.page-about {
  --ab-light-bg: var(--paper);
  --ab-light-ink: var(--ink);
  --ab-light-muted: #6B6B75;
  --ab-chapter-gap: clamp(56px, 8vw, 120px);
  --ab-figure-radius: var(--r-xs);
}

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

/* ============ 首屏 ============ */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(36px, 7vw, 72px) clamp(48px, 8vw, 96px);
  background: var(--black);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: -30% -10% auto -20%;
  height: 130%;
  background:
    radial-gradient(48% 52% at 26% 32%, var(--glow), transparent 72%),
    radial-gradient(38% 44% at 88% 78%, rgba(23, 224, 212, 0.12), transparent 70%);
  pointer-events: none;
}

.page-about .about-hero__pulse {
  position: absolute;
  top: -80px;
  right: -60px;
  width: 340px;
  height: 340px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(232, 18, 60, 0.42), transparent 68%);
  animation: about-pulse 1200ms var(--ease) 1 both;
  pointer-events: none;
}

@keyframes about-pulse {
  0% { opacity: 0; transform: scale(0.86); }
  55% { opacity: 0.85; transform: scale(1.05); }
  100% { opacity: 0.32; transform: scale(1.28); }
}

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

.page-about .about-hero .breadcrumb {
  margin-bottom: clamp(20px, 4vw, 40px);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(28px, 5vw, 56px);
  align-items: end;
}

.page-about .about-hero__copy h1 {
  font-family: var(--font-display);
  font-size: clamp(30px, 6.4vw, 60px);
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--text);
  margin: 14px 0 0;
  max-width: 16em;
}

.page-about .about-hero__copy .lead {
  margin-top: 22px;
  max-width: 640px;
  color: var(--muted);
  font-size: var(--fs-16);
  line-height: 1.85;
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.page-about .about-hero__aside {
  border-top: 1px solid var(--grid);
  padding-top: 20px;
}

.page-about .about-hero__aside .snapshot {
  display: inline-block;
  margin-bottom: 20px;
}

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

.page-about .about-facts li {
  background: var(--black);
  padding: 16px 14px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-about .about-facts__n {
  font-size: var(--fs-28);
  color: var(--red);
  letter-spacing: 0.04em;
  line-height: 1;
}

.page-about .about-facts__t {
  font-size: var(--fs-12);
  color: var(--muted);
  letter-spacing: 0.06em;
}

/* ============ 章节通用 ============ */
.page-about .about-chapter {
  position: relative;
  padding-block: var(--ab-chapter-gap);
  scroll-margin-top: 104px;
}

.page-about .about-chapter--dark {
  background: var(--black);
  color: var(--text);
}

.page-about .about-chapter--light {
  background: var(--ab-light-bg);
  color: var(--ab-light-ink);
}

.page-about .about-chapter--light::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: clamp(48px, 8vw, 110px);
  background: linear-gradient(180deg, rgba(10, 10, 15, 0.9), rgba(10, 10, 15, 0));
  pointer-events: none;
}

.page-about .about-chapter--tex {
  background-image:
    linear-gradient(var(--grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--grid) 1px, transparent 1px);
  background-size: 72px 72px;
  background-position: center top;
}

.page-about .about-chapter__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

.page-about .about-rail {
  display: flex;
  align-items: center;
  gap: 14px;
}

.page-about .about-num {
  font-size: clamp(20px, 4vw, 28px);
  letter-spacing: 0.16em;
  color: var(--muted);
  text-decoration: none;
  display: inline-block;
  transition: color var(--dur) var(--ease);
}

.page-about .about-chapter--light .about-num {
  color: #A9A5A0;
}

.page-about .about-chapter.is-active .about-num,
.page-about .about-num:hover {
  color: var(--red);
}

.page-about .about-num:focus-visible {
  outline: 1px solid var(--cyan);
  outline-offset: 5px;
}

.page-about .about-spine {
  display: block;
  width: 44px;
  height: 1px;
  background: currentColor;
  opacity: 0.24;
  transition: background var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.page-about .about-chapter.is-active .about-spine {
  background: var(--red);
  opacity: 1;
}

.page-about .about-chapter__title {
  font-family: var(--font-display);
  font-size: clamp(24px, 4.6vw, 40px);
  line-height: 1.24;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
  color: inherit;
  max-width: 20em;
}

.page-about .about-chapter__text {
  margin: 0 0 26px;
  max-width: 640px;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-chapter--light .about-chapter__text {
  color: var(--ab-light-muted);
}

.page-about .about-prose {
  max-width: 640px;
}

.page-about .about-prose p {
  margin: 0 0 18px;
  font-size: var(--fs-16);
  line-height: 1.85;
  color: inherit;
}

.page-about .about-chapter--light .about-prose p {
  color: #3A3A44;
}

.page-about .about-prose--note {
  margin: 18px 0 0;
  font-size: var(--fs-14);
  color: var(--muted);
  line-height: 1.8;
}

.page-about .about-chapter--light .about-prose--note {
  color: var(--ab-light-muted);
}

/* ============ 图片 ============ */
.page-about .about-figure {
  margin: 0;
  border: 1px solid var(--grid);
  border-radius: var(--ab-figure-radius);
  overflow: hidden;
  background: var(--panel);
}

.page-about .about-chapter--light .about-figure {
  border-color: #DEDAD4;
  background: #EFEDE9;
}

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

.page-about .about-figure .figure__caption {
  font-size: var(--fs-12);
  line-height: 1.7;
  padding: 12px 14px;
  color: var(--muted);
  border-top: 1px solid var(--grid);
  margin: 0;
}

.page-about .about-chapter--light .about-figure .figure__caption {
  color: var(--ab-light-muted);
  border-top-color: #DEDAD4;
}

.page-about .about-figure--wide {
  margin-bottom: 26px;
}

/* ============ 第一章 ============ */
.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
}

/* ============ 时间线 ============ */
.page-about .about-scale {
  display: block;
  width: 100%;
  height: auto;
  margin: 0 0 22px;
}

.page-about .about-timeline {
  list-style: none;
  margin: 0;
  padding: 0 0 0 24px;
  border-left: 1px solid var(--grid);
}

.page-about .about-tl {
  position: relative;
  padding: 0 0 30px;
  outline: none;
}

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

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: -28px;
  top: 7px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--red);
  border: 1px solid var(--cyan);
  transition: transform var(--dur) var(--ease);
}

.page-about .about-tl:hover::before,
.page-about .about-tl:focus-within::before {
  transform: scale(1.6);
}

.page-about .about-tl:focus-visible {
  outline: 1px solid var(--cyan);
  outline-offset: 6px;
}

.page-about .about-tl__yr {
  display: block;
  font-size: var(--fs-12);
  letter-spacing: 0.1em;
  color: var(--gold);
  margin-bottom: 6px;
}

.page-about .about-tl__title {
  font-family: var(--font-display);
  font-size: var(--fs-20);
  line-height: 1.4;
  letter-spacing: -0.01em;
  margin: 0 0 6px;
  color: var(--text);
}

.page-about .about-tl__brief {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--muted);
  max-width: 620px;
  transition: max-height 280ms var(--ease), opacity 280ms var(--ease);
}

/* ============ 团队 ============ */
.page-about .about-team {
  position: relative;
  overflow: hidden;
  border: 1px solid #DEDAD4;
  border-radius: var(--ab-figure-radius);
  margin-bottom: 24px;
}

.page-about .about-team__bg {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0.16;
  pointer-events: none;
}

.page-about .about-team__inner {
  position: relative;
  z-index: 1;
  padding: clamp(20px, 4vw, 36px);
}

.page-about .about-roles {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}

.page-about .about-role__n {
  display: block;
  font-size: var(--fs-28);
  color: var(--red);
  line-height: 1;
  letter-spacing: 0.02em;
  margin-bottom: 10px;
}

.page-about .about-role__t {
  font-family: var(--font-display);
  font-size: var(--fs-20);
  margin: 0 0 8px;
  color: var(--ab-light-ink);
  letter-spacing: -0.01em;
}

.page-about .about-role p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--ab-light-muted);
}

.page-about .about-flow {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 6px;
}

.page-about .about-flow__chip {
  font-family: var(--font-mono);
  font-size: var(--fs-12);
  letter-spacing: 0.06em;
  padding: 7px 12px;
  border: 1px solid #D5D1CB;
  border-radius: var(--r-xs);
  color: var(--ab-light-ink);
  background: #FFFFFF;
  position: relative;
}

.page-about .about-flow__chip::after {
  content: "→";
  position: absolute;
  right: -11px;
  top: 50%;
  transform: translateY(-50%);
  color: #BDB8B1;
  font-size: 12px;
}

.page-about .about-flow__chip--last::after {
  content: none;
}

/* ============ 体验准则 ============ */
.page-about .about-rules {
  list-style: none;
  margin: 6px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: 1px solid var(--grid);
}

.page-about .about-rule {
  padding: 24px 0;
  border-bottom: 1px solid var(--grid);
  display: grid;
  grid-template-columns: 42px minmax(0, 1fr);
  gap: 4px 16px;
}

.page-about .about-rule__idx {
  font-size: var(--fs-20);
  color: var(--red);
  letter-spacing: 0.08em;
  grid-row: 1 / span 2;
  line-height: 1.5;
}

.page-about .about-rule__t {
  font-family: var(--font-display);
  font-size: var(--fs-20);
  margin: 0 0 10px;
  color: var(--text);
  letter-spacing: -0.01em;
}

.page-about .about-rule p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--muted);
  max-width: 620px;
  grid-column: 2;
}

/* ============ 继续了解 ============ */
.page-about .about-next {
  list-style: none;
  margin: 8px 0 0;
  padding: 0;
  border-top: 1px solid var(--grid);
}

.page-about .about-next li {
  border-bottom: 1px solid var(--grid);
}

.page-about .about-next__link {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr) 28px;
  grid-template-areas:
    "k t go"
    "k d go";
  gap: 4px 14px;
  align-items: center;
  padding: 20px 4px;
  text-decoration: none;
  position: relative;
  transition: background var(--dur) var(--ease);
}

.page-about .about-next__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 0;
  height: 1px;
  background: var(--red);
  transition: width var(--dur) var(--ease);
}

.page-about .about-next__link:hover::before,
.page-about .about-next__link:focus-visible::before {
  width: 24px;
}

.page-about .about-next__link:focus-visible {
  outline: 1px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .about-next__k {
  grid-area: k;
  font-size: var(--fs-14);
  color: var(--muted);
  letter-spacing: 0.1em;
  align-self: start;
  padding-top: 3px;
}

.page-about .about-next__t {
  grid-area: t;
  font-family: var(--font-display);
  font-size: var(--fs-20);
  color: var(--text);
  letter-spacing: -0.01em;
}

.page-about .about-next__d {
  grid-area: d;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--muted);
}

.page-about .about-next__go {
  grid-area: go;
  color: var(--cyan);
  font-size: var(--fs-20);
  text-align: right;
  transition: transform var(--dur) var(--ease);
}

.page-about .about-next__link:hover .about-next__go,
.page-about .about-next__link:focus-visible .about-next__go {
  transform: translateX(4px);
}

/* ============ 断点：平板及以上 ============ */
@media (min-width: 760px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
  }

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

  .page-about .about-roles {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 28px;
  }

  .page-about .about-rule {
    grid-template-columns: 56px minmax(0, 1fr);
  }

  .page-about .about-next__link {
    grid-template-columns: 56px 170px minmax(0, 1fr) 40px;
    grid-template-areas: "k t d go";
    gap: 20px;
    padding: 24px 0;
  }
}

/* ============ 断点：桌面 ============ */
@media (min-width: 960px) {
  .page-about .about-chapter__grid {
    grid-template-columns: 92px minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 22px;
    position: sticky;
    top: 108px;
    align-self: start;
  }

  .page-about .about-spine {
    width: 1px;
    height: 128px;
    background: currentColor;
  }

  .page-about .about-chapter.is-active .about-spine {
    background: linear-gradient(180deg, var(--red), rgba(232, 18, 60, 0.05));
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.02fr);
    gap: 44px;
    align-items: start;
  }

  .page-about .about-tl__brief {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
  }

  .page-about .about-tl:hover .about-tl__brief,
  .page-about .about-tl:focus-within .about-tl__brief {
    max-height: 160px;
    opacity: 1;
  }

  .page-about .about-tl {
    padding-bottom: 26px;
  }
}

/* ============ 降低动态效果 ============ */
@media (prefers-reduced-motion: reduce) {
  .page-about .about-hero__pulse {
    animation: none;
    opacity: 0.3;
  }

  .page-about .about-tl,
  .page-about .about-tl::before,
  .page-about .about-next__go,
  .page-about .about-next__link::before,
  .page-about .about-num,
  .page-about .about-spine {
    transition: none;
  }
}