.page-about {
  --about-rail-w: 172px;
  color: var(--paper);
  padding-bottom: clamp(56px, 8vw, 104px);
  background:
    radial-gradient(980px 560px at 84% -8%, rgba(255, 138, 61, 0.13), transparent 62%),
    radial-gradient(860px 520px at 4% 104%, rgba(53, 224, 200, 0.10), transparent 60%),
    var(--ink);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(28px, 5vw, 64px) 0 clamp(30px, 5vw, 56px);
  max-width: 980px;
}

.page-about .about-eyebrow {
  margin: 0;
  font: 500 12px/1 var(--font-mono);
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--mist);
}

.page-about .about-hero h1 {
  margin: 18px 0 0;
  font-size: clamp(32px, 6.2vw, 72px);
  line-height: 1.08;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero h1 em {
  font-style: normal;
  color: var(--amber);
}

.page-about .about-lead {
  margin: 24px 0 0;
  max-width: 34em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.78;
  color: var(--mist);
}

/* ---------- 左右分栏骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 44px);
  align-items: start;
}

.page-about .about-stream {
  min-width: 0;
}

/* ---------- 左侧年份索引 ---------- */
.page-about .about-rail {
  min-width: 0;
}

.page-about .about-rail-cap {
  margin: 0 0 12px;
  font: 500 11px/1 var(--font-mono);
  letter-spacing: 0.18em;
  color: var(--mist);
}

.page-about .about-rail-list {
  list-style: none;
  margin: 0;
  padding: 0 0 6px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-rail-list li {
  flex: 0 0 auto;
}

.page-about .about-rail-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 14px;
  border-radius: 999px;
  border: 1px solid var(--ink-3);
  color: var(--mist);
  font-size: 13px;
  line-height: 1;
  white-space: nowrap;
  text-decoration: none;
  transition: color 0.18s ease, border-color 0.18s ease, background-color 0.18s ease;
}

.page-about .about-rail-link:hover {
  color: var(--paper);
  border-color: var(--amber);
}

.page-about .about-rail-link.is-active {
  color: var(--ink);
  background: var(--amber);
  border-color: var(--amber);
}

.page-about .about-rail-idx {
  font: 500 11px/1 var(--font-mono);
  opacity: 0.75;
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  padding: clamp(34px, 5.5vw, 60px) 0;
  border-top: 1px solid rgba(155, 176, 196, 0.16);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 22px;
}

.page-about .about-sec-num {
  flex: 0 0 auto;
  font: 500 13px/1 var(--font-mono);
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .about-sec h2 {
  margin: 0;
  font-size: clamp(21px, 3.2vw, 34px);
  line-height: 1.26;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-sec-intro {
  max-width: 34em;
  margin: 0 0 24px;
  font-size: 15px;
  line-height: 1.78;
  color: var(--mist);
}

.page-about .about-sec-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(22px, 3.5vw, 40px);
  align-items: start;
}

.page-about .about-sec-body .prose p {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-sec-body .prose p:last-child {
  margin-bottom: 0;
}

.page-about .about-fig {
  margin: 0;
  border-radius: var(--r-md);
  overflow: hidden;
  background: var(--ink-2);
  border: 1px solid var(--ink-3);
}

.page-about .about-fig img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
}

.page-about .about-fig figcaption {
  padding: 11px 16px;
  font: 400 12px/1.6 var(--font-mono);
  color: var(--mist);
  background: var(--ink-2);
  border-top: 1px solid rgba(155, 176, 196, 0.14);
}

/* ---------- 班次 ---------- */
.page-about .about-shifts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .about-shift {
  padding: 18px 20px;
  border-radius: var(--r-md);
  border: 1px solid rgba(53, 224, 200, 0.22);
  background: linear-gradient(155deg, rgba(53, 224, 200, 0.10), rgba(18, 40, 60, 0.92));
}

.page-about .about-shift-k {
  margin: 0;
  font-size: 14px;
  font-weight: 600;
  color: var(--paper);
}

.page-about .about-shift-t {
  margin: 6px 0 0;
  font: 500 20px/1 var(--font-mono);
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.page-about .about-shift-d {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 统计卡 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
}

.page-about .about-stat {
  padding: 20px;
  border-radius: var(--r-md);
  background: var(--ink-2);
  border: 1px solid var(--ink-3);
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.page-about .about-stat:hover {
  background: #16324a;
  border-color: rgba(53, 224, 200, 0.42);
}

.page-about .about-stat-num {
  margin: 0;
  font: 600 clamp(26px, 3.4vw, 36px)/1 var(--font-mono);
  letter-spacing: -0.02em;
  color: var(--cyan);
}

.page-about .about-stat-num small {
  margin-left: 5px;
  font-size: 0.44em;
  font-weight: 500;
  letter-spacing: 0;
  color: var(--mist);
}

.page-about .about-stat-label {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .about-stat-note {
  margin: 8px 0 0;
  padding: 5px 9px;
  display: inline-block;
  border-radius: var(--r-sm);
  background: rgba(181, 242, 231, 0.12);
  font: 400 11.5px/1.5 var(--font-mono);
  color: var(--cyan-soft);
}

/* ---------- 版本时间带 ---------- */
.page-about .about-tl {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-tl-node {
  position: relative;
  padding: 0 0 26px 26px;
  border-left: 1px solid rgba(155, 176, 196, 0.24);
}

.page-about .about-tl-node:last-child {
  padding-bottom: 0;
}

.page-about .about-tl-dot {
  position: absolute;
  left: -5px;
  top: 4px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 4px rgba(255, 138, 61, 0.16);
}

.page-about .about-tl-year {
  display: inline-block;
  margin-bottom: 10px;
  padding: 5px 10px;
  border-radius: 999px;
  background: var(--amber-soft);
  color: var(--ink);
  font: 600 12px/1 var(--font-mono);
  letter-spacing: 0.14em;
}

.page-about .about-tl-title {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 600;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-tl-desc {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.72;
  color: var(--mist);
}

/* ---------- 结尾引导区 ---------- */
.page-about .about-close {
  position: relative;
  margin-top: clamp(40px, 6vw, 72px);
  border-radius: var(--r-lg);
  overflow: hidden;
  border: 1px solid var(--ink-3);
  min-height: 340px;
  display: flex;
  align-items: flex-end;
  isolation: isolate;
}

.page-about .about-close-bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.42;
  z-index: -1;
}

.page-about .about-close-inner {
  width: 100%;
  padding: clamp(24px, 4.5vw, 52px);
  background: linear-gradient(0deg, rgba(11, 27, 43, 0.96) 34%, rgba(11, 27, 43, 0.18) 100%);
}

.page-about .about-close h2 {
  margin: 12px 0 18px;
  font-size: clamp(21px, 3.2vw, 34px);
  line-height: 1.26;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-close-cols {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  max-width: 68em;
}

.page-about .about-close-cols p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--mist);
}

.page-about .about-close-cols a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 620px) {
  .page-about .about-shifts {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

  .page-about .about-close-cols {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 24px;
  }
}

@media (min-width: 760px) {
  .page-about .about-sec-body {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  }

  .page-about .about-sec-body--single {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }

  .page-about .about-sec-body--flip .prose {
    order: 2;
  }

  .page-about .about-sec-body--flip .about-fig {
    order: 1;
  }
}

@media (min-width: 900px) {
  .page-about .about-tl {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    column-gap: 18px;
  }

  .page-about .about-tl-node {
    padding: 28px 0 0;
    border-left: 0;
    border-top: 1px solid rgba(155, 176, 196, 0.24);
  }

  .page-about .about-tl-node:last-child {
    padding-bottom: 0;
  }

  .page-about .about-tl-dot {
    left: 0;
    top: -5px;
  }

  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
  }
}

@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
  }

  .page-about .about-rail-list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-rail-list li + li {
    margin-top: 6px;
  }

  .page-about .about-rail-link {
    display: flex;
    width: 100%;
    padding: 10px 12px;
    border-radius: var(--r-sm);
    border-color: transparent;
    border-left: 2px solid transparent;
  }

  .page-about .about-rail-link:hover {
    color: var(--paper);
    border-color: transparent;
    border-left-color: var(--amber);
  }

  .page-about .about-rail-link.is-active {
    color: var(--paper);
    background: rgba(255, 138, 61, 0.12);
    border-color: transparent;
    border-left-color: var(--amber);
  }

  .page-about .about-rail-link.is-active .about-rail-idx {
    color: var(--amber);
    opacity: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail-link,
  .page-about .about-stat {
    transition: none;
  }
}