.page-about {
  --about-rail-space: 0px;
  position: relative;
  max-width: 1440px;
  margin: 0 auto;
  padding: 24px clamp(16px, 4vw, 48px) 72px;
  overflow-x: hidden;
  color: var(--text-secondary);
  font-family: var(--font-body);
  line-height: 1.6;
  background:
    repeating-linear-gradient(115deg, transparent 0 20px, rgba(0,212,255,0.025) 20px 21px, transparent 21px 42px),
    radial-gradient(circle at 88% 6%, rgba(0,255,135,0.07), transparent 26%), var(--bg);
}
.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}
.page-about [hidden] {
  display: none !important;
}
.page-about a {
  color: var(--electric-blue);
  text-decoration: none;
  transition: color 0.18s ease;
}
.page-about a:hover {
  color: var(--neon-green);
}
.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-heading);
  color: var(--text-white);
  line-height: 1.16;
  letter-spacing: 0.01em;
}
.page-about h2 {
  font-size: clamp(24px, 4vw, 38px);
  margin: 8px 0 24px;
}
.page-about .btn {
  display: inline-block;
  margin-top: 4px;
}
.page-about .crumb-sep {
  margin: 0 2px;
  color: var(--grid-line);
}
.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
  font-size: 12px;
  letter-spacing: 0.05em;
  padding-bottom: 14px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--grid-line);
  text-transform: uppercase;
}
.page-about .breadcrumbs a {
  color: var(--text-secondary);
}
.page-about .breadcrumbs a:hover {
  color: var(--electric-blue);
}
.page-about .breadcrumbs [aria-current="page"] {
  color: var(--neon-green);
}
.page-about .about-rail {
  display: none;
}

/* ===== Hero · 起点与使命 ===== */
.page-about .about-hero {
  display: grid;
  gap: 24px;
  padding: 28px 0 36px;
  margin-bottom: 64px;
  border-bottom: 1px solid var(--grid-line);
}
.page-about .about-hero-inner {
  display: grid;
  gap: 16px;
}
.page-about .about-kicker {
  margin: 0;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--neon-green);
}
.page-about .about-hero h1 {
  margin: 0;
  max-width: 11em;
  font-size: clamp(30px, 6vw, 64px);
  text-transform: uppercase;
  color: var(--text-white);
}
.page-about .about-lede {
  max-width: 46em;
  margin: 0;
  font-size: 15px;
  color: var(--text-secondary);
}
.page-about .about-principle {
  margin: 0;
  padding: 10px 0 10px 14px;
  border-left: 4px solid var(--data-orange);
  font-weight: 700;
  font-size: 15px;
  color: var(--text-white);
}
.page-about .about-hero-metrics {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}
.page-about .about-metric {
  padding: 14px 16px;
  background: var(--panel);
  border: 1px solid var(--grid-line);
  clip-path: polygon(0 0, calc(100% - 12px) 0, 100% 12px, 100% 100%, 0 100%);
}
.page-about .about-metric-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 28px;
  line-height: 1;
  color: var(--neon-green);
}
.page-about .about-metric:nth-child(2) .about-metric-num {
  color: var(--electric-blue);
}
.page-about .about-metric:nth-child(3) .about-metric-num {
  color: var(--data-orange);
}
.page-about .about-metric:nth-child(4) .about-metric-num {
  color: var(--warning-yellow);
}
.page-about .about-metric-label {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
}

/* ===== 数据版图 ===== */
.page-about .about-map {
  margin-bottom: 80px;
  position: relative;
}
.page-about .about-section-index {
  margin: 0;
  font-family: var(--font-heading);
  font-size: 42px;
  line-height: 1;
  color: transparent;
  -webkit-text-stroke: 1px var(--electric-blue);
  opacity: 0.9;
}
.page-about .about-section-index::after {
  content: "";
  display: inline-block;
  width: 100px;
  height: 2px;
  margin-left: 12px;
  vertical-align: middle;
  background: repeating-linear-gradient(90deg, var(--neon-green) 0 5px, transparent 5px 10px);
}
.page-about .about-map-layout {
  display: grid;
  gap: 24px;
  align-items: start;
}
.page-about .about-map-visual {
  overflow: hidden;
  background: var(--panel-glass);
  border: 1px solid var(--grid-line);
  backdrop-filter: blur(4px);
}
.page-about .tab-list {
  display: flex;
  gap: 4px;
  padding: 10px;
  border-bottom: 1px solid var(--grid-line);
  background: rgba(0, 212, 255, 0.04);
}
.page-about .tab-trigger {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 13px;
  letter-spacing: 0.05em;
  cursor: pointer;
  padding: 8px 14px;
  position: relative;
  transition: color 0.18s ease, background 0.18s ease;
}
.page-about .tab-trigger:hover {
  color: var(--electric-blue);
}
.page-about .tab-trigger[aria-selected="true"] {
  color: var(--neon-green);
  background: rgba(0, 255, 135, 0.08);
}
.page-about .about-map-visual img,
.page-about .about-map-visual svg {
  display: block;
  width: 100%;
  height: auto;
}
.page-about .about-map-img {
  object-fit: cover;
}
.page-about .about-league-svg {
  min-height: 280px;
  padding: 18px 16px 10px;
}
.page-about .about-map-stats {
  padding: 18px 18px 22px;
  background: var(--panel);
  border: 1px solid var(--grid-line);
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 0 100%);
}
.page-about .about-map-stats h3 {
  margin: 0 0 12px;
  font-size: 18px;
}
.page-about .about-map-stats ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}
.page-about .about-map-stats li {
  font-size: 13px;
  padding-left: 12px;
  border-left: 3px solid var(--electric-blue);
}
.page-about .about-map-stats li:nth-child(2) {
  border-left-color: var(--neon-green);
}
.page-about .about-map-stats li:nth-child(3) {
  border-left-color: var(--data-orange);
}
.page-about .about-map-stats li:nth-child(4) {
  border-left-color: var(--warning-yellow);
}
.page-about .about-map-stats p {
  margin: 18px 0 0;
  font-size: 13px;
}

/* ===== 版本演进 · 时间轴 ===== */
.page-about .about-timeline-section {
  margin-bottom: 80px;
}
.page-about .about-timeline {
  position: relative;
  margin: 18px 0 28px;
}
.page-about .about-trackline {
  position: absolute;
  left: 19px;
  top: 32px;
  bottom: 32px;
  width: 2px;
  background: linear-gradient(180deg, var(--neon-green), var(--electric-blue) 55%, rgba(0, 212, 255, 0.2));
}
.page-about .about-timeline-row {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 16px;
  margin-bottom: 20px;
  position: relative;
}
.page-about .about-timeline-row:last-child {
  margin-bottom: 0;
}
.page-about .about-tl-dot {
  justify-self: center;
  align-self: start;
  margin-top: 26px;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--bg);
  border: 4px solid var(--neon-green);
  box-shadow: 0 0 0 4px rgba(0, 255, 135, 0.12), 0 0 14px rgba(0, 255, 135, 0.3);
  z-index: 1;
  transition: transform 0.18s ease, box-shadow 0.18s ease, border-color 0.18s ease;
}
.page-about .about-timeline-row[data-year="2019"] .about-tl-dot {
  border-color: var(--electric-blue);
  box-shadow: 0 0 0 4px rgba(0, 212, 255, 0.12), 0 0 14px rgba(0, 212, 255, 0.3);
}
.page-about .about-timeline-row[data-year="2022"] .about-tl-dot {
  border-color: var(--data-orange);
  box-shadow: 0 0 0 4px rgba(255, 107, 0, 0.12), 0 0 14px rgba(255, 107, 0, 0.3);
}
.page-about .about-timeline-row[data-year="now"] .about-tl-dot {
  border-color: var(--warning-yellow);
  box-shadow: 0 0 0 4px rgba(245, 213, 71, 0.12), 0 0 14px rgba(245, 213, 71, 0.3);
}
.page-about .about-timeline-row:hover .about-tl-dot {
  transform: scale(1.3);
}
.page-about .about-timeline-card {
  padding: 16px 16px 18px;
  background: var(--panel);
  border: 1px solid var(--grid-line);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
  transition: border-color 0.2s ease, background 0.2s ease;
}
.page-about .about-timeline-row:hover .about-timeline-card {
  border-color: var(--neon-green);
  background: rgba(0, 255, 135, 0.04);
}
.page-about .about-timeline-row[data-year="2019"]:hover .about-timeline-card {
  border-color: var(--electric-blue);
}
.page-about .about-timeline-row[data-year="2022"]:hover .about-timeline-card {
  border-color: var(--data-orange);
}
.page-about .about-timeline-row[data-year="now"]:hover .about-timeline-card {
  border-color: var(--warning-yellow);
}
.page-about .about-timeline-year {
  margin: 0 0 6px;
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--neon-green);
}
.page-about .about-timeline-row[data-year="2019"] .about-timeline-year {
  color: var(--electric-blue);
}
.page-about .about-timeline-row[data-year="2022"] .about-timeline-year {
  color: var(--data-orange);
}
.page-about .about-timeline-row[data-year="now"] .about-timeline-year {
  color: var(--warning-yellow);
}
.page-about .about-timeline-card h3 {
  margin: 0 0 8px;
  font-size: 20px;
}
.page-about .about-timeline-card p {
  margin: 0;
  font-size: 13px;
}

/* 旧版本资料库 */
.page-about .about-archive-panel {
  display: grid;
  gap: 18px;
  padding: 18px;
  background: var(--panel);
  border: 1px solid var(--grid-line);
  clip-path: polygon(0 0, calc(100% - 22px) 0, 100% 22px, 100% 100%, 0 100%);
}
.page-about .about-archive-panel img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--grid-line);
}
.page-about .about-archive-copy h3 {
  margin: 0 0 10px;
  font-size: 22px;
}
.page-about .about-archive-copy p {
  margin: 0 0 18px;
  font-size: 13px;
}

/* ===== 行家方法论 ===== */
.page-about .about-method {
  margin-bottom: 80px;
}
.page-about .about-method-grid {
  display: grid;
  gap: 16px;
}
.page-about .about-method-card {
  position: relative;
  padding: 20px 20px 24px;
  background: var(--panel-glass);
  border: 1px solid var(--grid-line);
  backdrop-filter: blur(3px);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.2s ease;
}
.page-about .about-method-card:hover {
  background: rgba(0, 255, 135, 0.05);
  border-color: var(--neon-green);
}
.page-about .about-method-num {
  display: block;
  font-family: var(--font-heading);
  font-size: 42px;
  line-height: 1;
  color: var(--neon-green);
  opacity: 0.9;
}
.page-about .about-method-card:nth-child(2) .about-method-num {
  color: var(--electric-blue);
}
.page-about .about-method-card:nth-child(3) .about-method-num {
  color: var(--data-orange);
}
.page-about .about-method-card:nth-child(4) .about-method-num {
  color: var(--warning-yellow);
}
.page-about .about-method-card h3 {
  margin: 14px 0 8px;
  font-size: 18px;
}
.page-about .about-method-card p {
  margin: 0;
  font-size: 13px;
}

/* ===== 团队与运营 ===== */
.page-about .about-team {
  margin-bottom: 80px;
}
.page-about .about-team-layout {
  display: grid;
  gap: 20px;
}
.page-about .about-team-img {
  overflow: hidden;
  border: 1px solid var(--grid-line);
  background: var(--panel);
}
.page-about .about-team-img img {
  display: block;
  width: 100%;
  height: auto;
  object-fit: cover;
  min-height: 180px;
}
.page-about .about-team-copy p {
  margin: 0 0 14px;
  font-size: 14px;
}
.page-about .about-team-copy p:last-of-type {
  margin-bottom: 0;
}
.page-about .about-team-channels {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 18px 0;
}
.page-about .about-team-channels span {
  padding: 5px 10px;
  font-size: 12px;
  color: var(--text-secondary);
  background: rgba(0, 212, 255, 0.07);
  border: 1px solid var(--grid-line);
  clip-path: polygon(0 0, calc(100% - 7px) 0, 100% 7px, 100% 100%, 0 100%);
}
.page-about .about-team-channels span:nth-child(2) {
  color: var(--neon-green);
}
.page-about .about-team-channels span:nth-child(4) {
  color: var(--data-orange);
}

/* ===== 页内导航卡片 ===== */
.page-about .about-inline-nav {
  display: grid;
  gap: 16px;
  margin-top: 56px;
}
.page-about .about-nav-card {
  position: relative;
  display: grid;
  gap: 6px;
  padding: 20px 22px;
  background: var(--panel);
  border: 1px solid var(--grid-line);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
  transition: background 0.2s ease, border-color 0.2s ease;
}
.page-about .about-nav-card:hover {
  background: rgba(0, 255, 135, 0.05);
  border-color: var(--neon-green);
}
.page-about .about-nav-tag {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--neon-green);
}
.page-about .about-nav-card:hover .about-nav-tag {
  color: var(--electric-blue);
}
.page-about .about-nav-title {
  font-family: var(--font-heading);
  font-size: 22px;
  color: var(--text-white);
}
.page-about .about-nav-arrow {
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 24px;
  color: var(--data-orange);
  transition: right 0.2s ease;
}
.page-about .about-nav-card:hover .about-nav-arrow {
  right: 14px;
}

/* ===== 桌面端增强 ===== */
@media (min-width: 720px) {
  .page-about {
    padding-top: 32px;
  }
  .page-about .about-hero {
    grid-template-columns: minmax(0, 1fr) minmax(280px, 0.62fr);
    align-items: end;
  }
  .page-about .about-hero-metrics {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-archive-panel {
    grid-template-columns: 280px minmax(0, 1fr);
    align-items: center;
  }
  .page-about .about-method-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }
  .page-about .about-method-card:nth-child(2),
  .page-about .about-method-card:nth-child(4) {
    transform: translateY(18px);
  }
  .page-about .about-team-layout {
    grid-template-columns: minmax(280px, 0.9fr) minmax(0, 1fr);
    align-items: center;
  }
  .page-about .about-inline-nav {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 880px) {
  .page-about .about-map-layout {
    grid-template-columns: minmax(0, 1.45fr) minmax(260px, 0.8fr);
    gap: 28px;
  }
}

@media (min-width: 1280px) {
  .page-about {
    --about-rail-space: 52px;
    padding-left: calc(var(--about-rail-space) + 6vw);
  }
  .page-about::after {
    content: "";
    position: fixed;
    left: 44px;
    top: 0;
    bottom: 0;
    width: 1px;
    pointer-events: none;
    background: linear-gradient(180deg, transparent, var(--grid-line) 12%, rgba(0, 255, 135, 0.3) 50%, var(--grid-line) 88%, transparent);
  }
  .page-about .about-rail {
    display: block;
    position: fixed;
    left: 14px;
    top: 50%;
    transform: translateY(-50%) rotate(180deg);
    writing-mode: vertical-rl;
    font-size: 11px;
    letter-spacing: 0.34em;
    text-transform: uppercase;
    color: rgba(0, 212, 255, 0.5);
    pointer-events: none;
    z-index: 0;
  }
  .page-about .about-method-card:nth-child(3) {
    transform: translateX(-14px);
  }
  .page-about .about-method-card:nth-child(4) {
    transform: translateX(14px);
  }
}