.page-about {
  --about-rail-w: 72px;
  --about-gap: 40px;
  color: var(--paper);
  background: var(--bg);
}

/* ========== 首屏 ========== */
.page-about .about-hero {
  padding: 40px 0 48px;
  background:
    radial-gradient(1200px 360px at 85% -10%, rgba(192, 57, 43, 0.16), transparent 60%),
    linear-gradient(180deg, #15181C 0%, var(--bg) 100%);
}

.page-about .about-hero-inner {
  display: grid;
  gap: 32px;
  align-items: center;
}

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

.page-about .breadcrumbs {
  margin-bottom: 28px;
}

.page-about .about-hero-kicker {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 12px;
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--gold);
}

.page-about .about-hero-kicker::before {
  content: "";
  width: 28px;
  height: 2px;
  background: var(--red);
}

.page-about .about-hero h1 {
  margin: 0 0 16px;
  font-family: var(--font-heading);
  font-size: 34px;
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: 0.02em;
  color: var(--paper);
}

.page-about .about-hero-lead {
  max-width: 60ch;
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--muted);
}

.page-about .about-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 28px;
}

.page-about .about-hero-stats .stat-block {
  position: relative;
  background: var(--bg-panel);
  border: 1px solid var(--brick);
  padding: 16px 14px;
}

.page-about .about-hero-stats .stat-block::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 3px;
  height: 100%;
  background: var(--red);
}

.page-about .about-hero-stats .stat-block:nth-child(2)::before {
  background: var(--gold);
}

.page-about .about-hero-stats .stat-value {
  display: block;
  font-family: var(--font-data);
  font-size: 26px;
  line-height: 1.2;
  color: var(--paper);
}

.page-about .about-hero-stats .stat-label {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--muted);
}

.page-about .about-chapter-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 26px;
  padding-top: 16px;
  border-top: 1px solid var(--brick);
}

.page-about .about-chapter-nav a {
  color: var(--muted);
  font-size: 13px;
  text-decoration: none;
  letter-spacing: 0.04em;
  border-bottom: 1px solid transparent;
  transition: color 0.25s ease, border-color 0.25s ease;
}

.page-about .about-chapter-nav a:hover {
  color: var(--paper);
  border-color: var(--red);
}

.page-about .about-hero-visual {
  position: relative;
  margin: 0;
  min-width: 0;
}

.page-about .about-hero-img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--brick);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
}

.page-about .about-figcap {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ========== 章节骨架 ========== */
.page-about .about-section {
  padding: 52px 0;
}

.page-about .about-section-inner {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px var(--about-gap);
}

.page-about .about-section-rail {
  display: flex;
  align-items: baseline;
  gap: 14px;
  min-width: 0;
}

.page-about .about-section-index {
  font-family: var(--font-data);
  font-size: 28px;
  line-height: 1;
  color: var(--red);
  transition: color 0.3s ease, transform 0.3s ease;
}

.page-about .about-section-vernote {
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: var(--muted);
}

.page-about .about-section:target .about-section-index {
  color: var(--gold);
  transform: scale(1.12);
}

.page-about .about-section-body {
  min-width: 0;
  display: grid;
  gap: 28px;
}

.page-about .about-section-body h2 {
  margin: 0 0 4px;
  font-family: var(--font-heading);
  font-size: 30px;
  line-height: 1.35;
  color: var(--paper);
}

.page-about .about-section-body h2::after {
  content: "";
  display: block;
  width: 44px;
  height: 3px;
  margin-top: 12px;
  background: linear-gradient(90deg, var(--red), var(--gold));
  transition: width 0.3s ease;
}

.page-about .about-section:target .about-section-body h2::after {
  width: 88px;
}

.page-about .about-prose {
  max-width: 680px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

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

.page-about .about-prose strong {
  color: var(--paper);
  font-weight: 600;
}

.page-about .about-split {
  display: grid;
  gap: 24px;
  min-width: 0;
}

.page-about .about-visual {
  margin: 0;
  min-width: 0;
}

.page-about .about-visual figcaption {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .about-vernote {
  margin: 12px 0 0 auto;
  height: 108px;
  writing-mode: vertical-rl;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.32em;
  color: var(--gold);
  border-right: 1px solid var(--brick);
  padding-right: 10px;
}

/* ========== 长城轮廓 SVG ========== */
.page-about .about-wall-svg {
  display: block;
  width: 100%;
  height: auto;
  box-sizing: border-box;
  padding: 12px;
  background: var(--bg-panel);
  border: 1px solid var(--brick);
}

.page-about .about-wall-base {
  stroke: var(--brick);
  stroke-width: 2;
  fill: none;
}

.page-about .about-wall-ridge,
.page-about .about-wall-tower {
  fill: var(--bg-raised);
  stroke: var(--gold);
  stroke-width: 1.5;
}

.page-about .about-wall-dataline {
  stroke: var(--teal);
  stroke-width: 2;
  stroke-dasharray: 8 6;
  fill: none;
}

.page-about .about-wall-beacon {
  fill: var(--red-dark);
}

.page-about .about-wall-flame {
  fill: var(--red);
}

.page-about .about-wall-marker {
  fill: var(--gold);
}

/* ========== 数据流 SVG ========== */
.page-about .about-flow-svg {
  display: block;
  width: 100%;
  height: auto;
  box-sizing: border-box;
  background: var(--bg-panel);
  border: 1px solid var(--brick);
}

.page-about .about-flow-line {
  stroke: var(--teal);
  stroke-width: 2;
  stroke-dasharray: 7 5;
  fill: none;
}

.page-about .about-flow-node {
  fill: var(--bg-raised);
  stroke: var(--gold);
  stroke-width: 2;
}

.page-about .about-flow-text {
  fill: var(--paper);
  font-size: 14px;
  font-family: var(--font-body);
}

/* ========== 机制卡片 ========== */
.page-about .about-mech-grid,
.page-about .about-feature-grid {
  display: grid;
  gap: 16px;
  min-width: 0;
}

.page-about .about-mech-card {
  position: relative;
  background: var(--bg-panel);
  border: 1px solid var(--brick);
  border-top: 3px solid var(--red);
  padding: 20px;
  clip-path: polygon(0 0, calc(100% - 14px) 0, 100% 14px, 100% 100%, 0 100%);
}

.page-about .about-mech-card.about-feature-card {
  border-top-color: var(--gold);
}

.page-about .about-mech-tag {
  display: inline-block;
  margin-bottom: 10px;
  padding: 2px 8px;
  font-family: var(--font-data);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--gold);
  border: 1px solid var(--brick);
}

.page-about .about-mech-card h3 {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-size: 18px;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-mech-card p {
  margin: 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

/* ========== 时间线 ========== */
.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
  min-width: 0;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 19px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: repeating-linear-gradient(to bottom, var(--brick) 0 8px, transparent 8px 14px);
}

.page-about .about-timeline-item {
  position: relative;
  padding: 0 0 30px 58px;
  min-width: 0;
}

.page-about .about-timeline-mark {
  position: absolute;
  left: 0;
  top: 2px;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: var(--bg-panel);
  border: 1px solid var(--brick);
  clip-path: polygon(0 0, calc(100% - 9px) 0, 100% 9px, 100% 100%, 0 100%);
  font-family: var(--font-data);
  font-size: 13px;
  color: var(--gold);
}

.page-about .about-timeline-body h3 {
  margin: 0 0 8px;
  font-family: var(--font-heading);
  font-size: 21px;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .about-timeline-body p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-timeline-note {
  margin: 12px 0 0;
  background: var(--bg-panel);
  border-left: 3px solid var(--teal);
}

.page-about .about-timeline-note summary {
  cursor: pointer;
  padding: 10px 14px;
  list-style: none;
  font-family: var(--font-data);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--paper);
}

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

.page-about .about-timeline-note summary::before {
  content: "＋";
  margin-right: 8px;
  color: var(--teal);
  font-family: var(--font-data);
}

.page-about .about-timeline-note[open] summary::before {
  content: "－";
}

.page-about .about-timeline-note p {
  margin: 0;
  padding: 0 14px 12px;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-timeline-media {
  position: relative;
  padding: 6px 0 30px 58px;
  min-width: 0;
}

.page-about .about-timeline-media figure {
  margin: 0;
}

.page-about .about-timeline-media img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--brick);
}

.page-about .about-timeline-media figcaption {
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

/* ========== 服务理念与联系 ========== */
.page-about .about-philosophy-visual img {
  display: block;
  width: 100%;
  max-width: 460px;
  height: auto;
  margin-inline: auto;
  border: 1px solid var(--brick);
  border-radius: 50%;
}

.page-about .about-philosophy-visual figcaption {
  text-align: center;
}

.page-about .about-contact-panel {
  display: grid;
  gap: 14px;
  padding: 22px 20px;
  background: var(--bg-panel);
  border: 1px solid var(--brick);
  border-left: 4px solid var(--red);
  min-width: 0;
}

.page-about .about-contact-panel h3 {
  margin: 0;
  font-family: var(--font-heading);
  font-size: 18px;
  color: var(--paper);
}

.page-about .about-contact-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
  min-width: 0;
}

.page-about .about-contact-list li {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 8px;
  font-size: 14px;
  color: var(--paper);
  overflow-wrap: anywhere;
}

.page-about .about-contact-list span {
  font-family: var(--font-data);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .about-contact-note {
  margin: 0;
  padding-top: 12px;
  border-top: 1px solid var(--brick);
  font-size: 12px;
  line-height: 1.7;
  color: var(--muted);
}

/* ========== 结束导向 ========== */
.page-about .about-outro {
  padding: 48px 0 64px;
  background:
    linear-gradient(135deg, rgba(123, 45, 38, 0.3), transparent 60%),
    var(--bg-panel);
  border-top: 1px solid var(--brick);
}

.page-about .about-outro-inner {
  display: grid;
  gap: 24px;
  justify-items: start;
}

.page-about .about-outro-title {
  margin: 0;
  font-family: var(--font-heading);
  font-size: 26px;
  color: var(--paper);
}

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

.page-about .about-outro-trust {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

/* ========== 滚动显现（无 JS 时保持完整可读） ========== */
.page-about [data-reveal] {
  transition: transform 0.45s ease;
}

.page-about [data-reveal]:not([data-visible]) {
  transform: translateY(12px);
}

@media (prefers-reduced-motion: reduce) {
  .page-about [data-reveal] {
    transform: none !important;
    transition: none !important;
  }
}

/* ========== 响应式 ========== */
@media (min-width: 700px) {
  .page-about .about-hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-hero h1 {
    font-size: 44px;
  }

  .page-about .about-hero-lead {
    font-size: 17px;
  }

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

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

@media (min-width: 768px) {
  .page-about .about-timeline::before {
    left: 31px;
  }

  .page-about .about-timeline-item,
  .page-about .about-timeline-media {
    padding-left: 86px;
  }

  .page-about .about-timeline-mark {
    width: 64px;
    height: 64px;
    font-size: 16px;
  }

  .page-about .about-section-body h2 {
    font-size: 36px;
  }
}

@media (min-width: 900px) {
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: center;
  }

  .page-about .about-split-reverse .about-visual {
    order: 1;
  }

  .page-about .about-split-reverse .about-prose {
    order: 2;
  }
}

@media (min-width: 1024px) {
  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    gap: 48px;
  }

  .page-about .about-hero h1 {
    font-size: 52px;
  }

  .page-about .about-section-inner {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .about-section-rail {
    flex-direction: column;
    align-items: flex-end;
    gap: 14px;
    position: sticky;
    top: calc(var(--header-total-h) + 32px);
    align-self: start;
    height: fit-content;
    padding-top: 6px;
  }

  .page-about .about-section-vernote {
    writing-mode: vertical-rl;
    height: 120px;
    border-right: 1px solid var(--brick);
    padding-right: 10px;
  }

  .page-about .about-section-body h2 {
    font-size: 44px;
  }

  .page-about .about-mech-card h3 {
    font-size: 19px;
  }

  .page-about .about-timeline-body h3 {
    font-size: 23px;
  }

  .page-about .about-outro-title {
    font-size: 30px;
  }
}