.page-about {
  padding-block: clamp(20px, 4vw, 40px) clamp(56px, 9vw, 104px);
}

.page-about .breadcrumbs {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--mist-300);
  margin-bottom: clamp(20px, 4vw, 40px);
}

.page-about .breadcrumbs__link {
  color: var(--mist-300);
  text-decoration: none;
  transition: color 180ms var(--ease);
}

.page-about .breadcrumbs__link:hover,
.page-about .breadcrumbs__link:focus-visible {
  color: var(--cyan-500);
}

.page-about .breadcrumbs__sep {
  color: var(--mist-500);
}

.page-about .breadcrumbs__current {
  color: var(--fog-050);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  padding-bottom: clamp(40px, 6vw, 72px);
  border-bottom: 1px solid var(--mist-500);
}

.page-about .about-hero__lead {
  max-width: 34em;
}

.page-about .about-hero .eyebrow {
  display: block;
  margin: 0 0 18px;
  padding-left: 12px;
  border-left: 2px solid var(--cyan-500);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--cyan-500);
}

.page-about .about-hero__title {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-size: clamp(32px, 6.2vw, 64px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.02em;
  color: var(--fog-050);
}

.page-about .about-hero .lede {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist-300);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
  gap: 16px 20px;
  margin: 28px 0;
  padding-top: 20px;
  border-top: 1px solid var(--mist-500);
}

.page-about .about-hero__fact span:first-child {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.4vw, 26px);
  letter-spacing: -0.02em;
  color: var(--fog-050);
}

.page-about .about-hero__fact span:last-child {
  display: block;
  margin-top: 6px;
  font-size: 11px;
  letter-spacing: 0.1em;
  line-height: 1.5;
  color: var(--mist-300);
}

.page-about .about-hero__media {
  margin: 0;
  position: relative;
  overflow: hidden;
}

.page-about .about-hero__media .media__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
  filter: saturate(0.85) contrast(1.05);
}

/* ---------- 主体骨架 ---------- */

.page-about .about-body {
  display: grid;
  gap: clamp(24px, 4vw, 40px);
  padding-top: clamp(40px, 6vw, 72px);
}

.page-about .about-rail {
  display: none;
}

.page-about .about-chapters {
  --chapter-pad: clamp(18px, 3.6vw, 40px);
  border-left: 1px solid var(--mist-500);
  padding-left: var(--chapter-pad);
  min-width: 0;
}

/* ---------- 章节 ---------- */

.page-about .chapter {
  position: relative;
  padding-bottom: clamp(48px, 7vw, 80px);
}

.page-about .chapter:last-of-type {
  padding-bottom: 0;
}

.page-about .chapter::before {
  content: "";
  position: absolute;
  top: 12px;
  left: calc(-1 * var(--chapter-pad) - 5px);
  width: 9px;
  height: 9px;
  background: var(--ink-900);
  border: 1px solid var(--cyan-500);
}

.page-about .chapter__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(36px, 6.4vw, 64px);
  font-weight: 300;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--mist-500);
}

.page-about .chapter__title {
  margin: 10px 0 20px;
  font-family: var(--font-display);
  font-size: clamp(23px, 3.4vw, 36px);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: -0.01em;
  color: var(--fog-050);
}

.page-about .chapter__body {
  max-width: 34em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist-300);
}

.page-about .chapter__body p {
  margin: 0 0 16px;
}

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

/* ---------- 年份轴 ---------- */

.page-about .years {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  max-width: 34em;
}

.page-about .years__item {
  display: grid;
  grid-template-columns: 3.6em minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--mist-500);
}

.page-about .years__item:last-child {
  border-bottom: 1px solid var(--mist-500);
}

.page-about .years__year {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--cyan-500);
}

.page-about .years__title {
  margin: 0 0 4px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--fog-050);
}

.page-about .years__text p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist-300);
}

/* ---------- 流程步骤 ---------- */

.page-about .steps {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  max-width: 34em;
}

.page-about .step {
  display: grid;
  grid-template-columns: 1.4em minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--mist-500);
}

.page-about .step:last-child {
  border-bottom: 1px solid var(--mist-500);
}

.page-about .step__no {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.6;
  color: var(--orange-500);
}

.page-about .step__title {
  margin: 0 0 4px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--fog-050);
}

.page-about .step__text p {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist-300);
}

.page-about .about-figure {
  margin: 28px 0 0;
  max-width: 44em;
}

.page-about .about-figure .media__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  filter: saturate(0.85);
}

.page-about .about-figure .media__caption {
  display: block;
  margin-top: 10px;
  font-size: 11px;
  letter-spacing: 0.08em;
  line-height: 1.6;
  color: var(--mist-300);
}

.page-about .pullquote {
  margin: 32px 0 0;
  padding: 6px 0 6px 20px;
  border-left: 3px solid var(--cyan-500);
  max-width: 30em;
  font-family: var(--font-display);
  font-size: clamp(18px, 2.2vw, 24px);
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--fog-050);
}

/* ---------- 版本节奏 ---------- */

.page-about .cadence {
  display: grid;
  gap: 18px;
  margin: 28px 0;
  max-width: 44em;
}

.page-about .cadence__item {
  padding-top: 14px;
  border-top: 2px solid var(--cyan-500);
}

.page-about .cadence__item--last {
  border-top-color: var(--orange-500);
}

.page-about .cadence__when {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan-500);
}

.page-about .cadence__item--last .cadence__when {
  color: var(--orange-500);
}

.page-about .cadence__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--mist-300);
}

.page-about .revisions {
  list-style: none;
  margin: 20px 0 26px;
  padding: 0;
  max-width: 34em;
}

.page-about .revisions__item {
  position: relative;
  padding: 10px 0 10px 20px;
  border-top: 1px solid var(--mist-500);
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist-300);
}

.page-about .revisions__item:last-child {
  border-bottom: 1px solid var(--mist-500);
}

.page-about .revisions__item::before {
  content: "";
  position: absolute;
  top: 20px;
  left: 0;
  width: 8px;
  height: 1px;
  background: var(--cyan-500);
}

/* ---------- 服务半径 ---------- */

.page-about .partners {
  list-style: none;
  margin: 24px 0 0;
  padding: 0;
  display: grid;
  gap: 18px;
  max-width: 44em;
}

.page-about .partners__item {
  padding-top: 14px;
  border-top: 1px solid var(--mist-500);
}

.page-about .partners__name {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 16px;
  font-weight: 700;
  line-height: 1.3;
  color: var(--cyan-500);
}

.page-about .partners__text {
  margin: 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist-300);
}

.page-about .region {
  display: grid;
  gap: 24px;
  margin-top: 32px;
  max-width: 44em;
}

.page-about .region__text p {
  margin: 0 0 18px;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist-300);
  max-width: 30em;
}

.page-about .region__media {
  margin: 0;
}

.page-about .region__media .media__img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  aspect-ratio: 8 / 5;
  object-fit: cover;
  filter: saturate(0.7) brightness(0.9);
}

/* ---------- 内容标准 ---------- */

.page-about .accordion {
  margin-top: 26px;
  max-width: 44em;
}

.page-about .accordion__item {
  border-top: 1px solid var(--mist-500);
}

.page-about .accordion__item:last-child {
  border-bottom: 1px solid var(--mist-500);
}

.page-about .accordion__trigger {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 6px 20px;
  width: 100%;
  padding: 18px 0;
  background: none;
  border: 0;
  text-align: left;
  cursor: pointer;
  color: var(--fog-050);
  transition: color 180ms var(--ease);
}

.page-about .accordion__trigger:hover,
.page-about .accordion__trigger:focus-visible {
  color: var(--cyan-500);
}

.page-about .std__name {
  font-family: var(--font-display);
  font-size: clamp(18px, 2.2vw, 22px);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.01em;
}

.page-about .std__hint {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--mist-300);
}

.page-about .accordion__panel {
  overflow: hidden;
}

.page-about .accordion__panel-inner {
  padding: 0 0 18px;
  max-width: 32em;
  font-size: 14px;
  line-height: 1.85;
  color: var(--mist-300);
}

.page-about .accordion__panel-inner p {
  margin: 0;
}

/* ---------- 团队 ---------- */

.page-about .metrics {
  display: grid;
  gap: 1px;
  margin: 26px 0;
  max-width: 44em;
  background: var(--mist-500);
  border: 1px solid var(--mist-500);
}

.page-about .metric {
  background: var(--ink-800);
  padding: 20px 18px;
}

.page-about .metric__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(26px, 3.6vw, 34px);
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--cyan-500);
}

.page-about .metric__label {
  display: block;
  margin-top: 8px;
  font-size: 11px;
  letter-spacing: 0.1em;
  line-height: 1.5;
  color: var(--mist-300);
}

/* ---------- 收尾 ---------- */

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-top: clamp(40px, 6vw, 72px);
  padding-top: clamp(24px, 4vw, 40px);
  border-top: 1px solid var(--mist-500);
}

.page-about .about-cta__text p {
  margin: 0;
  max-width: 30em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--fog-050);
}

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

/* ---------- 断点 ---------- */

@media (min-width: 720px) {
  .page-about .cadence {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }

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

@media (min-width: 820px) {
  .page-about .region {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
    align-items: end;
    gap: 32px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
    align-items: center;
    gap: clamp(32px, 5vw, 64px);
  }

  .page-about .about-hero__media {
    clip-path: polygon(10% 0, 100% 0, 100% 100%, 0 100%);
    margin-left: -8%;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: 140px minmax(0, 1fr);
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .about-rail {
    display: block;
    position: sticky;
    top: 24px;
    align-self: start;
  }

  .page-about .about-rail__label {
    margin: 0 0 14px;
    font-size: 11px;
    letter-spacing: 0.16em;
    color: var(--mist-300);
  }

  .page-about .about-rail__list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: grid;
    gap: 2px;
  }

  .page-about .about-rail__link {
    display: flex;
    align-items: baseline;
    gap: 10px;
    padding: 8px 0 8px 12px;
    border-left: 2px solid transparent;
    font-size: 12px;
    line-height: 1.4;
    color: var(--mist-300);
    text-decoration: none;
    transition: color 180ms var(--ease), border-color 180ms var(--ease);
  }

  .page-about .about-rail__link:hover,
  .page-about .about-rail__link:focus-visible {
    border-left-color: var(--cyan-500);
    color: var(--fog-050);
  }

  .page-about .about-rail__num {
    font-family: var(--font-mono);
    font-size: 11px;
    color: var(--cyan-500);
  }
}