.page-about {
  background-color: var(--surface-base);
  background-image:
    linear-gradient(rgba(244, 241, 232, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(244, 241, 232, 0.035) 1px, transparent 1px);
  background-size: 72px 72px, 72px 72px;
  color: var(--text-on-dark);
}

.page-about .eyebrow {
  color: var(--c-sand);
  letter-spacing: 0.16em;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding-block: clamp(20px, 4vw, 40px) clamp(36px, 6vw, 72px);
  background:
    radial-gradient(120% 90% at 84% 0%, rgba(79, 138, 91, 0.34), transparent 62%),
    linear-gradient(180deg, var(--surface-deep), var(--surface-base) 92%);
  border-bottom: 1px solid var(--line-strong);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(20px, 4vw, 40px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(26px, 4vw, 52px);
}

.page-about .about-hero__lead h1 {
  margin: 14px 0 0;
  font-size: var(--fs-h1);
  font-weight: 900;
  line-height: 1.02;
  letter-spacing: -0.025em;
  max-width: 15ch;
}

.page-about .about-hero__deck {
  margin: 20px 0 0;
  max-width: 52ch;
  font-size: 1.02rem;
  line-height: 1.75;
  color: var(--text-muted);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
  border: 1px solid var(--line-soft);
  background-color: var(--line-soft);
}

.page-about .about-fact {
  background-color: var(--surface-deep);
  padding: 14px 16px 16px;
}

.page-about .about-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.35rem, 4vw, 1.6rem);
  line-height: 1.1;
  color: var(--c-sand);
  font-variant-numeric: tabular-nums;
}

.page-about .about-fact__label {
  display: block;
  margin-top: 6px;
  font-size: var(--fs-ann);
  letter-spacing: 0.08em;
  color: var(--text-muted);
}

.page-about .about-hero__figure {
  margin: 0;
  border: 1px solid var(--line-strong);
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .media-frame__caption {
  font-size: var(--fs-ann);
  line-height: 1.6;
  color: rgba(244, 241, 232, 0.68);
}

/* ---------- 章节索引 ---------- */

.page-about .about-index {
  background-color: var(--surface-deep);
  border-bottom: 1px solid var(--line-strong);
}

.page-about .about-index__nav {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  padding-block: 12px;
  scrollbar-width: none;
}

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

.page-about .about-index__link {
  flex: 0 0 auto;
  display: inline-block;
  padding: 7px 14px;
  border: 1px solid var(--line-soft);
  font-size: var(--fs-sm);
  color: var(--text-on-dark);
  text-decoration: none;
  white-space: nowrap;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  border-color: var(--c-sand);
  color: var(--c-sand);
}

/* ---------- 通用章节 ---------- */

.page-about .about-section {
  padding-block: clamp(40px, 6vw, 78px);
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-section .section__head {
  margin-bottom: clamp(22px, 3.5vw, 38px);
}

.page-about .about-section .section__title {
  margin: 10px 0 0;
  font-weight: 900;
  line-height: 1.1;
  letter-spacing: -0.015em;
}

/* ---------- 01 内容方法 ---------- */

.page-about .about-why__grid {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
}

.page-about .about-why__list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-why__item {
  display: flex;
  gap: 16px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-why__idx {
  flex: 0 0 auto;
  width: 26px;
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--c-sand);
}

.page-about .about-why__body {
  font-size: var(--fs-sm);
  line-height: 1.72;
  color: var(--text-muted);
}

.page-about .about-why__body strong {
  display: block;
  margin-bottom: 3px;
  font-size: var(--fs-base);
  font-weight: 700;
  color: var(--text-on-dark);
}

/* ---------- 02 团队 ---------- */

.page-about .about-team__grid {
  display: grid;
  gap: clamp(26px, 4vw, 48px);
}

.page-about .about-team__lead {
  margin: 0 0 22px;
  max-width: 54ch;
  font-size: var(--fs-base);
  line-height: 1.75;
  color: var(--text-muted);
}

.page-about .about-numbers {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-number {
  display: flex;
  align-items: baseline;
  gap: 18px;
  padding: 16px 4px;
  border-bottom: 1px solid var(--line-soft);
  transition: background-color var(--dur) var(--ease);
}

.page-about .about-number:hover,
.page-about .about-number:focus-visible {
  background-color: rgba(201, 164, 92, 0.09);
  outline: none;
}

.page-about .about-number:focus-visible {
  box-shadow: inset 0 0 0 1px var(--c-sand);
}

.page-about .about-number__value {
  flex: 0 0 auto;
  min-width: 3.2ch;
  font-family: var(--font-mono);
  font-size: clamp(1.7rem, 5vw, 2.35rem);
  line-height: 1;
  color: var(--c-fog);
  font-variant-numeric: tabular-nums;
}

.page-about .about-number__body {
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--text-muted);
}

.page-about .about-number__body strong {
  display: block;
  margin-bottom: 3px;
  font-size: var(--fs-base);
  font-weight: 700;
  color: var(--text-on-dark);
}

.page-about .about-team__visual {
  position: relative;
}

.page-about .about-team__visual .media-frame {
  margin: 0;
  border: 1px solid var(--line-strong);
}

.page-about .about-team__note {
  margin: 16px 0 0;
  max-width: 48ch;
  font-size: var(--fs-sm);
  line-height: 1.75;
  color: var(--text-muted);
}

.page-about .about-side-note {
  display: none;
  font-size: var(--fs-ann);
  letter-spacing: 0.3em;
  color: var(--c-sand);
  writing-mode: vertical-rl;
}

/* ---------- 03 节奏 ---------- */

.page-about .about-cadence__lead {
  margin: 0 0 clamp(20px, 3vw, 30px);
  max-width: 62ch;
  font-size: var(--fs-base);
  line-height: 1.78;
  color: var(--text-muted);
}

.page-about .about-cadence {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line-soft);
  background-color: var(--line-soft);
}

.page-about .about-cadence__cell {
  background-color: var(--surface-deep);
  padding: 18px 16px 20px;
}

.page-about .about-cadence__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 5.5vw, 2.1rem);
  line-height: 1;
  color: var(--c-sand);
  font-variant-numeric: tabular-nums;
}

.page-about .about-cadence__label {
  display: block;
  margin-top: 8px;
  font-size: var(--fs-ann);
  line-height: 1.5;
  letter-spacing: 0.06em;
  color: var(--text-muted);
}

.page-about .about-cadence__notes {
  display: grid;
  gap: 16px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-cadence__notes p {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--text-muted);
  border-left: 2px solid var(--c-sand);
  padding-left: 14px;
}

/* ---------- 04 合作 ---------- */

.page-about .about-partners__lead {
  margin: 0 0 clamp(20px, 3vw, 30px);
  max-width: 62ch;
  font-size: var(--fs-base);
  line-height: 1.78;
  color: var(--text-muted);
}

.page-about .about-partners {
  display: grid;
  gap: 12px;
}

.page-about .about-node {
  position: relative;
  padding: 18px 18px 20px;
  border: 1px solid var(--line-strong);
  background-color: rgba(18, 51, 40, 0.55);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 2px;
  height: 0;
  background-color: var(--c-sand);
  transition: height var(--dur) var(--ease);
}

.page-about .about-node:hover,
.page-about .about-node:focus-visible {
  border-color: rgba(201, 164, 92, 0.7);
  background-color: rgba(201, 164, 92, 0.1);
  outline: none;
}

.page-about .about-node:hover::before,
.page-about .about-node:focus-visible::before {
  height: 100%;
}

.page-about .about-node__type {
  margin: 0;
  font-size: var(--fs-ann);
  letter-spacing: 0.14em;
  color: var(--c-sand);
}

.page-about .about-node__count {
  margin: 10px 0 8px;
  font-family: var(--font-mono);
  font-size: clamp(1.6rem, 5vw, 2rem);
  line-height: 1;
  color: var(--c-fog);
  font-variant-numeric: tabular-nums;
}

.page-about .about-node__desc {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--text-muted);
}

.page-about .about-partners__foot {
  display: grid;
  gap: 18px;
  margin-top: clamp(20px, 3vw, 30px);
  padding-top: clamp(18px, 3vw, 26px);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-honor {
  padding: 16px 18px;
  border-left: 3px solid var(--c-red);
  background-color: var(--surface-night);
}

.page-about .about-honor__name {
  margin: 0;
  font-size: var(--fs-base);
  font-weight: 700;
  color: var(--c-fog);
}

.page-about .about-honor__desc {
  margin: 6px 0 0;
  font-size: var(--fs-sm);
  line-height: 1.7;
  color: var(--text-muted);
}

.page-about .about-partners__extra {
  margin: 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--text-muted);
}

/* ---------- 05 演进 ---------- */

.page-about .about-rail {
  margin-bottom: 8px;
  overflow: hidden;
}

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

.page-about .about-stages {
  margin: 0 0 clamp(24px, 4vw, 40px);
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-stage {
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-stage__summary {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 2px;
  cursor: pointer;
  list-style: none;
}

.page-about .about-stage__summary::-webkit-details-marker {
  display: none;
}

.page-about .about-stage__summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 1.1rem;
  line-height: 1;
  color: var(--c-sand);
}

.page-about .about-stage__details[open] .about-stage__summary::after {
  content: "−";
}

.page-about .about-stage__year {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: var(--fs-sm);
  color: var(--c-sand);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stage__name {
  font-size: var(--fs-base);
  font-weight: 700;
  line-height: 1.5;
  color: var(--text-on-dark);
}

.page-about .about-stage__summary:hover .about-stage__name,
.page-about .about-stage__summary:focus-visible .about-stage__name {
  color: var(--c-sand);
}

.page-about .about-stage__content {
  padding: 0 2px 18px;
}

.page-about .about-stage__content p {
  margin: 0;
  max-width: 66ch;
  font-size: var(--fs-sm);
  line-height: 1.82;
  color: var(--text-muted);
}

.page-about .about-history__figure {
  margin: 0;
  max-height: 320px;
  overflow: hidden;
  border: 1px solid var(--line-strong);
}

/* ---------- 06 合作入口 ---------- */

.page-about .about-start {
  border-bottom: none;
}

.page-about .about-start__panel {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  padding: clamp(22px, 4vw, 40px);
  border: 1px solid var(--line-strong);
  background:
    linear-gradient(145deg, rgba(22, 36, 61, 0.92), rgba(18, 51, 40, 0.92));
}

.page-about .about-start__intro p {
  margin: 16px 0 0;
  max-width: 54ch;
  font-size: var(--fs-sm);
  line-height: 1.82;
  color: var(--text-muted);
}

.page-about .about-start__intro .section__title {
  font-size: var(--fs-h3);
}

.page-about .about-start__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .about-start__links {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1px;
  background-color: var(--line-soft);
  border: 1px solid var(--line-soft);
}

.page-about .about-start__link {
  display: block;
  padding: 16px 18px;
  background-color: rgba(11, 21, 17, 0.42);
  text-decoration: none;
  transition: background-color var(--dur) var(--ease);
}

.page-about .about-start__link:hover,
.page-about .about-start__link:focus-visible {
  background-color: rgba(201, 164, 92, 0.14);
}

.page-about .about-start__link-title {
  display: block;
  font-size: var(--fs-base);
  font-weight: 700;
  color: var(--c-fog);
}

.page-about .about-start__link-desc {
  display: block;
  margin-top: 5px;
  font-size: var(--fs-ann);
  line-height: 1.65;
  color: var(--text-muted);
}

.page-about .about-start__contact {
  margin: 20px 0 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--text-muted);
}

/* ---------- 响应式 ---------- */

@media (min-width: 600px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .about-cadence__notes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 12px;
  }

  .page-about .about-partners__foot {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 880px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
  }

  .page-about .about-why__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }

  .page-about .about-team__grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
    align-items: start;
  }

  .page-about .about-cadence {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

  .page-about .about-start__panel {
    grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
    align-items: start;
  }
}

@media (min-width: 1080px) {
  .page-about .about-team__visual {
    padding-right: 34px;
  }

  .page-about .about-side-note {
    display: block;
    position: absolute;
    right: 0;
    top: 6px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index__link,
  .page-about .about-number,
  .page-about .about-node,
  .page-about .about-node::before,
  .page-about .about-start__link {
    transition: none;
  }
}