.page-about {
  --about-rail-w: 180px;
  --about-node-pad: 34px;
}

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: 44px 0 84px;
  background: var(--ink-900);
  border-bottom: 4px solid var(--ink-500);
}

.page-about .about-hero__bg {
  position: absolute;
  inset: 0;
  z-index: -2;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 30%;
  opacity: 0.32;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(5, 11, 26, 0.62) 0%, rgba(5, 11, 26, 0.9) 62%, var(--ink-900) 100%),
    repeating-linear-gradient(90deg, rgba(74, 111, 165, 0.16) 0 1px, transparent 1px 72px),
    repeating-linear-gradient(0deg, rgba(74, 111, 165, 0.1) 0 1px, transparent 1px 72px);
}

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

.page-about .about-hero .breadcrumbs {
  margin-bottom: 40px;
}

.page-about .about-hero__kicker {
  margin: 0 0 14px;
  color: var(--orange-500);
}

.page-about .about-hero__title {
  max-width: 18ch;
  margin: 0 0 22px;
  color: var(--white);
  letter-spacing: -0.02em;
}

.page-about .about-hero__hl {
  color: var(--orange-500);
  display: inline-block;
}

.page-about .about-hero__lede {
  max-width: 58ch;
  margin: 0 0 44px;
  color: var(--mist-100);
}

.page-about .about-hero__marks {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 2px solid var(--steel-300);
}

.page-about .about-hero__marks li {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 16px 4px;
  border-bottom: 1px solid var(--line-soft);
  color: var(--mist-100);
  font-size: 0.95rem;
}

.page-about .about-hero__num {
  min-width: 5ch;
  color: var(--orange-500);
  font-size: 1.6rem;
  font-weight: 700;
  line-height: 1;
}

@media (min-width: 720px) {
  .page-about .about-hero {
    padding: 64px 0 104px;
  }

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

  .page-about .about-hero__marks li {
    flex-direction: column;
    gap: 8px;
    padding: 20px 20px 20px 0;
    border-bottom: 0;
    border-right: 1px solid var(--line-soft);
  }

  .page-about .about-hero__marks li:last-child {
    border-right: 0;
  }
}

/* ============ 章节通用 ============ */
.page-about .about-chapter {
  padding: 72px 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-chapter:first-of-type {
  border-top: 0;
}

.page-about .about-kicker {
  font-family: var(--font-serif);
  color: var(--mist-100);
  letter-spacing: 0.06em;
}

.page-about .chapter__title {
  max-width: 24ch;
  margin: 20px 0 26px;
  color: var(--white);
}

.page-about .chapter__lede {
  max-width: 52ch;
  margin: 0 0 44px;
  color: var(--mist-100);
}

.page-about .about-chapter__lede {
  margin-bottom: 32px;
  color: var(--mist-100);
}

.page-about .about-chapter__body p {
  color: var(--mist-100);
}

.page-about .about-lead {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  line-height: 1.9;
  color: var(--white);
}

.page-about .about-lead::first-letter {
  float: left;
  margin: 6px 12px 0 0;
  font-family: var(--font-display);
  font-size: 3.6rem;
  font-weight: 700;
  line-height: 0.82;
  color: var(--orange-500);
}

.page-about .about-side .aside-note + .aside-note {
  margin-top: 22px;
}

.page-about .about-side__strong {
  color: var(--orange-500);
  font-weight: 600;
}

.page-about .about-media {
  margin: 32px 0 0;
}

/* 章节之间的细分隔与衬线导读 */
.page-about .about-rule {
  margin: 0;
  border: 0;
  border-top: 2px solid var(--ink-500);
}

.page-about .about-quote {
  max-width: 34ch;
  margin: 0 auto;
  padding: 40px 24px;
  font-family: var(--font-serif);
  font-size: 1.1rem;
  line-height: 1.85;
  color: var(--mist-100);
  text-align: center;
}

@media (min-width: 880px) {
  .page-about .about-chapter {
    padding: 104px 0;
  }

  .page-about .about-quote {
    padding: 56px 24px;
    font-size: 1.25rem;
  }
}

/* ============ 时间线 ============ */
.page-about .about-timeline__layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 36px;
  margin-top: 8px;
}

.page-about .about-rail__label {
  margin: 0 0 12px;
  color: var(--data-400);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-size: 0.75rem;
}

.page-about .about-rail__list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 6px 0;
  color: var(--mist-100);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 0.18s ease, border-color 0.18s ease;
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--orange-500);
  border-bottom-color: var(--orange-500);
}

.page-about .about-rail__ver {
  font-size: 0.8rem;
  color: var(--data-400);
}

.page-about .about-timeline__body {
  display: flex;
  flex-direction: column;
}

.page-about .about-node {
  position: relative;
  padding: 0 0 46px calc(var(--about-node-pad) + 4px);
  border-left: 2px solid var(--ink-500);
}

.page-about .about-node:last-child {
  padding-bottom: 0;
  border-left-color: transparent;
}

.page-about .about-node__marker {
  position: absolute;
  left: -13px;
  top: 2px;
  display: block;
  width: 24px;
  height: 24px;
  background: var(--ink-900);
  border-radius: 50%;
}

.page-about .about-node__marker svg {
  display: block;
}

.page-about .about-node__year {
  margin: 0 0 8px;
  color: var(--orange-500);
  font-size: 0.85rem;
  letter-spacing: 0.08em;
}

.page-about .about-node__title {
  margin: 0 0 12px;
  font-size: 1.25rem;
  color: var(--white);
  letter-spacing: -0.01em;
}

.page-about .about-node__text {
  max-width: 62ch;
  margin: 0 0 18px;
  color: var(--mist-100);
  line-height: 1.78;
}

.page-about .about-node__facts {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-node__facts li {
  padding: 6px 12px;
  font-size: 0.82rem;
  color: var(--mist-100);
  border: 1px solid var(--steel-300);
  background: rgba(20, 40, 77, 0.5);
}

@media (min-width: 880px) {
  .page-about .about-timeline__layout {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: calc(var(--header-h-scrolled) + 40px);
    align-self: start;
    padding-top: 4px;
  }

  .page-about .about-rail__list {
    flex-direction: column;
    gap: 0;
  }

  .page-about .about-rail__link {
    display: flex;
    justify-content: space-between;
    width: 100%;
    border-bottom: 1px solid var(--line-soft);
  }

  .page-about .about-node__title {
    font-size: 1.5rem;
  }
}

/* ============ 三道工序 ============ */
.page-about .about-steps {
  margin: 0 0 8px;
  padding: 0;
  list-style: none;
}

.page-about .about-steps__item {
  position: relative;
  padding: 22px 0 22px 26px;
  border-left: 3px solid var(--ink-500);
}

.page-about .about-steps__item + .about-steps__item {
  margin-top: 6px;
}

.page-about .about-steps__num {
  display: block;
  margin-bottom: 8px;
  color: var(--data-400);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
}

.page-about .about-steps__title {
  margin: 0 0 8px;
  font-size: 1.2rem;
  color: var(--white);
}

.page-about .about-steps__item p {
  max-width: 60ch;
  margin: 0;
  color: var(--mist-100);
  line-height: 1.78;
}

.page-about .about-steps__item::before {
  content: "";
  position: absolute;
  left: -3px;
  top: 0;
  width: 3px;
  height: 0;
  background: var(--orange-500);
  transition: height 0.3s ease;
}

.page-about .about-steps__item:hover::before {
  height: 100%;
}

/* ============ 团队与协作 ============ */
.page-about .about-media--side {
  margin: 0 0 22px;
}

/* ============ 坚持的事 ============ */
.page-about .about-principles {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: 2px solid var(--ink-500);
}

.page-about .about-principle {
  padding: 28px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .about-principle__idx {
  margin: 0 0 10px;
  color: var(--orange-500);
  font-family: var(--font-serif);
  font-size: 0.9rem;
  letter-spacing: 0.16em;
}

.page-about .about-principle__title {
  margin: 0 0 10px;
  font-size: 1.15rem;
  color: var(--white);
  letter-spacing: -0.01em;
}

.page-about .about-principle p:last-child {
  max-width: 58ch;
  margin: 0;
  color: var(--mist-100);
  line-height: 1.78;
}

@media (min-width: 880px) {
  .page-about .about-principles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 56px;
  }

  .page-about .about-principle:nth-child(odd) {
    padding-right: 8px;
  }

  .page-about .about-principle:nth-child(1),
  .page-about .about-principle:nth-child(2) {
    border-top: 2px solid var(--orange-500);
    margin-top: -2px;
    padding-top: 32px;
  }
}

/* ============ 覆盖与人群 ============ */
.page-about .about-reach__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 0 0 52px;
  background: var(--line-soft);
  border: 2px solid var(--ink-500);
}

.page-about .about-stat {
  padding: 26px 22px 28px;
  background: var(--ink-700);
}

.page-about .about-stat .stat__value {
  display: block;
  color: var(--orange-500);
  font-family: var(--font-mono);
  font-size: 2.4rem;
  font-weight: 700;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}

.page-about .about-stat .stat__unit {
  display: block;
  margin: 8px 0 14px;
  color: var(--mist-100);
  font-size: 0.9rem;
}

.page-about .about-stat .stat__label {
  display: block;
  color: var(--data-400);
  font-size: 0.8rem;
  line-height: 1.6;
}

@media (min-width: 720px) {
  .page-about .about-reach__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1080px) {
  .page-about .about-reach__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-stat:nth-child(even) {
    padding-top: 40px;
  }
}

.page-about .about-reach__audience {
  align-items: start;
}

.page-about .about-reach__subtitle {
  margin: 0 0 18px;
  font-size: 1.1rem;
  color: var(--white);
}

.page-about .about-audience {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-audience li {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line-soft);
  color: var(--mist-100);
  line-height: 1.7;
}

.page-about .about-audience .status-dot {
  margin-top: 9px;
  flex: 0 0 auto;
}

.page-about .about-reach__aside {
  padding: 26px 22px;
  background: var(--ink-500);
  border: 2px solid var(--steel-300);
  box-shadow: var(--shadow-hard-sm);
}

.page-about .about-reach__aside p {
  color: var(--mist-100);
  line-height: 1.78;
}

.page-about .about-reach__aside p:first-child {
  margin-top: 0;
  color: var(--data-400);
  letter-spacing: 0.12em;
  font-size: 0.78rem;
  text-transform: uppercase;
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .about-reach__foot {
  margin: 44px 0 0;
  padding-top: 24px;
  border-top: 2px solid var(--ink-500);
  color: var(--mist-100);
  line-height: 1.78;
}

.page-about .about-reach__foot a {
  color: var(--orange-500);
}

/* ============ 通用收敛 ============ */
.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about .grid--split > .about-chapter__body,
.page-about .grid--split > .about-side {
  min-width: 0;
}

@media (min-width: 880px) {
  .page-about .grid--split {
    align-items: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-steps__item::before {
    transition: none;
  }
}