.page-about {
  --about-measure: 66ch;
  --about-gap: clamp(24px, 4vw, 48px);
  padding-bottom: clamp(72px, 10vw, 120px);
}

.page-about h1,
.page-about .about-heading,
.page-about .stage-title,
.page-about .panel-title,
.page-about .duty-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
  line-height: 1.24;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: calc(var(--header-h) + clamp(26px, 6vw, 60px)) 0 clamp(48px, 6vw, 76px);
  border-bottom: 1px solid var(--line);
  overflow: hidden;
  background:
    radial-gradient(900px 480px at 84% -12%, rgba(69, 240, 224, 0.16), transparent 68%),
    radial-gradient(680px 420px at 2% 108%, rgba(255, 138, 61, 0.09), transparent 70%),
    linear-gradient(180deg, var(--ink-900) 0%, var(--ink-800) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), transparent);
  opacity: 0.35;
}

.page-about .hero-grid {
  display: grid;
  gap: clamp(32px, 5vw, 56px);
  margin-top: clamp(24px, 4vw, 44px);
}

.page-about .hero-copy h1 {
  font-size: clamp(28px, 5vw, 52px);
  line-height: 1.16;
  margin-bottom: 20px;
  max-width: 24ch;
}

.page-about .lede {
  margin: 0;
  max-width: 58ch;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--muted);
}

.page-about .hero-preview {
  border-top: 1px solid var(--line);
  padding-top: 16px;
}

.page-about .preview-title {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--muted);
}

.page-about .path-preview {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
}

.page-about .path-preview a {
  position: relative;
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 2px 10px;
  padding: 12px 8px 12px 0;
  border-bottom: 1px solid rgba(42, 53, 102, 0.65);
  text-decoration: none;
  color: var(--text);
  transition: color 0.16s var(--ease), background-color 0.16s var(--ease);
}

.page-about .path-preview a::before {
  content: "";
  position: absolute;
  left: -12px;
  top: 12px;
  bottom: 12px;
  width: 2px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.16s var(--ease);
}

.page-about .path-preview a:hover,
.page-about .path-preview a:focus-visible {
  color: var(--cyan-soft);
}

.page-about .path-preview a:hover::before,
.page-about .path-preview a:focus-visible::before {
  transform: scaleY(1);
}

.page-about .path-num {
  font-variant-numeric: tabular-nums;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  padding-top: 3px;
}

.page-about .path-label {
  font-size: 15px;
  font-weight: 600;
}

.page-about .path-hint {
  grid-column: 2;
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---------- 通用区块 ---------- */

.page-about .about-section {
  padding-top: clamp(48px, 7vw, 88px);
}

.page-about .about-head {
  max-width: 74ch;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .section-no {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.page-about .about-heading {
  font-size: clamp(23px, 3.3vw, 36px);
  margin-bottom: 14px;
}

.page-about .about-sub {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-body p {
  margin: 0 0 18px;
  max-width: var(--about-measure);
  font-size: 16px;
  line-height: 1.85;
  color: var(--text);
}

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

.page-about .split,
.page-about .media-split {
  display: grid;
  gap: clamp(24px, 3vw, 40px);
  align-items: start;
}

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

.page-about .about-note .fact-list {
  margin-top: 0;
}

.page-about .fact-list li {
  position: relative;
  padding-left: 18px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--text);
}

.page-about .fact-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.72em;
  width: 8px;
  height: 1px;
  background: var(--cyan);
}

.page-about .about-note {
  padding: clamp(20px, 3vw, 30px);
}

.page-about .note-title {
  margin: 0 0 16px;
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--amber);
}

/* ---------- 阶段时间轴 ---------- */

.page-about .about-stages {
  padding-top: clamp(48px, 7vw, 88px);
}

.page-about .stage-track {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
  align-items: start;
}

.page-about .stage-figure {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--ink-900);
  height: clamp(220px, 40vw, 320px);
}

.page-about .stage-figure img {
  display: block;
  width: 100%;
  height: 100%;
  max-width: 100%;
  object-fit: cover;
  opacity: 0.85;
}

.page-about .stage-list {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  position: relative;
}

.page-about .stage-list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 34px;
  bottom: 34px;
  width: 1px;
  background: linear-gradient(180deg, transparent, var(--line) 10%, var(--line) 90%, transparent);
}

.page-about .stage-item {
  position: relative;
  padding: 26px 0;
  border-top: 1px solid rgba(42, 53, 102, 0.7);
}

.page-about .stage-item:first-child {
  border-top-color: transparent;
  padding-top: 8px;
}

.page-about .stage-item:first-child::before {
  top: 18px;
}

.page-about .stage-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 34px;
  width: 11px;
  height: 11px;
  border-radius: 50%;
  background: var(--ink-900);
  border: 1px solid var(--amber);
  transition: background-color 0.16s var(--ease), border-color 0.16s var(--ease), transform 0.16s var(--ease);
}

.page-about .stage-item:hover::before,
.page-about .stage-item:focus-within::before {
  background: var(--amber);
  transform: scale(1.28);
}

.page-about .stage-item:last-child::before {
  background: var(--cyan);
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(69, 240, 224, 0.14);
}

.page-about .stage-meta {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 8px;
}

.page-about .stage-no {
  font-size: 12px;
  letter-spacing: 0.16em;
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}

.page-about .stage-ver {
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.page-about .stage-item:last-child .stage-ver {
  color: var(--orange);
}

.page-about .stage-title {
  font-size: clamp(17px, 2.1vw, 21px);
  line-height: 1.45;
  margin-bottom: 10px;
}

.page-about .stage-text {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 规模数字带 ---------- */

.page-about .about-band {
  margin-top: clamp(48px, 7vw, 88px);
  padding: clamp(32px, 5vw, 52px) 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background:
    linear-gradient(115deg, var(--ink-800) 0%, var(--ink-700) 52%, var(--ink-800) 100%);
}

.page-about .band-grid {
  display: grid;
  gap: clamp(20px, 3vw, 30px);
}

.page-about .band-item {
  padding-left: 18px;
  border-left: 1px solid var(--line);
}

.page-about .band-figure {
  margin: 0 0 6px;
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.page-about .band-num {
  font-size: clamp(30px, 4.6vw, 50px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.page-about .band-cap {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

@supports (animation-timeline: view()) {
  .page-about .band-item {
    animation: aboutBandIn linear both;
    animation-timeline: view();
    animation-range: entry 12% cover 42%;
  }
}

@keyframes aboutBandIn {
  from {
    opacity: 0.3;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- 配图 ---------- */

.page-about .about-figure {
  margin: 0;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--ink-800);
}

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

.page-about .about-figure figcaption {
  padding: 12px 16px;
  border-top: 1px solid var(--line);
  font-size: 12px;
  line-height: 1.65;
  color: var(--muted);
}

.page-about .link-row {
  margin-top: 22px;
}

.page-about .text-link {
  display: inline-block;
  position: relative;
  color: var(--cyan);
  text-decoration: none;
  font-size: 15px;
  padding-bottom: 3px;
}

.page-about .text-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 100%;
  height: 1px;
  background: currentColor;
  transform: scaleX(0.25);
  transform-origin: left;
  opacity: 0.5;
  transition: transform 0.18s var(--ease), opacity 0.18s var(--ease);
}

.page-about .text-link:hover::after,
.page-about .text-link:focus-visible::after {
  transform: scaleX(1);
  opacity: 1;
}

/* ---------- 帮助文档 / 会员权益 对照 ---------- */

.page-about .panel-pair {
  display: grid;
  gap: clamp(20px, 3vw, 28px);
}

.page-about .doc-panel {
  padding: clamp(22px, 3vw, 32px);
}

.page-about .panel-tag {
  margin: 0 0 12px;
  display: inline-block;
  padding: 4px 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ink-900);
  background: var(--cyan-soft);
  border-radius: 2px;
}

.page-about .doc-panel--member .panel-tag {
  background: var(--amber);
}

.page-about .panel-title {
  font-size: clamp(18px, 2.2vw, 22px);
  margin-bottom: 12px;
}

.page-about .panel-text {
  margin: 0 0 8px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .row-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .row-list li {
  position: relative;
  padding: 13px 12px 13px 16px;
  border-top: 1px solid rgba(42, 53, 102, 0.6);
  font-size: 14px;
  line-height: 1.7;
  color: var(--text);
  transition: background-color 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .row-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 13px;
  bottom: 13px;
  width: 2px;
  background: var(--cyan);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 0.16s var(--ease);
}

.page-about .doc-panel--member .row-list li::before {
  background: var(--orange);
}

.page-about .row-list li:hover,
.page-about .row-list li:focus-within {
  background: rgba(69, 240, 224, 0.07);
  color: var(--cyan-soft);
}

.page-about .doc-panel--member .row-list li:hover,
.page-about .doc-panel--member .row-list li:focus-within {
  background: rgba(255, 138, 61, 0.08);
  color: var(--amber);
}

.page-about .row-list li:hover::before,
.page-about .row-list li:focus-within::before {
  transform: scaleY(1);
}

/* ---------- 维护团队 ---------- */

.page-about .duty-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .duty-list li {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
  padding: 22px 0;
  border-top: 1px solid rgba(42, 53, 102, 0.7);
}

.page-about .duty-list li:last-child {
  border-bottom: 1px solid rgba(42, 53, 102, 0.7);
}

.page-about .duty-num {
  font-size: clamp(28px, 3.6vw, 38px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  color: var(--cyan);
}

.page-about .duty-title {
  font-size: clamp(16px, 2vw, 19px);
  margin-bottom: 8px;
}

.page-about .duty-text {
  margin: 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 收尾 ---------- */

.page-about .about-cta {
  margin-top: clamp(56px, 8vw, 96px);
  padding: clamp(36px, 5vw, 60px) 0;
  border-top: 1px solid var(--line);
  background:
    radial-gradient(700px 340px at 12% 0%, rgba(255, 138, 61, 0.1), transparent 70%),
    var(--ink-800);
}

.page-about .about-cta-inner {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  align-items: center;
}

.page-about .about-cta .about-heading {
  font-size: clamp(21px, 2.8vw, 30px);
  margin-bottom: 12px;
}

.page-about .cta-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 断点 ---------- */

@media (min-width: 720px) {
  .page-about .band-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .duty-list li {
    grid-template-columns: 90px minmax(0, 1fr);
    padding: 26px 0;
  }
}

@media (min-width: 900px) {
  .page-about .split {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .media-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.86fr);
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .media-split--flip {
    grid-template-columns: minmax(0, 0.86fr) minmax(0, 1fr);
  }

  .page-about .media-split--flip .about-figure {
    order: -1;
  }
}

@media (min-width: 1024px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: clamp(40px, 5vw, 72px);
  }

  .page-about .stage-track {
    grid-template-columns: minmax(0, 360px) minmax(0, 1fr);
    gap: clamp(36px, 4vw, 60px);
  }

  .page-about .stage-figure {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    height: clamp(320px, 48vh, 520px);
  }

  .page-about .about-cta-inner {
    grid-template-columns: minmax(0, 1fr) auto;
    gap: clamp(32px, 5vw, 64px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .band-item {
    animation: none;
    opacity: 1;
    transform: none;
  }

  .page-about .path-preview a::before,
  .page-about .stage-item::before,
  .page-about .row-list li::before,
  .page-about .text-link::after {
    transition: none;
  }
}