.page-about {
  color: var(--ink);
  background: var(--bg);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
}

.page-about .about-hero__split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 4vw, 56px);
  align-items: center;
  padding-block: clamp(20px, 3vw, 44px) clamp(32px, 5vw, 60px);
}

.page-about .about-hero__copy h1 {
  margin: 10px 0 0;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: clamp(28px, 6.4vw, 48px);
  line-height: 1.14;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .about-hero__copy .lede {
  margin-top: 18px;
}

.page-about .about-hero__copy .prose {
  margin-top: 18px;
}

.page-about .about-hero__copy .prose p {
  margin: 0;
  font-size: 16px;
  line-height: 1.75;
  color: var(--muted);
}

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

.page-about .about-hero__visual {
  margin: 0;
}

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

/* ---------- 数据条 ---------- */
.page-about .about-metrics {
  list-style: none;
  margin: clamp(8px, 2vw, 20px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  clip-path: var(--cut-panel);
}

.page-about .about-metrics .stat {
  display: block;
  padding: 16px 14px 18px;
  background: var(--panel);
}

.page-about .about-metrics .stat__value {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(24px, 4vw, 32px);
  line-height: 1.05;
  letter-spacing: -0.01em;
  color: var(--teal);
}

.page-about .about-metrics .stat__unit {
  font-size: 0.6em;
  color: var(--orange);
}

.page-about .about-metrics .stat__label {
  display: block;
  margin-top: 8px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--muted);
}

/* ---------- 页内锚点导航 ---------- */
.page-about .hub-nav {
  margin-top: 18px;
}

.page-about .hub-nav ul {
  list-style: none;
  margin: 0;
  padding: 4px 0;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .hub-nav a {
  display: inline-block;
  white-space: nowrap;
  padding: 9px 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
  text-decoration: none;
  border: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.page-about .hub-nav a:hover,
.page-about .hub-nav a:focus-visible {
  color: var(--teal);
  border-color: var(--line-teal);
}

/* ---------- 宽幅视觉带 ---------- */
.page-about .about-banner {
  position: relative;
  margin: clamp(28px, 5vw, 56px) 0 0;
}

.page-about .about-banner img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 400px;
  object-fit: cover;
}

.page-about .about-banner::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(90deg, rgba(6, 11, 20, 0.88), rgba(6, 11, 20, 0.18) 52%, rgba(6, 11, 20, 0.72));
  pointer-events: none;
}

/* ---------- 通用章节 ---------- */
.page-about .band {
  position: relative;
  padding-block: clamp(48px, 7vw, 96px);
}

.page-about .band--data {
  background:
    radial-gradient(120% 90% at 8% 0%, rgba(0, 229, 196, 0.07), transparent 62%),
    var(--bg);
}

.page-about .band--violet {
  background: linear-gradient(164deg, var(--violet) 0%, var(--bg) 74%);
}

.page-about .band--phases {
  background: linear-gradient(198deg, var(--slot) 0%, var(--bg) 66%);
  overflow: hidden;
}

.page-about .band--cta {
  padding-block: clamp(32px, 5vw, 56px);
  background: linear-gradient(90deg, var(--panel-2), var(--bg) 78%);
  border-top: 1px solid var(--line);
}

.page-about .sec-head {
  max-width: 64ch;
  margin-bottom: clamp(24px, 3.5vw, 44px);
}

.page-about h2 {
  margin: 10px 0 0;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: clamp(22px, 4vw, 34px);
  line-height: 1.2;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .sec-head .lede {
  margin-top: 14px;
}

.page-about h3 {
  margin: 8px 0 0;
  font-family: var(--font-narrow);
  font-weight: 700;
  font-size: clamp(17px, 2.2vw, 20px);
  line-height: 1.38;
  letter-spacing: -0.01em;
  color: var(--ink);
}

/* ---------- 服务范围 ---------- */
.page-about .about-scope {
  padding-block: clamp(44px, 6.5vw, 88px);
}

.page-about .scope-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 48px);
}

.page-about .scope-head h2 {
  max-width: 22ch;
}

.page-about .scope-body p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ink);
}

.page-about .scope-body p + p {
  margin-top: 16px;
}

/* ---------- 能力矩阵 ---------- */
.page-about .cap-grid {
  row-gap: 16px;
}

.page-about .cap {
  display: flex;
  flex-direction: column;
  padding: 20px 20px 20px;
}

.page-about .cap .eyebrow {
  margin: 0;
}

.page-about .cap p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--muted);
}

.page-about .cap__extra {
  margin-top: 14px;
  padding-left: 12px;
  font-size: 14px;
  line-height: 1.65;
  color: var(--muted);
  border-left: 2px solid var(--line-teal);
}

@media (hover: hover) and (min-width: 760px) {
  .page-about .cap__extra {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.22s var(--ease), opacity 0.22s var(--ease), margin-top 0.22s var(--ease);
  }

  .page-about .cap:hover .cap__extra,
  .page-about .cap:focus-within .cap__extra {
    max-height: 9em;
    margin-top: 14px;
    opacity: 1;
  }
}

/* ---------- 资料归档 ---------- */
.page-about .archive-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.5vw, 48px);
  align-items: start;
}

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

.page-about .archive-item {
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .archive-item__idx {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--teal);
}

.page-about .archive-item h3 {
  margin-top: 8px;
}

.page-about .archive-item p {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.72;
  color: var(--muted);
}

.page-about .archive-figure {
  margin: 0;
}

.page-about .archive-figure img {
  display: block;
  width: 100%;
  height: auto;
}

/* ---------- 迭代节奏 ---------- */
.page-about .phase-bg {
  position: absolute;
  inset: 0;
  margin: 0;
  z-index: 0;
  opacity: 0.2;
}

.page-about .phase-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.page-about .band--phases .shell {
  position: relative;
  z-index: 1;
}

.page-about .phase-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 44px);
  align-items: start;
}

.page-about .time-rail {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .time-rail__item {
  display: block;
  padding: 12px 14px;
  text-decoration: none;
  color: inherit;
  border-left: 2px solid var(--line);
  transition: border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-about .time-rail__item:hover,
.page-about .time-rail__item:focus-visible,
.page-about .time-rail__item.is-active {
  border-left-color: var(--teal);
  background: rgba(0, 229, 196, 0.07);
}

.page-about .time-rail__stamp {
  display: block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .time-rail__title {
  display: block;
  margin-top: 6px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
}

.page-about .phase-notes {
  display: grid;
  gap: 14px;
}

.page-about .phase {
  padding: 18px 20px;
  background: rgba(13, 21, 38, 0.74);
  border: 1px solid var(--line);
  clip-path: var(--cut-panel);
  scroll-margin-top: 120px;
  transition: border-color 0.2s var(--ease), background-color 0.2s var(--ease);
}

.page-about .phase:target {
  border-color: var(--line-teal);
  background: rgba(0, 229, 196, 0.1);
}

.page-about .phase h3 {
  margin-top: 0;
}

.page-about .phase p {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.74;
  color: var(--muted);
}

/* ---------- 运营支持 ---------- */
.page-about .support-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.5vw, 44px);
  align-items: start;
}

.page-about .support-main h2 {
  max-width: 24ch;
}

.page-about .support-main .prose {
  margin-top: 18px;
}

.page-about .support-main .prose p {
  margin: 0;
  font-size: 16px;
  line-height: 1.78;
  color: var(--ink);
}

.page-about .support-main .prose p + p {
  margin-top: 16px;
}

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

.page-about .support-aside {
  padding: 22px 22px 20px;
}

.page-about .support-aside h3 {
  margin-top: 0;
}

.page-about .support-aside ul {
  list-style: none;
  margin: 16px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .support-aside .contact-line {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 10px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--ink);
}

.page-about .support-aside .contact-line__key {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--teal);
  padding-top: 2px;
}

.page-about .support-aside .note {
  margin-top: 16px;
}

/* ---------- 底部行动条 ---------- */
.page-about .cta-row {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.page-about .cta-row p {
  margin: 0;
  max-width: 54ch;
  font-size: 16px;
  line-height: 1.72;
  color: var(--ink);
}

.page-about .cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

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

@media (min-width: 900px) {
  .page-about .about-hero__split {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  }

  .page-about .scope-layout {
    grid-template-columns: minmax(0, 0.82fr) minmax(0, 1.18fr);
  }

  .page-about .phase-layout {
    grid-template-columns: minmax(0, 250px) minmax(0, 1fr);
  }

  .page-about .support-layout {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }

  .page-about .cta-row {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

@media (min-width: 960px) {
  .page-about .archive-layout {
    grid-template-columns: minmax(0, 1fr) minmax(0, 0.92fr);
  }

  .page-about .time-rail__item {
    padding: 14px 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .cap__extra,
  .page-about .time-rail__item,
  .page-about .phase,
  .page-about .hub-nav a {
    transition: none;
  }
}