.page-about {
  --about-line: var(--c-grid);
  --about-num-size: clamp(2rem, 5.5vw, 3rem);
  font-family: var(--font-body);
  color: var(--c-ink);
  background: var(--c-salt);
  overflow-x: clip;
}

.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: clamp(14px, 3vw, 26px) 0;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--c-mist);
}

.page-about .breadcrumbs a {
  color: var(--c-glacier);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease-out), border-color 0.2s var(--ease-out);
}

.page-about .breadcrumbs a:hover,
.page-about .breadcrumbs a:focus-visible {
  color: var(--c-ember);
  border-bottom-color: var(--c-orange);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(26px, 5vw, 46px) clamp(46px, 7vw, 84px);
  background:
    radial-gradient(90% 80% at 94% -12%, rgba(15, 110, 140, 0.18), transparent 62%),
    linear-gradient(180deg, var(--c-salt) 0%, var(--c-lake) 82%);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  right: -10%;
  bottom: -42%;
  width: min(52vw, 540px);
  aspect-ratio: 1;
  background: linear-gradient(140deg, rgba(240, 122, 43, 0.22), rgba(11, 92, 122, 0.1));
  transform: rotate(-14deg);
  pointer-events: none;
}

.page-about .about-hero__inner {
  position: relative;
  z-index: 1;
}

.page-about .about-hero__kicker {
  margin: 0 0 clamp(14px, 2vw, 20px);
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  letter-spacing: 0.14em;
  color: var(--c-glacier);
}

.page-about .about-hero__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.25rem, 8vw, 4.75rem);
  line-height: 1.08;
  letter-spacing: -0.02em;
  color: var(--c-teal);
  max-width: 18ch;
}

.page-about .about-hero__lead {
  margin: clamp(18px, 3vw, 28px) 0 0;
  max-width: 58ch;
  font-size: clamp(1rem, 1.7vw, 1.125rem);
  line-height: 1.85;
  color: var(--c-ink);
}

.page-about .hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(16px, 4vw, 46px);
  margin: clamp(24px, 4vw, 38px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .hero-facts li {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding-left: 12px;
  border-left: 2px solid var(--c-orange);
}

.page-about .hero-facts__num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: clamp(1.375rem, 3vw, 1.75rem);
  color: var(--c-teal);
}

.page-about .hero-facts__label {
  font-size: 0.8125rem;
  letter-spacing: 0.04em;
  color: var(--c-mist);
}

/* ---------- 章节索引条 ---------- */
.page-about .chapter-rail {
  margin-top: clamp(8px, 2vw, 18px);
  border-block: 1px solid var(--about-line);
}

.page-about .chapter-rail__inner {
  display: flex;
  gap: clamp(14px, 3vw, 34px);
  padding-block: 12px;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .chapter-rail__inner::-webkit-scrollbar {
  display: none;
}

.page-about .chapter-rail a {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  white-space: nowrap;
  padding-block: 3px;
  font-size: 0.875rem;
  color: var(--c-ink);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color 0.2s var(--ease-out), border-color 0.2s var(--ease-out);
}

.page-about .chapter-rail a .mono {
  font-size: 0.75rem;
  color: var(--c-teal);
}

.page-about .chapter-rail a:hover,
.page-about .chapter-rail a:focus-visible {
  color: var(--c-ember);
  border-bottom-color: var(--c-orange);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-body {
  padding-top: clamp(8px, 2vw, 16px);
}

.page-about .chapter {
  display: grid;
  gap: clamp(14px, 2.5vw, 24px);
  padding-block: clamp(38px, 6vw, 72px);
  border-bottom: 1px solid var(--about-line);
  scroll-margin-top: 96px;
}

.page-about .chapter__index {
  display: flex;
  align-items: center;
  gap: 12px;
}

.page-about .chapter__num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: var(--about-num-size);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--c-teal);
}

.page-about .chapter__mark {
  display: block;
  width: 13px;
  height: 13px;
  border: 1px solid var(--c-orange);
  background: transparent;
}

.page-about .chapter:nth-child(odd) .chapter__mark {
  border-radius: 50%;
}

.page-about .chapter__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.5rem, 3.6vw, 2.25rem);
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--c-teal);
}

.page-about .chapter__lead {
  margin: clamp(12px, 2vw, 18px) 0 0;
  max-width: 62ch;
  font-size: clamp(1rem, 1.6vw, 1.0625rem);
  line-height: 1.85;
  color: var(--c-mist);
}

.page-about .chapter__content p {
  max-width: 66ch;
  margin: 0 0 1em;
  line-height: 1.85;
}

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

.page-about .chapter__content a {
  color: var(--c-glacier);
  text-decoration: none;
  border-bottom: 1px solid var(--c-orange);
  transition: color 0.2s var(--ease-out);
}

.page-about .chapter__content a:hover,
.page-about .chapter__content a:focus-visible {
  color: var(--c-ember);
}

/* ---------- 图文分栏 ---------- */
.page-about .split {
  display: grid;
  gap: clamp(20px, 3.5vw, 40px);
  margin-top: clamp(18px, 3vw, 30px);
}

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

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .about-figure figcaption {
  padding: 10px 14px;
  border-top: 1px solid var(--about-line);
  font-family: var(--font-mono);
  font-size: 0.75rem;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--c-mist);
}

.page-about .brand-quote {
  margin: clamp(22px, 3.6vw, 34px) 0 0;
  padding: 4px 0 4px 18px;
  border-left: 4px solid var(--c-orange);
  font-size: clamp(1.0625rem, 2.1vw, 1.25rem);
  font-weight: 500;
  line-height: 1.75;
  color: var(--c-teal);
}

/* ---------- 三条主张 ---------- */
.page-about .claims {
  list-style: none;
  margin: clamp(18px, 3vw, 30px) 0 0;
  padding: 0;
}

.page-about .claim {
  display: grid;
  gap: 8px;
  padding-block: clamp(18px, 3vw, 26px);
  border-top: 1px solid var(--about-line);
}

.page-about .claim:last-child {
  border-bottom: 1px solid var(--about-line);
}

.page-about .claim__name {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--c-teal);
}

.page-about .claim__name .mono {
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--c-orange);
}

.page-about .claim__text {
  margin: 0;
  max-width: 68ch;
  font-size: 0.9688rem;
  line-height: 1.9;
}

/* ---------- 视觉章节 ---------- */
.page-about .visual-wrap {
  position: relative;
  margin-top: clamp(18px, 3vw, 28px);
}

.page-about .visual-text p {
  position: relative;
  z-index: 1;
}

.page-about .contour {
  position: absolute;
  top: -18px;
  right: -6px;
  width: clamp(120px, 26vw, 210px);
  height: auto;
  fill: none;
  stroke: var(--c-grid);
  stroke-width: 1;
  opacity: 0.9;
  pointer-events: none;
}

.page-about .swatches {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: clamp(22px, 3.4vw, 34px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .swatch {
  flex: 1 1 140px;
  border: 1px solid var(--about-line);
  background: var(--c-snow);
}

.page-about .swatch__chip {
  display: block;
  height: 54px;
}

.page-about .swatch__chip--teal {
  background: var(--c-teal);
}

.page-about .swatch__chip--glacier {
  background: var(--c-glacier);
}

.page-about .swatch__chip--orange {
  background: var(--c-orange);
}

.page-about .swatch__chip--snow {
  background: var(--c-lake);
  box-shadow: inset 0 0 0 1px var(--c-grid);
}

.page-about .swatch__text {
  display: block;
  padding: 9px 12px 11px;
  font-size: 0.8125rem;
  line-height: 1.6;
  color: var(--c-mist);
}

.page-about .swatch__text b {
  display: block;
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--c-ink);
}

/* ---------- 时间轴 ---------- */
.page-about .stages {
  position: relative;
  margin: clamp(18px, 3vw, 30px) 0 0;
  padding: 0 0 0 34px;
  list-style: none;
}

.page-about .stages::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: var(--about-line);
}

.page-about .stages__item {
  position: relative;
  padding-bottom: clamp(22px, 3.4vw, 34px);
}

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

.page-about .stages__node {
  position: absolute;
  left: -34px;
  top: 4px;
  width: 19px;
  height: 19px;
  border: 1px solid var(--c-teal);
  background: var(--c-snow);
  transition: background 0.25s var(--ease-out), border-color 0.25s var(--ease-out);
}

.page-about .stages__node--circle {
  border-radius: 50%;
}

.page-about .stages__item:hover .stages__node {
  background: var(--c-orange);
  border-color: var(--c-ember);
}

.page-about .stages__title {
  margin: 0 0 6px;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--c-ink);
}

.page-about .stages__text {
  margin: 0;
  max-width: 64ch;
  font-size: 0.9375rem;
  line-height: 1.85;
  color: var(--c-mist);
}

.page-about .about-figure--wide {
  margin-top: clamp(22px, 3.4vw, 34px);
}

/* ---------- 选择理由 ---------- */
.page-about .reasons {
  display: grid;
  margin: clamp(18px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .reason {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: 2px 10px;
  padding-block: clamp(16px, 2.6vw, 22px);
  border-top: 1px solid var(--about-line);
}

.page-about .reason__num {
  grid-row: span 2;
  padding-top: 2px;
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--c-ember);
}

.page-about .reason__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  color: var(--c-teal);
}

.page-about .reason__text {
  margin: 0;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: var(--c-mist);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  position: relative;
  overflow: hidden;
  margin-top: clamp(40px, 6vw, 76px);
  padding-block: clamp(34px, 6vw, 62px);
  background: var(--c-deep);
  color: var(--c-snow);
}

.page-about .about-cta::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(199, 219, 226, 0.16) 1px, transparent 1px),
    linear-gradient(90deg, rgba(199, 219, 226, 0.16) 1px, transparent 1px);
  background-size: 96px 96px;
  pointer-events: none;
}

.page-about .about-cta__inner {
  position: relative;
  z-index: 1;
  display: grid;
  gap: clamp(22px, 4vw, 48px);
}

.page-about .about-cta__kicker {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.16em;
  color: var(--c-orange);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.5rem, 4vw, 2.25rem);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--c-snow);
  max-width: 20ch;
}

.page-about .about-cta__text {
  margin: 14px 0 0;
  max-width: 56ch;
  font-size: 0.9688rem;
  line-height: 1.85;
  color: var(--c-lake);
}

.page-about .about-cta__links {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid rgba(199, 219, 226, 0.3);
}

.page-about .about-cta__links li {
  border-bottom: 1px solid rgba(199, 219, 226, 0.3);
}

.page-about .about-cta__links a {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  padding-block: 14px;
  color: var(--c-snow);
  text-decoration: none;
  font-size: 0.9375rem;
  transition: color 0.2s var(--ease-out), padding-left 0.2s var(--ease-out);
}

.page-about .about-cta__links a::after {
  content: "→";
  font-family: var(--font-mono);
  color: var(--c-orange);
}

.page-about .about-cta__links a:hover,
.page-about .about-cta__links a:focus-visible {
  color: var(--c-orange);
  padding-left: 6px;
}

/* ---------- 媒体查询 ---------- */
@media (min-width: 720px) {
  .page-about .reasons {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: clamp(24px, 4vw, 48px);
  }

  .page-about .reasons .reason:last-child {
    grid-column: 1 / -1;
  }
}

@media (min-width: 880px) {
  .page-about .chapter {
    grid-template-columns: 74px minmax(0, 1fr);
    gap: clamp(22px, 3.6vw, 48px);
  }

  .page-about .chapter__index {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }

  .page-about .chapter__index::after {
    content: "";
    display: block;
    width: 1px;
    flex: 1 1 auto;
    min-height: 48px;
    background: var(--about-line);
  }

  .page-about .split {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
    align-items: start;
  }

  .page-about .split--reverse {
    grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
  }

  .page-about .split__figure {
    margin-top: clamp(6px, 1.6vw, 22px);
  }

  .page-about .claim {
    grid-template-columns: 176px minmax(0, 1fr);
    gap: clamp(20px, 3vw, 42px);
    align-items: start;
  }

  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    align-items: start;
  }

  .page-about .contour {
    top: -30px;
    right: -14px;
  }
}

@media (min-width: 1120px) {
  .page-about .chapter {
    grid-template-columns: 96px minmax(0, 1fr);
  }

  .page-about .stages {
    padding-left: 42px;
  }

  .page-about .stages__node {
    left: -42px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-cta__links a,
  .page-about .stages__node,
  .page-about .chapter-rail a,
  .page-about .breadcrumbs a {
    transition: none;
  }
}