border-bottom-color: var(--volt-400); }

/* 滚动进度线 */
.header-progress {
  position: absolute;
  left: 0;
  bottom: 0;
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--brand-orange);
  transform: scaleX(0);
  transform-origin: 0 50%;
  opacity: 0;
  transition: opacity var(--t-mid) var(--ease);
}

.site-header[data-scrolled] .header-progress { opacity: 1; }

html.nav-locked { overflow: hidden; }

/* ---------- 7. 页脚 ---------- */
.site-footer {
  position: relative;
  margin-top: clamp(56px, 8vw, 110px);
  background-color: var(--ink-900);
  color: rgba(247, 243, 236, .74);
  border-top: 2px solid var(--brand-orange);
  overflow: hidden;
}

.footer-speedlines {
  position: absolute;
  top: 0;
  right: 0;
  width: min(560px, 62%);
  height: 100%;
  pointer-events: none;
  background: repeating-linear-gradient(
    118deg,
    rgba(255, 90, 31, .16) 0 2px,
    transparent 2px 22px
  );
  -webkit-mask-image: linear-gradient(205deg, #000 0%, transparent 72%);
  mask-image: linear-gradient(205deg, #000 0%, transparent 72%);
}

.footer-inner {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding: clamp(44px, 5vw, 72px) var(--gutter) clamp(28px, 3vw, 44px);
  display: grid;
  grid-template-columns: 1.5fr repeat(3, minmax(0, 1fr));
  gap: 40px 32px;
}

.footer-brand { min-width: 0; }

.brand--footer .brand-name { font-size: 22px; }
.brand--footer .brand-mark { width: 44px; height: 44px; font-size: 23px; }

.footer-sign {
  margin-top: 18px;
  max-width: 30em;
  font-size: 15px;
  line-height: 1.8;
  color: rgba(247, 243, 236, .68);
}

.footer-contact {
  margin-top: 20px;
  display: grid;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .04em;
  color: rgba(247, 243, 236, .6);
  word-break: break-word;
}

.footer-col { min-width: 0; }

.footer-col-title {
  display: flex;
  align-items: center;
  gap: 9px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--paper-050);
  margin-bottom: 18px;
}

.footer-col-title::before {
  content: "";
  width: 9px;
  height: 9px;
  flex: 0 0 auto;
  background-color: var(--brand-orange);
  clip-path: polygon(0 0, 100% 0, 100% 100%);
}

.footer-links {
  display: grid;
  gap: 2px;
}

.footer-link {
  display: inline-block;
  padding: 7px 0;
  font-size: 15px;
  color: rgba(247, 243, 236, .74);
  border-bottom: 1px solid rgba(198, 190, 176, .14);
  transition: color var(--t-fast) var(--ease), padding-left var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.footer-links .footer-link { display: block; }

.footer-link:hover {
  color: var(--brand-orange);
  padding-left: 6px;
  border-bottom-color: rgba(255, 90, 31, .5);
}

.footer-link--inline {
  display: inline;
  padding: 0;
  border-bottom: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
}

.footer-link--inline:hover { padding-left: 0; }

.footer-base {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding: 20px var(--gutter) 34px;
  border-top: 1px solid rgba(198, 190, 176, .18);
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 28px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: rgba(247, 243, 236, .54);
}

.footer-sig { color: var(--brand-orange); }

/* ---------- 8. 通用按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  padding: 13px 24px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: .08em;
  border: 1px solid transparent;
  transition: background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease), transform var(--t-fast) var(--ease);
}

.btn--primary {
  background-color: var(--brand-orange);
  border-color: var(--brand-orange);
  color: var(--ink-900);
}

.btn--primary:hover {
  background-color: var(--ink-900);
  border-color: var(--ink-900);
  color: var(--paper-050);
}

.btn--ghost {
  background-color: transparent;
  border-color: var(--ink-900);
  color: var(--ink-900);
}

.btn--ghost:hover {
  background-color: var(--ink-900);
  color: var(--paper-050);
}

.btn--quiet {
  padding: 8px 0;
  border: 0;
  color: var(--brand-orange);
  border-bottom: 2px solid var(--brand-orange);
}

.btn--quiet:hover { color: var(--ink-900); border-bottom-color: var(--ink-900); }

/* ---------- 9. 档案资料卡 ---------- */
.paper-card {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 24px 22px 22px;
  background-color: var(--paper-050);
  border: 1px solid var(--rule-300);
  box-shadow: var(--shadow-card);
  transition: transform var(--t-mid) var(--ease), border-color var(--t-mid) var(--ease), box-shadow var(--t-mid) var(--ease);
}

.paper-card:hover {
  transform: translateY(-2px);
  border-color: var(--brand-orange);
  box-shadow: var(--shadow-card-hover);
}

.paper-card--ink {
  background-color: var(--ink-700);
  border-color: rgba(198, 190, 176, .22);
  color: var(--paper-050);
  box-shadow: 4px 4px 0 rgba(255, 90, 31, .18);
}

.paper-card__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .2em;
  color: var(--brand-orange);
}

.paper-card__tag {
  position: absolute;
  top: 0;
  right: 0;
}

.paper-card__title {
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -.01em;
}

.paper-card__body {
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--muted-600);
}

.paper-card--ink .paper-card__body { color: rgba(247, 243, 236, .70); }

.paper-card__meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 18px;
  margin-top: auto;
  padding-top: 14px;
  border-top: 1px dashed var(--rule-300);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .05em;
  color: var(--muted-600);
}

.paper-card--ink .paper-card__meta {
  border-top-color: rgba(198, 190, 176, .24);
  color: rgba(247, 243, 236, .6);
}

.paper-card__action {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: .08em;
  color: var(--brand-orange);
}

.paper-card__action::after {
  content: "→";
  transition: transform var(--t-fast) var(--ease);
}

.paper-card:hover .paper-card__action::after { transform: translateX(4px); }

/* ---------- 10. 标签 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 5px 11px;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .16em;
  text-transform: uppercase;
  white-space: nowrap;
  border: 1px solid currentColor;
}

.tag--orange { background-color: var(--orange-200); color: #8A2A00; border-color: var(--orange-200); }
.tag--paper { background-color: var(--paper-100); color: var(--ink-900); border-color: var(--rule-300); }
.tag--volt { background-color: var(--ink-900); color: var(--volt-400); border-color: rgba(200, 255, 61, .5); }
.tag--blue { background-color: var(--signal-blue); color: #FFFFFF; border-color: var(--signal-blue); }
.tag--amber { background-color: rgba(255, 176, 32, .2); color: #7A4D00; border-color: var(--amber-500); }

/* ---------- 11. 数据条带 ---------- */
.stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 22px 20px;
  border-left: 3px solid var(--brand-orange);
  background-color: var(--paper-100);
}

.section--ink .stat {
  background-color: var(--ink-700);
  border-left-color: var(--brand-orange);
}

.stat__value {
  font-family: var(--font-mono);
  font-size: clamp(28px, 3.6vw, 44px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: .01em;
  color: var(--ink-900);
  white-space: nowrap;
}

.section--ink .stat__value { color: var(--paper-050); }

.stat__label {
  font-family: var(--font-display);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: .08em;
}

.stat__note {
  font-size: 12.5px;
  line-height: 1.65;
  color: var(--muted-600);
}

.section--ink .stat__note { color: rgba(247, 243, 236, .6); }

/* ---------- 12. 数据表 ---------- */
.data-table {
  font-family: var(--font-mono);
  font-size: 14px;
  letter-spacing: .03em;
  border: 1px solid var(--rule-300);
}

.data-table caption {
  caption-side: top;
  padding: 12px 0;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--muted-600);
}

.data-table th,
.data-table td {
  padding: 12px 14px;
  text-align: left;
  border-bottom: 1px solid var(--rule-300);
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

.data-table thead th {
  background-color: var(--ink-900);
  color: var(--paper-050);
  font-weight: 700;
  border-bottom-color: var(--ink-900);
}

.data-table tbody tr:nth-child(even) { background-color: var(--paper-100); }
.data-table tbody tr:hover { background-color: var(--orange-200); }

/* ---------- 13. 跟随式章节目录 ---------- */
.rail {
  position: sticky;
  top: calc(var(--header-h) + 28px);
  padding-top: 16px;
  border-top: 3px solid var(--ink-900);
}

.rail__title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: .22em;
  text-transform: uppercase;
  color: var(--muted-600);
  margin-bottom: 12px;
}

.rail__list { display: grid; gap: 1px; }

.rail__link {
  display: grid;
  grid-template-columns: auto 1fr;
  align-items: baseline;
  gap: 10px;
  padding: 10px 12px;
  font-size: 14.5px;
  color: var(--muted-600);
  border-left: 2px solid transparent;
  transition: color var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease), border-color var(--t-fast) var(--ease);
}

.rail__link:hover {
  color: var(--ink-900);
  background-color: var(--paper-100);
}

.rail__link[aria-current="true"] {
  color: var(--ink-900);
  font-weight: 700;
  background-color: var(--paper-100);
  border-left-color: var(--brand-orange);
}

.rail__no {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--brand-orange);
}

/* ---------- 14. 正文与面包屑 ---------- */
.prose {
  max-width: 40em;
  font-size: 17px;
  line-height: 1.78;
}

.prose > * + * { margin-top: 1.15em; }

.prose h2,
.prose h3 { margin-top: 1.9em; }

.prose ul,
.prose ol {
  padding-left: 1.2em;
  display: grid;
  gap: .5em;
}

.prose ul { list-style: square; }
.prose ol { list-style: decimal; }

.prose li::marker { color: var(--brand-orange); }

.prose a {
  color: var(--ink-900);
  border-bottom: 2px solid var(--brand-orange);
  transition: background-color var(--t-fast) var(--ease);
}

.prose a:hover { background-color: var(--orange-200); }

.prose blockquote {
  padding: 14px 20px;
  border-left: 3px solid var(--brand-orange);
  background-color: var(--paper-100);
  color: var(--ink-700);
}

.breadcrumbs {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .08em;
  color: var(--muted-600);
}

.breadcrumbs__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
}

.breadcrumbs__item + .breadcrumbs__item::before {
  content: "/";
  margin-right: 10px;
  color: var(--rule-300);
}

.breadcrumbs__item a:hover { color: var(--brand-orange); }

/* ---------- 15. 图片容器（供页面阶段使用） ---------- */
.media-frame {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background-color: var(--ink-700);
  border: 1px solid var(--rule-300);
}

.media-frame--tall { aspect-ratio: 4 / 5; }
.media-frame--square { aspect-ratio: 1 / 1; }

.media-frame img,
.media-frame__img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.media-frame::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(158deg, rgba(10, 14, 26, .12) 0%, rgba(10, 14, 26, .74) 100%);
}

.media-frame__caption {
  position: absolute;
  left: 0;
  bottom: 0;
  z-index: 2;
  padding: 10px 16px;
  background-color: var(--ink-900);
  color: var(--paper-050);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  text-transform: uppercase;
}

/* ---------- 16. 返回顶部（脚本生成） ---------- */
.to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 110;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 12px 16px;
  background-color: var(--ink-900);
  color: var(--paper-050);
  border: 1px solid var(--brand-orange);
  box-shadow: 4px 4px 0 rgba(10, 14, 26, .22);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  transition: transform var(--t-fast) var(--ease), background-color var(--t-fast) var(--ease), color var(--t-fast) var(--ease);
}

.to-top[hidden] { display: none; }

.to-top:hover {
  background-color: var(--brand-orange);
  color: var(--ink-900);
  transform: translateY(-2px);
}

.to-top__mark {
  font-size: 15px;
  line-height: 1;
  color: var(--brand-orange);
}

.to-top:hover .to-top__mark { color: var(--ink-900); }

/* ---------- 17. 滚动显现 ---------- */
.js-ready [data-reveal] {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity var(--t-slow) var(--ease), transform var(--t-slow) var(--ease);
}

.js-ready [data-reveal].is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 18. 响应式 ---------- */
@media (max-width: 1200px) {
  .header-inner { gap: 14px; }
  .nav-link { padding: 11px 10px; font-size: 14.5px; }
  .footer-inner { grid-template-columns: 1.4fr repeat(3, minmax(0, 1fr)); gap: 34px 24px; }
}

@media (max-width: 1020px) {
  :root { --header-h: 68px; }

  .header-inner {
    grid-template-columns: auto 1fr auto;
    padding: 10px var(--gutter);
    gap: 10px;
  }

  .brand-tag { display: none; }

  .nav-toggle {
    display: inline-flex;
    justify-self: end;
  }

  .header-tools { justify-self: end; }

  .primary-nav {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 125;
    display: block;
    justify-content: flex-start;
    padding: 20px var(--gutter) 48px;
    overflow-y: auto;
    background-color: var(--ink-900);
    border-top: 1px solid rgba(255, 90, 31, .4);
    background-image: repeating-linear-gradient(
      118deg,
      rgba(255, 90, 31, .07) 0 2px,
      transparent 2px 26px
    );
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: opacity var(--t-mid) var(--ease), transform var(--t-mid) var(--ease), visibility 0s linear var(--t-mid);
  }

  .site-header[data-open] .primary-nav {
    opacity: 1;
    visibility: visible;
    transform: none;
    transition-delay: 0s, 0s, 0s;
  }

  .nav-list {
    flex-direction: column;
    align-items: stretch;
    gap: 0;
  }

  .nav-item + .nav-item .nav-link { border-top: 1px solid rgba(247, 243, 236, .1); }

  .nav-link {
    display: flex;
    align-items: baseline;
    gap: 14px;
    padding: 18px 4px;
    font-size: 21px;
    font-weight: 700;
    color: var(--paper-050);
    border-bottom: 0;
  }

  .nav-link::after {
    left: 4px;
    right: auto;
    width: 40px;
    bottom: 8px;
  }

  .nav-idx { font-size: 12px; }

  .search-panel {
    right: var(--gutter);
    left: var(--gutter);
    width: auto;
  }

  .layout-split { grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 28px 20px; }
  .layout-split__main { grid-column: 1 / -1; }
  .layout-split__rail { grid-column: 1 / -1; }

  .rail {
    position: static;
    padding-top: 14px;
  }

  .rail__list { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px 10px; }

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

@media (max-width: 860px) {
  .footer-inner {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 34px 24px;
  }

  .footer-brand { grid-column: 1 / -1; }
  .footer-speedlines { width: 100%; opacity: .6; }
}

@media (max-width: 760px) {
  body { font-size: 16px; line-height: 1.75; }

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

  .rail__list { grid-template-columns: minmax(0, 1fr); }

  .btn-login { padding: 10px 14px; font-size: 14px; letter-spacing: .06em; }

  .icon-btn { width: 40px; height: 40px; }

  .to-top { right: 12px; bottom: 12px; padding: 10px 13px; }
  .to-top__label { display: none; }

  .footer-base { flex-direction: column; align-items: flex-start; }
}

@media (max-width: 520px) {
  :root { --gutter: 16px; }

  .brand-mark { width: 34px; height: 34px; font-size: 18px; }
  .brand-name { font-size: 17px; }

  .header-tools { gap: 8px; }
  .btn-login { padding: 10px 12px; font-size: 13px; }
  .nav-toggle-label { display: none; }

  .footer-inner { grid-template-columns: minmax(0, 1fr); }
  .footer-brand { grid-column: auto; }
}

/* ---------- 19. 动效偏好 ---------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }

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

  .js-ready [data-reveal] {
    opacity: 1;
    transform: none;
  }

  .paper-card:hover { transform: none; }
  .to-top:hover { transform: none; }
}