.page-about {
  --ab-pad: clamp(1rem, 4vw, 2.5rem);
  --ab-sec: clamp(3.5rem, 8vw, 7rem);
  --ab-tl-pad: clamp(1.1rem, 3vw, 2rem);

  display: block;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--font-body);
  font-size: var(--fs-16);
  line-height: 1.75;
  overflow-x: clip;
}

.page-about .wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--ab-pad);
}

.page-about h1,
.page-about h2,
.page-about h3 {
  margin: 0;
  font-family: var(--font-head);
  font-weight: 700;
  letter-spacing: -.02em;
  line-height: 1.08;
  color: inherit;
}

.page-about p {
  margin: 0;
}

.page-about a {
  color: var(--blue);
  text-decoration: none;
}

.page-about a:hover {
  text-decoration: underline;
}

.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 2px;
}

/* ---------- 面包屑 ---------- */

.page-about .breadcrumb {
  background: var(--ink-2);
  border-bottom: 1px solid var(--line);
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .35rem;
  margin: 0;
  padding: .85rem 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .06em;
}

.page-about .breadcrumb li {
  color: var(--paper-2);
}

.page-about .breadcrumb li + li::before {
  content: "/";
  margin-inline-end: .35rem;
  opacity: .5;
}

.page-about .breadcrumb a {
  color: var(--blue);
  text-decoration: none;
}

/* ---------- 首屏 ---------- */

.page-about .ab-hero {
  position: relative;
  padding-block: clamp(2.75rem, 6vw, 5.5rem) var(--ab-sec);
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(115% 85% at 84% 0%, rgba(53, 210, 255, .13), transparent 62%),
    radial-gradient(85% 70% at 4% 96%, rgba(255, 106, 24, .11), transparent 62%),
    var(--ink);
}

.page-about .ab-hero__grid {
  display: grid;
  gap: clamp(2rem, 5vw, 3.25rem);
}

.page-about .eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .2em;
  text-transform: uppercase;
  color: var(--orange);
}

.page-about .ab-hero h1 {
  margin-block: .8rem 0;
  font-size: clamp(2.2rem, 6vw, 4.25rem);
  line-height: .98;
  overflow-wrap: break-word;
}

.page-about .lede {
  margin-top: clamp(1.1rem, 2.5vw, 1.6rem);
  max-width: 46ch;
  font-size: clamp(1rem, 2.1vw, 1.2rem);
  line-height: 1.8;
  color: var(--paper);
  opacity: .9;
}

.page-about .ab-hero__aside {
  padding: clamp(1.25rem, 3vw, 1.85rem);
  border: 1px solid var(--line-strong);
  border-top: 2px solid var(--blue);
  background: linear-gradient(160deg, rgba(23, 57, 46, .72), rgba(7, 19, 15, .92));
  box-shadow: var(--shadow);
}

.page-about .ab-hero__aside h2 {
  font-size: var(--fs-20);
  letter-spacing: 0;
}

.page-about .ab-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(1rem, 2.5vw, 1.4rem) 0 0;
  padding: 0;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-facts > div {
  min-width: 0;
  padding: .85rem .95rem;
  background: var(--ink-2);
}

.page-about .ab-facts dt {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .08em;
  color: var(--paper-2);
}

.page-about .ab-facts dd {
  margin: .35rem 0 0;
  font-family: var(--font-mono);
  font-size: clamp(1.35rem, 3.4vw, 1.75rem);
  line-height: 1.1;
  color: var(--paper);
}

.page-about .ab-facts__unit {
  margin-left: .25rem;
  font-family: var(--font-body);
  font-size: var(--fs-12);
  color: var(--paper-2);
}

/* ---------- 章节通用 ---------- */

.page-about .ab-sec {
  position: relative;
  padding-block: var(--ab-sec);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-sec--alt {
  background: var(--ink-2);
}

.page-about .ab-head {
  display: grid;
  gap: .75rem;
  max-width: 64ch;
  margin-bottom: clamp(2rem, 4.5vw, 3.25rem);
}

.page-about .ab-head h2 {
  font-size: clamp(1.9rem, 5vw, 3.5rem);
}

.page-about .ab-head__sub {
  font-size: clamp(1rem, 2vw, 1.1rem);
  line-height: 1.8;
  color: var(--paper-2);
}

.page-about .ab-num {
  display: inline-flex;
  align-items: center;
  gap: .6rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .2em;
  color: var(--orange);
}

.page-about .ab-num::after {
  content: "";
  width: clamp(2rem, 8vw, 5rem);
  height: 1px;
  background: currentColor;
  opacity: .5;
}

.page-about .ab-note {
  margin-top: clamp(1.5rem, 3.5vw, 2.25rem);
  max-width: 62ch;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--paper-2);
}

/* ---------- 起点 / 时间线 ---------- */

.page-about .ab-origin__grid {
  display: grid;
  gap: clamp(2rem, 5vw, 3rem);
}

.page-about .ab-timeline {
  display: grid;
  gap: clamp(1.5rem, 3.5vw, 2.25rem);
  margin: 0;
  padding: 0 0 0 var(--ab-tl-pad);
  list-style: none;
  border-left: 1px solid var(--line-strong);
}

.page-about .ab-tl {
  position: relative;
}

.page-about .ab-tl::before {
  content: "";
  position: absolute;
  top: .5rem;
  left: calc(-1 * var(--ab-tl-pad) - 4.5px);
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--gold);
  box-shadow: 0 0 0 3px rgba(232, 200, 106, .16);
}

.page-about .ab-tl__year {
  display: block;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: .12em;
  color: var(--gold);
}

.page-about .ab-tl h3 {
  margin-top: .35rem;
  font-size: var(--fs-20);
  letter-spacing: 0;
}

.page-about .ab-tl p {
  margin-top: .5rem;
  max-width: 58ch;
  line-height: 1.85;
  color: var(--paper-2);
}

.page-about .ab-figure {
  margin: 0;
  padding: 10px;
  border: 1px solid var(--line-strong);
  background: var(--ink-2);
  box-shadow: var(--shadow);
}

.page-about .ab-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  filter: saturate(.9) brightness(.92);
}

.page-about .ab-figure figcaption {
  margin-top: .75rem;
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  line-height: 1.6;
  letter-spacing: .04em;
  color: var(--paper-2);
}

/* ---------- 覆盖看板 ---------- */

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

.page-about .ab-board__item {
  display: grid;
  gap: .4rem;
  align-content: start;
  min-width: 0;
  padding: clamp(1.1rem, 3vw, 1.75rem) clamp(.9rem, 2vw, 1.25rem);
  background: var(--ink-3);
}

.page-about .ab-board__num {
  font-family: var(--font-mono);
  font-size: clamp(1.75rem, 4.6vw, 2.75rem);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--orange);
}

.page-about .ab-board__item:nth-child(even) .ab-board__num {
  color: var(--blue);
}

.page-about .ab-board__label {
  font-size: var(--fs-14);
  line-height: 1.6;
  color: var(--paper-2);
}

.page-about .ab-strip {
  position: relative;
  margin: clamp(1.75rem, 4vw, 2.75rem) 0 0;
  border: 1px solid var(--line);
  background: var(--ink-3);
  overflow: hidden;
}

.page-about .ab-strip img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: clamp(160px, 24vw, 260px);
  object-fit: cover;
  opacity: .82;
}

.page-about .ab-strip figcaption {
  position: absolute;
  inset: auto 0 0 0;
  padding: .9rem clamp(1rem, 2.5vw, 1.5rem);
  background: linear-gradient(transparent, rgba(7, 19, 15, .94));
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .06em;
  color: var(--paper);
}

/* ---------- 栏目组色带 ---------- */

.page-about .ab-bands {
  display: flex;
  flex-direction: column;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-band {
  appearance: none;
  display: grid;
  gap: .35rem;
  min-width: 0;
  padding: clamp(1rem, 2.5vw, 1.4rem);
  border: 0;
  border-bottom: 2px solid transparent;
  background: var(--ink-2);
  color: var(--paper);
  text-align: left;
  cursor: pointer;
  transition: background .18s var(--ease), border-color .18s var(--ease);
}

.page-about .ab-band:hover {
  background: var(--ink-3);
}

.page-about .ab-band[aria-selected="true"] {
  background: var(--ink-3);
  border-bottom-color: var(--orange);
}

.page-about .ab-band__idx {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .16em;
  color: var(--orange);
}

.page-about .ab-band__name {
  font-family: var(--font-head);
  font-size: var(--fs-20);
  font-weight: 700;
  letter-spacing: -.01em;
}

.page-about .ab-band__tag {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: .05em;
  color: var(--paper-2);
}

.page-about .ab-bandpanel {
  padding: clamp(1.35rem, 3.5vw, 2.25rem);
  border: 1px solid var(--line);
  border-top: 0;
  background: linear-gradient(150deg, rgba(23, 57, 46, .55), rgba(7, 19, 15, .88));
}

.page-about .ab-bandpanel[hidden] {
  display: none;
}

.page-about .ab-bandpanel h3 {
  font-size: var(--fs-28);
  letter-spacing: -.01em;
}

.page-about .ab-bandpanel p {
  margin-top: .85rem;
  max-width: 72ch;
  line-height: 1.85;
  color: var(--paper-2);
}

/* ---------- 浅色阅读区 ---------- */

.page-about .ab-paper {
  background: var(--paper);
  color: var(--deep);
  border-bottom-color: rgba(11, 27, 22, .16);
}

.page-about .ab-paper .ab-head__sub {
  color: rgba(11, 27, 22, .72);
}

.page-about .ab-versus {
  display: grid;
  gap: 1px;
  margin-top: clamp(1.25rem, 3vw, 2rem);
  background: rgba(11, 27, 22, .14);
  border: 1px solid rgba(11, 27, 22, .14);
}

.page-about .ab-versus > div {
  padding: clamp(1.25rem, 3vw, 1.85rem);
  background: var(--paper-3);
}

.page-about .ab-versus__now {
  background: var(--paper);
  box-shadow: inset 3px 0 0 var(--orange);
}

.page-about .ab-versus h3 {
  font-size: var(--fs-20);
  letter-spacing: 0;
}

.page-about .ab-versus p {
  margin-top: .65rem;
  max-width: 52ch;
  line-height: 1.85;
  color: rgba(11, 27, 22, .76);
}

.page-about .ab-paper .ab-note {
  color: rgba(11, 27, 22, .76);
}

.page-about .ab-paper a {
  color: #1a5f7a;
  border-bottom: 1px solid currentColor;
}

/* ---------- 长期维护 ---------- */

.page-about .ab-keep__grid {
  display: grid;
  gap: clamp(2rem, 5vw, 3rem);
}

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

.page-about .ab-keeps li {
  display: grid;
  gap: .45rem;
  padding: clamp(1rem, 2.5vw, 1.4rem);
  background: var(--ink-2);
}

.page-about .ab-keeps strong {
  font-family: var(--font-head);
  font-size: var(--fs-20);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--gold);
}

.page-about .ab-keeps p {
  max-width: 62ch;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--paper-2);
}

/* ---------- 协作与认可 ---------- */

.page-about .ab-ally__grid {
  display: grid;
  gap: clamp(1rem, 2.5vw, 1.5rem);
}

.page-about .ab-ally__grid .card {
  display: grid;
  gap: .6rem;
  align-content: start;
  padding: clamp(1.25rem, 3vw, 1.75rem);
  border: 1px solid var(--line);
  border-top: 2px solid var(--blue);
  background: var(--ink-3);
  transition: border-color .18s var(--ease), transform .18s var(--ease);
}

.page-about .ab-ally__grid .card:nth-child(2) {
  border-top-color: var(--green);
}

.page-about .ab-ally__grid .card:nth-child(3) {
  border-top-color: var(--gold);
}

.page-about .ab-ally__grid .card:hover {
  border-color: var(--orange);
  transform: translateY(-3px);
}

.page-about .ab-ally__grid .card__title {
  font-family: var(--font-head);
  font-size: var(--fs-20);
  font-weight: 700;
  letter-spacing: -.01em;
  color: var(--paper);
}

.page-about .ab-ally__grid .card p {
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--paper-2);
}

/* ---------- 结尾动作区 ---------- */

.page-about .ab-cta {
  padding-block: var(--ab-sec);
  background: linear-gradient(140deg, var(--ink-3), var(--ink) 58%);
}

.page-about .ab-cta__grid {
  display: grid;
  gap: clamp(1.5rem, 4vw, 3rem);
}

.page-about .ab-cta h2 {
  margin-top: .7rem;
  font-size: clamp(1.6rem, 4.2vw, 2.5rem);
  max-width: 22ch;
}

.page-about .ab-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: .75rem;
}

.page-about .ab-cta .btn {
  display: inline-flex;
  align-items: center;
  padding: .8rem 1.2rem;
  border: 1px solid var(--line-strong);
  background: transparent;
  color: var(--paper);
  font-family: var(--font-head);
  font-size: var(--fs-16);
  font-weight: 600;
  letter-spacing: .01em;
  text-decoration: none;
  transition: background .18s var(--ease), border-color .18s var(--ease), color .18s var(--ease), transform .18s var(--ease);
}

.page-about .ab-cta .btn:hover {
  border-color: var(--orange);
  transform: translateY(-2px);
  text-decoration: none;
}

.page-about .ab-cta .btn--primary {
  border-color: var(--orange);
  background: var(--orange);
  color: var(--ink);
  font-weight: 700;
}

.page-about .ab-cta .btn--primary:hover {
  filter: brightness(1.08);
}

/* ---------- 断点 ---------- */

@media (min-width: 760px) {
  .page-about .ab-bands {
    flex-direction: row;
  }

  .page-about .ab-band {
    flex-basis: 0;
    flex-shrink: 0;
    border-bottom: 0;
    border-top: 2px solid transparent;
  }

  .page-about .ab-band:nth-child(1) { flex-grow: 1; }
  .page-about .ab-band:nth-child(2) { flex-grow: 1.35; }
  .page-about .ab-band:nth-child(3) { flex-grow: 1.15; }
  .page-about .ab-band:nth-child(4) { flex-grow: .9; }

  .page-about .ab-band[aria-selected="true"] {
    border-top-color: var(--orange);
    border-bottom-color: transparent;
  }

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

@media (min-width: 780px) {
  .page-about .ab-ally__grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .ab-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }

  .page-about .ab-cta__grid {
    grid-template-columns: minmax(0, 6fr) minmax(0, 5fr);
    align-items: center;
  }
}

@media (min-width: 960px) {
  .page-about .ab-origin__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
  }

  .page-about .ab-origin__side {
    position: sticky;
    top: 7rem;
  }

  .page-about .ab-keep__grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: start;
  }

  .page-about .ab-keep__side {
    position: sticky;
    top: 7rem;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-board {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-band,
  .page-about .ab-cta .btn,
  .page-about .ab-ally__grid .card {
    transition: none;
  }

  .page-about .ab-cta .btn:hover,
  .page-about .ab-ally__grid .card:hover {
    transform: none;
  }
}