.page-about {
  --about-arc: rgba(59, 242, 196, 0.22);
  position: relative;
  overflow-x: clip;
  font-family: var(--font-body);
  color: var(--text);
  background-color: var(--bg);
  background-image:
    linear-gradient(to right, rgba(31, 61, 51, 0.28) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(31, 61, 51, 0.28) 1px, transparent 1px);
  background-size: 72px 72px;
  background-position: center top;
}

.page-about::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(58% 34% at 12% 0%, rgba(59, 242, 196, 0.10), transparent 72%),
    radial-gradient(46% 28% at 100% 26%, rgba(245, 184, 65, 0.06), transparent 72%);
}

.page-about .about-shell {
  position: relative;
  z-index: 1;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: clamp(20px, 4vw, 52px) var(--gutter) clamp(56px, 9vw, 104px);
}

/* ---- 竖向索引轨 ---- */
.page-about .index-rail {
  display: none;
  font-family: var(--font-mono);
}

.page-about .index-rail__list,
.page-about .index-rail__tools {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 12px;
  justify-items: start;
}

.page-about .index-rail__tools {
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.page-about .index-rail__link,
.page-about .index-rail__tool {
  display: inline-block;
  writing-mode: vertical-rl;
  text-decoration: none;
  color: var(--muted);
  font-size: 12px;
  letter-spacing: 0.2em;
  padding: 10px 5px;
  border-left: 1px solid var(--line);
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .index-rail__link:hover,
.page-about .index-rail__link:focus-visible,
.page-about .index-rail__link[aria-current="true"] {
  color: var(--accent);
  border-left-color: var(--accent);
}

.page-about .index-rail__tool:hover,
.page-about .index-rail__tool:focus-visible {
  color: var(--score);
  border-left-color: var(--score);
}

/* ---- 首屏 ---- */
.page-about .about-hero {
  position: relative;
  border: 1px solid var(--line);
  padding: clamp(18px, 3.4vw, 46px);
  background:
    linear-gradient(158deg, rgba(16, 40, 33, 0.92), rgba(6, 18, 15, 0.55)),
    var(--bg);
}

.page-about .about-hero::before,
.page-about .about-hero::after {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  border-style: solid;
  border-color: var(--accent);
  pointer-events: none;
}

.page-about .about-hero::before {
  top: -1px;
  left: -1px;
  border-width: 2px 0 0 2px;
}

.page-about .about-hero::after {
  bottom: -1px;
  right: -1px;
  border-width: 0 2px 2px 0;
}

.page-about .breadcrumb {
  margin-bottom: clamp(18px, 3vw, 34px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(24px, 4vw, 44px);
}

.page-about .eyebrow {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--accent);
  text-transform: uppercase;
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-body);
  font-weight: 700;
  font-size: clamp(30px, 5.4vw, 60px);
  line-height: 1.12;
  letter-spacing: 0.01em;
  color: var(--text);
}

.page-about .about-hero__lead {
  margin: 0 0 14px;
  max-width: 34em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.8;
  color: var(--muted);
}

.page-about .about-hero__lead:first-of-type {
  color: var(--text);
}

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

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

.page-about .hero-figure {
  margin: 0;
  padding: 16px 15px 18px;
  background: var(--surface);
}

.page-about .hero-figure__key {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--muted);
}

.page-about .hero-figure__val {
  margin: 8px 0 0;
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.page-about .hero-figure__num {
  font-family: var(--font-display);
  font-size: clamp(32px, 5vw, 44px);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--score);
}

.page-about .hero-figure__unit {
  font-size: 13px;
  color: var(--text);
}

/* ---- 章节通用 ---- */
.page-about .about-section {
  margin-top: clamp(48px, 7vw, 92px);
}

.page-about .about-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  column-gap: 16px;
  align-items: baseline;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  margin-bottom: clamp(24px, 3.6vw, 40px);
}

.page-about .about-head__num {
  grid-row: 1 / span 2;
  font-family: var(--font-display);
  font-size: clamp(34px, 5vw, 52px);
  line-height: 1;
  letter-spacing: 0.04em;
  color: var(--accent);
  opacity: 0.9;
}

.page-about .about-head__title {
  margin: 0;
  font-size: clamp(21px, 2.6vw, 30px);
  line-height: 1.3;
  font-weight: 700;
  color: var(--text);
}

.page-about .about-head__sub {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.6;
  color: var(--muted);
}

/* ---- 01 起点 ---- */
.page-about .origin {
  display: grid;
  gap: clamp(24px, 3.4vw, 40px);
}

.page-about .origin__body p {
  margin: 0 0 16px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
  max-width: 34em;
}

.page-about .origin__body p:first-child {
  color: var(--text);
}

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

.page-about .origin__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  padding: 16px 16px 18px;
  background: var(--surface);
}

.page-about .origin__k {
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--score);
  letter-spacing: 0.08em;
}

.page-about .origin__t {
  margin: 0 0 6px;
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

.page-about .origin__d {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---- 02 时间轴 ---- */
.page-about .track-wrap {
  display: grid;
  gap: clamp(22px, 3vw, 40px);
}

.page-about .track-figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--bg-2);
  position: relative;
}

.page-about .track-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 4;
  object-fit: cover;
  opacity: 0.72;
}

.page-about .track-figure__cap,
.page-about .flow-figure__cap,
.page-about .area-figure__cap {
  display: block;
  padding: 9px 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.page-about .track {
  position: relative;
}

.page-about .track__arc {
  position: absolute;
  left: -4px;
  top: 0;
  width: 54px;
  height: 100%;
  color: var(--accent);
  opacity: 0.16;
  pointer-events: none;
}

.page-about .track__list {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 4px 0 4px 30px;
  display: grid;
  gap: 18px;
}

.page-about .track__list::before {
  content: "";
  position: absolute;
  left: 8px;
  top: 14px;
  bottom: 14px;
  width: 1px;
  background: linear-gradient(to bottom, var(--accent), var(--accent-deep) 55%, var(--line));
}

.page-about .track__item {
  position: relative;
}

.page-about .track__item::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 9px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent);
  box-shadow: 0 0 0 4px rgba(59, 242, 196, 0.1);
  transition: box-shadow 0.2s ease, background-color 0.2s ease;
}

.page-about .track__item:hover::before {
  background: var(--accent);
  box-shadow: 0 0 0 6px rgba(59, 242, 196, 0.18);
}

.page-about .track__year {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--score);
}

.page-about .track__panel {
  border: 1px solid var(--line);
  border-left: 2px solid var(--accent-deep);
  background: var(--surface);
  padding: 16px 16px 14px;
  transition: border-color 0.2s ease, background-color 0.2s ease;
}

.page-about .track__item:hover .track__panel {
  border-left-color: var(--accent);
  background: var(--bg-2);
}

.page-about .track__title {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}

.page-about .track__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--muted);
}

.page-about .track__more {
  margin-top: 12px;
  border-top: 1px dashed var(--line);
  padding-top: 10px;
}

.page-about .track__more-sum {
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--accent);
}

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

.page-about .track__more-sum::after {
  content: " ＋";
}

.page-about .track__more[open] .track__more-sum::after {
  content: " －";
}

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

.page-about .track__more-body a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---- 03 流程 ---- */
.page-about .flow-wrap {
  display: grid;
  gap: clamp(22px, 3vw, 36px);
}

.page-about .flow-figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--bg-2);
}

.page-about .flow-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 7 / 4;
  object-fit: cover;
  opacity: 0.7;
}

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

.page-about .flow__box {
  border: 1px solid var(--line);
  background: var(--surface);
  transition: border-color 0.2s ease;
}

.page-about .flow__box[open] {
  border-color: rgba(59, 242, 196, 0.5);
  background: var(--bg-2);
}

.page-about .flow__sum {
  cursor: pointer;
  list-style: none;
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 14px 16px;
}

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

.page-about .flow__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--score);
}

.page-about .flow__name {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

.page-about .flow__hint {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  color: var(--muted);
}

.page-about .flow__box[open] .flow__hint {
  color: var(--accent);
}

.page-about .flow__body {
  padding: 0 16px 16px;
  border-top: 1px dashed var(--line);
  margin-top: -1px;
  padding-top: 14px;
}

.page-about .flow__body p {
  margin: 0 0 12px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .flow__meta {
  margin: 0;
  display: grid;
  gap: 6px;
}

.page-about .flow__meta div {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 10px;
  font-size: 12px;
}

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

.page-about .flow__meta dd {
  margin: 0;
  color: var(--text);
}

/* ---- 04 团队 ---- */
.page-about .crew {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 22px;
}

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

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

.page-about .crew__head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 10px;
}

.page-about .crew__name {
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}

.page-about .crew__count {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--score);
}

.page-about .crew__track {
  position: relative;
  height: 8px;
  background: rgba(31, 61, 51, 0.6);
  border-left: 1px solid var(--line);
  overflow: hidden;
}

.page-about .crew__fill {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-deep), var(--accent));
}

.page-about .crew__fill--data {
  width: 42%;
}

.page-about .crew__fill--editor {
  width: 35%;
}

.page-about .crew__fill--client {
  width: 23%;
}

.page-about .crew__desc {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  max-width: 46em;
}

.page-about .crew__foot {
  margin: 28px 0 0;
  padding: 16px 16px 16px 18px;
  border-left: 2px solid var(--score);
  background: var(--surface);
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

.page-about .crew__foot a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---- 05 区域 ---- */
.page-about .area-wrap {
  display: grid;
  gap: clamp(22px, 3vw, 38px);
}

.page-about .area-figure {
  margin: 0;
  border: 1px solid var(--line);
  background: var(--bg-2);
}

.page-about .area-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  opacity: 0.75;
}

.page-about .area-body p {
  margin: 0 0 18px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
  max-width: 34em;
}

.page-about .area-body p:first-child {
  color: var(--text);
}

.page-about .areas {
  list-style: none;
  margin: 0 0 18px;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .areas__item {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 13px 12px;
  background: var(--surface);
  transition: background-color 0.2s ease;
}

.page-about .areas__item:hover,
.page-about .areas__item:focus-within {
  background: var(--bg-2);
}

.page-about .areas__dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 3px rgba(59, 242, 196, 0.14);
  flex: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.page-about .areas__item:hover .areas__dot {
  transform: scale(1.35);
  box-shadow: 0 0 0 6px rgba(59, 242, 196, 0.2);
}

.page-about .areas__name {
  font-size: 14px;
  color: var(--text);
}

.page-about .areas__tag {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .area-note {
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
  padding-top: 16px;
  border-top: 1px dashed var(--line);
  max-width: 40em;
}

/* ---- 06 生态 ---- */
.page-about .eco {
  display: grid;
  gap: 14px;
}

.page-about .eco__card {
  padding: 20px 18px;
  border: 1px solid var(--line);
}

.page-about .eco__card--solid {
  background: var(--surface);
}

.page-about .eco__card--glass {
  background: var(--glass);
  border-color: rgba(245, 184, 65, 0.35);
  backdrop-filter: blur(6px);
}

.page-about .eco__t {
  margin: 0 0 10px;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}

.page-about .eco__card--glass .eco__t {
  color: var(--score);
}

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

.page-about .next {
  margin-top: clamp(26px, 4vw, 42px);
  padding: clamp(20px, 3vw, 32px);
  border: 1px solid var(--line);
  border-top: 2px solid var(--accent);
  background: linear-gradient(150deg, rgba(16, 40, 33, 0.9), rgba(6, 18, 15, 0.6));
}

.page-about .next__lead {
  margin: 0 0 20px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--text);
  max-width: 42em;
}

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

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

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

  .page-about .origin__item {
    grid-template-columns: minmax(0, 1fr);
    gap: 8px;
  }

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

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

  .page-about .eco__card--glass {
    grid-column: 1 / -1;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.65fr) minmax(0, 1fr);
    align-items: start;
  }

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

  .page-about .origin {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .track-wrap {
    grid-template-columns: 260px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .track-figure {
    position: sticky;
    top: 120px;
  }

  .page-about .track__item {
    display: grid;
    grid-template-columns: 84px minmax(0, 1fr);
    gap: 14px;
    align-items: start;
  }

  .page-about .track__year {
    margin: 0;
    padding-top: 17px;
    text-align: right;
  }

  .page-about .flow-wrap {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    align-items: start;
  }

  .page-about .flow-figure {
    position: sticky;
    top: 120px;
  }

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

  .page-about .area-wrap {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    align-items: start;
  }

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

  .page-about .areas__item {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .page-about .areas__tag {
    margin-left: 0;
  }

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

  .page-about .eco__card--glass {
    grid-column: auto;
  }
}

@media (min-width: 1120px) {
  .page-about .about-shell {
    padding-left: calc(var(--rail) + var(--gutter));
  }

  .page-about .index-rail {
    display: block;
    position: fixed;
    top: 220px;
    left: clamp(10px, calc((100vw - var(--maxw)) / 2 + 8px), 220px);
    z-index: 4;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .index-rail__link,
  .page-about .index-rail__tool,
  .page-about .track__item::before,
  .page-about .track__panel,
  .page-about .flow__box,
  .page-about .areas__item,
  .page-about .areas__dot {
    transition: none;
  }
}