.page-about {
  overflow-x: hidden;
}

/* ===== 首屏定位 ===== */
.page-about__hero {
  position: relative;
  background: linear-gradient(135deg, var(--section-blue) 0%, #F2F8F9 72%);
  padding: 36px 0 32px;
  border-bottom: 1px solid var(--border-light);
  overflow: hidden;
}

.page-about__hero::before {
  content: "";
  position: absolute;
  top: -60px;
  right: -50px;
  width: 200px;
  height: 200px;
  background: var(--accent-teal);
  opacity: .14;
  border-radius: 30px;
  transform: rotate(16deg);
}

.page-about__hero::after {
  content: "";
  position: absolute;
  bottom: -48px;
  left: 4%;
  width: 110px;
  height: 110px;
  background: var(--accent-orange);
  opacity: .10;
  border-radius: 50%;
}

.page-about__hero-inner {
  position: relative;
  z-index: 1;
  padding-right: 24px;
}

.page-about__hero .breadcrumb {
  font-size: 13px;
  color: var(--text-muted);
}

.page-about__crumb-sep {
  margin: 0 6px;
  color: var(--text-muted);
}

.page-about__hero .eyebrow {
  margin-top: 18px;
}

.page-about__hero h1 {
  margin: 10px 0 14px;
  font-size: 26px;
  line-height: 1.28;
  font-weight: 900;
  letter-spacing: .01em;
  color: var(--text-dark);
  max-width: 640px;
}

.page-about__hero-lead {
  font-size: 15px;
  line-height: 1.8;
  color: var(--text-dark);
  max-width: 500px;
  margin-bottom: 18px;
}

.page-about__hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about__hero-actions .btn {
  padding: 10px 16px;
  border-radius: 20px;
  font-size: 14px;
}

/* ===== Section 头 ===== */
.page-about__section-head {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
}

.page-about__section-head .section-head__title {
  margin: 4px 0 0;
  font-size: 26px;
  line-height: 1.3;
  color: var(--text-dark);
}

.page-about__section-mark {
  display: none;
}

.page-about__section-desc {
  margin-top: 6px;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-muted);
  max-width: 420px;
}

/* ===== 本站是什么 ===== */
.page-about__nature {
  padding: 40px 0;
}

.page-about__nature-grid {
  margin-top: 24px;
  display: grid;
  gap: 24px;
  align-items: start;
}

.page-about__nature-copy p {
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-dark);
  margin-bottom: 12px;
}

.page-about__nature-list {
  list-style: none;
  margin: 16px 0 18px;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.page-about__nature-list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.6;
}

.page-about__nature-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .55em;
  width: 7px;
  height: 7px;
  border-radius: 3px;
  background: var(--accent-orange);
}

.page-about__nature-list li:nth-child(2)::before {
  background: var(--accent-teal);
}

.page-about__nature-list li:nth-child(3)::before {
  background: var(--accent-purple);
}

.page-about__nature-list li:nth-child(4)::before {
  background: var(--status-orange);
}

.page-about__intro-action {
  margin-top: 8px;
}

.page-about__nature-figure {
  margin: 0;
}

.page-about__nature-figure img {
  display: block;
  width: 100%;
  max-width: 400px;
  height: auto;
  border-radius: 14px;
  box-shadow: 0 10px 30px rgba(31, 41, 55, .12);
}

/* ===== 收录范围与规模 ===== */
.page-about__scale {
  background: var(--section-yellow);
  padding: 40px 0;
}

.page-about__scale-texture {
  display: block;
  width: 100%;
  max-width: 600px;
  height: auto;
  border-radius: 10px;
  margin: 0 auto 22px;
  opacity: .85;
}

.page-about__stats-row {
  display: grid;
  gap: 14px;
  margin-bottom: 24px;
}

.page-about__stat-card {
  background: var(--card-bg);
  border-radius: 14px;
  padding: 18px 20px;
  border-top: 4px solid var(--accent-orange);
  box-shadow: 0 4px 12px rgba(31, 41, 55, .05);
}

.page-about__stat-card--tier1 {
  border-top-color: var(--accent-teal);
}

.page-about__stat-card--tier2 {
  border-top-color: var(--accent-purple);
}

.page-about__stat-label {
  display: block;
  font-size: 12px;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.page-about__stat-card strong {
  display: block;
  font-size: 42px;
  line-height: 1.1;
  margin: 8px 0 2px;
  font-weight: 900;
  color: var(--accent-orange);
  letter-spacing: .01em;
}

.page-about__stat-card--tier1 strong {
  color: var(--accent-teal);
}

.page-about__stat-card--tier2 strong {
  color: var(--accent-purple);
}

.page-about__stat-note {
  font-size: 12px;
  color: var(--text-muted);
}

.page-about__dist-grid {
  display: grid;
  gap: 18px;
}

.page-about__dist-card {
  background: rgba(255, 255, 255, .82);
  border-radius: 12px;
  padding: 18px 16px;
}

.page-about__dist-card h3 {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 16px;
  margin-bottom: 14px;
  color: var(--text-dark);
}

.page-about__dist-card h3 span {
  font-size: 12px;
  font-weight: 500;
  background: var(--tag-yellow);
  color: var(--text-muted);
  padding: 3px 10px;
  border-radius: 20px;
}

.page-about__bar-list {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.page-about__bar {
  display: grid;
  grid-template-columns: 70px 1fr 38px;
  align-items: center;
  gap: 8px;
  font-size: 12px;
}

.page-about__bar-name {
  color: var(--text-dark);
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.page-about__bar-track {
  height: 8px;
  border-radius: 99px;
  background: rgba(0, 0, 0, .07);
  overflow: hidden;
}

.page-about__bar-fill {
  display: block;
  height: 100%;
  border-radius: 99px;
}

.page-about__bar-fill--orange {
  background: var(--accent-orange);
}

.page-about__bar-fill--teal {
  background: var(--accent-teal);
}

.page-about__bar-value {
  text-align: right;
  font-weight: 700;
  color: var(--text-dark);
}

/* ===== 分类与筛选路径 ===== */
.page-about__paths {
  padding: 40px 0;
}

.page-about__path-grid {
  margin-top: 28px;
  display: grid;
  gap: 20px;
}

.page-about__path-card {
  background: var(--card-bg);
  border-radius: 14px;
  padding: 22px 18px 18px;
  text-align: center;
  border-top: 4px solid var(--accent-orange);
  box-shadow: 0 4px 12px rgba(31, 41, 55, .06);
  transition: transform .2s ease, box-shadow .2s ease;
}

.page-about__path-card:nth-child(2) {
  border-top-color: var(--accent-teal);
}

.page-about__path-card:nth-child(3) {
  border-top-color: var(--accent-purple);
}

.page-about__path-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 10px 24px rgba(31, 41, 55, .10);
}

.page-about__path-card img {
  display: block;
  width: 100%;
  max-width: 150px;
  height: auto;
  margin: 0 auto 14px;
  border-radius: 10px;
}

.page-about__path-card h3 {
  font-size: 20px;
  font-weight: 900;
  margin-bottom: 8px;
  color: var(--text-dark);
}

.page-about__path-card p {
  font-size: 14px;
  line-height: 1.75;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.page-about__path-link {
  display: inline-block;
  font-size: 14px;
  font-weight: 700;
  color: var(--accent-purple);
  text-decoration: none;
  border-bottom: 2px solid var(--accent-purple);
  transition: background .2s ease, color .2s ease, padding .2s ease;
}

.page-about__path-link:hover {
  background: var(--accent-purple);
  color: #fff;
  border-radius: 4px;
  padding: 2px 6px;
  margin: -2px -6px;
}

/* ===== 更新与版本动态 ===== */
.page-about__version {
  background: var(--section-blue);
  padding: 40px 0;
}

.page-about__timeline {
  margin-top: 26px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.page-about__tl-item {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 14px;
}

.page-about__tl-node {
  font-size: 12px;
  font-weight: 900;
  text-align: center;
  color: #fff;
  background: var(--accent-purple);
  border-radius: 10px;
  padding: 8px 4px;
  align-self: start;
  letter-spacing: .02em;
}

.page-about__tl-item:nth-child(2) .page-about__tl-node {
  background: var(--accent-teal);
}

.page-about__tl-item:nth-child(3) .page-about__tl-node {
  background: var(--accent-orange);
}

.page-about__tl-card {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 16px;
  box-shadow: 0 4px 12px rgba(31, 41, 55, .06);
}

.page-about__tl-card h3 {
  font-size: 16px;
  font-weight: 900;
  margin-bottom: 6px;
  color: var(--text-dark);
}

.page-about__tl-card p {
  font-size: 14px;
  line-height: 1.7;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.page-about__tl-card .status-badge {
  font-size: 12px;
}

.page-about__version-links {
  margin-top: 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about__version-links .btn {
  padding: 10px 16px;
  border-radius: 20px;
  font-size: 14px;
}

/* ===== 桌面端增强 ===== */
@media (min-width: 768px) {
  .page-about__hero {
    padding: 64px 0 60px;
  }

  .page-about__hero-inner {
    max-width: 800px;
  }

  .page-about__hero h1 {
    font-size: 40px;
    line-height: 1.2;
  }

  .page-about__hero-lead {
    font-size: 17px;
    max-width: 540px;
  }

  .page-about__section-head .section-head__title {
    font-size: 32px;
  }

  .page-about__section-mark {
    display: block;
    position: absolute;
    right: -4px;
    top: 24px;
    writing-mode: vertical-rl;
    font-size: 12px;
    font-weight: 900;
    letter-spacing: .36em;
    color: var(--text-muted);
    opacity: .35;
  }

  .page-about__section-desc {
    margin-left: auto;
    margin-right: auto;
  }

  .page-about__nature {
    padding: 64px 0;
  }

  .page-about__nature-grid {
    grid-template-columns: 1fr 400px;
    gap: 48px;
    align-items: center;
  }

  .page-about__nature-copy p {
    font-size: 16px;
  }

  .page-about__scale {
    padding: 64px 0;
  }

  .page-about__scale-texture {
    max-width: 600px;
    margin-left: 0;
    margin-right: auto;
  }

  .page-about__stats-row {
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
  }

  .page-about__stat-card {
    padding: 24px;
  }

  .page-about__stat-card strong {
    font-size: 56px;
  }

  .page-about__dist-grid {
    grid-template-columns: 1fr 1fr;
    gap: 24px;
  }

  .page-about__dist-card {
    padding: 22px 20px;
  }

  .page-about__bar {
    grid-template-columns: 84px 1fr 44px;
    font-size: 13px;
  }

  .page-about__paths {
    padding: 64px 0;
  }

  .page-about__path-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
  }

  .page-about__path-card {
    position: relative;
    padding: 28px 22px 20px;
  }

  .page-about__path-card + .page-about__path-card::before {
    content: "";
    position: absolute;
    left: -22px;
    top: 50%;
    width: 14px;
    height: 3px;
    border-radius: 2px;
    background: var(--accent-purple);
    transform: translateY(-50%);
  }

  .page-about__path-card + .page-about__path-card::after {
    content: "";
    position: absolute;
    left: -26px;
    top: 50%;
    width: 9px;
    height: 9px;
    border-right: 3px solid var(--accent-purple);
    border-top: 3px solid var(--accent-purple);
    transform: translateY(-50%) rotate(45deg);
  }

  .page-about__version {
    padding: 64px 0;
  }

  .page-about__timeline {
    max-width: 760px;
    margin-left: auto;
    margin-right: auto;
    gap: 18px;
  }

  .page-about__tl-item {
    grid-template-columns: 76px 1fr;
    gap: 22px;
  }

  .page-about__tl-node {
    font-size: 13px;
    padding: 10px 6px;
  }

  .page-about__tl-card {
    padding: 20px 24px;
  }

  .page-about__version-links {
    justify-content: center;
    margin-top: 32px;
  }
}