.page-about {
  --ab-sec: clamp(52px, 7.5vw, 100px);
  --ab-gap: clamp(24px, 4vw, 48px);
  --ab-cyan-soft: rgba(63, 224, 208, 0.12);
  --ab-amber-soft: rgba(240, 178, 74, 0.1);
  --ab-coral-soft: rgba(255, 107, 94, 0.12);
  padding-bottom: clamp(56px, 8vw, 104px);
}

/* ---------- Hero ---------- */

.page-about .about-hero {
  padding: clamp(18px, 3vw, 34px) 0 clamp(36px, 5vw, 64px);
}

.page-about .about-hero-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 4vw, 48px);
  align-items: center;
}

.page-about .about-hero-copy h1 {
  margin: 14px 0 20px;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(1.9rem, 6vw, 3.5rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .about-hero-copy .lede {
  margin: 0;
  max-width: 54ch;
  font-size: clamp(0.9875rem, 1.5vw, 1.0625rem);
  line-height: 1.82;
  color: var(--muted);
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.page-about .about-hero-figure {
  margin: 0;
}

.page-about .about-hero-figure .figure-media {
  position: relative;
  aspect-ratio: 16 / 10;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
  box-shadow: 0 0 0 1px rgba(63, 224, 208, 0.06), 0 46px 90px -56px rgba(63, 224, 208, 0.5);
}

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

.page-about .about-hero-figure .figure-cap {
  margin-top: 12px;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .hero-meta {
  list-style: none;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--line);
  overflow: hidden;
}

.page-about .hero-meta li {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: 16px 18px;
  background: linear-gradient(150deg, var(--panel), var(--panel-2));
}

.page-about .hero-meta-k {
  font-family: var(--font-serif);
  font-size: 0.75rem;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .hero-meta-v {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--paper);
}

/* ---------- 章节锚点 ---------- */

.page-about .chapter-nav {
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(90deg, rgba(18, 33, 58, 0.92), rgba(10, 17, 32, 0.55));
}

.page-about .chapter-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 4px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}

.page-about .chapter-nav ul::-webkit-scrollbar {
  display: none;
}

.page-about .chapter-nav a {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 12px;
  font-size: 0.875rem;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 2px solid transparent;
  transition: color 200ms var(--ease), border-color 200ms var(--ease);
}

.page-about .chapter-nav a .mono {
  font-size: 0.75rem;
  color: var(--amber);
  letter-spacing: 0.08em;
}

.page-about .chapter-nav a:hover,
.page-about .chapter-nav a:focus-visible {
  color: var(--cyan);
  border-bottom-color: var(--cyan);
}

/* ---------- 通用章节骨架 ---------- */

.page-about .about-sec {
  padding: var(--ab-sec) 0;
  position: relative;
}

.page-about .sec-head {
  display: grid;
  gap: 10px;
  max-width: 62ch;
  margin-bottom: clamp(26px, 3.5vw, 44px);
}

.page-about .sec-head .chapter-no {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.16em;
  color: var(--amber);
}

.page-about .sec-head .h-section {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.6vw, 2.3rem);
  line-height: 1.26;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .sec-lede {
  margin: 0;
  max-width: 58ch;
  font-size: 0.9875rem;
  line-height: 1.82;
  color: var(--muted);
}

.page-about .band {
  position: relative;
  height: 3px;
  width: 100%;
}

.page-about .band::after {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--amber), var(--cyan));
  opacity: 0.55;
}

.page-about .band--narrow::after { width: 32%; }
.page-about .band--mid::after { width: 58%; }
.page-about .band--wide::after { width: 84%; }

/* ---------- 01 时间轴 ---------- */

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 2px 0 0;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 16px;
  bottom: 20px;
  width: 1px;
  background: linear-gradient(180deg, var(--amber), var(--cyan) 55%, var(--coral));
  opacity: 0.4;
}

.page-about .tl-item {
  position: relative;
  padding: 0 0 30px 32px;
}

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

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: 0;
  top: 7px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink);
  border: 2px solid var(--amber);
  transition: transform 240ms var(--ease), border-color 240ms var(--ease), box-shadow 240ms var(--ease);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  transform: scale(1.2);
  border-color: var(--coral);
  box-shadow: 0 0 0 6px var(--ab-coral-soft);
}

.page-about .tl-year {
  display: inline-block;
  margin-bottom: 10px;
  padding: 2px 11px;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--amber);
  background: var(--ab-amber-soft);
  border: 1px solid rgba(240, 178, 74, 0.32);
  border-radius: 999px;
}

.page-about .tl-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.125rem;
  line-height: 1.45;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .tl-card > p {
  margin: 0;
  max-width: 66ch;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .tl-extra {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  transition: grid-template-rows 260ms var(--ease), opacity 220ms var(--ease);
}

.page-about .tl-extra > p {
  overflow: hidden;
  margin: 0;
  max-width: 64ch;
  padding-left: 14px;
  border-left: 2px solid rgba(63, 224, 208, 0.4);
  font-size: 0.875rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .tl-item:hover .tl-extra,
.page-about .tl-item:focus-within .tl-extra {
  grid-template-rows: 1fr;
  opacity: 1;
  margin-top: 12px;
}

@media (hover: none) {
  .page-about .tl-extra {
    grid-template-rows: 1fr;
    opacity: 1;
    margin-top: 12px;
  }
}

/* ---------- 02 团队 ---------- */

.page-about .team-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--ab-gap);
  align-items: start;
}

.page-about .team-figure {
  margin: 0;
}

.page-about .team-figure .figure-media {
  aspect-ratio: 14 / 9;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
}

.page-about .team-figure .figure-cap {
  margin-top: 12px;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .team-cards {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .team-card {
  padding: 20px 20px 22px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--cyan);
  border-radius: var(--r-md);
  background: linear-gradient(140deg, rgba(18, 33, 58, 0.92), rgba(14, 27, 47, 0.66));
  transition: transform 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .team-card:nth-child(2) { border-left-color: var(--amber); }
.page-about .team-card:nth-child(3) { border-left-color: var(--coral); }

.page-about .team-card:hover,
.page-about .team-card:focus-within {
  transform: translateY(-2px);
  border-color: rgba(63, 224, 208, 0.55);
}

.page-about .team-num {
  margin: 0 0 10px;
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: clamp(1.7rem, 3.6vw, 2.35rem);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  font-variant-numeric: tabular-nums;
}

.page-about .stat-unit {
  font-family: var(--font-head);
  font-size: 0.875rem;
  color: var(--muted);
}

.page-about .team-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.0625rem;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .team-card > p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.76;
  color: var(--muted);
}

.page-about .stat-note {
  margin-top: 12px !important;
  padding-top: 11px;
  border-top: 1px dashed var(--line);
  font-size: 0.8125rem !important;
  opacity: 0.6;
  transition: opacity 220ms var(--ease), color 220ms var(--ease);
}

.page-about .team-card:hover .stat-note,
.page-about .team-card:focus-within .stat-note {
  opacity: 1;
  color: var(--paper);
}

/* ---------- 03 分类 ---------- */

.page-about .class-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .class-item {
  position: relative;
  padding: 24px 20px 22px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--panel-2);
  overflow: hidden;
  transition: transform 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .class-item::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: var(--cyan);
}

.page-about .class-item:nth-child(2)::before { background: var(--amber); }
.page-about .class-item:nth-child(3)::before { background: var(--coral); }

.page-about .class-item:hover,
.page-about .class-item:focus-within {
  transform: translateY(-3px);
  border-color: rgba(63, 224, 208, 0.5);
}

.page-about .class-name {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.25rem;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .class-desc {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .class-tags {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .class-foot {
  margin: clamp(24px, 3vw, 36px) 0 0;
  max-width: 62ch;
  padding-left: 16px;
  border-left: 2px solid var(--cyan);
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 04 更新节拍 ---------- */

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

.page-about .rhythm-time {
  display: block;
  margin-bottom: 8px;
  font-size: 0.9375rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--amber);
}

.page-about .rhythm-item h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1rem;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .rhythm-item p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .rhythm-foot {
  margin: clamp(26px, 3.5vw, 40px) 0 0;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 05 内容来源 ---------- */

.page-about .partner-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .partner-card {
  padding: 24px 20px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(160deg, rgba(18, 33, 58, 0.9), rgba(10, 17, 32, 0.7));
  transition: transform 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .partner-card:hover,
.page-about .partner-card:focus-within {
  transform: translateY(-2px);
  border-color: rgba(240, 178, 74, 0.5);
}

.page-about .partner-num {
  margin: 0 0 12px;
  display: flex;
  align-items: baseline;
  gap: 8px;
  flex-wrap: wrap;
}

.page-about .partner-num .stat-num {
  color: var(--amber);
}

.page-about .partner-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.0625rem;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .partner-card p {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .partner-foot {
  margin: clamp(24px, 3vw, 36px) 0 0;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 06 版本演进 ---------- */

.page-about .about-sec--version::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: repeating-linear-gradient(
    180deg,
    rgba(234, 241, 250, 0.028) 0 1px,
    transparent 1px 5px
  );
  opacity: 0.8;
}

.page-about .about-sec--version > .container {
  position: relative;
}

.page-about .version-stack {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .version-item {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding: 18px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: linear-gradient(120deg, rgba(18, 33, 58, 0.86), rgba(14, 27, 47, 0.44));
  transition: transform 240ms var(--ease), border-color 240ms var(--ease), background 240ms var(--ease);
}

.page-about .version-item:hover,
.page-about .version-item:focus-within {
  transform: translateY(-2px);
  border-color: rgba(63, 224, 208, 0.55);
  background: linear-gradient(120deg, rgba(18, 33, 58, 0.98), rgba(14, 27, 47, 0.6));
}

.page-about .version-no {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 30px;
  padding: 0 10px;
  font-size: 0.8125rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
  border: 1px solid rgba(63, 224, 208, 0.4);
  border-radius: var(--r-sm);
  background: var(--ab-cyan-soft);
}

.page-about .version-item:last-child .version-no {
  color: var(--amber);
  border-color: rgba(240, 178, 74, 0.45);
  background: var(--ab-amber-soft);
}

.page-about .version-body h3 {
  margin: 4px 0 8px;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.0625rem;
  line-height: 1.5;
  color: var(--paper);
}

.page-about .version-body p {
  margin: 0;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .version-figure {
  margin: clamp(28px, 4vw, 44px) 0 0;
}

.page-about .version-figure .figure-media {
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  overflow: hidden;
}

.page-about .version-figure .figure-cap {
  margin-top: 12px;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .version-foot {
  margin: clamp(24px, 3vw, 34px) 0 0;
  max-width: 62ch;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 延伸入口 ---------- */

.page-about .about-next {
  margin-top: clamp(30px, 4vw, 52px);
  padding: clamp(36px, 5vw, 60px) 0;
  border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(18, 33, 58, 0.6), rgba(10, 17, 32, 0));
}

.page-about .about-next .h-section {
  margin: 0 0 clamp(20px, 3vw, 32px);
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(1.25rem, 2.6vw, 1.7rem);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .next-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 10px;
}

.page-about .next-link {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  text-decoration: none;
  color: var(--paper);
  background: rgba(18, 33, 58, 0.5);
  transition: transform 240ms var(--ease), border-color 240ms var(--ease), background 240ms var(--ease);
}

.page-about .next-link:hover,
.page-about .next-link:focus-visible {
  transform: translateY(-2px);
  border-color: var(--cyan);
  background: rgba(18, 33, 58, 0.92);
}

.page-about .next-link-k {
  flex: 0 0 auto;
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--amber);
}

.page-about .next-link-t {
  font-size: 0.9375rem;
  line-height: 1.6;
}

/* ---------- 响应式 ---------- */

@media (min-width: 768px) {
  .page-about .hero-meta {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .class-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }

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

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

@media (min-width: 900px) {
  .page-about .rhythm-list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
  }

  .page-about .rhythm-item {
    padding: 0 22px;
    border-left: 1px solid var(--line);
  }

  .page-about .rhythm-item:first-child {
    padding-left: 0;
    border-left: 0;
  }

  .page-about .rhythm-item:last-child {
    padding-right: 0;
  }

  .page-about .version-item:nth-child(1) { margin-right: 88px; }
  .page-about .version-item:nth-child(2) { margin-right: 58px; }
  .page-about .version-item:nth-child(3) { margin-right: 29px; }
  .page-about .version-item:nth-child(4) { margin-right: 0; }
}

@media (min-width: 992px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: end;
  }

  .page-about .team-layout {
    grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
  }

  .page-about .class-list {
    gap: 20px;
  }

  .page-about .class-item:nth-child(2) {
    margin-top: 32px;
  }

  .page-about .class-item:nth-child(3) {
    margin-top: 64px;
  }

  .page-about .next-links {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .next-link {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
    height: 100%;
  }
}

@media (max-width: 480px) {
  .page-about .about-hero-copy h1 {
    font-size: clamp(1.7rem, 8.4vw, 2.2rem);
  }

  .page-about .hero-meta-v {
    font-size: 1rem;
  }

  .page-about .chapter-nav a {
    padding: 12px 10px;
    font-size: 0.8125rem;
  }
}