/* ==========================================================================
   体验赛场 · 共享样式表  /assets/site.css
   深靛蓝夜空 × 经幡珊瑚橙 · 侧边轨道导航 · Bento 展览板
   ========================================================================== */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: 96px;
}

body {
  margin: 0;
  min-height: 100vh;
}

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

h1, h2, h3, h4, h5, h6, p, figure, dl, dd {
  margin: 0;
}

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

button {
  font: inherit;
  color: inherit;
}

a {
  color: inherit;
}

[hidden] {
  display: none !important;
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

/* ---------- 2. 变量 ---------- */
:root {
  /* 主色 */
  --ink: #101A3A;
  --ink-deep: #0A1130;
  --ink-1: #1B2A55;
  --ink-2: #22326A;

  /* 强调色 */
  --coral: #FF6B4A;
  --coral-soft: #FFB39E;

  /* 功能色 */
  --barley: #4FAE7E;
  --butter: #F2C14E;

  /* 中性 */
  --snow: #F7F7F5;
  --char: #14161C;
  --gray: #8C93A8;
  --text-body: #C9CFE0;

  /* 结构与字号 */
  --rail-w: 276px;
  --shell: 1280px;
  --r-lg: 28px;
  --r-md: 18px;
  --r-sm: 12px;
  --pill: 999px;
  --edge: rgba(247, 247, 245, 0.13);
  --edge-strong: rgba(247, 247, 245, 0.28);
  --shadow: 0 24px 52px -30px rgba(3, 7, 22, 0.92);

  --font-display: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-body: "Noto Sans SC", "Source Han Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "JetBrains Mono", "SFMono-Regular", "Roboto Mono", ui-monospace, monospace;
}

@media (min-width: 901px) and (max-width: 1180px) {
  :root { --rail-w: 238px; }
}

/* ---------- 3. 页面骨架与夜空纹理 ---------- */
body {
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.75;
  letter-spacing: 0.01em;
  color: var(--text-body);
  background-color: var(--ink);
  background-image:
    radial-gradient(circle at 88% 6%, rgba(255, 107, 74, 0.20), transparent 44%),
    radial-gradient(circle at 8% 92%, rgba(79, 174, 126, 0.15), transparent 48%),
    linear-gradient(rgba(247, 247, 245, 0.038) 1px, transparent 1px),
    linear-gradient(90deg, rgba(247, 247, 245, 0.038) 1px, transparent 1px);
  background-size: auto, auto, 48px 48px, 48px 48px;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

@media (min-width: 901px) {
  body { padding-left: var(--rail-w); }
}

main {
  display: block;
  min-height: 42vh;
}

.wrap {
  width: 100%;
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: clamp(18px, 3.4vw, 48px);
}

/* ---------- 4. 标题与文字 ---------- */
h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.18;
  letter-spacing: -0.01em;
  color: var(--snow);
}

h1 { font-size: clamp(2.2rem, 5vw, 4.2rem); font-weight: 900; }
h2 { font-size: clamp(1.5rem, 2.6vw, 2.2rem); }
h3 { font-size: clamp(1.15rem, 1.8vw, 1.5rem); }

p { max-width: 76ch; }

.eyebrow {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--coral-soft);
  margin-bottom: 12px;
}

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

.section-head p {
  color: var(--gray);
  font-size: 0.95rem;
}

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

/* ---------- 5. 焦点与动效偏好 ---------- */
:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 3px;
  border-radius: 8px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  transform: translateY(-180%);
  padding: 10px 18px;
  border-radius: var(--pill);
  background: var(--coral);
  color: var(--char);
  font-weight: 800;
  font-size: 0.9rem;
  text-decoration: none;
  transition: transform 0.26s ease;
}

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

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.62s ease, transform 0.62s cubic-bezier(0.2, 0.7, 0.3, 1);
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}

/* ---------- 6. 侧边轨道导航（头部） ---------- */
.site-rail {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  width: var(--rail-w);
  z-index: 70;
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 26px 22px 22px;
  color: var(--snow);
  overflow-y: auto;
  overscroll-behavior: contain;
  scrollbar-width: thin;
  scrollbar-color: rgba(247, 247, 245, 0.24) transparent;
  border-right: 1px solid var(--edge);
  background:
    linear-gradient(180deg, var(--coral) 0%, var(--butter) 46%, var(--barley) 100%) right top / 3px 100% no-repeat,
    linear-gradient(172deg, #16234B 0%, #0C1533 68%, #101A3A 100%);
}

.site-rail::-webkit-scrollbar { width: 6px; }
.site-rail::-webkit-scrollbar-thumb {
  background: rgba(247, 247, 245, 0.22);
  border-radius: var(--pill);
}

.rail-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--snow);
  min-width: 0;
}

.brand-mark {
  position: relative;
  flex: 0 0 auto;
  width: 40px;
  height: 40px;
  border-radius: 13px;
  background: linear-gradient(150deg, var(--coral), #D8481F);
  box-shadow: 0 10px 22px -12px rgba(255, 107, 74, 0.95);
}

.brand-mark::before {
  content: "";
  position: absolute;
  inset: 9px;
  border: 2px solid rgba(247, 247, 245, 0.94);
  border-radius: 50%;
}

.brand-mark::after {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: rgba(247, 247, 245, 0.94);
  transform: translate(-50%, -50%) rotate(-34deg);
  box-shadow: 0 -7px 0 -0.5px rgba(247, 247, 245, 0.5), 0 7px 0 -0.5px rgba(247, 247, 245, 0.5);
}

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

.brand-text strong {
  display: block;
  font-size: 1.06rem;
  font-weight: 900;
  letter-spacing: 0.03em;
  line-height: 1.3;
}

.brand-text small {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--gray);
  white-space: nowrap;
}

.nav-toggle {
  display: none;
  align-items: center;
  gap: 8px;
  padding: 8px 13px;
  border-radius: var(--pill);
  border: 1px solid var(--edge);
  background: rgba(247, 247, 245, 0.06);
  color: var(--snow);
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.14em;
  cursor: pointer;
  transition: border-color 0.2s ease, background 0.2s ease;
}

.nav-toggle:hover {
  border-color: var(--coral);
  background: rgba(255, 107, 74, 0.16);
}

.nav-toggle-bars {
  position: relative;
  display: inline-block;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
}

.nav-toggle-bars::before,
.nav-toggle-bars::after {
  content: "";
  position: absolute;
  left: 0;
  width: 16px;
  height: 2px;
  border-radius: 2px;
  background: currentColor;
  transition: transform 0.24s ease;
}

.nav-toggle-bars::before { top: -5px; }
.nav-toggle-bars::after { top: 5px; }

.site-rail[data-open="true"] .nav-toggle-bars { background: transparent; }
.site-rail[data-open="true"] .nav-toggle-bars::before { transform: translateY(5px) rotate(45deg); }
.site-rail[data-open="true"] .nav-toggle-bars::after { transform: translateY(-5px) rotate(-45deg); }

.rail-panel {
  display: flex;
  flex-direction: column;
  gap: 22px;
  flex: 1 1 auto;
  min-height: 0;
}

.rail-label {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--gray);
  margin-bottom: 10px;
}

.nav-list {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.nav-list a {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 14px 11px 16px;
  border-radius: var(--r-sm);
  color: #C4CADB;
  font-size: 0.99rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: background 0.18s ease, color 0.18s ease;
}

.nav-list a::before {
  content: "";
  position: absolute;
  left: 0;
  top: 50%;
  width: 3px;
  height: 0;
  border-radius: var(--pill);
  background: var(--coral);
  transform: translateY(-50%);
  transition: height 0.24s ease;
}

.nav-list a:hover {
  background: rgba(247, 247, 245, 0.07);
  color: var(--snow);
}

.nav-list a[aria-current="page"] {
  background: rgba(255, 107, 74, 0.13);
  color: var(--snow);
}

.nav-list a[aria-current="page"]::before { height: 58%; }

.nav-idx {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--gray);
  min-width: 1.9em;
  transition: color 0.18s ease;
}

.nav-list a[aria-current="page"] .nav-idx { color: var(--coral); }

.rail-tools {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 18px;
  border-top: 1px dashed rgba(247, 247, 245, 0.16);
}

.rail-cta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 10px 13px;
  border-radius: var(--r-sm);
  border: 1px solid var(--edge);
  background: rgba(247, 247, 245, 0.045);
  color: var(--snow);
  font-size: 0.9rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.rail-cta:hover {
  transform: translateY(-2px);
  border-color: var(--coral);
  background: rgba(255, 107, 74, 0.15);
}

.cta-arrow {
  font-family: var(--font-mono);
  color: var(--coral-soft);
}

.rail-foot {
  margin-top: auto;
  padding-top: 16px;
  border-top: 1px solid var(--edge);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  line-height: 1.9;
  letter-spacing: 0.04em;
  color: var(--gray);
}

.rail-foot p { margin: 0; max-width: none; }

.rail-progress {
  height: 3px;
  margin-bottom: 12px;
  border-radius: var(--pill);
  background: rgba(247, 247, 245, 0.12);
  overflow: hidden;
}

.rail-progress span {
  display: block;
  width: 100%;
  height: 100%;
  transform: scaleX(0);
  transform-origin: left center;
  background: linear-gradient(90deg, var(--coral), var(--butter));
  transition: transform 0.08s linear;
}

.rail-scrim {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 60;
  padding: 0;
  border: 0;
  background: rgba(5, 9, 24, 0.62);
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease;
  cursor: pointer;
}

/* ---------- 7. 移动端：顶栏 + 抽屉 ---------- */
@media (max-width: 900px) {
  body { padding-left: 0; padding-top: 76px; }

  .site-rail {
    top: 0;
    left: 0;
    right: 0;
    bottom: auto;
    width: auto;
    max-height: 100vh;
    gap: 0;
    padding: 13px 16px;
    overflow: visible;
    border-right: 0;
    border-bottom: 1px solid var(--edge);
    background: linear-gradient(180deg, rgba(12, 21, 51, 0.99), rgba(16, 26, 58, 0.96));
    backdrop-filter: blur(12px);
  }

  .site-rail::after {
    content: "";
  }

  .rail-top { min-height: 46px; }

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

  .rail-panel {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    gap: 16px;
    max-height: 0;
    padding: 0 16px;
    overflow: hidden;
    background: linear-gradient(180deg, #0F1A3F, #101A3A);
    border-bottom: 1px solid var(--edge);
    transition: max-height 0.34s ease, padding 0.34s ease;
  }

  .site-rail[data-open="true"] .rail-panel {
    max-height: 78vh;
    padding: 18px 16px 24px;
    overflow-y: auto;
    overscroll-behavior: contain;
  }

  .rail-foot { margin-top: 6px; }

  .rail-scrim { display: block; }
  .rail-scrim[data-open="true"] {
    opacity: 1;
    visibility: visible;
  }
}

/* ---------- 8. 页脚 ---------- */
.site-footer {
  margin-top: clamp(50px, 7vw, 100px);
  border-top: 1px solid var(--edge);
  background:
    linear-gradient(180deg, rgba(27, 42, 85, 0.55), rgba(8, 14, 38, 0.98) 62%),
    var(--ink-deep);
  color: #C4CADB;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.5fr 0.9fr 0.9fr 1.6fr;
  gap: clamp(22px, 3vw, 44px);
  padding-block: clamp(36px, 5vw, 66px);
}

.footer-logo {
  font-size: 1.34rem;
  font-weight: 900;
  letter-spacing: 0.05em;
  color: var(--snow);
  max-width: none;
}

.footer-brand > p {
  margin-top: 10px;
  font-size: 0.9rem;
  color: var(--gray);
  max-width: 34ch;
}

.footer-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 16px;
}

.footer-tags li {
  font-family: var(--font-mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  padding: 5px 11px;
  border-radius: var(--pill);
  border: 1px solid var(--edge);
  color: var(--coral-soft);
}

.footer-col h3,
.footer-contact h3 {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--butter);
  margin-bottom: 16px;
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-col a {
  display: inline-block;
  font-size: 0.93rem;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.footer-col a:hover {
  color: var(--snow);
  border-bottom-color: var(--coral);
}

.contact-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.contact-row {
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 10px;
  align-items: baseline;
}

.contact-row dt {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  color: var(--gray);
}

.contact-row dd {
  font-size: 0.9rem;
  word-break: break-word;
}

.contact-row dd a {
  color: var(--coral-soft);
  text-decoration: none;
  border-bottom: 1px dashed rgba(255, 179, 158, 0.5);
}

.contact-row dd a:hover {
  color: var(--snow);
  border-bottom-color: var(--snow);
}

.footer-note {
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--gray);
  max-width: 40ch;
}

.footer-base {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 12px 26px;
  padding-block: 18px 30px;
  border-top: 1px solid var(--edge);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  color: var(--gray);
}

.footer-base p { margin: 0; max-width: none; }

.footer-base a {
  text-decoration: none;
  color: #B9C0D2;
}

.footer-base a:hover { color: var(--coral-soft); }

@media (max-width: 1080px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .footer-brand,
  .footer-contact { grid-column: 1 / -1; }
}

@media (max-width: 620px) {
  .footer-grid { grid-template-columns: 1fr; }
  .footer-brand,
  .footer-contact { grid-column: auto; }
  .footer-base { flex-direction: column; align-items: flex-start; }
}

/* ---------- 9. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5em;
  padding: 0.78em 1.35em;
  border-radius: var(--pill);
  border: 1px solid transparent;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  text-decoration: none;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}

.btn:hover { transform: translateY(-2px); }

.btn--primary {
  background: var(--coral);
  color: var(--char);
  box-shadow: 0 16px 30px -20px rgba(255, 107, 74, 0.95);
}

.btn--primary:hover {
  background: var(--coral-soft);
  color: var(--char);
}

.btn--ghost {
  border-color: var(--edge-strong);
  color: var(--snow);
  background: rgba(247, 247, 245, 0.04);
}

.btn--ghost:hover {
  border-color: var(--coral);
  color: var(--coral-soft);
}

.btn--sm {
  padding: 0.55em 1.05em;
  font-size: 0.84rem;
}

/* ---------- 10. 标签 / 展览说明牌 ---------- */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 0.42em;
  padding: 5px 11px;
  border-radius: var(--pill);
  border: 1px solid var(--edge);
  background: rgba(247, 247, 245, 0.05);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: #C4CADB;
  white-space: nowrap;
}

.tag--coral {
  background: rgba(255, 107, 74, 0.16);
  border-color: rgba(255, 107, 74, 0.5);
  color: var(--coral-soft);
}

.tag--barley {
  background: rgba(79, 174, 126, 0.16);
  border-color: rgba(79, 174, 126, 0.5);
  color: #9FDCC0;
}

.tag--butter {
  background: rgba(242, 193, 78, 0.16);
  border-color: rgba(242, 193, 78, 0.52);
  color: #F7D98A;
}

.tag--tilt {
  transform: rotate(-3.2deg);
  transform-origin: left center;
}

/* ---------- 11. 卡片 ---------- */
.card {
  position: relative;
  border-radius: var(--r-lg);
  border: 1px solid var(--edge);
  background: linear-gradient(160deg, rgba(27, 42, 85, 0.92), rgba(16, 26, 58, 0.94));
  padding: clamp(18px, 2.4vw, 28px);
  box-shadow: var(--shadow);
  transition: transform 0.22s ease, border-color 0.22s ease;
}

.card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 107, 74, 0.45);
}

.card--light {
  background: var(--snow);
  border-color: rgba(20, 22, 28, 0.08);
  color: #3A3F52;
}

.card--light .card-title { color: var(--char); }
.card--light .card-meta { color: #6A7085; }
.card--light p { color: #3A3F52; }

.card-title {
  font-family: var(--font-display);
  font-size: 1.16rem;
  font-weight: 800;
  line-height: 1.35;
  color: var(--snow);
  margin: 0 0 8px;
}

.card-meta {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.06em;
  color: var(--gray);
}

/* ---------- 12. 网格工具 ---------- */
.grid {
  display: grid;
  gap: clamp(14px, 2vw, 22px);
}

.grid--2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid--3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid--auto { grid-template-columns: repeat(auto-fit, minmax(248px, 1fr)); }

@media (max-width: 900px) {
  .grid--3 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (max-width: 640px) {
  .grid--2,
  .grid--3 { grid-template-columns: 1fr; }
}

/* ---------- 13. 正文容器 ---------- */
.prose {
  max-width: 74ch;
}

.prose h2 {
  font-size: clamp(1.4rem, 2.4vw, 1.9rem);
  margin: 2.2em 0 0.7em;
}

.prose h2:first-child { margin-top: 0; }

.prose h3 {
  font-size: clamp(1.1rem, 1.7vw, 1.35rem);
  margin: 1.8em 0 0.6em;
}

.prose p {
  margin-bottom: 1.15em;
  color: var(--text-body);
}

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

.prose ul,
.prose ol {
  padding-left: 1.25em;
  margin-bottom: 1.3em;
}

.prose li { margin-bottom: 0.5em; }

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

.prose strong { color: var(--snow); }

.prose code {
  font-family: var(--font-mono);
  font-size: 0.86em;
  padding: 0.14em 0.42em;
  border-radius: 6px;
  background: rgba(247, 247, 245, 0.09);
}

.prose blockquote {
  margin: 0 0 1.4em;
  padding: 0.95em 1.25em;
  border-left: 3px solid var(--coral);
  border-radius: 0 var(--r-sm) var(--r-sm) 0;
  background: rgba(255, 107, 74, 0.08);
  color: #D6DBEA;
}

.prose blockquote p { margin: 0; }

.card--light .prose p,
.card--light .prose li,
.card--light .prose blockquote { color: #3A3F52; }

.card--light .prose strong,
.card--light .prose h2,
.card--light .prose h3 { color: var(--char); }

/* ---------- 14. 折叠面板 ---------- */
.folding {
  border: 1px solid var(--edge);
  border-radius: var(--r-md);
  background: rgba(27, 42, 85, 0.58);
  overflow: hidden;
}

.folding + .folding { margin-top: 10px; }

.folding > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 18px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 800;
  color: var(--snow);
}

.folding > summary::-webkit-details-marker { display: none; }

.folding > summary::after {
  content: "+";
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 1.15rem;
  line-height: 1;
  color: var(--coral);
  transition: transform 0.24s ease;
}

.folding[open] > summary::after { transform: rotate(45deg); }

.folding-body {
  padding: 0 18px 18px;
  font-size: 0.95rem;
  color: var(--text-body);
}

.folding-body p { max-width: 70ch; }

/* ---------- 15. 滤镜条 ---------- */
.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: clamp(16px, 2.4vw, 26px);
}

.filter-btn {
  padding: 8px 16px;
  border-radius: var(--pill);
  border: 1px solid var(--edge);
  background: transparent;
  color: #C4CADB;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.12em;
  cursor: pointer;
  transition: background 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.filter-btn:hover {
  border-color: var(--coral-soft);
  color: var(--snow);
}

.filter-btn[aria-pressed="true"] {
  background: var(--coral);
  border-color: var(--coral);
  color: var(--char);
  font-weight: 700;
}

/* ---------- 16. 面包屑 ---------- */
.breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--gray);
  margin-bottom: clamp(14px, 2vw, 22px);
}

.breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.6em;
}

.breadcrumb li {
  display: flex;
  align-items: center;
  gap: 0.6em;
}

.breadcrumb li + li::before {
  content: "/";
  color: rgba(140, 147, 168, 0.6);
}

.breadcrumb a {
  text-decoration: none;
  color: var(--gray);
  transition: color 0.18s ease;
}

.breadcrumb a:hover { color: var(--coral-soft); }

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

/* ---------- 17. 媒体容器（供页面阶段放置图片） ---------- */
.media {
  position: relative;
  display: block;
  width: 100%;
  overflow: hidden;
  isolation: isolate;
  border-radius: var(--r-md);
  background-color: #131E42;
  background-image:
    radial-gradient(circle at 28% 18%, rgba(255, 107, 74, 0.24), transparent 56%),
    radial-gradient(circle at 78% 86%, rgba(79, 174, 126, 0.18), transparent 58%),
    repeating-linear-gradient(45deg, #16224A 0 12px, #131E42 12px 24px);
}

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

.media::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(ellipse at 50% 44%, transparent 38%, rgba(8, 13, 33, 0.74) 100%);
}

.media--16x9 { aspect-ratio: 16 / 9; }
.media--4x3 { aspect-ratio: 4 / 3; }
.media--1x1 { aspect-ratio: 1 / 1; }
.media--21x9 { aspect-ratio: 21 / 9; }
.media--tall { aspect-ratio: 3 / 4; }

@media (max-width: 640px) {
  .media--21x9 { aspect-ratio: 16 / 9; }
  .media--tall { aspect-ratio: 4 / 5; }
}

.media-cap {
  position: absolute;
  left: 14px;
  bottom: 14px;
  z-index: 2;
  display: inline-flex;
  align-items: center;
  gap: 0.5em;
  padding: 5px 12px;
  border-radius: var(--pill);
  background: rgba(10, 17, 48, 0.82);
  border: 1px solid var(--edge);
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  color: var(--coral-soft);
}

/* ---------- 18. 杂项 ---------- */
.rule {
  height: 1px;
  border: 0;
  margin: clamp(28px, 4vw, 54px) 0;
  background: linear-gradient(90deg, var(--coral), var(--butter) 42%, var(--barley) 70%, transparent);
  opacity: 0.65;
}