.page-about {
  --about-line: 1px solid var(--color-metal);
  --about-gold-line: 1px solid var(--color-gold);
  --about-panel-bg: var(--color-white);
  --about-dark-bg: var(--color-dark);
  background: var(--color-sand);
}

/* ===== 首屏品牌背景区 ===== */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--color-dark);
  padding: 28px 0 48px;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.035) 1px, transparent 1px);
  background-size: 44px 44px;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -1px;
  height: 42px;
  pointer-events: none;
  background: radial-gradient(90% 100% at 50% 0%, transparent 55%, var(--color-sand) 56%);
}

.page-about .about-hero .container {
  position: relative;
  z-index: 1;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: 36px;
  color: rgba(255, 255, 255, 0.7);
}

.page-about .about-hero .breadcrumb a {
  color: var(--color-gold);
}

.page-about .about-hero-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  align-items: center;
}

.page-about .about-hero-copy {
  max-width: 680px;
}

.page-about .about-hero .page-title {
  margin: 10px 0 18px;
  color: var(--color-gold);
  font-size: clamp(28px, 4.4vw, 46px);
  line-height: 1.22;
}

.page-about .about-hero-lead {
  margin: 0 0 12px;
  color: rgba(255, 255, 255, 0.94);
  font-size: 17px;
  line-height: 1.8;
}

.page-about .about-hero-sub {
  margin: 0 0 26px;
  color: rgba(255, 255, 255, 0.68);
  font-family: var(--font-mono);
  font-size: 13px;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.page-about .about-hero-actions .btn--outline {
  color: rgba(255, 255, 255, 0.9);
  border-color: rgba(255, 255, 255, 0.55);
  background: transparent;
}

.page-about .about-hero-panel {
  position: relative;
  background: var(--color-sand);
  border-top: 4px solid var(--color-gold);
  padding: 26px 22px;
  box-shadow: 12px 12px 0 rgba(217, 168, 68, 0.18);
}

.page-about .about-hero-panel-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--color-rock);
}

.page-about .about-hero .stat-group {
  display: grid;
  gap: 0;
}

.page-about .about-hero .stat {
  display: flex;
  flex-direction: column;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-metal);
}

.page-about .about-hero .stat:last-child {
  border-bottom: 0;
}

.page-about .about-hero .stat-value {
  font-family: var(--font-mono);
  font-size: 40px;
  line-height: 1.25;
  color: var(--color-blue-dark);
}

.page-about .about-hero .stat-label {
  font-size: 13px;
  color: var(--color-rock);
}

/* ===== 移动端横向章节索引 ===== */
.page-about .about-mobile-toc {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 14px var(--gutter);
  background: var(--color-white);
  border-bottom: 1px solid var(--color-metal);
  scrollbar-width: none;
}

.page-about .about-mobile-toc::-webkit-scrollbar {
  display: none;
}

.page-about .about-mobile-toc a {
  flex: 0 0 auto;
  padding: 6px 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-rock);
  border: 1px solid var(--color-metal);
  background: var(--color-sand);
  text-decoration: none;
}

.page-about .about-mobile-toc a:hover,
.page-about .about-mobile-toc a:focus-visible {
  color: var(--color-blue);
  border-color: var(--color-blue);
}

/* ===== 主体布局 ===== */
.page-about .about-layout {
  padding: 40px 0 64px;
}

.page-about .about-layout-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  row-gap: 40px;
  align-items: start;
}

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

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

.page-about .about-section {
  padding: 32px 0 40px;
  border-bottom: 1px solid var(--color-metal);
}

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

.page-about .section-head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin: 0 0 26px;
}

.page-about .section-head .section-title {
  margin: 2px 0 4px;
}

.page-about .section-head .section-sub {
  margin: 0;
}

.page-about .section-index {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-gold);
  background: var(--color-sand);
  border: 1px solid var(--color-metal);
  padding: 4px 10px;
  letter-spacing: 0.08em;
}

.page-about .about-sub-title {
  margin: 0 0 12px;
  font-family: var(--font-serif);
  font-size: 22px;
  line-height: 1.35;
  color: var(--color-ink);
}

/* ===== 01 站点定位 ===== */
.page-about .about-position-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
}

.page-about .about-copy-block {
  max-width: 66ch;
}

.page-about .about-copy-block p {
  margin: 0 0 14px;
}

.page-about .about-check-list {
  list-style: none;
  margin: 0 0 16px;
  padding: 0;
}

.page-about .about-check-list li {
  position: relative;
  padding: 8px 0 8px 28px;
  border-bottom: 1px dashed var(--color-metal);
  font-size: 15px;
  line-height: 1.65;
}

.page-about .about-check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 17px;
  width: 14px;
  height: 2px;
  background: var(--color-gold);
}

.page-about .about-position-side {
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  border-left: 4px solid var(--color-gold);
  padding: 18px;
  align-self: start;
}

.page-about .about-mini-label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--color-rock);
}

.page-about .about-nav-list {
  list-style: none;
  margin: 0 0 14px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 4px 12px;
}

.page-about .about-nav-list a {
  display: inline-block;
  padding: 5px 0;
  color: var(--color-blue);
  text-decoration: none;
  font-size: 14px;
  border-bottom: 1px solid transparent;
}

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

.page-about .about-nav-list a[aria-current="page"] {
  color: var(--color-ink);
  font-weight: 600;
  border-bottom-color: var(--color-gold);
}

.page-about .about-position-note {
  margin: 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--color-rock);
}

/* ===== 02 运营主体与备案 ===== */
.page-about .about-company-card {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  border-top: 4px solid var(--color-gold);
  padding: 26px 22px;
}

.page-about .about-shield {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 96px;
  height: 96px;
  color: var(--color-gold);
  border: 1px solid var(--color-metal);
  background:
    linear-gradient(135deg, rgba(217, 168, 68, 0.06) 25%, transparent 25%) 0 0 / 16px 16px,
    var(--color-sand);
}

.page-about .about-shield svg {
  display: block;
  transition: transform 0.35s ease;
}

.page-about .about-company-card:hover .about-shield svg,
.page-about .about-company-card:focus-within .about-shield svg {
  transform: rotate(-7deg) scale(1.06);
}

.page-about .about-company-info {
  min-width: 0;
}

.page-about .about-company-info > p {
  margin: 0 0 14px;
}

.page-about .about-icp {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.04em;
  color: var(--color-ink);
  background: var(--color-gold-bright);
  border: 1px solid var(--color-gold);
  padding: 6px 12px;
  margin: 4px 0 18px;
}

.page-about .about-company-meta {
  margin: 0 0 16px;
  display: grid;
  gap: 8px;
}

.page-about .about-company-meta div {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 10px;
  padding: 8px 0;
  border-bottom: 1px dashed var(--color-metal);
}

.page-about .about-company-meta dt {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-rock);
  padding-top: 3px;
}

.page-about .about-company-meta dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
}

.page-about .about-company-meta a {
  color: var(--color-blue);
  text-decoration: none;
}

.page-about .about-company-meta a:hover,
.page-about .about-company-meta a:focus-visible {
  text-decoration: underline;
}

.page-about .about-company-note {
  font-size: 13px;
  color: var(--color-rock);
  background: var(--color-sand);
  border-left: 3px solid var(--color-blue);
  padding: 10px 14px;
}

/* ===== 03 发展历程 ===== */
.page-about .about-history-banner {
  margin: 0 0 30px;
  background: var(--color-metal);
  border: 1px solid var(--color-metal);
}

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

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

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 22px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--color-gold);
}

.page-about .about-timeline-item {
  position: relative;
  padding-left: 62px;
  margin-bottom: 20px;
}

.page-about .about-timeline-item:last-child {
  margin-bottom: 0;
}

.page-about .about-timeline-badge {
  position: absolute;
  left: 9px;
  top: 12px;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--color-gold);
  background: var(--color-sand);
  font-family: var(--font-mono);
  font-size: 10px;
  color: var(--color-rock);
  letter-spacing: 0.02em;
}

.page-about .about-timeline-card {
  position: relative;
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  padding: 14px 18px;
}

.page-about .about-timeline-card:hover {
  border-color: var(--color-blue);
}

.page-about .about-timeline-card summary {
  list-style: none;
  cursor: pointer;
  position: relative;
  padding-right: 28px;
  display: block;
}

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

.page-about .about-timeline-card summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 2px;
  font-family: var(--font-mono);
  font-size: 18px;
  line-height: 1;
  color: var(--color-gold);
}

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

.page-about .about-timeline-title {
  display: block;
  font-family: var(--font-serif);
  font-size: 18px;
  font-weight: 700;
  color: var(--color-ink);
  margin-bottom: 2px;
}

.page-about .about-timeline-desc {
  display: block;
  font-size: 13px;
  color: var(--color-rock);
  line-height: 1.6;
}

.page-about .about-timeline-body {
  margin-top: 12px;
  padding-top: 12px;
  border-top: 1px dashed var(--color-metal);
}

.page-about .about-timeline-body p {
  margin: 0 0 10px;
  font-size: 14px;
  line-height: 1.75;
}

/* ===== 04 内容目录演进 ===== */
.page-about .about-evolution-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .about-evolution-copy {
  min-width: 0;
}

.page-about .about-evolution-copy > p {
  max-width: 62ch;
}

.page-about .about-evolution-list {
  list-style: none;
  margin: 18px 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.page-about .about-evolution-list li {
  display: flex;
  align-items: baseline;
  gap: 8px;
  background: var(--color-gold-bright);
  border: 1px solid rgba(217, 168, 68, 0.4);
  padding: 12px 14px;
}

.page-about .about-evolution-num {
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1;
  color: var(--color-gold-dark);
}

.page-about .about-evolution-text {
  font-size: 14px;
  color: var(--color-ink);
}

.page-about .about-evolution-figure {
  margin: 0;
  align-self: center;
}

.page-about .about-evolution-figure figcaption {
  font-size: 13px;
  color: var(--color-rock);
  padding-top: 8px;
  text-align: right;
}

/* ===== 05 团队与协作 ===== */
.page-about .about-team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

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

.page-about .about-team-figure figcaption {
  font-size: 13px;
  color: var(--color-rock);
  padding-top: 8px;
  text-align: left;
}

.page-about .about-team-copy {
  min-width: 0;
}

.page-about .about-team-roles {
  list-style: none;
  margin: 16px 0 18px;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .about-team-roles li {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 12px 14px;
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  border-left: 4px solid var(--color-blue);
}

.page-about .about-team-role-tag {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-blue);
  padding-top: 2px;
}

.page-about .about-team-role-desc {
  font-size: 14px;
  line-height: 1.7;
  color: var(--color-ink);
}

/* ===== 06 服务理念 ===== */
.page-about .about-principles-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin-bottom: 24px;
}

.page-about .about-principle-card {
  position: relative;
  padding: 22px 20px;
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  border-top: 4px solid var(--color-gold);
  margin: 0;
}

.page-about .about-principle-card:hover {
  border-top-color: var(--color-blue);
  transform: translateY(-2px);
}

.page-about .about-principle-id {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--color-gold-dark);
  letter-spacing: 0.08em;
  margin-bottom: 10px;
}

.page-about .about-principle-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-serif);
  font-size: 19px;
  color: var(--color-ink);
}

.page-about .about-principle-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--color-rock);
}

.page-about .about-trust {
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  border-left: 4px solid var(--color-gold);
  padding: 18px 20px;
}

.page-about .about-trust p {
  margin: 0 0 10px;
  font-size: 14px;
  line-height: 1.75;
  color: var(--color-rock);
}

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

.page-about .about-trust a {
  color: var(--color-blue);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

.page-about .about-trust a:hover,
.page-about .about-trust a:focus-visible {
  border-bottom-color: var(--color-blue);
}

/* ===== 延伸阅读 ===== */
.page-about .about-exit-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  padding-top: 28px;
}

.page-about .about-exit-card {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: var(--color-white);
  border: 1px solid var(--color-metal);
  padding: 18px;
  text-decoration: none;
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.page-about .about-exit-card:hover,
.page-about .about-exit-card:focus-visible {
  border-color: var(--color-blue);
  transform: translateY(-2px);
}

.page-about .about-exit-id {
  flex: 0 0 auto;
  width: 30px;
  height: 30px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--color-gold-dark);
  border: 1px solid var(--color-gold);
  background: var(--color-sand);
}

.page-about .about-exit-body {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-exit-title {
  font-size: 15px;
  font-weight: 600;
  color: var(--color-ink);
  line-height: 1.5;
}

/* ===== 响应式：中等宽度 ===== */
@media (min-width: 620px) {
  .page-about .about-position-grid {
    grid-template-columns: minmax(0, 1fr) 240px;
    gap: 32px;
  }

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

  .page-about .about-company-card {
    grid-template-columns: 120px minmax(0, 1fr);
    gap: 28px;
  }

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

/* ===== 响应式：桌面端 ===== */
@media (min-width: 900px) {
  .page-about .about-hero {
    padding: 40px 0 64px;
  }

  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1fr) 360px;
    gap: 52px;
  }

  .page-about .about-mobile-toc {
    display: none;
  }

  .page-about .about-layout {
    padding: 56px 0 72px;
  }

  .page-about .about-layout-grid {
    grid-template-columns: 210px minmax(0, 1fr);
    column-gap: 48px;
  }

  .page-about .about-sidebar {
    display: block;
    position: sticky;
    top: 24px;
    padding-top: 8px;
  }

  .page-about .about-toc {
    display: flex;
    flex-direction: column;
    border-left: 2px solid var(--color-metal);
    padding-left: 0;
  }

  .page-about .about-toc-title {
    margin: 0 0 10px;
    padding-left: 16px;
    font-family: var(--font-mono);
    font-size: 13px;
    letter-spacing: 0.1em;
    color: var(--color-rock);
  }

  .page-about .about-toc .toc-link {
    display: block;
    padding: 7px 16px;
    font-family: var(--font-mono);
    font-size: 13px;
    line-height: 1.5;
    color: var(--color-rock);
    text-decoration: none;
    border-left: 2px solid transparent;
    margin-left: -2px;
    transition: color 0.2s ease, border-color 0.2s ease;
  }

  .page-about .about-toc .toc-link:hover,
  .page-about .about-toc .toc-link:focus-visible {
    color: var(--color-blue);
    border-left-color: var(--color-blue);
  }

  .page-about .about-section {
    padding: 40px 0 52px;
  }

  .page-about .about-evolution-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.8fr);
    gap: 48px;
    align-items: center;
  }

  .page-about .about-team-grid {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1fr);
    gap: 48px;
    align-items: center;
  }

  .page-about .about-exit-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }
}

/* ===== 响应式：桌面端时间线交替布局 ===== */
@media (min-width: 1100px) {
  .page-about .about-timeline::before {
    left: 50%;
  }

  .page-about .about-timeline-item {
    width: 50%;
    padding-left: 0;
    padding-right: 44px;
    margin-bottom: 26px;
    text-align: right;
  }

  .page-about .about-timeline-item:nth-child(even) {
    margin-left: 50%;
    padding-left: 44px;
    padding-right: 0;
    text-align: left;
  }

  .page-about .about-timeline-badge {
    left: auto;
    right: -14px;
  }

  .page-about .about-timeline-item:nth-child(even) .about-timeline-badge {
    right: auto;
    left: -14px;
  }

  .page-about .about-timeline-card summary {
    padding-right: 0;
  }

  .page-about .about-timeline-card summary::after {
    display: none;
  }

  .page-about .about-timeline-item:nth-child(even) .about-timeline-card summary {
    padding-right: 0;
    padding-left: 0;
  }

  .page-about .about-timeline-card:hover {
    border-color: var(--color-blue);
  }
}