.page-about {
  --rail-line: rgba(18, 21, 28, .18);
  --node-bg: var(--paper);
  display: block;
  overflow-x: clip;
  background: var(--paper);
  color: var(--ink);
}

.page-about .container {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: 20px;
}

/* ── 首屏 ───────────────────────────── */
.page-about .about-hero {
  position: relative;
  padding: 104px 0 48px;
  background:
    radial-gradient(120% 80% at 8% -20%, rgba(122, 92, 255, .14), transparent 58%),
    radial-gradient(90% 70% at 100% 0%, rgba(228, 168, 84, .10), transparent 55%),
    var(--paper);
  border-bottom: 1px solid var(--line-paper);
}

.page-about .breadcrumb {
  margin-bottom: 22px;
}

.page-about .crumb-list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
}

.page-about .crumb-link {
  color: var(--moss);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .16s ease-out, border-color .16s ease-out;
}

.page-about .crumb-link:hover {
  color: var(--clay);
  border-bottom-color: var(--clay);
}

.page-about .crumb-sep {
  color: rgba(18, 21, 28, .32);
}

.page-about .crumb-list [aria-current="page"] {
  color: var(--ink);
}

.page-about .hero-frame {
  position: relative;
  padding: 30px 22px 26px;
  border: 1px solid var(--line-paper);
  border-radius: var(--radius-card);
  background: linear-gradient(180deg, var(--paper-2) 0%, var(--paper) 100%);
  box-shadow: var(--shadow-paper);
}

.page-about .hero-frame::before {
  content: "";
  position: absolute;
  top: -1px;
  left: -1px;
  width: 58px;
  height: 3px;
  border-radius: 3px 0 3px 0;
  background: linear-gradient(90deg, var(--violet) 0%, var(--violet-soft) 100%);
}

.page-about .hero-frame > * {
  position: relative;
  z-index: 1;
}

.page-about .hero-kicker {
  margin: 0 0 14px;
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--clay);
  text-transform: uppercase;
}

.page-about .hero-frame h1 {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-size: 34px;
  line-height: 1.18;
  font-weight: 900;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .hero-lead {
  margin: 0;
  max-width: 62ch;
  font-size: 16.5px;
  line-height: 1.75;
  color: var(--ink-soft);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  border: 1px solid var(--line-paper);
  border-radius: 4px;
  overflow: hidden;
  background: var(--line-paper);
}

.page-about .hero-stat {
  background: var(--paper-2);
  padding: 14px 12px;
}

.page-about .hero-stat-label {
  margin: 0;
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--moss);
}

.page-about .hero-stat-value {
  margin: 6px 0 0;
  margin-inline-start: 0;
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
  color: var(--gold);
}

.page-about .hero-stat-value .unit {
  margin-left: 2px;
  font-family: var(--font-body);
  font-size: 12px;
  font-weight: 500;
  color: var(--ink-soft);
}

/* ── 章节标题组 ─────────────────────── */
.page-about .rail-head {
  max-width: 62ch;
  margin-bottom: 30px;
}

.page-about .rail-kicker {
  margin: 0 0 12px;
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--clay);
}

.page-about .rail-title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: 26px;
  line-height: 1.25;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .rail-lead {
  margin: 0;
  font-size: 16px;
  line-height: 1.72;
  color: var(--ink-soft);
}

/* ── 纸面时间线 ─────────────────────── */
.page-about .about-timeline {
  padding: 54px 0 58px;
  background: var(--paper);
}

.page-about .story-rail {
  position: relative;
  padding-left: 34px;
}

.page-about .story-rail::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 10px;
  bottom: 10px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg,
    var(--violet) 0%,
    rgba(122, 92, 255, .38) 42%,
    var(--rail-line) 100%);
}

.page-about .story-node {
  position: relative;
  padding-bottom: 42px;
}

.page-about .story-node:last-child {
  padding-bottom: 0;
}

.page-about .story-node::before {
  content: "";
  position: absolute;
  left: -31px;
  top: 8px;
  width: 12px;
  height: 12px;
  box-sizing: border-box;
  border-radius: 50%;
  background: var(--node-bg);
  border: 2px solid var(--clay);
  box-shadow: 0 0 0 3px var(--node-bg);
  transition: border-color .16s ease-out, transform .16s ease-out, box-shadow .16s ease-out;
}

.page-about .story-node:hover::before,
.page-about .story-node:focus-within::before {
  border-color: var(--violet);
  transform: scale(1.12);
  box-shadow: 0 0 0 3px var(--node-bg), var(--glow-violet);
}

.page-about .node-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.page-about .node-num {
  display: inline-block;
  padding: 2px 7px;
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--clay);
  border: 1px solid rgba(180, 115, 90, .45);
  border-radius: 3px;
  background: rgba(180, 115, 90, .08);
}

.page-about .node-era {
  font-size: 11px;
  letter-spacing: .08em;
  color: var(--moss);
}

.page-about .story-node h3 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-size: 21px;
  line-height: 1.35;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .story-node p {
  margin: 0 0 10px;
  max-width: 62ch;
  font-size: 16.5px;
  line-height: 1.78;
  color: var(--ink-soft);
}

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

/* ── 时间线配图 ─────────────────────── */
.page-about .rail-figure {
  margin: 0 0 28px;
  padding: 0;
  border: 1px solid var(--line-paper);
  border-radius: var(--radius-card);
  overflow: hidden;
  background: var(--paper-2);
  box-shadow: var(--shadow-paper);
}

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

.page-about .rail-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--line-paper);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.6;
  letter-spacing: .04em;
  color: var(--moss);
}

.page-about .rail-figure--inline {
  margin: 20px 0 0;
}

/* ── 夜间段 ─────────────────────────── */
.page-about .about-night {
  position: relative;
  padding: 58px 0 62px;
  background: var(--deep);
  color: var(--mist);
  overflow: hidden;
}

.page-about .about-night::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(75% 60% at 88% 0%, rgba(122, 92, 255, .24), transparent 62%),
    radial-gradient(60% 50% at 0% 100%, rgba(201, 228, 76, .10), transparent 60%);
}

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

.page-about .about-night .rail-kicker {
  color: var(--gold);
}

.page-about .about-night .rail-title {
  color: var(--mist);
}

.page-about .about-night .rail-lead {
  color: var(--mist-soft);
}

.page-about .about-night .story-rail::before {
  background: linear-gradient(180deg,
    rgba(201, 228, 76, .75) 0%,
    rgba(122, 92, 255, .55) 45%,
    rgba(217, 211, 198, .16) 100%);
}

.page-about .about-night .story-node::before {
  background: var(--deep-2);
  border-color: var(--clay);
  box-shadow: 0 0 0 3px var(--deep-2);
}

.page-about .about-night .story-node:hover::before,
.page-about .about-night .story-node:focus-within::before {
  border-color: var(--lime);
  box-shadow: 0 0 0 3px var(--deep-2), 0 0 16px rgba(201, 228, 76, .45);
}

.page-about .about-night .story-node h3 {
  color: var(--mist);
}

.page-about .about-night .story-node p {
  color: var(--mist-soft);
}

.page-about .about-night .node-num {
  color: var(--gold);
  border-color: rgba(228, 168, 84, .45);
  background: rgba(228, 168, 84, .10);
}

.page-about .about-night .node-era {
  color: rgba(232, 235, 242, .55);
}

.page-about .about-night .rail-figure {
  border-color: var(--line-night);
  background: var(--deep-2);
  box-shadow: var(--shadow-night);
}

.page-about .about-night .rail-figure figcaption {
  border-top-color: var(--line-night);
  color: rgba(232, 235, 242, .62);
}

/* ── 服务承诺 ───────────────────────── */
.page-about .about-promise {
  position: relative;
  padding: 54px 0 66px;
  background: linear-gradient(180deg, var(--deep) 0%, #070C15 100%);
  color: var(--mist);
}

.page-about .about-promise::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 1px;
  background: linear-gradient(90deg,
    transparent 0%,
    rgba(122, 92, 255, .55) 20%,
    rgba(201, 228, 76, .55) 55%,
    transparent 100%);
}

.page-about .about-promise .rail-kicker {
  color: var(--gold);
}

.page-about .about-promise .rail-title {
  color: var(--mist);
}

.page-about .about-promise .rail-lead {
  color: var(--mist-soft);
}

.page-about .promise-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
}

.page-about .promise-card {
  position: relative;
  padding: 22px 18px 20px;
  border: 1px solid var(--line-night);
  border-radius: var(--radius-card);
  background: var(--deep-2);
  transition: transform .16s ease-out, border-color .16s ease-out, box-shadow .16s ease-out;
}

.page-about .promise-card:hover,
.page-about .promise-card:focus-within {
  transform: translateY(-2px);
  border-color: var(--violet);
  box-shadow: var(--glow-violet);
}

.page-about .promise-num {
  margin: 0 0 14px;
  font-size: 11px;
  letter-spacing: .1em;
  color: var(--gold);
}

.page-about .promise-title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 19px;
  line-height: 1.35;
  font-weight: 800;
  color: var(--mist);
}

.page-about .promise-text {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.72;
  color: var(--mist-soft);
}

/* ── 收尾 ───────────────────────────── */
.page-about .about-next {
  padding: 44px 0 58px;
  background: #070C15;
  color: var(--mist);
}

.page-about .next-inner {
  padding: 26px 20px;
  border: 1px solid var(--line-night);
  border-radius: var(--radius-card);
  background: linear-gradient(135deg, rgba(122, 92, 255, .20) 0%, rgba(228, 168, 84, .10) 100%);
}

.page-about .next-text {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-size: 19px;
  line-height: 1.5;
  font-weight: 700;
  color: var(--mist);
}

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

.page-about .next-actions .btn {
  text-decoration: none;
}

.page-about .next-note {
  margin: 18px 0 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--mist-soft);
}

.page-about .next-note a {
  color: var(--gold);
  text-decoration: none;
  border-bottom: 1px solid rgba(228, 168, 84, .45);
  transition: border-color .16s ease-out;
}

.page-about .next-note a:hover {
  border-bottom-color: var(--gold);
}

/* ── 键盘焦点 ───────────────────────── */
.page-about a:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 2px;
  border-radius: 3px;
}

/* ── 桌面端 ─────────────────────────── */
@media (min-width: 768px) {
  .page-about .about-hero {
    padding: 128px 0 64px;
  }

  .page-about .hero-frame {
    padding: 42px 40px 38px;
  }

  .page-about .hero-frame h1 {
    font-size: clamp(38px, 4.6vw, 52px);
  }

  .page-about .hero-stat {
    padding: 18px 20px;
  }

  .page-about .hero-stat-value {
    font-size: 30px;
  }

  .page-about .rail-title {
    font-size: 34px;
  }

  .page-about .about-timeline {
    padding: 68px 0 76px;
  }

  .page-about .story-rail {
    padding-left: 56px;
  }

  .page-about .story-rail::before {
    left: 12px;
  }

  .page-about .story-node::before {
    left: -49px;
  }

  .page-about .story-node {
    padding-bottom: 52px;
  }

  .page-about .story-node h3 {
    font-size: 24px;
  }

  .page-about .about-night {
    padding: 72px 0 78px;
  }

  .page-about .about-promise {
    padding: 66px 0 80px;
  }

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

  .page-about .promise-card {
    padding: 28px 24px 26px;
  }

  .page-about .about-next {
    padding: 52px 0 72px;
  }

  .page-about .next-inner {
    display: grid;
    grid-template-columns: 1fr auto;
    grid-template-areas:
      "text actions"
      "note note";
    gap: 14px 32px;
    padding: 34px 32px;
  }

  .page-about .next-text {
    grid-area: text;
    margin-bottom: 0;
  }

  .page-about .next-actions {
    grid-area: actions;
    align-self: center;
  }

  .page-about .next-note {
    grid-area: note;
    margin-top: 0;
  }
}

@media (min-width: 1100px) {
  .page-about .container {
    padding-inline: 28px;
  }

  .page-about .story-node p {
    font-size: 17px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .story-node::before,
  .page-about .promise-card,
  .page-about .crumb-link,
  .page-about .next-note a {
    transition: none;
  }
}