/* ==========================================================================
   完美体育赛事 · 共享样式 /assets/site.css
   竞技场深蓝底 · 看台面板蓝 · 荧光青 · 活力橙 · 射门琥珀 · 场馆钢灰
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 6rem;
}

body, h1, h2, h3, h4, p, ul, ol, li, figure, blockquote, dl, dd { margin: 0; }
ul, ol { padding: 0; list-style: none; }
img, svg { display: block; max-width: 100%; }
button, input, select, textarea { font: inherit; color: inherit; }
button { background: none; border: 0; cursor: pointer; }
a { color: inherit; }
table { border-collapse: collapse; }

/* 2. 设计令牌 ------------------------------------------------------------- */
:root {
  --arena: #0B1B2B;
  --arena-deep: #081420;
  --panel: #12283D;
  --panel-soft: rgba(18, 40, 61, 0.66);
  --cyan: #35E0D4;
  --cyan-dim: rgba(53, 224, 212, 0.14);
  --orange: #FF7A2F;
  --amber: #F2B03C;
  --steel: #8A99A6;
  --cold: #EAF1F6;
  --moss: #2C4A3E;
  --clay: #A65A3A;
  --sand: #EDE6D6;
  --line: #1F3A52;
  --ink-soft: rgba(234, 241, 246, 0.74);
  --ink-faint: rgba(234, 241, 246, 0.52);

  --font-display: "Barlow Condensed", "Oswald", "Archivo Narrow", "Noto Sans SC", "Source Han Sans SC", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;

  --shell: 1200px;
  --shell-wide: 1380px;
  --gutter: clamp(16px, 4vw, 40px);
  --measure: 38ch;

  --radius-s: 10px;
  --radius: 16px;
  --radius-l: 22px;
  --radius-pill: 999px;

  --shadow-panel: 0 18px 40px -28px rgba(0, 0, 0, 0.85);
  --shadow-float: 0 30px 60px -32px rgba(0, 0, 0, 0.9);
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* 3. 基准排版 ------------------------------------------------------------- */
body {
  min-height: 100vh;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.7;
  color: var(--cold);
  background-color: var(--arena);
  background-image:
    radial-gradient(1100px 620px at 8% -12%, rgba(53, 224, 212, 0.10), transparent 62%),
    radial-gradient(900px 520px at 104% 2%, rgba(255, 122, 47, 0.09), transparent 58%),
    radial-gradient(760px 760px at 50% 122%, rgba(44, 74, 62, 0.38), transparent 66%);
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.005em;
}
h1 { font-size: clamp(2.5rem, 5.6vw, 4rem); }
h2 { font-size: clamp(1.75rem, 3.1vw, 2.25rem); }
h3 { font-size: clamp(1.15rem, 1.6vw, 1.375rem); line-height: 1.25; }
h4 { font-size: 1.0625rem; line-height: 1.3; }

p { max-width: 68ch; }
strong { font-weight: 700; color: #ffffff; }
small { font-size: 0.8125rem; }

::selection { background: rgba(53, 224, 212, 0.3); color: #ffffff; }

.mono, .u-mono { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.muted { color: var(--steel); }
.measure { max-width: var(--measure); }
.lede { font-size: clamp(1rem, 1.2vw, 1.125rem); color: var(--ink-soft); max-width: 44ch; }

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0;
  overflow: hidden; clip: rect(0 0 0 0); clip-path: inset(50%);
  white-space: nowrap; border: 0;
}

:focus-visible {
  outline: 2px solid var(--orange);
  outline-offset: 3px;
  border-radius: 6px;
}

/* 4. 跳至主要内容 --------------------------------------------------------- */
.skip-link {
  position: fixed;
  left: 50%;
  top: 10px;
  z-index: 120;
  transform: translate(-50%, -180%);
  padding: 10px 20px;
  border-radius: var(--radius-pill);
  background: var(--cyan);
  color: #06131f;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  text-decoration: none;
  transition: transform 0.2s var(--ease);
}
.skip-link:focus { transform: translate(-50%, 0); }

/* 5. 容器与章节 ----------------------------------------------------------- */
.shell {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--gutter);
}
.shell--wide { max-width: var(--shell-wide); }

.section { padding-block: clamp(40px, 6vw, 84px); }
.section--tight { padding-block: clamp(26px, 3.4vw, 44px); }
.section--sand { background: var(--sand); color: #16232e; }
.section--sand h1, .section--sand h2, .section--sand h3 { color: #0f1c27; }
.section--moss { background: linear-gradient(180deg, var(--moss), #223a30); }

.section-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: clamp(20px, 3vw, 36px);
}
.section-head__text { max-width: 54ch; }

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--cyan);
}
.eyebrow::before { content: ""; width: 26px; height: 1px; background: currentColor; opacity: 0.75; }

.with-index { position: relative; padding-left: clamp(0px, 4vw, 64px); }
.index-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--clay);
}
.with-index > .index-num { position: absolute; left: 0; top: 0.4em; }

.rule { height: 1px; background: var(--line); border: 0; margin-block: clamp(24px, 3vw, 40px); }

/* 6. 按钮与标签 ----------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  text-decoration: none;
  cursor: pointer;
  transition: transform 0.2s var(--ease), background-color 0.2s var(--ease),
              color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.btn:hover { transform: translateY(-1px); }
.btn--accent { background: var(--orange); color: #1a0d05; border-color: rgba(255, 122, 47, 0.9); }
.btn--accent:hover { background: #ff8f4d; }
.btn--cyan { background: var(--cyan); color: #06131f; border-color: rgba(53, 224, 212, 0.9); }
.btn--ghost { background: rgba(18, 40, 61, 0.5); border-color: var(--line); color: var(--cold); }
.btn--ghost:hover { border-color: rgba(53, 224, 212, 0.55); color: var(--cyan); }
.btn--quiet { padding: 8px 12px; color: var(--steel); }
.btn--quiet:hover { color: var(--cyan); }

.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(11, 27, 43, 0.5);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}
.tag--cyan { color: var(--cyan); border-color: rgba(53, 224, 212, 0.42); background: var(--cyan-dim); }
.tag--orange { color: var(--orange); border-color: rgba(255, 122, 47, 0.42); background: rgba(255, 122, 47, 0.12); }
.tag--amber { color: var(--amber); border-color: rgba(242, 176, 60, 0.4); background: rgba(242, 176, 60, 0.12); }
.tag--steel { color: var(--steel); }

/* 7. 页头：悬浮胶囊 + 索引带 ---------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 80;
  background: linear-gradient(180deg, rgba(8, 20, 32, 0.95), rgba(8, 20, 32, 0.78));
  -webkit-backdrop-filter: blur(14px);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
  transition: box-shadow 0.3s var(--ease);
}
.site-header[data-scrolled="true"] { box-shadow: 0 16px 34px -26px rgba(0, 0, 0, 0.95); }

.header-inner {
  position: relative;
  width: 100%;
  max-width: var(--shell-wide);
  margin-inline: auto;
  padding: 12px var(--gutter);
  display: flex;
  align-items: center;
  gap: 14px;
  transition: padding 0.28s var(--ease);
}
.site-header[data-scrolled="true"] .header-inner { padding-block: 6px; }

.brand-island {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  flex: none;
  padding: 7px 15px 7px 8px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--panel-soft);
  text-decoration: none;
  transition: border-color 0.25s var(--ease);
}
.brand-island:hover { border-color: rgba(53, 224, 212, 0.5); }

.brand-mark {
  position: relative;
  flex: none;
  width: 34px;
  height: 34px;
  border-radius: 11px;
  background: linear-gradient(140deg, var(--cyan), #1b8f8a 55%, var(--moss));
  box-shadow: inset 0 0 0 1px rgba(11, 27, 43, 0.55);
  transition: width 0.28s var(--ease), height 0.28s var(--ease);
}
.brand-mark::after {
  content: "";
  position: absolute;
  inset: 9px 7px;
  border-left: 1px solid rgba(8, 20, 32, 0.55);
  border-right: 1px solid rgba(8, 20, 32, 0.55);
  background-image: repeating-linear-gradient(90deg, rgba(8, 20, 32, 0.42) 0 1px, transparent 1px 5px);
}
.brand-mark--lg { width: 46px; height: 46px; border-radius: 14px; }
.brand-mark--lg::after { inset: 12px 9px; }
.site-header[data-scrolled="true"] .brand-mark { width: 28px; height: 28px; border-radius: 9px; }
.site-header[data-scrolled="true"] .brand-mark::after { inset: 7px 5px; }

.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name {
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--cold);
  transition: font-size 0.28s var(--ease);
}
.brand-note {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--steel);
  white-space: nowrap;
  max-height: 18px;
  overflow: hidden;
  transition: max-height 0.26s var(--ease), opacity 0.2s var(--ease);
}
.site-header[data-scrolled="true"] .brand-note { max-height: 0; opacity: 0; }
.site-header[data-scrolled="true"] .brand-name { font-size: 17px; }

.header-trail {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-left: 2px;
  padding-left: 12px;
  border-left: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--cyan);
  white-space: nowrap;
  max-width: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-width 0.3s var(--ease), opacity 0.22s var(--ease);
}
.header-trail::before {
  content: "";
  flex: none;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--orange);
}
.site-header[data-scrolled="true"] .header-trail { max-width: 260px; opacity: 1; }

.nav-capsule {
  margin-left: auto;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--panel-soft);
}
.nav-list { display: flex; align-items: center; gap: 2px; counter-reset: navIndex; }
.nav-item { list-style: none; counter-increment: navIndex; }

.nav-link {
  display: block;
  padding: 9px 14px;
  border-radius: var(--radius-pill);
  font-size: 14px;
  color: var(--ink-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), background-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.nav-link:hover { color: var(--cyan); background: var(--cyan-dim); }
.nav-link[aria-current="page"] {
  color: var(--cyan);
  background: var(--cyan-dim);
  box-shadow: inset 0 0 0 1px rgba(53, 224, 212, 0.5);
}

.header-actions { display: flex; align-items: center; gap: 10px; }
.header-action { white-space: nowrap; }

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: var(--panel-soft);
  color: var(--cold);
  transition: border-color 0.22s var(--ease), color 0.22s var(--ease);
}
.nav-toggle-bar {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.22s var(--ease), opacity 0.18s var(--ease);
}
.nav-toggle[aria-expanded="true"] { border-color: rgba(53, 224, 212, 0.55); color: var(--cyan); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] .nav-toggle-bar:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

.header-progress {
  position: absolute;
  left: 0;
  bottom: -1px;
  z-index: 1;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--amber) 60%, var(--orange));
  transform: scaleX(0);
  transform-origin: 0 50%;
}

/* 8. 页脚 ---------------------------------------------------------------- */
.site-footer {
  position: relative;
  margin-top: clamp(48px, 7vw, 96px);
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(11, 27, 43, 0.55), var(--arena-deep) 42%);
}
.site-footer::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(53, 224, 212, 0.55), rgba(255, 122, 47, 0.42), transparent);
}

.footer-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) repeat(2, minmax(0, 1fr)) minmax(0, 1.3fr);
  gap: clamp(24px, 3.4vw, 48px);
  padding-block: clamp(40px, 6vw, 72px) clamp(26px, 4vw, 44px);
}

.footer-brand { max-width: 42ch; }
.footer-brand-name {
  margin-top: 14px;
  font-family: var(--font-display);
  font-size: 24px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--cold);
}
.footer-lede { margin-top: 10px; font-size: 14.5px; color: var(--ink-soft); max-width: 36ch; }
.footer-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 16px; }

.footer-group-title {
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 500;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--steel);
}
.footer-links { display: grid; gap: 10px; margin-top: 16px; }

.footer-link {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  font-size: 14.5px;
  color: var(--ink-soft);
  text-decoration: none;
  transition: color 0.2s var(--ease);
}
.footer-link::before {
  content: "";
  width: 10px;
  height: 1px;
  background: var(--line);
  transition: width 0.2s var(--ease), background-color 0.2s var(--ease);
}
.footer-link:hover { color: var(--cyan); }
.footer-link:hover::before { width: 18px; background: var(--cyan); }

.footer-contact { min-width: 0; }
.contact-row {
  display: flex;
  gap: 12px;
  align-items: baseline;
  margin-top: 12px;
  font-size: 14px;
  color: var(--ink-soft);
}
.contact-key {
  flex: none;
  width: 38px;
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--steel);
}
.contact-val { color: var(--cold); overflow-wrap: anywhere; }
.contact-note {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--steel);
}

.footer-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding-block: 18px 24px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--steel);
}
.footer-legal { display: flex; flex-wrap: wrap; gap: 18px; }
.footer-legal-link { color: var(--steel); text-decoration: none; }
.footer-legal-link:hover { color: var(--cyan); }
.footer-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.footer-meta__sep { color: var(--line); }

/* 9. 面包屑 -------------------------------------------------------------- */
.crumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--steel);
}
.crumbs li { display: flex; align-items: center; gap: 10px; }
.crumbs li + li::before { content: "/"; color: #2b4864; margin-left: 2px; }
.crumbs a { color: var(--steel); text-decoration: none; }
.crumbs a:hover { color: var(--cyan); }
.crumbs [aria-current="page"] { color: var(--cold); }

/* 10. 正文、面板与卡片 ---------------------------------------------------- */
.prose { max-width: var(--measure); }
.prose p { max-width: var(--measure); color: var(--ink-soft); }
.prose p + p { margin-top: 1em; }
.prose h1, .prose h2, .prose h3 { max-width: 30ch; }
.prose h2 { margin-top: 1.6em; margin-bottom: 0.5em; }
.prose h3 { margin-top: 1.4em; margin-bottom: 0.4em; }
.prose ul { display: grid; gap: 10px; margin-top: 1em; }
.prose ul li { position: relative; padding-left: 18px; color: var(--ink-soft); }
.prose ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.75em;
  width: 8px;
  height: 1px;
  background: var(--cyan);
}
.prose a { color: var(--cyan); text-decoration: none; border-bottom: 1px solid rgba(53, 224, 212, 0.4); }
.prose a:hover { border-bottom-color: var(--cyan); }

.panel {
  padding: clamp(18px, 2.4vw, 26px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  box-shadow: var(--shadow-panel);
}
.panel--flat { background: rgba(18, 40, 61, 0.5); }
.panel--quiet { background: rgba(11, 27, 43, 0.6); box-shadow: none; }
.panel--sand { background: var(--sand); color: #16232e; border-color: rgba(166, 90, 58, 0.35); }
.panel--sand h3, .panel--sand h2 { color: #0f1c27; }

.card {
  display: block;
  padding: clamp(18px, 2.2vw, 24px);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  color: inherit;
  text-decoration: none;
  transition: transform 0.22s var(--ease), border-color 0.22s var(--ease), box-shadow 0.22s var(--ease);
}
.card:hover { transform: translateY(-2px); border-color: rgba(53, 224, 212, 0.45); box-shadow: var(--shadow-panel); }

.quote {
  padding: clamp(18px, 2.4vw, 28px);
  border-left: 3px solid var(--clay);
  border-radius: 0 var(--radius) var(--radius) 0;
  background: var(--sand);
  color: #16232e;
  font-size: 1.0625rem;
}

/* 11. 数据带与统计 ------------------------------------------------------- */
.data-band {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--line);
  overflow: hidden;
}
.data-band__item {
  padding: 16px 18px;
  background: linear-gradient(180deg, rgba(18, 40, 61, 0.95), rgba(11, 27, 43, 0.95));
}
.data-band__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--steel);
}
.data-band__value {
  margin-top: 4px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.3rem, 2.4vw, 1.75rem);
  letter-spacing: -0.01em;
  color: var(--amber);
}
.data-band__value--cyan { color: var(--cyan); }
.data-band__value--cold { color: var(--cold); }
.data-band__value--steel { color: var(--steel); }
.data-band__note { margin-top: 4px; font-size: 12.5px; color: var(--ink-faint); }

.stat__label {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--steel);
}
.stat__value {
  display: block;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  line-height: 1.1;
  color: var(--amber);
}
.stat__unit { font-size: 0.45em; letter-spacing: 0.06em; color: var(--steel); margin-left: 4px; }

/* 12. 网格 --------------------------------------------------------------- */
.grid { display: grid; gap: clamp(16px, 2.2vw, 26px); }
.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)); }
.grid--aside { grid-template-columns: minmax(0, 5fr) minmax(0, 7fr); }
.grid--aside-rev { grid-template-columns: minmax(0, 7fr) minmax(0, 5fr); }
.grid--gap-lg { gap: clamp(24px, 3.6vw, 48px); }

/* 13. 图文容器（页面阶段放图片占位） -------------------------------------- */
.media {
  position: relative;
  overflow: hidden;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(150deg, var(--panel), #0d1f2f);
}
.media--wide { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 4 / 5; }
.media--square { aspect-ratio: 1 / 1; }
.media img { width: 100%; height: 100%; object-fit: cover; }
.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.55;
  background-image:
    linear-gradient(rgba(53, 224, 212, 0.10) 1px, transparent 1px),
    linear-gradient(90deg, rgba(53, 224, 212, 0.10) 1px, transparent 1px);
  background-size: 48px 48px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 72%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 72%);
}
.media__placeholder {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: rgba(138, 153, 166, 0.75);
}
.media__caption {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
  background: linear-gradient(180deg, transparent, rgba(8, 20, 32, 0.92));
}
.media__tag { position: absolute; top: 12px; left: 12px; }

/* 14. 分段切换（原生 radio） --------------------------------------------- */
.seg { display: block; }
.seg-controls {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 4px;
  padding: 5px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(18, 40, 61, 0.6);
}
.seg-input { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }
.seg-tab {
  cursor: pointer;
  padding: 8px 16px;
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--steel);
  transition: background-color 0.2s var(--ease), color 0.2s var(--ease);
}
.seg-tab:hover { color: var(--cold); }
.seg-input:checked + .seg-tab { background: var(--cyan); color: #071522; }
.seg-input:focus-visible + .seg-tab { outline: 2px solid var(--orange); outline-offset: 2px; }
.seg-panels { margin-top: clamp(16px, 2.2vw, 26px); }
.seg-panel { display: none; }
.seg-panel[data-active="true"] { display: block; }

/* 15. 折叠面板 ----------------------------------------------------------- */
.disclosure { border-top: 1px solid var(--line); }
.disclosure > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0;
  cursor: pointer;
  font-family: var(--font-display);
  font-size: 1.1875rem;
  font-weight: 700;
  color: var(--cold);
  list-style: none;
}
.disclosure > summary::-webkit-details-marker { display: none; }
.disclosure > summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 16px;
  color: var(--cyan);
}
.disclosure[open] > summary::after { content: "–"; }
.disclosure__body { padding-bottom: 18px; color: var(--ink-soft); max-width: 62ch; }

/* 16. 显现与返回顶部 ----------------------------------------------------- */
.reveal.is-in { animation: reveal-rise 0.52s var(--ease) both; }
@keyframes reveal-rise {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: none; }
}

.to-top {
  position: fixed;
  right: clamp(14px, 3vw, 28px);
  bottom: clamp(14px, 3vw, 28px);
  z-index: 70;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius-pill);
  background: rgba(18, 40, 61, 0.92);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--steel);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.22s var(--ease), transform 0.22s var(--ease),
              visibility 0.22s var(--ease), color 0.2s var(--ease), border-color 0.2s var(--ease);
}
.to-top[data-visible="true"] { opacity: 1; visibility: visible; transform: none; }
.to-top:hover { color: var(--cyan); border-color: rgba(53, 224, 212, 0.5); }

/* 17. 断点 --------------------------------------------------------------- */
@media (max-width: 1080px) {
  .nav-toggle { display: inline-flex; }
  .header-actions { margin-left: auto; }

  .nav-capsule {
    position: absolute;
    top: calc(100% + 10px);
    left: var(--gutter);
    right: var(--gutter);
    margin-left: 0;
    padding: 12px;
    border-radius: var(--radius-l);
    background: linear-gradient(180deg, rgba(18, 40, 61, 0.99), rgba(11, 27, 43, 0.99));
    box-shadow: var(--shadow-float);
    visibility: hidden;
    opacity: 0;
    transform: translateY(-8px);
    pointer-events: none;
    transition: opacity 0.22s var(--ease), transform 0.22s var(--ease), visibility 0.22s var(--ease);
  }
  .nav-capsule[data-open="true"],
  [data-nav][data-open="true"] {
    visibility: visible;
    opacity: 1;
    transform: none;
    pointer-events: auto;
  }

  .nav-list { flex-direction: column; align-items: stretch; gap: 4px; }
  .nav-link {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 13px 16px;
    border-radius: 14px;
    font-size: 15.5px;
  }
  .nav-link::after {
    content: counter(navIndex, decimal-leading-zero);
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.14em;
    color: var(--steel);
  }
  .nav-link[aria-current="page"]::after { color: var(--cyan); }

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

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

@media (max-width: 720px) {
  .header-action { display: none; }
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  .brand-note { display: none; }
  .brand-name { font-size: 17px; }
  .header-trail { display: none; }
  .grid--2, .grid--3, .grid--4 { grid-template-columns: minmax(0, 1fr); }
  .with-index { padding-left: 0; }
  .with-index > .index-num { position: static; margin-bottom: 6px; }
  .footer-grid { grid-template-columns: minmax(0, 1fr); }
  .footer-bottom { flex-direction: column; align-items: flex-start; }
}

/* 18. 降低动效 ----------------------------------------------------------- */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  .reveal.is-in { animation: none; }
  .card:hover, .btn:hover { transform: none; }
}