.page-about {
  --about-muted: #57666f;
  --about-rule: rgba(16, 24, 32, 0.13);
  --about-rail-w: 152px;
  background: var(--paper-2);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.75;
}

.page-about img {
  max-width: 100%;
  height: auto;
  display: block;
}

.page-about .about-crumbbar {
  background: var(--paper-2);
  border-bottom: 1px solid var(--about-rule);
  padding: 10px 0;
  font-size: 13px;
}

.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  color: var(--about-muted);
  flex-wrap: wrap;
}

.page-about .breadcrumb a {
  color: var(--cyan-deep);
  text-decoration: none;
}

.page-about .breadcrumb a:hover {
  text-decoration: underline;
}

.page-about .breadcrumb-sep {
  color: var(--about-rule);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  background: var(--ink);
  color: var(--paper-2);
  padding: clamp(30px, 7vw, 72px) 0 clamp(34px, 7vw, 80px);
  border-bottom: 3px solid var(--amber);
  position: relative;
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(var(--line-soft) 1px, transparent 1px),
    linear-gradient(90deg, var(--line-soft) 1px, transparent 1px);
  background-size: 72px 72px;
  opacity: 0.5;
  pointer-events: none;
}

.page-about .about-hero-grid {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(24px, 5vw, 44px);
  grid-template-columns: 1fr;
  align-items: center;
}

.page-about .about-hero .chapter-eyebrow {
  color: var(--cyan);
}

.page-about h1 {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 8vw, 68px);
  line-height: 1.06;
  letter-spacing: -0.02em;
  margin: 14px 0 0;
  max-width: 20ch;
}

.page-about .about-lead {
  margin: 18px 0 0;
  max-width: 60ch;
  font-size: clamp(15px, 2.4vw, 17px);
  color: var(--mist);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-legacy-hint {
  margin: 22px 0 0;
  font-size: 13px;
  color: var(--mist);
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  max-width: 46ch;
}

.page-about .about-hero-media {
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--ink-2);
}

.page-about .about-hero-media img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* ---------- 主体骨架 ---------- */
.page-about .about-body {
  padding-top: clamp(24px, 5vw, 48px);
  padding-bottom: clamp(40px, 7vw, 96px);
}

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

.page-about .about-rail {
  display: none;
}

/* ---------- 章节 ---------- */
.page-about .about-section {
  padding: clamp(26px, 5vw, 52px) 0;
  border-top: 1px solid var(--about-rule);
  scroll-margin-top: calc(var(--topbar-h) + 18px);
}

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

.page-about .about-section-head {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px;
  align-items: start;
  margin-bottom: 16px;
}

.page-about .chapter-index {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--text);
  background: var(--cyan-soft);
  border-radius: var(--radius-sm);
  padding: 2px 7px;
  letter-spacing: 0.04em;
}

.page-about h2 {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 4.4vw, 38px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  margin: 0;
}

.page-about p {
  margin: 0 0 14px;
  max-width: 66ch;
}

.page-about h3 {
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  margin: 8px 0 4px;
  letter-spacing: -0.005em;
}

.page-about a {
  color: var(--cyan-deep);
}

.page-about .about-next {
  margin-top: 18px;
  padding-left: 14px;
  border-left: 3px solid var(--amber);
  font-size: 14px;
  color: var(--about-muted);
}

/* 分类标签说明 */
.page-about .about-tags {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-tags li {
  font-size: 14px;
  color: var(--about-muted);
  background: var(--paper);
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  padding: 10px 14px;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 10px;
  align-items: baseline;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 24px 0 0;
  padding: 0 0 0 20px;
  border-left: 2px solid var(--about-rule);
}

.page-about .about-timeline > li {
  position: relative;
  padding-bottom: 22px;
  scroll-margin-top: calc(var(--topbar-h) + 24px);
}

.page-about .about-timeline > li:last-child {
  padding-bottom: 0;
}

.page-about .about-timeline > li::before {
  content: "";
  position: absolute;
  left: -29px;
  top: 6px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--paper-2);
  border: 2px solid var(--cyan-deep);
}

.page-about .about-timeline > li[data-latest="true"]::before {
  background: var(--ember);
  border-color: var(--ember);
  box-shadow: 0 0 0 5px rgba(217, 98, 69, 0.14);
}

.page-about .about-timeline p {
  font-size: 14px;
  color: var(--about-muted);
  margin: 0;
}

.page-about .about-figure {
  margin: 22px 0 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--about-rule);
  background: var(--paper);
}

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

.page-about .about-figcaption {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--about-muted);
  padding: 10px 14px;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-figure--team {
  max-width: 520px;
}

/* ---------- 服务范围面板 ---------- */
.page-about .about-panel {
  background: var(--paper);
  border: 1px solid var(--about-rule);
  border-radius: var(--radius-lg);
  padding: clamp(20px, 4vw, 38px);
  margin: clamp(20px, 4vw, 36px) 0;
}

.page-about .about-cards {
  display: grid;
  gap: 10px;
  margin-top: 20px;
}

.page-about .about-card {
  background: var(--paper-2);
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-card > summary {
  cursor: pointer;
  list-style: none;
  padding: 13px 16px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
}

.page-about .about-card > summary::-webkit-details-marker {
  display: none;
}

.page-about .about-card > summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  color: var(--cyan-deep);
  font-size: 16px;
  line-height: 1;
}

.page-about .about-card[open] {
  border-color: var(--cyan-deep);
}

.page-about .about-card[open] > summary::after {
  content: "−";
}

.page-about .about-card-body {
  padding: 0 16px 16px;
  border-top: 1px dashed var(--about-rule);
  padding-top: 12px;
}

.page-about .about-card-body p {
  font-size: 14px;
  color: var(--about-muted);
  margin-bottom: 8px;
}

.page-about .about-card-link {
  font-family: var(--font-mono);
  font-size: 13px;
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 1px;
}

.page-about .about-stats {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.page-about .about-stats li {
  background: var(--ink);
  color: var(--paper-2);
  border-radius: var(--radius);
  padding: 14px 14px 12px;
}

.page-about .about-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 4vw, 28px);
  line-height: 1.2;
  color: var(--cyan);
  letter-spacing: -0.01em;
}

.page-about .about-stat-label {
  display: block;
  font-size: 12px;
  color: var(--mist);
  margin-top: 4px;
}

/* ---------- 团队角色 ---------- */
.page-about .about-roles {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-roles li {
  background: var(--paper-2);
  border: 1px solid var(--about-rule);
  border-left: 3px solid var(--amber);
  border-radius: var(--radius-sm);
  padding: 12px 14px;
}

.page-about .about-roles h3 {
  margin: 0 0 2px;
  font-size: 15px;
}

.page-about .about-roles p {
  margin: 0;
  font-size: 13.5px;
  color: var(--about-muted);
}

/* ---------- 深色收束面板 ---------- */
.page-about .about-panel--ink {
  background: var(--ink-2);
  border-color: transparent;
  color: var(--paper-2);
}

.page-about .about-panel--ink .chapter-index {
  background: rgba(56, 225, 198, 0.16);
  color: var(--cyan);
}

.page-about .about-panel--ink h2 {
  color: var(--paper-2);
}

.page-about .about-ink-text {
  color: var(--mist);
  font-size: 15px;
}

.page-about .about-honors {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-honors li {
  font-size: 13.5px;
  color: var(--mist);
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 10px;
  align-items: baseline;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-cta {
  margin-top: 22px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.page-about .about-cta p {
  font-size: 14.5px;
  color: var(--paper-2);
  margin-bottom: 14px;
}

/* ---------- 桌面端 ---------- */
@media (min-width: 640px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .about-cards .about-card:first-child {
    grid-column: 1 / -1;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
    align-items: center;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    display: grid;
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
    align-items: start;
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: calc(var(--topbar-h) + 24px);
  }

  .page-about .about-rail-caption {
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.14em;
    color: var(--about-muted);
    margin: 0 0 8px;
  }

  .page-about .about-rail-caption--years {
    margin-top: 22px;
  }

  .page-about .about-rail-list,
  .page-about .about-rail-years {
    list-style: none;
    margin: 0;
    padding: 0;
  }

  .page-about .about-rail-list a {
    display: grid;
    grid-template-columns: 22px minmax(0, 1fr);
    gap: 8px;
    align-items: baseline;
    padding: 9px 8px 9px 10px;
    border-left: 2px solid var(--about-rule);
    color: var(--text);
    text-decoration: none;
    font-size: 13px;
    line-height: 1.35;
    transition: border-color 0.2s var(--ease), color 0.2s var(--ease), background 0.2s var(--ease);
  }

  .page-about .about-rail-list a:hover,
  .page-about .about-rail-list a:focus-visible {
    border-left-color: var(--cyan-deep);
    background: var(--paper);
    color: var(--cyan-deep);
  }

  .page-about .about-rail-index {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--about-muted);
  }

  .page-about .about-rail-years a {
    display: block;
    padding: 4px 0 4px 18px;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--about-muted);
    text-decoration: none;
    position: relative;
  }

  .page-about .about-rail-years a::before {
    content: "";
    position: absolute;
    left: 4px;
    top: 11px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--amber);
  }

  .page-about .about-rail-years a:hover,
  .page-about .about-rail-years a:focus-visible {
    color: var(--cyan-deep);
  }
}

@media (min-width: 1200px) {
  .page-about .about-cards {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-cards .about-card:first-child {
    grid-column: auto;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}