.page-about {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  padding-top: clamp(20px, 3vw, 40px);
  padding-bottom: clamp(44px, 6vw, 88px);
  align-items: center;
}

.page-about .about-hero__code {
  margin: 0 0 18px;
  font-size: var(--step-1);
  letter-spacing: .22em;
  color: var(--stone);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-size: clamp(30px, 4.6vw, 52px);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: .06em;
  color: var(--abyss);
}

.page-about .about-hero__lede {
  margin: 0 0 16px;
  font-size: clamp(16.5px, 1.5vw, 19px);
  line-height: 1.75;
  color: var(--ink-soft);
}

.page-about .about-hero__sub {
  margin: 0 0 32px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-mute);
}

.page-about .about-hero__stats {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule);
  border-top: 1px solid var(--rule-strong);
  border-bottom: 1px solid var(--rule-strong);
}

.page-about .about-hero__stats li {
  background: var(--paper);
  padding: 16px 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-stat__num {
  font-family: var(--font-display);
  font-size: clamp(26px, 2.6vw, 36px);
  line-height: 1;
  letter-spacing: .04em;
  color: var(--abyss);
}

.page-about .about-stat__label {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--stone);
}

.page-about .about-hero__visual {
  background: var(--abyss);
  border: 1px solid var(--rule-dark);
  box-shadow: 14px 14px 0 rgba(11, 34, 57, .08);
}

.page-about .about-hero__visual svg {
  display: block;
  width: 100%;
  height: auto;
}

/* ---------- 章节通用 ---------- */
.page-about .about-chapter {
  padding: clamp(44px, 6vw, 96px) 0;
  border-top: 1px solid var(--rule);
}

.page-about .about-chapter__grid {
  display: grid;
  gap: 24px;
}

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

.page-about .about-chapter__code {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: var(--step-2);
  letter-spacing: .2em;
  color: var(--stone);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--rule-strong);
  margin-bottom: 16px;
}

.page-about .about-chapter__title {
  margin: 0 0 12px;
  font-family: var(--font-serif);
  font-size: clamp(23px, 2.9vw, 34px);
  font-weight: 600;
  line-height: 1.32;
  letter-spacing: .01em;
  color: var(--abyss);
}

.page-about .about-chapter__note {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ink-mute);
}

.page-about .about-chapter__body > p {
  margin: 0 0 1.15em;
  font-size: 16.5px;
  line-height: 1.8;
  color: var(--ink-soft);
  max-width: 64ch;
}

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

/* ---------- 流程 ---------- */
.page-about .flow-list {
  list-style: none;
  margin: 0 0 36px;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .flow-step {
  position: relative;
  background: var(--paper-2);
  padding: 22px 20px 20px 24px;
  transition: background 200ms ease;
}

.page-about .flow-step::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--silver);
  transition: background 200ms ease;
}

.page-about .flow-step:hover,
.page-about .flow-step:focus-within {
  background: #ffffff;
}

.page-about .flow-step:hover::before,
.page-about .flow-step:focus-within::before {
  background: var(--aurora);
}

.page-about .flow-step:hover .flow-step__out,
.page-about .flow-step:focus-within .flow-step__out {
  color: var(--coral);
  border-color: var(--coral);
}

.page-about .flow-step__no {
  display: block;
  margin-bottom: 8px;
  font-size: 11.5px;
  letter-spacing: .2em;
  color: var(--stone);
}

.page-about .flow-step__title {
  margin: 0 0 8px;
  font-size: var(--step-3);
  font-weight: 600;
  letter-spacing: .04em;
  color: var(--abyss);
  font-family: var(--font-display);
}

.page-about .flow-step__text {
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.75;
  color: var(--ink-mute);
}

.page-about .flow-step__out {
  display: inline-block;
  margin: 0;
  padding: 4px 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--ink-mute);
  border: 1px dashed var(--rule-strong);
  transition: color 200ms ease, border-color 200ms ease;
}

/* ---------- 栏目色相索引 ---------- */
.page-about .about-chapter--taxonomy {
  background: var(--paper-2);
}

.page-about .about-chapter__head--wide {
  max-width: 46rem;
  margin-bottom: 30px;
}

.page-about .tone-board {
  list-style: none;
  margin: 0 0 34px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}

.page-about .tone-chip {
  background: var(--paper);
  padding: 16px 14px 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 3px solid var(--silver);
}

.page-about .tone-chip--abyss { border-top-color: var(--abyss); }
.page-about .tone-chip--terracotta { border-top-color: var(--terracotta); }
.page-about .tone-chip--coral { border-top-color: var(--coral); }
.page-about .tone-chip--moss { border-top-color: var(--moss); }
.page-about .tone-chip--mineral { border-top-color: var(--mineral); }
.page-about .tone-chip--aurora { border-top-color: var(--aurora); }

.page-about .tone-chip__code {
  font-size: 11.5px;
  letter-spacing: .18em;
  color: var(--stone);
}

.page-about .tone-chip__name {
  font-size: 16px;
  font-weight: 600;
  letter-spacing: .04em;
  color: var(--abyss);
}

.page-about .tone-chip__hint {
  font-size: 12.5px;
  color: var(--ink-mute);
}

.page-about .taxonomy-note {
  max-width: 62ch;
}

.page-about .taxonomy-note p {
  margin: 0 0 1.1em;
  font-size: 16px;
  line-height: 1.8;
  color: var(--ink-soft);
}

.page-about .tag-sample {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 1.4em;
}

.page-about .taxonomy-note__foot {
  font-size: 14px;
  color: var(--ink-mute);
  padding-left: 14px;
  border-left: 2px solid var(--aurora);
}

/* ---------- 里程碑 ---------- */
.page-about .figure--band {
  margin: 0 0 34px;
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--rule);
  border-top: 1px solid var(--rule-strong);
  border-bottom: 1px solid var(--rule-strong);
}

.page-about .timeline__item {
  background: var(--paper);
}

.page-about .timeline__button {
  width: 100%;
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  align-items: center;
  gap: 6px 16px;
  padding: 22px 6px 12px;
  background: none;
  border: 0;
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
}

.page-about .timeline__year {
  grid-column: 1;
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--coral);
}

.page-about .timeline__title {
  grid-column: 1;
  font-family: var(--font-serif);
  font-size: clamp(17px, 1.9vw, 21px);
  line-height: 1.4;
  color: var(--abyss);
}

.page-about .timeline__arrow {
  grid-column: 2;
  grid-row: 1 / span 2;
  width: 9px;
  height: 9px;
  border-right: 1.5px solid var(--stone);
  border-bottom: 1.5px solid var(--stone);
  transform: rotate(45deg);
  transition: transform 200ms ease;
}

.page-about .timeline__button[aria-expanded="true"] .timeline__arrow {
  transform: rotate(-135deg);
}

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

.page-about .timeline__panel[hidden] {
  display: none;
}

.page-about .timeline__panel-inner {
  padding: 0 6px 24px;
  max-width: 60ch;
}

.page-about .timeline__panel-inner p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--ink-mute);
}

/* ---------- 团队与服务范围 ---------- */
.page-about .about-chapter--team {
  background: var(--paper-2);
}

.page-about .about-chapter__grid--media {
  align-items: center;
}

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

/* ---------- 品质标准 ---------- */
.page-about .about-chapter--quality {
  background: var(--abyss);
  color: var(--paper);
  border-top: 1px solid var(--rule-dark);
}

.page-about .about-chapter__head--dark .about-chapter__code {
  color: var(--aurora);
  border-bottom-color: var(--rule-dark-2);
}

.page-about .about-chapter__head--dark .about-chapter__title {
  color: var(--paper);
}

.page-about .about-chapter__head--dark .about-chapter__note {
  color: var(--silver);
}

.page-about .quality-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--rule-dark);
  border: 1px solid var(--rule-dark);
}

.page-about .quality-item {
  background: var(--abyss);
  padding: 26px 22px 28px;
}

.page-about .quality-item__no {
  display: block;
  margin-bottom: 10px;
  font-size: 11.5px;
  letter-spacing: .22em;
  color: var(--aurora);
}

.page-about .quality-item h3 {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: var(--step-3);
  font-weight: 600;
  letter-spacing: .05em;
  color: var(--paper);
}

.page-about .quality-item p {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--silver);
}

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  background: var(--midnight);
  color: var(--paper);
  padding: clamp(46px, 6vw, 84px) 0;
}

.page-about .about-cta__inner {
  display: grid;
  gap: 28px;
}

.page-about .about-cta h2 {
  margin: 0 0 14px;
  font-family: var(--font-serif);
  font-size: clamp(24px, 3vw, 34px);
  font-weight: 600;
  line-height: 1.3;
  color: var(--paper);
}

.page-about .about-cta p {
  margin: 0 0 14px;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--silver);
  max-width: 56ch;
}

.page-about .about-cta__contact {
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--aurora);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-content: start;
}

.page-about .about-cta .btn--ghost {
  color: var(--paper);
  border-color: var(--rule-dark-2);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

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

@media (min-width: 960px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }

  .page-about .about-chapter__grid {
    grid-template-columns: minmax(0, 3fr) minmax(0, 9fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .about-chapter__grid--media {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    gap: 52px;
    align-items: center;
  }

  .page-about .about-chapter__head {
    position: sticky;
    top: calc(var(--header-h) + 26px);
  }

  .page-about .tone-board {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }

  .page-about .timeline__button {
    grid-template-columns: 150px minmax(0, 1fr) auto;
    align-items: baseline;
    padding: 26px 6px 14px;
  }

  .page-about .timeline__year {
    grid-column: 1;
    grid-row: 1;
  }

  .page-about .timeline__title {
    grid-column: 2;
    grid-row: 1;
  }

  .page-about .timeline__arrow {
    grid-column: 3;
    grid-row: 1;
    align-self: center;
  }

  .page-about .timeline__panel-inner {
    padding-left: 156px;
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: center;
    gap: 48px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .flow-step,
  .page-about .flow-step::before,
  .page-about .flow-step__out,
  .page-about .timeline__arrow {
    transition: none;
  }
}