.page-about {
  --about-rail: 208px;
  --about-gap: clamp(18px, 3vw, 40px);
  color: var(--yy-text);
  overflow-x: clip;
}

.page-about .about-crumb {
  padding-top: clamp(14px, 2vw, 24px);
  padding-bottom: 4px;
}

.page-about .about-crumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--yy-text-dim);
}

.page-about .about-crumb a {
  color: var(--yy-text-dim);
  text-decoration: none;
  transition: color 200ms var(--yy-ease);
}

.page-about .about-crumb a:hover {
  color: var(--yy-cyan);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(24px, 4vw, 54px) clamp(32px, 5vw, 66px);
  border-bottom: 1px solid var(--yy-line);
  background:
    radial-gradient(115% 85% at 88% -10%, rgba(53, 224, 209, 0.12), transparent 62%),
    radial-gradient(95% 80% at -5% 105%, rgba(242, 169, 59, 0.1), transparent 62%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: linear-gradient(118deg, transparent 63.6%, rgba(43, 58, 53, 0.5) 63.8%, transparent 64.1%);
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(24px, 3.4vw, 40px);
}

.page-about .about-hero__title {
  margin-top: 10px;
  max-width: 13em;
  letter-spacing: 0.01em;
}

.page-about .about-hero__lead {
  margin-top: 16px;
  max-width: 46em;
  font-size: clamp(15px, 1.1vw, 17px);
  line-height: 1.85;
  color: var(--yy-text);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: clamp(20px, 3vw, 30px);
}

.page-about .about-hero__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 var(--about-gap);
  align-content: start;
  border-top: 1px solid var(--yy-line);
}

.page-about .about-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 0;
  border-bottom: 1px solid var(--yy-line-soft);
}

.page-about .about-stat dt {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--yy-text-dim);
}

.page-about .about-stat dd {
  margin: 0;
  display: flex;
  align-items: baseline;
  gap: 5px;
  line-height: 1.1;
}

.page-about .about-stat__num {
  font-family: var(--yy-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(21px, 2.6vw, 28px);
  font-weight: 700;
  color: var(--yy-cream);
}

.page-about .about-stat__unit {
  font-size: 12px;
  color: var(--yy-rock);
  letter-spacing: 0.04em;
}

/* ---------- 主体骨架 ---------- */

.page-about .about-body {
  display: grid;
  gap: clamp(24px, 3vw, 44px);
  padding-block: clamp(32px, 5vw, 70px) clamp(44px, 7vw, 96px);
}

.page-about .about-rail__label {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--yy-rock);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .about-rail__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 7px 11px;
  border: 1px solid var(--yy-line-soft);
  background: rgba(15, 46, 42, 0.5);
  color: var(--yy-text);
  font-size: 13px;
  text-decoration: none;
  transition: border-color 220ms var(--yy-ease), color 220ms var(--yy-ease);
}

.page-about .about-rail__list .k {
  font-family: var(--yy-font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--yy-amber);
}

.page-about .about-rail__list a:hover {
  border-color: var(--yy-amber);
  color: var(--yy-cream);
}

.page-about .about-rail__list a:focus-visible {
  outline: 2px solid var(--yy-cyan);
  outline-offset: 2px;
}

/* ---------- 章节 ---------- */

.page-about .about-chapter {
  padding-block: clamp(26px, 4vw, 52px);
  border-top: 1px solid var(--yy-line);
  scroll-margin-top: 100px;
}

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

.page-about .about-chapter__head {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 10px;
  margin-bottom: 14px;
}

.page-about .about-chapter h2 {
  margin: 0;
}

.page-about .about-chapter p {
  margin: 0 0 14px;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--yy-text);
}

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

.page-about .about-lead {
  font-family: var(--yy-font-serif);
  font-weight: 600;
  font-size: clamp(17px, 1.7vw, 21px);
  line-height: 1.7;
  color: var(--yy-cream);
  margin-bottom: 16px;
}

.page-about .about-quote {
  margin: clamp(18px, 2.6vw, 28px) 0;
  padding: 2px 0 2px 18px;
  border-left: 3px solid var(--yy-moss);
  font-family: var(--yy-font-serif);
  font-weight: 600;
  font-size: clamp(20px, 2.4vw, 28px);
  line-height: 1.55;
  color: var(--yy-cream);
}

.page-about .about-link {
  color: var(--yy-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 209, 0.38);
  transition: color 200ms var(--yy-ease), border-color 200ms var(--yy-ease);
}

.page-about .about-link:hover {
  color: var(--yy-cream);
  border-bottom-color: var(--yy-amber);
}

.page-about .about-link:focus-visible {
  outline: 2px solid var(--yy-cyan);
  outline-offset: 2px;
}

/* ---------- 图片 ---------- */

.page-about .about-figure {
  position: relative;
  margin: 0 0 clamp(20px, 3vw, 30px);
  border: 1px solid var(--yy-line);
  background: var(--yy-teal);
  overflow: hidden;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  filter: saturate(0.92) contrast(1.06);
}

.page-about .about-figure--wide img {
  aspect-ratio: 16 / 9;
}

.page-about .about-figure--split img {
  aspect-ratio: 3 / 2;
}

.page-about .about-figure figcaption {
  padding: 10px 13px;
  border-top: 1px solid var(--yy-line);
  background: rgba(8, 19, 17, 0.6);
  font-size: 12px;
  letter-spacing: 0.06em;
  line-height: 1.65;
  color: var(--yy-text-dim);
}

/* ---------- 三入口 ---------- */

.page-about .about-entries {
  list-style: none;
  margin: clamp(18px, 2.4vw, 26px) 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-entry {
  padding: 15px 16px 18px;
  border: 1px solid var(--yy-line-soft);
  border-top-width: 3px;
  background: rgba(15, 46, 42, 0.55);
}

.page-about .about-entry--moss {
  border-top-color: var(--yy-moss);
}

.page-about .about-entry--amber {
  border-top-color: var(--yy-amber);
}

.page-about .about-entry--cyan {
  border-top-color: var(--yy-cyan);
}

.page-about .about-entry__k {
  display: block;
  margin-bottom: 8px;
  font-family: var(--yy-font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--yy-amber);
}

.page-about .about-entry h3 {
  margin: 0 0 8px;
  font-size: clamp(17px, 1.7vw, 21px);
  line-height: 1.4;
  color: var(--yy-cream);
}

.page-about .about-entry p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
}

/* ---------- 团队 ---------- */

.page-about .about-teamnums {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: clamp(16px, 2.4vw, 24px) 0;
}

.page-about .about-teamnums > div {
  padding: 4px 0 4px 14px;
  border-left: 2px solid var(--yy-moss);
}

.page-about .about-teamnums strong {
  display: block;
  font-family: var(--yy-font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(23px, 3vw, 32px);
  line-height: 1.1;
  color: var(--yy-amber);
}

.page-about .about-teamnums span {
  font-size: 13px;
  color: var(--yy-text-dim);
}

.page-about .about-flow {
  margin-top: clamp(16px, 2.4vw, 24px);
  border-top: 1px solid var(--yy-line);
}

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

.page-about .about-step summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 14px 0;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 600;
  color: var(--yy-cream);
  transition: color 200ms var(--yy-ease);
}

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

.page-about .about-step summary:hover {
  color: var(--yy-amber);
}

.page-about .about-step summary:focus-visible {
  outline: 2px solid var(--yy-cyan);
  outline-offset: 3px;
}

.page-about .about-step__k {
  font-family: var(--yy-font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--yy-moss-lt);
}

.page-about .about-step summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--yy-font-mono);
  color: var(--yy-rock);
}

.page-about .about-step[open] summary::after {
  content: "–";
  color: var(--yy-amber);
}

.page-about .about-step__body {
  padding-bottom: 16px;
}

.page-about .about-step__body p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  max-width: 58ch;
}

/* ---------- 旧版入口 ---------- */

.page-about .about-legacy {
  margin-top: clamp(14px, 2vw, 20px);
  padding: clamp(16px, 2.6vw, 26px);
  border: 1px solid var(--yy-line);
  border-left: 3px solid var(--yy-clay);
  background: rgba(26, 29, 28, 0.62);
}

.page-about .about-legacy p {
  max-width: 60ch;
}

.page-about .about-legacy__note {
  margin: 12px 0 0;
  padding-top: 12px;
  border-top: 1px dashed var(--yy-line-soft);
  font-size: 13px;
  line-height: 1.75;
  color: var(--yy-text-dim);
}

/* ---------- 服务与合作 ---------- */

.page-about .about-eco {
  display: grid;
  gap: 12px;
  margin-top: clamp(16px, 2.4vw, 24px);
}

.page-about .about-eco__panel {
  padding: clamp(15px, 2.2vw, 24px);
  border: 1px solid var(--yy-line-soft);
  border-top-width: 3px;
  background: rgba(15, 46, 42, 0.5);
}

.page-about .about-eco__panel--moss {
  border-top-color: var(--yy-moss);
}

.page-about .about-eco__panel--clay {
  border-top-color: var(--yy-clay);
}

.page-about .about-eco__panel h3 {
  margin: 0 0 10px;
  font-size: clamp(17px, 1.6vw, 19px);
  color: var(--yy-cream);
}

.page-about .about-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-list li {
  display: flex;
  gap: 10px;
  padding: 9px 0;
  border-bottom: 1px dashed var(--yy-line-soft);
  font-size: 14px;
  line-height: 1.75;
  color: var(--yy-text);
}

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

.page-about .about-list .k {
  flex: 0 0 auto;
  padding-top: 3px;
  font-family: var(--yy-font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--yy-moss-lt);
}

.page-about .about-eco + p {
  margin-top: clamp(14px, 2vw, 20px);
}

/* ---------- 联系 ---------- */

.page-about .about-contact {
  display: grid;
  gap: clamp(16px, 2.4vw, 28px);
  margin-top: clamp(14px, 2vw, 20px);
}

.page-about .about-contact__rows {
  margin: 0;
  border-top: 1px solid var(--yy-line);
}

.page-about .about-contact__row {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  padding: 12px 0;
  border-bottom: 1px solid var(--yy-line-soft);
  font-size: 14px;
}

.page-about .about-contact__row dt {
  flex: 0 0 auto;
  min-width: 84px;
  padding-top: 2px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--yy-rock);
}

.page-about .about-contact__row dd {
  margin: 0;
  font-family: var(--yy-font-mono);
  font-variant-numeric: tabular-nums;
  color: var(--yy-cream);
  word-break: break-word;
}

.page-about .about-contact__aside p {
  margin: 0 0 14px;
  max-width: 46ch;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--yy-text);
}

.page-about .about-contact__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 4px;
}

.page-about .about-contact__fineprint {
  margin: 14px 0 0;
  padding-top: 12px;
  border-top: 1px dashed var(--yy-line-soft);
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--yy-text-dim);
}

.page-about .about-contact__fineprint a {
  color: var(--yy-cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 209, 0.38);
}

.page-about .about-contact__fineprint a:hover {
  color: var(--yy-cream);
  border-bottom-color: var(--yy-amber);
}

/* ---------- 断点 ---------- */

@media (min-width: 620px) {
  .page-about .about-step__body {
    padding-left: 40px;
  }

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

@media (min-width: 860px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.62fr) minmax(240px, 0.88fr);
    align-items: end;
    gap: clamp(28px, 4vw, 64px);
  }

  .page-about .about-hero__stats {
    grid-template-columns: minmax(0, 1fr);
    padding-bottom: 4px;
  }

  .page-about .about-chapter p {
    font-size: 16px;
  }

  .page-about .about-eco {
    grid-template-columns: 1.08fr 0.92fr;
    align-items: start;
  }

  .page-about .about-contact {
    grid-template-columns: 1.02fr 0.98fr;
    align-items: start;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
    gap: clamp(32px, 4vw, 64px);
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 0;
    border-left: 1px solid var(--yy-line);
  }

  .page-about .about-rail__list a {
    width: 100%;
    padding: 10px 0 10px 16px;
    border: 0;
    background: none;
    font-size: 14px;
    position: relative;
  }

  .page-about .about-rail__list a::before {
    content: "";
    position: absolute;
    left: -4px;
    top: 50%;
    width: 7px;
    height: 7px;
    margin-top: -3.5px;
    border-radius: 50%;
    background: var(--yy-line);
    transition: background 220ms var(--yy-ease), box-shadow 220ms var(--yy-ease);
  }

  .page-about .about-rail__list a:hover::before {
    background: var(--yy-amber);
    box-shadow: 0 0 0 3px rgba(242, 169, 59, 0.18);
  }

  .page-about .about-rail__list a:hover {
    color: var(--yy-cream);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about * {
    transition: none !important;
    animation: none !important;
  }
}