.page-about {
  --about-edge: rgba(60, 70, 86, .14);
  --about-edge-dark: rgba(170, 180, 192, .2);
  background: var(--frost);
  color: var(--graphite);
  font-family: var(--font-sans);
}

/* ---------- 面包屑 ---------- */
.page-about .crumb {
  padding-top: clamp(1rem, 3vw, 1.75rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  margin-top: clamp(.75rem, 2vw, 1.5rem);
  padding-block: clamp(2.5rem, 7vw, 5.5rem);
  border-radius: var(--r-lg);
  background:
    radial-gradient(900px 460px at 88% 0%, rgba(232, 163, 61, .18), transparent 62%),
    radial-gradient(700px 520px at 4% 100%, rgba(95, 122, 97, .24), transparent 60%),
    linear-gradient(158deg, var(--ink) 0%, var(--indigo) 58%, var(--indigo-deep) 100%);
  color: var(--frost);
}

.page-about .about-hero__mark {
  position: absolute;
  right: -3vw;
  bottom: -5vw;
  font-family: var(--font-mono);
  font-size: clamp(7rem, 24vw, 20rem);
  line-height: .8;
  letter-spacing: -.05em;
  color: rgba(170, 180, 192, .07);
  pointer-events: none;
  user-select: none;
}

.page-about .about-hero__inner {
  position: relative;
  display: grid;
  gap: clamp(2rem, 5vw, 3.5rem);
  align-items: center;
}

.page-about .about-hero h1 {
  margin: .75rem 0 1.25rem;
  font-size: clamp(2rem, 6vw, 3.5rem);
  line-height: 1.12;
  letter-spacing: -.02em;
  font-weight: 800;
  color: var(--frost);
}

.page-about .about-hero .lede {
  max-width: 46ch;
  margin: 0;
  color: rgba(244, 246, 248, .8);
  line-height: 1.8;
}

.page-about .about-hero .eyebrow {
  color: var(--amber);
}

.page-about .hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 1.25rem 2.5rem;
  margin: 2.25rem 0 0;
  padding: 1.5rem 0 0;
  list-style: none;
  border-top: 1px solid var(--about-edge-dark);
}

.page-about .hero-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.35rem, 3vw, 1.7rem);
  line-height: 1.1;
  color: var(--amber);
}

.page-about .hero-fact__label {
  display: block;
  margin-top: .35rem;
  font-size: .8125rem;
  line-height: 1.5;
  color: rgba(244, 246, 248, .62);
}

.page-about .about-hero__shot {
  border-radius: var(--r-md);
  overflow: hidden;
  border: 1px solid var(--about-edge-dark);
  box-shadow: 0 30px 60px -34px rgba(0, 0, 0, .7);
}

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

.page-about .about-hero__shot .media__cap {
  color: rgba(244, 246, 248, .6);
  font-size: .75rem;
  padding: .75rem 1rem;
  background: rgba(14, 23, 38, .55);
}

/* ---------- 区块与面板 ---------- */
.page-about .about-block {
  padding-block: clamp(2.25rem, 6vw, 4.5rem);
}

.page-about .about-panel {
  border-radius: var(--r-lg);
  padding: clamp(1.5rem, 4.5vw, 3.5rem);
}

.page-about .about-panel--white {
  background: #fff;
  border: 1px solid var(--about-edge);
  box-shadow: 0 30px 70px -56px rgba(14, 23, 38, .6);
}

.page-about .about-panel--indigo {
  background: linear-gradient(155deg, var(--indigo) 0%, var(--indigo-deep) 100%);
  color: var(--frost);
}

.page-about .about-panel--ink {
  background: linear-gradient(160deg, var(--ink) 0%, #17223c 100%);
  color: var(--frost);
}

.page-about .about-panel h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.5rem, 3.4vw, 2.125rem);
  line-height: 1.28;
  letter-spacing: -.01em;
  font-weight: 800;
}

.page-about .about-panel--indigo h2,
.page-about .about-panel--ink h2 {
  color: var(--frost);
}

.page-about .about-panel--indigo .lede,
.page-about .about-panel--ink .lede {
  max-width: 62ch;
  margin: 0;
  color: rgba(244, 246, 248, .78);
  line-height: 1.8;
}

.page-about .about-panel--indigo .idx,
.page-about .about-panel--ink .idx {
  color: rgba(244, 246, 248, .5);
}

/* ---------- 左轴 + 右叙 ---------- */
.page-about .about-grid {
  display: grid;
  gap: clamp(1.5rem, 4vw, 3rem);
}

.page-about .about-grid__side {
  position: relative;
  padding-left: 1.25rem;
  border-left: 2px solid var(--about-edge);
}

.page-about .about-grid__span {
  display: block;
  margin-top: .5rem;
  font-size: .75rem;
  letter-spacing: .06em;
  color: var(--amber-deep);
}

.page-about .about-grid__main p {
  margin: 0 0 1.1rem;
  line-height: 1.8;
}

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

.page-about .about-method__figure {
  margin: 0;
  border-radius: var(--r-md);
  overflow: hidden;
  background: linear-gradient(150deg, var(--indigo) 0%, var(--indigo-deep) 100%);
}

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

.page-about .about-method__figure .media__cap {
  font-size: .75rem;
  padding: .75rem 1rem;
  color: rgba(244, 246, 248, .62);
  background: rgba(14, 23, 38, .45);
}

/* ---------- 区域覆盖 ---------- */
.page-about .about-panel__head {
  margin-bottom: clamp(1.5rem, 4vw, 2.5rem);
}

.page-about .region-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .625rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .region-cell {
  padding: .75rem .875rem;
  border-radius: var(--r-sm);
  border: 1px solid var(--about-edge-dark);
  background: rgba(244, 246, 248, .04);
  font-family: var(--font-mono);
  font-size: .8125rem;
  letter-spacing: .02em;
  color: rgba(244, 246, 248, .72);
}

.page-about .region-cell--key {
  border-color: rgba(232, 163, 61, .5);
  background: rgba(232, 163, 61, .1);
  color: var(--amber);
}

.page-about .region-facts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.5rem;
  margin-top: clamp(1.75rem, 4vw, 2.5rem);
  padding-top: clamp(1.5rem, 4vw, 2rem);
  border-top: 1px solid var(--about-edge-dark);
}

.page-about .region-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1.25rem, 2.6vw, 1.55rem);
  line-height: 1.15;
  color: var(--amber);
}

.page-about .region-fact__label {
  display: block;
  margin-top: .45rem;
  font-size: .875rem;
  line-height: 1.6;
  color: rgba(244, 246, 248, .66);
}

/* ---------- 案例清单折叠 ---------- */
.page-about .case-list {
  margin-top: clamp(2rem, 5vw, 3rem);
}

.page-about .case-item {
  border-top: 1px solid var(--about-edge);
}

.page-about .case-item:last-child {
  border-bottom: 1px solid var(--about-edge);
}

.page-about .case-item__summary {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 1rem;
  padding: 1.25rem .25rem;
  cursor: pointer;
  list-style: none;
}

.page-about .case-item__summary::-webkit-details-marker {
  display: none;
}

.page-about .case-item__no {
  font-size: .8125rem;
  letter-spacing: .08em;
  color: var(--silver);
}

.page-about .case-item__title {
  font-size: clamp(1rem, 2vw, 1.125rem);
  font-weight: 700;
  color: var(--indigo);
}

.page-about .case-item__cue {
  position: relative;
  width: 18px;
  height: 18px;
  flex: none;
}

.page-about .case-item__cue::before,
.page-about .case-item__cue::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  background: var(--amber-deep);
  transform: translateY(-50%);
  transition: transform .3s var(--ease), opacity .3s var(--ease);
}

.page-about .case-item__cue::after {
  transform: translateY(-50%) rotate(90deg);
}

.page-about .case-item[open] .case-item__cue::after {
  transform: translateY(-50%) rotate(0deg);
  opacity: 0;
}

.page-about .case-item[open] .case-item__title {
  color: var(--amber-deep);
}

.page-about .case-item__body {
  padding: 0 .25rem 1.5rem 2.5rem;
  animation: about-fade .32s var(--ease);
}

.page-about .case-item__body p {
  margin: 0 0 1rem;
  line-height: 1.8;
  color: var(--graphite);
}

.page-about .case-points {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: .6rem;
}

.page-about .case-points li {
  position: relative;
  padding-left: 1.25rem;
  font-size: .9375rem;
  line-height: 1.7;
  color: var(--graphite);
}

.page-about .case-points li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .65em;
  width: 6px;
  height: 6px;
  border-radius: var(--r-pill);
  background: var(--green);
}

@keyframes about-fade {
  from {
    opacity: 0;
    transform: translateY(-5px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

/* ---------- 版本里程碑 ---------- */
.page-about .tl-media {
  margin: 0 0 clamp(1.75rem, 4vw, 2.5rem);
  border-radius: var(--r-md);
  overflow: hidden;
  border: 1px solid var(--about-edge-dark);
}

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

.page-about .tl-media .media__cap {
  font-size: .75rem;
  padding: .75rem 1rem;
  color: rgba(244, 246, 248, .6);
  background: rgba(14, 23, 38, .5);
}

.page-about .timeline {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(228px, 76%);
  gap: 1rem;
  margin: 0;
  padding: .25rem .25rem 1rem;
  list-style: none;
  overflow-x: auto;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .tl-node {
  scroll-snap-align: start;
  padding: 1.25rem 1.25rem 1.5rem;
  border-radius: var(--r-md);
  border: 1px solid var(--about-edge-dark);
  background: rgba(244, 246, 248, .05);
  transition: border-color .3s var(--ease), background .3s var(--ease), transform .3s var(--ease);
}

.page-about .tl-node:hover,
.page-about .tl-node:focus-within {
  border-color: rgba(232, 163, 61, .75);
  background: rgba(232, 163, 61, .1);
  transform: translateY(-3px);
}

.page-about .tl-node__ver {
  display: block;
  font-size: 1.5rem;
  line-height: 1.1;
  letter-spacing: -.01em;
  color: rgba(244, 246, 248, .82);
  transition: color .3s var(--ease);
}

.page-about .tl-node:hover .tl-node__ver,
.page-about .tl-node:focus-within .tl-node__ver {
  color: var(--amber);
}

.page-about .tl-node__year {
  display: block;
  margin-top: .35rem;
  font-size: .75rem;
  letter-spacing: .08em;
  color: var(--amber);
}

.page-about .tl-node__desc {
  margin: .85rem 0 0;
  font-size: .875rem;
  line-height: 1.7;
  color: rgba(244, 246, 248, .7);
  transition: color .3s var(--ease);
}

.page-about .tl-node:hover .tl-node__desc,
.page-about .tl-node:focus-within .tl-node__desc {
  color: rgba(244, 246, 248, .95);
}

/* ---------- 下一步 ---------- */
.page-about .about-next {
  padding-block: clamp(1.5rem, 4vw, 2.5rem) clamp(3rem, 7vw, 5rem);
}

.page-about .about-next__label {
  margin: 0 0 1rem;
  font-size: .75rem;
  letter-spacing: .14em;
  color: var(--silver);
}

.page-about .about-next__list {
  display: grid;
  gap: .75rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-next__link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.05rem 1.35rem;
  border-radius: var(--r-pill);
  border: 1px solid var(--about-edge);
  background: #fff;
  color: var(--indigo);
  font-size: .9375rem;
  font-weight: 600;
  text-decoration: none;
  transition: border-color .3s var(--ease), transform .3s var(--ease), box-shadow .3s var(--ease);
}

.page-about .about-next__link::after {
  content: "→";
  font-family: var(--font-mono);
  color: var(--amber-deep);
  transition: transform .3s var(--ease);
}

.page-about .about-next__link:hover,
.page-about .about-next__link:focus-visible {
  border-color: var(--amber);
  transform: translateY(-2px);
  box-shadow: 0 18px 36px -28px rgba(14, 23, 38, .7);
}

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

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .region-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-next__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 880px) {
  .page-about .about-grid {
    grid-template-columns: minmax(0, 190px) minmax(0, 1fr);
    gap: clamp(2rem, 5vw, 4.5rem);
  }

  .page-about .about-grid__side {
    position: sticky;
    top: 6.5rem;
    align-self: start;
  }

  .page-about .about-grid__side::before {
    content: "";
    position: absolute;
    left: -2px;
    top: 0;
    width: 2px;
    height: 2.75rem;
    background: var(--amber);
  }

  .page-about .about-grid--reverse {
    grid-template-columns: minmax(0, 1fr) minmax(0, 190px);
  }

  .page-about .about-grid--reverse .about-grid__side {
    order: 2;
  }

  .page-about .about-grid--reverse .about-grid__main {
    order: 1;
  }

  .page-about .about-grid--reverse .about-method__figure {
    order: 3;
    grid-column: 1 / -1;
  }
}

@media (min-width: 940px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, .88fr);
    align-items: end;
  }

  .page-about .about-hero__shot {
    margin-bottom: clamp(0rem, 2vw, 1.5rem);
  }
}

@media (min-width: 980px) {
  .page-about .timeline {
    grid-auto-flow: row;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    overflow-x: visible;
    scroll-snap-type: none;
    padding-inline: 0;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .case-item__body {
    animation: none;
  }

  .page-about .tl-node,
  .page-about .about-next__link,
  .page-about .case-item__cue::before,
  .page-about .case-item__cue::after {
    transition: none;
  }

  .page-about .tl-node:hover,
  .page-about .about-next__link:hover {
    transform: none;
  }
}