.page-about {
  --about-rule: rgba(101, 120, 140, 0.26);
  background: var(--mist);
  color: var(--text);
  font-family: var(--font-body);
  overflow-x: hidden;
}

.page-about *,
.page-about *::before,
.page-about *::after {
  box-sizing: border-box;
}

.page-about a:focus-visible,
.page-about summary:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 3px;
  border-radius: 4px;
}

.page-about .breadcrumbs {
  font-size: 13px;
  padding-top: 16px;
}

/* 首屏 */
.page-about .about-intro {
  padding-block: clamp(20px, 4vw, 40px) clamp(32px, 5vw, 60px);
}

.page-about .about-intro__grid {
  display: grid;
  gap: clamp(24px, 4vw, 48px);
  align-items: start;
}

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

.page-about h1 {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 8vw, 56px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--ink);
  max-width: 16ch;
}

.page-about .about-intro__lede {
  margin: 18px 0 0;
  font-size: clamp(16px, 2.2vw, 18px);
  line-height: 1.8;
  color: var(--text);
  max-width: 60ch;
}

.page-about .about-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 26px;
  list-style: none;
  margin: 26px 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-meta li {
  display: flex;
  flex-direction: column;
  gap: 2px;
  font-size: 13px;
  color: var(--muted);
  min-width: 0;
}

.page-about .about-meta .mono {
  font-family: var(--font-mono);
  font-size: 20px;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.page-about figure {
  margin: 0;
  min-width: 0;
}

.page-about figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-m);
  object-fit: cover;
}

.page-about figcaption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.6;
  color: var(--muted);
}

.page-about .about-figure--wide {
  margin-top: 24px;
}

/* 目录与正文骨架 */
.page-about .shell {
  display: grid;
  gap: 28px;
  padding-bottom: clamp(40px, 6vw, 80px);
}

.page-about .rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .rail__link {
  display: block;
  padding: 8px 10px;
  border-radius: var(--radius-s);
  border-left: 2px solid transparent;
  font-size: 14px;
  color: var(--text);
  text-decoration: none;
  background: transparent;
}

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

.page-about .rail__link.is-active {
  border-left-color: var(--orange);
  background: var(--paper);
  color: var(--ink);
  font-weight: 700;
}

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

/* 章节通用 */
.page-about .about-section {
  padding-block: clamp(28px, 5vw, 56px);
  border-top: 1px solid var(--about-rule);
}

.page-about .about-section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-section__head {
  display: grid;
  gap: 14px;
  margin-bottom: 22px;
}

.page-about h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(22px, 3.4vw, 32px);
  line-height: 1.22;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.page-about .about-note {
  margin: 0;
  background: var(--teal-soft);
  border-left: 3px solid var(--teal-deep);
  border-radius: 0 var(--radius-s) var(--radius-s) 0;
  padding: 12px 14px;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--ink-2);
}

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

.page-about .about-section__body p {
  margin: 0 0 14px;
  font-size: 16px;
  line-height: 1.85;
  max-width: 68ch;
}

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

/* 三条原则 */
.page-about .principles {
  display: grid;
  gap: 20px;
}

.page-about .principle {
  border-top: 3px solid var(--teal);
  padding-top: 14px;
  min-width: 0;
}

.page-about .principle:nth-child(1) {
  border-top-color: var(--orange);
}

.page-about .principle:nth-child(2) {
  border-top-color: var(--amber);
}

.page-about .principle:nth-child(3) {
  border-top-color: var(--teal);
}

.page-about .principle__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .principle h3 {
  margin: 6px 0 8px;
  font-size: 19px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .principle p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text);
}

/* 时间线 */
.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .stage {
  position: relative;
  background: var(--paper);
  border-left: 4px solid var(--orange);
  border-radius: var(--radius-m);
  padding: 18px 18px 16px;
  min-width: 0;
}

.page-about .stage:nth-child(2) {
  border-left-color: var(--amber);
}

.page-about .stage:nth-child(3) {
  border-left-color: var(--teal);
}

.page-about .stage:nth-child(4) {
  border-left-color: var(--teal-deep);
}

.page-about .stage__year {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 24px;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.page-about .stage h3 {
  margin: 4px 0 6px;
  font-size: 17px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .stage__tag {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.03em;
  color: var(--teal-deep);
}

.page-about .stage > p {
  margin: 0 0 10px;
  font-size: 14.5px;
  line-height: 1.78;
}

.page-about .stage__more summary {
  cursor: pointer;
  font-size: 13px;
  font-weight: 700;
  color: var(--teal-deep);
  list-style: none;
}

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

.page-about .stage__more summary::before {
  content: "＋ ";
  font-family: var(--font-mono);
}

.page-about .stage__more[open] summary::before {
  content: "－ ";
}

.page-about .stage__more p {
  margin: 10px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--about-rule);
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* 团队 */
.page-about .team-grid {
  display: grid;
  gap: 16px;
}

.page-about .team-block {
  background: var(--paper);
  border-radius: var(--radius-m);
  padding: 20px;
  min-width: 0;
}

.page-about .team-block__count {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 30px;
  line-height: 1;
  color: var(--orange);
}

.page-about .team-block h3 {
  margin: 0 0 6px;
  font-size: 18px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .team-block p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
}

.page-about .team-block--dark {
  background: var(--ink-2);
  color: var(--on-dark);
}

.page-about .team-block--dark h3 {
  color: var(--paper);
}

.page-about .team-block--dark .team-block__count {
  color: var(--amber);
}

/* 数据带 */
.page-about .about-stats {
  margin-top: 26px;
  display: grid;
  gap: 20px;
  background: var(--ink);
  color: var(--paper);
  border-radius: var(--radius-l);
  padding: clamp(22px, 4vw, 40px);
}

.page-about .stat {
  border-top: 2px solid rgba(255, 255, 255, 0.16);
  padding-top: 12px;
  min-width: 0;
}

.page-about .stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 4vw, 38px);
  line-height: 1.1;
  color: var(--amber);
}

.page-about .stat__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--on-dark);
}

/* 伙伴协作 */
.page-about .partner-list {
  list-style: none;
  margin: 4px 0 20px;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .partner-list li {
  border-left: 2px solid var(--teal);
  padding-left: 14px;
  min-width: 0;
}

.page-about .partner-list h3 {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .partner-list p {
  margin: 0;
  font-size: 14px;
  line-height: 1.78;
}

/* 未来计划 */
.page-about .plans {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .plan {
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 6px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .plan:last-child {
  border-bottom: 0;
  padding-bottom: 0;
}

.page-about .plan__no {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--orange);
  padding-top: 4px;
}

.page-about .plan h3 {
  margin: 0 0 4px;
  font-size: 17px;
  font-weight: 800;
  color: var(--ink);
}

.page-about .plan p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  max-width: 62ch;
}

/* 出口路径 */
.page-about .about-nextpath {
  margin-top: clamp(32px, 5vw, 56px);
  background: var(--ink-2);
  color: var(--paper);
  border-radius: var(--radius-l);
  padding: clamp(24px, 4vw, 48px);
}

.page-about .about-nextpath h2 {
  color: var(--paper);
}

.page-about .about-nextpath > p {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--on-dark);
  max-width: 62ch;
}

.page-about .path-list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .path-list a {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  grid-template-areas:
    "name arrow"
    "note arrow";
  align-items: center;
  gap: 4px 12px;
  padding: 14px 16px;
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-m);
  background: rgba(255, 255, 255, 0.06);
  color: var(--paper);
  text-decoration: none;
  transition: background 0.25s var(--ease), border-color 0.25s var(--ease);
}

.page-about .path-list a:hover {
  background: rgba(242, 106, 61, 0.18);
  border-color: var(--orange);
}

.page-about .path-list__name {
  grid-area: name;
  font-size: 16px;
  font-weight: 700;
}

.page-about .path-list__note {
  grid-area: note;
  font-size: 12.5px;
  line-height: 1.6;
  color: var(--on-dark);
}

.page-about .path-list a::after {
  content: "→";
  grid-area: arrow;
  align-self: center;
  font-family: var(--font-mono);
  font-size: 18px;
  color: var(--amber);
  transition: transform 0.25s var(--ease);
}

.page-about .path-list a:hover::after {
  transform: translateX(4px);
}

/* 断点 */
@media (min-width: 620px) {
  .page-about .about-section__head {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
    align-items: end;
    gap: 20px;
  }

  .page-about .about-note {
    justify-self: end;
    max-width: 34ch;
  }

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

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

@media (min-width: 760px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .team-grid {
    grid-template-columns: repeat(6, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .team-block--a {
    grid-column: span 2;
  }

  .page-about .team-block--b {
    grid-column: span 2;
    margin-top: 20px;
  }

  .page-about .team-block--c {
    grid-column: span 2;
  }

  .page-about .principles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }
}

@media (min-width: 860px) {
  .page-about .timeline {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .stage:not(:last-child)::after {
    content: "";
    position: absolute;
    top: 30px;
    right: -14px;
    width: 8px;
    height: 8px;
    border-top: 2px solid var(--orange);
    border-right: 2px solid var(--orange);
    transform: rotate(45deg);
  }
}

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

@media (min-width: 1000px) {
  .page-about .shell {
    grid-template-columns: var(--rail-w) minmax(0, 1fr);
    gap: clamp(28px, 4vw, 56px);
  }

  .page-about .rail {
    position: sticky;
    top: var(--header-offset);
    align-self: start;
  }

  .page-about .rail__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
  }

  .page-about .rail__link {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .reveal {
    transition: none !important;
    transform: none !important;
    opacity: 1 !important;
  }

  .page-about * {
    animation: none !important;
    transition: none !important;
  }

  .page-about .path-list a:hover::after {
    transform: none;
  }
}