.page-about {
  --about-pad: 20px;
  --about-title-num: clamp(2rem, 7vw, 3.4rem);
  overflow-x: hidden;
}

.page-about .breadcrumb {
  padding-top: 18px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero-wrap {
  padding-top: 8px;
}

.page-about .about-hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 32px;
  align-items: start;
  padding-bottom: 12px;
}

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

.page-about .about-hero .display {
  font-family: var(--font-serif);
  color: var(--cream);
  font-size: clamp(2rem, 8.4vw, 4.2rem);
  line-height: 1.16;
  letter-spacing: -0.01em;
  margin: 14px 0 20px;
  max-width: 22em;
}

.page-about .about-hero .lede {
  max-width: 34em;
  color: var(--text-dim);
}

.page-about .about-stats {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--ink-700);
  border: 1px solid var(--ink-700);
}

.page-about .about-stats__item {
  background: var(--ink-850);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .about-stats__num {
  font-size: 22px;
  color: var(--cyan);
  letter-spacing: 0.04em;
  line-height: 1.1;
}

.page-about .about-stats__label {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}

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

.page-about .about-hero__figure .media-frame {
  border: 1px solid var(--ink-700);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 26px), calc(100% - 26px) 100%, 0 100%);
  background: var(--ink-850);
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.85);
  opacity: 0.92;
}

.page-about .about-hero__cap {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--text-mute);
}

/* ---------- 章节骨架 ---------- */
.page-about .chapter {
  border-top: 1px solid var(--ink-700);
}

.page-about .chapter-head {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
  flex-wrap: wrap;
}

.page-about .chapter-num {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--cyan);
  padding: 6px 12px;
  background: rgba(47, 224, 208, 0.08);
  border: 1px solid var(--ink-700);
  clip-path: polygon(0 0, 100% 0, 100% 68%, 86% 100%, 0 100%);
  flex: none;
}

.page-about .chapter-head .h2 {
  font-family: var(--font-serif);
  color: var(--cream);
  font-size: clamp(1.5rem, 4.6vw, 2.1rem);
  line-height: 1.3;
  margin: 0;
  min-width: 0;
}

.page-about .chapter-lede {
  color: var(--text-dim);
  max-width: 44em;
  margin-bottom: 34px;
}

.page-about .chapter-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

.page-about .chapter-body__main {
  min-width: 0;
}

.page-about .chapter-body__aside {
  border-left: 2px solid var(--cyan);
  padding: 4px 0 4px 18px;
  min-width: 0;
}

.page-about .aside-title {
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--cyan);
  margin: 0 0 10px;
}

.page-about .aside-text {
  margin: 0 0 14px;
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.7;
}

.page-about .aside-link {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text);
  text-decoration: none;
  border-bottom: 1px solid var(--cyan);
  padding-bottom: 3px;
  display: inline-block;
  min-height: 24px;
}

.page-about .aside-link:hover,
.page-about .aside-link:focus-visible {
  color: var(--cyan);
}

/* ---------- 三层校验 ---------- */
.page-about .chapter--flow {
  background:
    radial-gradient(120% 90% at 88% 0%, rgba(47, 224, 208, 0.1), rgba(10, 19, 48, 0) 62%);
}

.page-about .flow {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
}

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

.page-about .flow__figure .media-frame {
  border: 1px solid var(--ink-700);
  background: var(--ink-850);
  clip-path: polygon(0 0, 100% 0, 100% 100%, 24px 100%, 0 calc(100% - 24px));
}

.page-about .flow__figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.8);
}

.page-about .flow__cap {
  margin-top: 10px;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--text-mute);
}

.page-about .flow__layers {
  display: grid;
  gap: 12px;
  min-width: 0;
}

.page-about .layer {
  background: var(--ink-800);
  border: 1px solid var(--ink-700);
  clip-path: polygon(0 0, calc(100% - 16px) 0, 100% 16px, 100% 100%, 0 100%);
  transition: border-color 240ms var(--ease), transform 240ms var(--ease);
}

.page-about .layer[open] {
  border-color: var(--cyan-deep);
}

.page-about .layer:hover {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .layer__head {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
  min-height: 44px;
}

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

.page-about .layer__num {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ink-900);
  background: var(--cyan);
  padding: 4px 8px;
  flex: none;
}

.page-about .layer__name {
  font-family: var(--font-serif);
  font-size: 18px;
  color: var(--cream);
  margin: 0;
}

.page-about .layer__body {
  padding: 0 18px 18px;
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.75;
}

.page-about .layer__body p {
  margin: 0 0 10px;
}

.page-about .layer__meta {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--text-mute);
  margin: 0;
}

/* ---------- 版本演进 ---------- */
.page-about .versions__banner {
  border: 1px solid var(--ink-700);
  background: var(--ink-850);
  margin: 0 0 34px;
  clip-path: polygon(0 0, 100% 0, calc(100% - 30px) 100%, 30px 100%);
}

.page-about .versions__banner img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.75);
  opacity: 0.9;
}

.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 26px;
  position: relative;
  display: grid;
  gap: 30px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--cyan) 0%, var(--orange) 70%, rgba(255, 122, 41, 0) 100%);
}

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

.page-about .tl-item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 11px;
  height: 11px;
  background: var(--ink-900);
  border: 1px solid var(--cyan);
  transform: rotate(45deg);
  transition: background-color 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .tl-item:hover::before,
.page-about .tl-item:focus-within::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .tl-when {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--cyan);
  margin: 0 0 8px;
}

.page-about .tl-item .h3 {
  font-family: var(--font-serif);
  color: var(--cream);
  font-size: clamp(1.1rem, 3.6vw, 1.4rem);
  line-height: 1.4;
  margin: 0 0 10px;
}

.page-about .tl-text {
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.75;
  margin: 0 0 12px;
  max-width: 40em;
}

.page-about .tl-note {
  margin: 0;
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--text-mute);
  opacity: 0.72;
  border-left: 2px solid var(--ink-700);
  padding-left: 12px;
  transition: opacity 240ms var(--ease), color 240ms var(--ease), border-color 240ms var(--ease);
}

.page-about .tl-item:hover .tl-note,
.page-about .tl-item:focus-within .tl-note {
  opacity: 1;
  color: var(--orange-soft);
  border-color: var(--orange);
}

.page-about .versions__more {
  margin: 34px 0 0;
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.8;
  max-width: 44em;
}

.page-about .versions__more a {
  color: var(--text);
  border-bottom: 1px solid var(--cyan);
  text-decoration: none;
}

.page-about .versions__more a:hover,
.page-about .versions__more a:focus-visible {
  color: var(--cyan);
}

/* ---------- 团队 ---------- */
.page-about .team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 28px;
}

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

.page-about .team__facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--ink-700);
  border: 1px solid var(--ink-700);
  align-self: start;
}

.page-about .fact {
  background: var(--ink-800);
  padding: 20px 16px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-width: 0;
}

.page-about .fact__num {
  font-size: clamp(1.6rem, 6vw, 2.2rem);
  line-height: 1.05;
  color: var(--cyan);
  letter-spacing: 0.02em;
}

.page-about .fact:nth-child(2) .fact__num {
  color: var(--orange);
}

.page-about .fact__name {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}

/* ---------- 更新日历 ---------- */
.page-about .calendar {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .calendar__card {
  background: var(--ink-800);
  border: 1px solid var(--ink-700);
  padding: 22px 20px 24px;
  min-width: 0;
}

.page-about .calendar__tag {
  display: inline-block;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ink-900);
  background: var(--cyan);
  padding: 5px 10px;
  margin: 0 0 16px;
  clip-path: polygon(0 0, 100% 0, 100% 100%, 10px 100%, 0 calc(100% - 10px));
}

.page-about .calendar__tag--alt {
  background: var(--orange);
}

.page-about .calendar__card .h3 {
  font-family: var(--font-serif);
  color: var(--cream);
  font-size: 1.25rem;
  margin: 0 0 14px;
  line-height: 1.4;
}

.page-about .calendar__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .calendar__list li {
  position: relative;
  padding-left: 18px;
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.75;
}

.page-about .calendar__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 10px;
  width: 7px;
  height: 7px;
  border: 1px solid var(--cyan);
  transform: rotate(45deg);
}

.page-about .calendar__card--rev .calendar__list li::before {
  border-color: var(--orange-soft);
}

/* ---------- 延伸入口 ---------- */
.page-about .chapter--next {
  border-top: 1px solid var(--ink-700);
}

.page-about .next__title {
  font-family: var(--font-serif);
  color: var(--cream);
  font-size: clamp(1.4rem, 4.4vw, 1.9rem);
  margin: 12px 0 0;
}

.page-about .next__track {
  display: block;
  width: 100%;
  height: 12px;
  margin: 20px 0 30px;
}

.page-about .next__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .next__item {
  background: var(--ink-850);
  border: 1px solid var(--ink-700);
  padding: 20px 18px 22px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
  transition: border-color 240ms var(--ease), transform 240ms var(--ease);
  min-width: 0;
}

.page-about .next__item:nth-child(even) {
  clip-path: polygon(0 0, 100% 0, 100% 100%, 18px 100%, 0 calc(100% - 18px));
}

.page-about .next__item:hover {
  border-color: var(--cyan);
  transform: translateY(-2px);
}

.page-about .next__name {
  font-family: var(--font-serif);
  color: var(--cream);
  font-size: 1.05rem;
  margin: 0 0 8px;
}

.page-about .next__desc {
  color: var(--text-dim);
  font-size: 14px;
  line-height: 1.7;
  margin: 0 0 16px;
}

.page-about .next__item .btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-hero {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: 40px;
    align-items: center;
  }

  .page-about .chapter-body {
    grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .team {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .calendar {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 18px;
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1080px) {
  .page-about .about-hero {
    gap: 64px;
  }

  .page-about .flow {
    grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
    gap: 48px;
    align-items: start;
  }

  .page-about .timeline {
    padding-left: 34px;
    gap: 44px;
    max-width: 880px;
  }

  .page-about .tl-item::before {
    left: -34px;
    width: 13px;
    height: 13px;
  }

  .page-about .timeline::before {
    left: 6px;
  }

  .page-about .next__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .chapter-head {
    gap: 20px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .layer,
  .page-about .next__item,
  .page-about .tl-note,
  .page-about .tl-item::before {
    transition: none;
  }

  .page-about .layer:hover,
  .page-about .next__item:hover {
    transform: none;
  }
}