/* ==========================================================================
   完美体育看台 /assets/site.css
   夜场灯光 · 纸张叠层 · 战术板细线
   ========================================================================== */

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

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

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

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

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

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

a { color: inherit; }

table { border-collapse: collapse; border-spacing: 0; }

/* ---------- 2. Tokens ---------- */
:root {
  --night: #0B1B2B;
  --ink: #080A0C;
  --grass: #12452F;
  --grass-mid: #1E6B4A;
  --lime: #C6F24E;
  --paper: #F2EFE6;
  --brick: #9B3A2E;
  --lead: #7C8894;
  --steel: #2A3F55;
  --amber: #D98A3D;

  --line-dark: rgba(124, 136, 148, .34);
  --line-light: rgba(8, 10, 12, .18);
  --paper-72: rgba(242, 239, 230, .72);
  --paper-56: rgba(242, 239, 230, .56);
  --ink-72: rgba(8, 10, 12, .72);
  --ink-56: rgba(8, 10, 12, .56);

  --font-display: "Source Han Serif SC", "Noto Serif SC", "Songti SC", "STSong", "SimSun", Georgia, serif;
  --font-body: "Source Han Sans SC", "Noto 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;

  --wrap: 1320px;
  --gutter: 24px;
  --bar-h: 64px;

  --step-1: 8px;
  --step-2: 16px;
  --step-3: 24px;
  --step-4: 40px;
  --step-5: 64px;
  --step-6: 96px;

  --shadow-1: 6px 6px 0 0 rgba(42, 63, 85, .85);
  --shadow-paper: 6px 6px 0 0 rgba(8, 10, 12, .14);
  --ease: cubic-bezier(.22, .61, .36, 1);
  --column-pos: 0%;
}

/* ---------- 3. Typography ---------- */
body {
  background: var(--night);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  letter-spacing: .01em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.16;
  letter-spacing: -.02em;
}

h1 { font-size: clamp(34px, 5.4vw, 60px); }
h2 { font-size: clamp(26px, 3.2vw, 40px); }
h3 { font-size: clamp(20px, 2vw, 24px); font-weight: 700; letter-spacing: -.01em; }
h4 { font-size: 17px; font-weight: 700; letter-spacing: 0; }

p { max-width: 38em; }

.mono,
.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-feature-settings: "tnum" 1;
  letter-spacing: .02em;
}

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--lime);
}

.lead {
  max-width: 30em;
  font-size: clamp(18px, 2.1vw, 22px);
  line-height: 1.65;
  color: var(--paper-72);
}

.rule { height: 1px; border: 0; background: var(--line-dark); }

::selection { background: var(--lime); color: var(--night); }

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

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

.grid12 {
  display: grid;
  grid-template-columns: repeat(12, minmax(0, 1fr));
  gap: var(--step-3);
}

.section { padding-block: var(--step-6); }
.section--tight { padding-block: var(--step-5); }

.section-head {
  position: relative;
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 12px 24px;
  padding-top: 18px;
  padding-bottom: 16px;
  margin-bottom: var(--step-4);
  border-bottom: 1px solid var(--line-dark);
}

.section-head::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 48px;
  height: 2px;
  background: var(--lime);
}

/* ---------- 5. Bands ---------- */
.band { position: relative; padding-block: var(--step-6); }
.band--night { background: var(--night); color: var(--paper); }
.band--grass { background: var(--grass); color: var(--paper); }
.band--paper { background: var(--paper); color: var(--ink); }

.band--paper .eyebrow { color: var(--grass-mid); }
.band--paper .lead { color: var(--ink-72); }
.band--paper .rule { background: var(--line-light); }
.band--paper .section-head { border-bottom-color: var(--line-light); }
.band--paper .section-head::before { background: var(--brick); }

/* ---------- 6. Header ---------- */
.skip-link {
  position: absolute;
  left: 16px;
  top: -120px;
  z-index: 200;
  padding: 10px 16px;
  background: var(--lime);
  color: var(--night);
  border: 1px solid var(--ink);
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  transition: top .16s var(--ease);
}

.skip-link:focus { top: 12px; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 90;
  background: var(--night);
  border-bottom: 1px solid var(--line-dark);
}

.site-header::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 88px;
  height: 2px;
  background: var(--lime);
}

.command-bar {
  display: flex;
  align-items: stretch;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--gutter);
  min-height: var(--bar-h);
  transition: min-height .2s var(--ease);
}

.brand {
  display: flex;
  flex: 0 0 auto;
  flex-direction: column;
  justify-content: center;
  padding: 10px 20px 10px 0;
  border-right: 1px solid var(--line-dark);
  color: var(--paper);
  text-decoration: none;
}

.brand__name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -.02em;
}

.brand__sub {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 10px;
  line-height: 1;
  letter-spacing: .13em;
  color: var(--lime);
}

.nav {
  flex: 1 1 auto;
  display: flex;
  align-items: stretch;
  min-width: 0;
}

.nav__list {
  display: flex;
  align-items: stretch;
  margin: 0;
  padding: 0;
  list-style: none;
  counter-reset: navidx;
}

.nav__item { display: flex; }

.nav__link {
  position: relative;
  display: flex;
  align-items: center;
  padding: 0 16px;
  border-right: 1px solid var(--line-dark);
  color: var(--paper-72);
  font-size: 14.5px;
  line-height: 1.2;
  white-space: nowrap;
  text-decoration: none;
  transition: color .16s var(--ease), background-color .16s var(--ease);
}

.nav__link::before {
  counter-increment: navidx;
  content: "0" counter(navidx);
  margin-right: 8px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: .06em;
  color: var(--lead);
  transition: color .16s var(--ease);
}

.nav__link:hover {
  color: var(--paper);
  background: rgba(42, 63, 85, .5);
}

.nav__link:hover::before { color: var(--lime); }

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

.nav__link[aria-current="page"]::before { color: var(--lime); }

.nav__link[aria-current="page"]::after {
  content: "";
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 0;
  height: 3px;
  background: var(--lime);
}

.cta {
  display: inline-flex;
  align-items: center;
  align-self: center;
  margin-left: 16px;
  padding: 9px 16px;
  border: 1px solid var(--lime);
  color: var(--lime);
  font-size: 13.5px;
  font-weight: 700;
  letter-spacing: .06em;
  white-space: nowrap;
  text-decoration: none;
  transition: background-color .16s var(--ease), color .16s var(--ease);
}

.cta:hover { background: var(--lime); color: var(--night); }

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  align-self: center;
  margin-left: 12px;
  padding: 8px 12px;
  background: transparent;
  border: 1px solid var(--line-dark);
  color: var(--paper);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .08em;
  cursor: pointer;
  transition: border-color .16s var(--ease), color .16s var(--ease);
}

.nav-toggle__grid {
  display: grid;
  grid-template-columns: repeat(2, 4px);
  gap: 3px;
}

.nav-toggle__grid > span {
  display: block;
  width: 4px;
  height: 4px;
  background: var(--lime);
}

.nav-toggle[aria-expanded="true"] {
  border-color: var(--lime);
  color: var(--lime);
}

.to-top {
  display: none;
  align-items: center;
  justify-content: center;
  align-self: center;
  margin-left: 10px;
  width: 36px;
  height: 36px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--line-dark);
  color: var(--paper);
  font-size: 15px;
  line-height: 1;
  cursor: pointer;
  transition: border-color .16s var(--ease), color .16s var(--ease);
}

.to-top:hover { border-color: var(--lime); color: var(--lime); }

.to-top__arrow { display: block; line-height: 1; }

.header-rule {
  position: relative;
  height: 1px;
  background: var(--line-dark);
}

.header-rule__fill {
  display: block;
  width: var(--column-pos);
  height: 1px;
  background: var(--lime);
  transition: width .24s var(--ease);
}

.site-header[data-compact] .command-bar { min-height: 52px; }
.site-header[data-compact] .brand__name { font-size: 17px; }
.site-header[data-compact] .brand__sub { display: none; }
.site-header[data-compact] .to-top { display: inline-flex; }

/* ---------- 7. Footer ---------- */
.site-footer {
  position: relative;
  background: var(--night);
  color: var(--paper);
  border-top: 2px solid var(--lime);
}

.site-footer__inner {
  display: grid;
  grid-template-columns: minmax(240px, 1.1fr) minmax(0, 2fr);
  gap: 56px;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 56px var(--gutter) 44px;
}

.footer-brand__name {
  font-family: var(--font-display);
  font-size: clamp(23px, 2.8vw, 31px);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -.02em;
}

.footer-brand__sub {
  margin-top: 10px;
  max-width: 24em;
  font-size: 14px;
  line-height: 1.7;
  color: var(--paper-56);
}

.footer-brand__code {
  display: inline-block;
  margin-top: 20px;
  padding: 5px 9px;
  border: 1px dashed var(--line-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--lead);
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 32px 24px;
}

.footer-col__title {
  position: relative;
  padding-top: 12px;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .18em;
  color: var(--lime);
}

.footer-col__title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 24px;
  height: 2px;
  background: var(--lime);
}

.footer-col__list {
  display: grid;
  gap: 9px;
  margin: 14px 0 0;
  padding: 0;
  list-style: none;
}

.footer-col__list a {
  font-size: 14.5px;
  color: var(--paper-72);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}

.footer-col__list a:hover {
  color: var(--lime);
  border-bottom-color: var(--lime);
}

.site-footer__meta { border-top: 1px solid var(--line-dark); }

.site-footer__meta-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 32px;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: 20px var(--gutter) 28px;
}

.footer-contact {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 24px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .02em;
  color: var(--paper-56);
}

.footer-legal {
  max-width: none;
  font-size: 12.5px;
  color: var(--lead);
}

/* ---------- 8. Buttons / Tags ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border: 1px solid var(--lime);
  background: transparent;
  color: var(--lime);
  font-family: var(--font-body);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .04em;
  text-decoration: none;
  cursor: pointer;
  transition: background-color .16s var(--ease), color .16s var(--ease), transform .16s var(--ease);
}

.btn:hover { background: var(--lime); color: var(--night); }
.btn:active { transform: translateY(1px); }

.btn--solid { background: var(--lime); color: var(--night); }
.btn--solid:hover { background: var(--paper); border-color: var(--paper); color: var(--night); }

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

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

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 3px 8px;
  border: 1px solid currentColor;
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.55;
  letter-spacing: .08em;
  text-transform: uppercase;
  white-space: nowrap;
}

.tag--lime { color: var(--lime); background: rgba(198, 242, 78, .10); }
.tag--brick { color: var(--brick); background: rgba(155, 58, 46, .10); }
.tag--steel { color: var(--lead); background: rgba(42, 63, 85, .12); }

/* ---------- 9. Panels / Cards ---------- */
.panel {
  position: relative;
  padding: var(--step-3);
  background: var(--grass);
  border: 1px solid var(--line-dark);
  color: var(--paper);
}

.panel--night { background: var(--night); }

.panel--paper {
  background: var(--paper);
  border-color: var(--ink);
  color: var(--ink);
}

.panel__head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 8px 16px;
  padding-bottom: 12px;
  margin-bottom: 16px;
  border-bottom: 1px solid var(--line-dark);
}

.panel--paper .panel__head { border-bottom-color: var(--line-light); }

.stack { box-shadow: var(--shadow-1); }
.stack--paper { box-shadow: var(--shadow-paper); }
.band--paper .stack { box-shadow: var(--shadow-paper); }

/* ---------- 10. Table ---------- */
.dtable {
  width: 100%;
  font-size: 14.5px;
  border-top: 2px solid var(--lime);
}

.dtable caption {
  padding-bottom: 10px;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .1em;
  color: var(--lead);
}

.dtable th,
.dtable td {
  padding: 9px 12px;
  text-align: left;
  border-bottom: 1px solid var(--line-dark);
}

.dtable thead th {
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--lead);
}

.dtable tbody tr:nth-child(even) { background: rgba(42, 63, 85, .22); }

.dtable td.num,
.dtable th.num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  text-align: right;
}

.band--paper .dtable { border-top-color: var(--brick); }
.band--paper .dtable th,
.band--paper .dtable td { border-bottom-color: var(--line-light); }
.band--paper .dtable thead th { color: var(--ink-56); }
.band--paper .dtable tbody tr:nth-child(even) { background: rgba(42, 63, 85, .07); }

/* ---------- 11. Image Frames ---------- */
.frame {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  background: linear-gradient(158deg, var(--grass) 0%, var(--night) 100%);
  border: 1px solid var(--line-dark);
}

.frame > img,
.frame > svg,
.frame > video {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.frame--16x9 { aspect-ratio: 16 / 9; }
.frame--4x3 { aspect-ratio: 4 / 3; }
.frame--3x2 { aspect-ratio: 3 / 2; }
.frame--1x1 { aspect-ratio: 1 / 1; }
.frame--3x4 { aspect-ratio: 3 / 4; }
.frame--wide { aspect-ratio: 21 / 9; }

.frame__marks {
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(0deg, rgba(242, 239, 230, .08) 0 1px, transparent 1px 44px),
    repeating-linear-gradient(90deg, rgba(242, 239, 230, .08) 0 1px, transparent 1px 44px);
}

.frame__caption {
  display: block;
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--lead);
}

/* ---------- 12. Breadcrumbs / TOC ---------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--lead);
}

.crumbs a {
  color: var(--paper-72);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}

.crumbs a:hover { color: var(--lime); border-bottom-color: var(--lime); }

.crumbs__sep { color: var(--steel); }

.crumbs [aria-current="page"] { color: var(--lime); }

.band--paper .crumbs { color: var(--ink-56); }
.band--paper .crumbs a { color: var(--ink-72); }
.band--paper .crumbs a:hover { color: var(--grass-mid); border-bottom-color: var(--grass-mid); }
.band--paper .crumbs__sep { color: rgba(8, 10, 12, .3); }
.band--paper .crumbs [aria-current="page"] { color: var(--brick); }

.toc {
  position: sticky;
  top: calc(var(--bar-h) + 24px);
  font-size: 14px;
}

.toc__title {
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--lead);
}

.toc ul {
  display: grid;
  gap: 2px;
  margin: 12px 0 0;
  padding: 0;
  list-style: none;
}

.toc a {
  display: block;
  padding: 6px 0 6px 12px;
  border-left: 2px solid transparent;
  color: var(--paper-72);
  text-decoration: none;
  transition: color .16s var(--ease), border-color .16s var(--ease);
}

.toc a:hover { color: var(--paper); }

.toc a[aria-current] {
  color: var(--lime);
  border-left-color: var(--lime);
}

.band--paper .toc__title { border-bottom-color: var(--line-light); color: var(--ink-56); }
.band--paper .toc a { color: var(--ink-72); }
.band--paper .toc a:hover { color: var(--ink); }
.band--paper .toc a[aria-current] { color: var(--brick); border-left-color: var(--brick); }

/* ---------- 13. Prose ---------- */
.prose {
  max-width: 38em;
  font-size: 16.5px;
  line-height: 1.8;
}

.prose > * + * { margin-top: 1.1em; }

.prose h2 {
  margin-top: 2.2em;
  font-size: clamp(24px, 2.6vw, 32px);
}

.prose h3 { margin-top: 1.8em; }

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

.prose li + li { margin-top: .5em; }

.prose a {
  color: var(--lime);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.prose blockquote {
  margin: 1.6em 0;
  padding: 2px 0 2px 18px;
  border-left: 3px solid var(--lime);
  color: var(--paper-72);
}

.band--paper .prose a { color: var(--grass-mid); }
.band--paper .prose blockquote { border-left-color: var(--brick); color: var(--ink-72); }

/* ---------- 14. Reveal ---------- */
.has-js .reveal {
  opacity: 0;
  transform: translateY(14px);
  transition: opacity .4s var(--ease), transform .4s var(--ease);
}

.has-js .reveal.is-in {
  opacity: 1;
  transform: none;
}

/* ---------- 15. Responsive ---------- */
@media (max-width: 1140px) {
  .nav__link { padding: 0 10px; font-size: 13.5px; }
  .nav__link::before { margin-right: 5px; font-size: 9px; }
  .brand__name { font-size: 17px; }
  .cta { margin-left: 10px; padding: 8px 12px; font-size: 12.5px; }
}

@media (max-width: 960px) {
  :root { --gutter: 16px; --bar-h: 56px; }

  .command-bar { min-height: var(--bar-h); }

  .brand { padding-right: 14px; border-right: 0; }
  .brand__name { font-size: 17px; }
  .brand__sub { font-size: 9px; letter-spacing: .1em; }

  .nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    max-height: min(72vh, 520px);
    overflow-y: auto;
    background: var(--night);
    border-top: 1px solid var(--line-dark);
    border-bottom: 2px solid var(--lime);
    z-index: 95;
  }

  .nav[data-open] { display: block; }

  .nav__list {
    flex-direction: column;
    align-items: stretch;
  }

  .nav__item { display: block; }

  .nav__link {
    padding: 15px var(--gutter);
    border-right: 0;
    border-bottom: 1px solid var(--line-dark);
    font-size: 16px;
  }

  .nav__link::before { margin-right: 10px; font-size: 11px; }

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

  .cta { display: none; }

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

  .site-header[data-compact] .to-top { display: inline-flex; }

  .site-footer__inner {
    grid-template-columns: minmax(0, 1fr);
    gap: 40px;
    padding: 44px var(--gutter) 36px;
  }

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

  .toc { position: static; }
}

@media (max-width: 720px) {
  :root { --step-6: 56px; --step-5: 40px; }

  body { font-size: 15.5px; }

  .grid12 { display: block; }
  .grid12 > * + * { margin-top: 20px; }

  .section-head { margin-bottom: 24px; }

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

  .footer-contact { font-size: 11.5px; gap: 6px 18px; }

  .site-footer__meta-inner { padding-bottom: 24px; }

  .panel { padding: 18px; }

  .prose { font-size: 16px; }
}

@media (max-width: 420px) {
  .footer-nav { grid-template-columns: minmax(0, 1fr); }
  .nav-toggle__text { display: none; }
}

/* ---------- 16. Reduced motion ---------- */
@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;
  }

  .has-js .reveal { opacity: 1; transform: none; }

  .header-rule__fill { transition: none; }
}