.page-about {
  --about-num-col: 150px;
  --about-sec-gap: clamp(56px, 9vw, 112px);
  display: block;
  background: var(--ink);
  color: var(--text);
}

.page-about .mono {
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(36px, 6vw, 88px) clamp(40px, 6vw, 84px);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(120% 90% at 84% 0%, rgba(158, 232, 79, 0.1), transparent 62%),
    linear-gradient(180deg, var(--ink-2), var(--ink));
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.34;
  background-image:
    linear-gradient(to right, var(--line) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line) 1px, transparent 1px);
  background-size: 96px 96px;
  -webkit-mask-image: radial-gradient(120% 80% at 78% 0%, #000 0%, transparent 72%);
  mask-image: radial-gradient(120% 80% at 78% 0%, #000 0%, transparent 72%);
}

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

.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

.page-about .breadcrumbs a {
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.16s var(--ease), border-color 0.16s var(--ease);
}

.page-about .breadcrumbs a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.page-about .eyebrow {
  margin-top: clamp(28px, 5vw, 56px);
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--accent);
}

.page-about .eyebrow::before {
  content: "";
  width: 10px;
  height: 10px;
  background: var(--accent);
  display: block;
}

.page-about .about-hero__title {
  margin: clamp(16px, 2.4vw, 26px) 0 0;
  max-width: 22ch;
  font-family: var(--font-head);
  font-weight: 900;
  font-size: clamp(34px, 6.6vw, 88px);
  line-height: 1.04;
  letter-spacing: -0.03em;
  color: var(--title);
}

.page-about .about-hero__lede {
  margin: clamp(22px, 3vw, 36px) 0 0;
  max-width: 34em;
  font-size: clamp(16px, 1.8vw, 18px);
  line-height: 1.95;
  color: var(--text);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 clamp(16px, 3vw, 32px);
  margin: clamp(36px, 5vw, 68px) 0 0;
}

.page-about .about-hero__facts > div {
  padding: 16px 0 8px;
  border-top: 1px solid var(--line);
}

.page-about .about-hero__facts dt {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .about-hero__facts dd {
  margin: 8px 0 0;
  font-size: clamp(18px, 2vw, 22px);
  font-weight: 800;
  color: var(--title);
  letter-spacing: -0.01em;
}

/* ---------- 章节骨架 ---------- */

.page-about .about-section {
  padding-block: var(--about-sec-gap);
}

.page-about .about-section + .about-section {
  border-top: 1px solid var(--line);
}

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

.page-about .anchor-num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: clamp(52px, 13vw, 92px);
  line-height: 0.9;
  letter-spacing: -0.05em;
  color: var(--accent);
  margin-bottom: clamp(18px, 3vw, 28px);
}

.page-about .about-section__title {
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  max-width: 24ch;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: clamp(25px, 4.2vw, 42px);
  line-height: 1.26;
  letter-spacing: -0.02em;
  color: var(--title);
}

.page-about .prose {
  max-width: 38em;
  margin: 0 0 clamp(18px, 2.4vw, 26px);
  font-size: 17px;
  line-height: 1.95;
  color: var(--text);
}

.page-about .prose:last-child {
  margin-bottom: 0;
}

.page-about .about-note {
  max-width: 34em;
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .num-summary {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px clamp(16px, 3vw, 32px);
  margin: clamp(30px, 4.4vw, 52px) 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
  text-align: right;
}

.page-about .num-summary b {
  color: var(--accent);
  font-weight: 600;
}

.page-about .about-figure {
  margin: 0 0 clamp(28px, 4vw, 48px);
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 3px;
  object-fit: cover;
  background: var(--ink-2);
}

.page-about .media-frame__cap {
  display: block;
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

/* ---------- 时间轴 ---------- */

.page-about .timeline {
  position: relative;
  list-style: none;
  margin: clamp(24px, 3.4vw, 44px) 0 0;
  padding: 0 0 0 30px;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 3.6vw, 34px);
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--line);
}

.page-about .timeline__node {
  position: relative;
  min-width: 0;
}

.page-about .timeline__dot {
  position: absolute;
  left: -30px;
  top: 4px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--accent-dim);
  transition: border-color 0.16s var(--ease), box-shadow 0.16s var(--ease);
}

.page-about .timeline__dot::after {
  content: "";
  position: absolute;
  inset: 3px;
  border-radius: 50%;
  background: var(--accent);
}

.page-about .timeline__year {
  margin: 0;
  font-size: 13px;
  color: var(--accent);
}

.page-about .timeline__title {
  margin: 8px 0 10px;
  font-size: clamp(17px, 2vw, 19px);
  line-height: 1.5;
  font-weight: 800;
  color: var(--title);
}

.page-about .timeline__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

.page-about .timeline__more {
  margin: 10px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .timeline__node:hover .timeline__dot,
.page-about .timeline__node:focus-within .timeline__dot {
  border-color: var(--accent);
  box-shadow: 0 0 0 4px rgba(158, 232, 79, 0.12);
}

/* ---------- 团队 ---------- */

.page-about .crew {
  margin-top: clamp(24px, 3.4vw, 40px);
}

.page-about .crew__bar {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 10px;
}

.page-about .crew__seg {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 14px;
  min-height: 96px;
  padding: 16px 16px 18px;
  border-top: 2px solid var(--line);
  background: rgba(201, 214, 206, 0.04);
}

.page-about .crew__seg--lead {
  border-top-color: var(--accent);
  background: linear-gradient(180deg, rgba(158, 232, 79, 0.14), rgba(158, 232, 79, 0.03));
}

.page-about .crew__num {
  display: block;
  font-size: 38px;
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--title);
}

.page-about .crew__seg--lead .crew__num {
  color: var(--accent);
}

.page-about .crew__label {
  display: block;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .team-cards {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 20px;
  margin-top: clamp(24px, 3.4vw, 44px);
}

.page-about .team-card {
  padding: 24px 22px 22px;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 3px;
  box-shadow: inset 0 1px 0 rgba(201, 214, 206, 0.06);
}

.page-about .team-card__title {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin: 0 0 12px;
  font-size: 20px;
  font-weight: 800;
  color: var(--title);
}

.page-about .team-card__num {
  font-size: 13px;
  font-weight: 500;
  color: var(--accent);
}

.page-about .team-card__text {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.9;
  color: var(--text);
}

.page-about .team-card__list {
  list-style: none;
  margin: 16px 0 0;
  padding: 16px 0 0;
  border-top: 1px solid var(--line);
}

.page-about .team-card__list li {
  position: relative;
  padding: 0 0 10px 18px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .team-card__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 6px;
  height: 1px;
  background: var(--accent-dim);
}

/* ---------- 折叠 ---------- */

.page-about .foldable[data-open="false"] .foldable__body {
  display: none;
}

.page-about .foldable__toggle {
  display: inline-block;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: none;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: border-color 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .foldable__toggle:hover {
  border-color: var(--accent-dim);
  color: var(--title);
}

/* ---------- 覆盖与规模 ---------- */

.page-about .scale-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 48px);
  margin-bottom: clamp(28px, 4vw, 48px);
}

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

.page-about .stat-list {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  margin: 0;
  border-top: 1px solid var(--line);
}

.page-about .stat {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .stat dt {
  font-size: clamp(19px, 2.4vw, 24px);
  font-weight: 800;
  line-height: 1.3;
  color: var(--title);
  letter-spacing: -0.01em;
}

.page-about .stat dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* ---------- 三步方法 ---------- */

.page-about .steps {
  list-style: none;
  margin: clamp(24px, 3.4vw, 42px) 0 0;
  padding: 0;
}

.page-about .step {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  column-gap: 18px;
  padding: 24px 0;
  border-top: 1px solid var(--line);
}

.page-about .step:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .step__num {
  grid-column: 1;
  grid-row: 1 / -1;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1.15;
  color: var(--accent);
  letter-spacing: -0.03em;
}

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

.page-about .step__title {
  margin: 0 0 10px;
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 800;
  color: var(--title);
}

.page-about .step__text {
  margin: 0;
  max-width: 36em;
  font-size: 15px;
  line-height: 1.9;
  color: var(--text);
}

.page-about .step__meta {
  grid-column: 2;
  grid-row: 2;
  margin: 12px 0 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--amber);
}

.page-about .about-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(24px, 3.4vw, 36px);
}

.page-about .about-actions .btn {
  display: inline-block;
  padding: 12px 22px;
  border-radius: 2px;
  border: 1px solid var(--line);
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  transition: background 0.16s var(--ease), border-color 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .about-actions .btn--primary {
  background: var(--accent-dim);
  border-color: var(--accent-dim);
  color: var(--ink);
}

.page-about .about-actions .btn--primary:hover {
  background: var(--accent);
  border-color: var(--accent);
}

.page-about .about-actions .btn--ghost {
  background: transparent;
  color: var(--text);
}

.page-about .about-actions .btn--ghost:hover {
  border-color: var(--accent-dim);
  color: var(--accent);
}

/* ---------- 文档节奏 ---------- */

.page-about .rhythm {
  list-style: none;
  margin: clamp(24px, 3.4vw, 40px) 0 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .rhythm__item {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .rhythm__key {
  font-size: 13px;
  color: var(--accent);
}

.page-about .rhythm__text {
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

.page-about .foldable--doc {
  margin-top: clamp(26px, 3.6vw, 44px);
  padding: 22px 20px;
  background: var(--ink-2);
  border: 1px solid var(--line);
  border-radius: 3px;
}

.page-about .foldable__title {
  margin: 0 0 14px;
  font-size: 18px;
  font-weight: 800;
  color: var(--title);
}

.page-about .foldable--doc .foldable__body {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.page-about .foldable--doc .prose {
  margin: 0;
  font-size: 15px;
}

/* ---------- 协作与版本 ---------- */

.page-about .collab {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin-top: clamp(24px, 3.4vw, 40px);
}

.page-about .collab__panel {
  padding: 22px 20px;
  border: 1px solid var(--line);
  border-left: 2px solid var(--accent-dim);
  background: var(--card);
  border-radius: 2px;
}

.page-about .collab__panel--offset {
  border-left-color: var(--amber);
  background: var(--ink-2);
}

.page-about .collab__title {
  margin: 0 0 10px;
  font-size: 19px;
  font-weight: 800;
  color: var(--title);
}

.page-about .collab__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.9;
  color: var(--text);
}

.page-about .version-strip {
  margin-top: clamp(26px, 3.6vw, 44px);
  border-top: 1px solid var(--line);
}

.page-about .version-strip__row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .version-strip__label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--muted);
}

.page-about .version-strip__val {
  font-size: 20px;
  font-weight: 700;
  color: var(--title);
  letter-spacing: -0.01em;
}

.page-about .version-strip__desc {
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .version-strip__row--legacy .version-strip__val {
  color: var(--amber);
}

.page-about .tag {
  display: inline-block;
  padding: 2px 8px;
  border-radius: 2px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
}

.page-about .tag--amber {
  background: var(--amber);
  color: var(--ink);
  font-weight: 700;
}

/* ---------- 行动区 ---------- */

.page-about .about-section--start {
  background: linear-gradient(180deg, var(--ink), var(--ink-2));
}

.page-about .start-mail {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 16px;
  margin-top: clamp(22px, 3vw, 32px);
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--card);
}

.page-about .start-mail__label {
  font-size: 12px;
  color: var(--muted);
}

.page-about .start-mail__value {
  font-size: 15px;
  color: var(--title);
  word-break: break-all;
}

.page-about .copy-btn {
  margin-left: auto;
  padding: 6px 14px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: none;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  cursor: pointer;
  transition: border-color 0.16s var(--ease), color 0.16s var(--ease);
}

.page-about .copy-btn:hover {
  border-color: var(--accent-dim);
  color: var(--title);
}

.page-about .about-actions--wide {
  margin-top: clamp(20px, 3vw, 30px);
}

/* ---------- 响应式 ---------- */

@media (min-width: 600px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .stat {
    grid-template-columns: 180px minmax(0, 1fr);
    gap: 0 24px;
    align-items: baseline;
  }

  .page-about .rhythm__item {
    grid-template-columns: 160px minmax(0, 1fr);
    gap: 0 24px;
    align-items: baseline;
  }

  .page-about .version-strip__row {
    grid-template-columns: 190px 130px minmax(0, 1fr);
    gap: 0 20px;
    align-items: baseline;
  }
}

@media (min-width: 760px) {
  .page-about .crew__bar {
    grid-template-columns: 21fr 14fr 23fr;
    column-gap: 3px;
  }

  .page-about .team-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .team-cards .team-card:nth-child(2) {
    transform: translateY(20px);
  }

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

  .page-about .collab__panel--offset {
    transform: translateY(16px);
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }

  .page-about .about-section .container {
    display: grid;
    grid-template-columns: var(--about-num-col) minmax(0, 1fr);
    column-gap: var(--col-gap);
    align-items: start;
  }

  .page-about .anchor-num {
    grid-column: 1;
    position: sticky;
    top: calc(var(--top-h) + 40px);
    margin-bottom: 0;
  }

  .page-about .about-section__inner {
    grid-column: 2;
  }

  .page-about .timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    column-gap: var(--col-gap);
    padding: 34px 0 0;
  }

  .page-about .timeline::before {
    left: 6px;
    right: 6px;
    top: 6px;
    bottom: auto;
    width: auto;
    height: 1px;
  }

  .page-about .timeline__dot {
    left: 0;
    top: -34px;
  }

  .page-about .scale-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 420px);
    align-items: center;
  }
}

@media (min-width: 1100px) {
  .page-about .about-hero__title {
    max-width: 19ch;
  }
}

@media (hover: hover) and (pointer: fine) {
  .page-about .timeline__more {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    margin-top: 0;
    transition: max-height 0.32s var(--ease), opacity 0.32s var(--ease), margin-top 0.32s var(--ease);
  }

  .page-about .timeline__node:hover .timeline__more,
  .page-about .timeline__node:focus-within .timeline__more {
    max-height: 9em;
    opacity: 1;
    margin-top: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition-duration: 0.12s !important;
    animation-duration: 0.12s !important;
  }

  .page-about .timeline__more {
    max-height: none !important;
    opacity: 1 !important;
    margin-top: 10px !important;
  }

  .page-about .team-cards .team-card:nth-child(2),
  .page-about .collab__panel--offset {
    transform: none;
  }
}