.page-about{
  --about-rail: 92px;
  --about-soft: rgba(242,246,253,.05);
  padding-bottom: clamp(56px, 9vw, 112px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero{
  position: relative;
  margin-top: 20px;
  padding: clamp(26px, 5vw, 56px);
  border-radius: var(--r-xl);
  background: linear-gradient(148deg, var(--navy-800) 0%, var(--navy-850) 48%, var(--navy-900) 100%);
  border: 1px solid var(--line);
  overflow: hidden;
  isolation: isolate;
  display: grid;
  gap: clamp(26px, 4vw, 44px);
}
.page-about .about-hero::before{
  content: "";
  position: absolute;
  top: -32%;
  right: -12%;
  width: min(540px, 82vw);
  aspect-ratio: 1;
  background: radial-gradient(circle at 38% 38%, rgba(255,106,43,.34), transparent 62%);
  transform: rotate(12deg);
  z-index: -1;
}
.page-about .about-hero::after{
  content: "";
  position: absolute;
  left: -14%;
  bottom: -42%;
  width: min(500px, 78vw);
  aspect-ratio: 1;
  background: radial-gradient(circle at 58% 42%, rgba(124,108,255,.30), transparent 64%);
  z-index: -1;
}
.page-about .about-hero__tag{
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 0 0 14px;
}
.page-about .about-hero__title{
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -.02em;
  line-height: 1.08;
  font-size: clamp(30px, 6.2vw, 54px);
  color: var(--mist);
}
.page-about .about-hero__lede{
  margin: 18px 0 0;
  color: var(--gray);
  max-width: 46ch;
}
.page-about .about-hero__actions{
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}
.page-about .about-hero__media .media-frame{
  margin: 0;
}

/* ---------- 章节索引 ---------- */
.page-about .about-index{
  margin: clamp(34px, 5vw, 60px) 0 0;
  padding: 12px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  overflow-x: auto;
  scrollbar-width: none;
}
.page-about .about-index::-webkit-scrollbar{ display: none; }
.page-about .about-index__list{
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
  white-space: nowrap;
}
.page-about .about-index__link{
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  border-radius: var(--r-pill);
  border: 1px solid var(--line);
  color: var(--gray);
  text-decoration: none;
  font-size: var(--fs-14);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.page-about .about-index__link .mono{
  color: var(--orange);
  font-size: var(--fs-12);
}
.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible{
  color: var(--mist);
  border-color: var(--line-strong);
}
.page-about .about-index__link[aria-current="true"]{
  color: var(--navy-900);
  background: var(--orange);
  border-color: var(--orange);
}
.page-about .about-index__link[aria-current="true"] .mono{ color: var(--orange-ink); }

/* ---------- 编号章节 ---------- */
.page-about .about-step{
  display: grid;
  gap: clamp(14px, 2.6vw, 26px);
  padding-top: clamp(46px, 7vw, 84px);
  scroll-margin-top: 96px;
}
.page-about .about-step__num{
  display: inline-block;
  font-size: clamp(30px, 5.4vw, 46px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: .02em;
  color: var(--orange);
}
.page-about .about-step--02 .about-step__num{ color: var(--violet); }
.page-about .about-step--03 .about-step__num{ color: var(--cyan); }
.page-about .about-step--04 .about-step__num{ color: var(--amber); }
.page-about .about-step--05 .about-step__num{ color: var(--mint); }

.page-about .about-step--01 .section__title{ font-size: clamp(26px, 4.4vw, 40px); }
.page-about .about-step--02 .section__title{ font-size: clamp(25px, 4.1vw, 37px); }
.page-about .about-step--03 .section__title{ font-size: clamp(24px, 3.8vw, 34px); }
.page-about .about-step--04 .section__title{ font-size: clamp(23px, 3.6vw, 31px); }
.page-about .about-step--05 .section__title{ font-size: clamp(22px, 3.4vw, 28px); }

.page-about .about-step .section__lede{
  margin: 12px 0 0;
  color: var(--gray);
  max-width: 62ch;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline-wrap{
  display: grid;
  gap: clamp(20px, 3vw, 32px);
  margin-top: clamp(22px, 3.4vw, 34px);
}
.page-about .about-timeline-figure{
  margin: 0;
}
.page-about .timeline{
  position: relative;
  margin: 0;
  padding: 0 0 0 clamp(20px, 3.6vw, 32px);
  list-style: none;
  display: grid;
  gap: clamp(18px, 2.8vw, 26px);
}
.page-about .timeline::before{
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  border-left: 2px dashed var(--dash-amber);
}
.page-about .timeline__item{
  position: relative;
  padding: clamp(16px, 2.4vw, 22px);
  border-radius: var(--r-lg);
  background: var(--navy-800);
  border: 1px solid var(--line);
  transition: border-color var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.page-about .timeline__item::before{
  content: "";
  position: absolute;
  top: clamp(24px, 3vw, 30px);
  left: calc(-1 * clamp(20px, 3.6vw, 32px) - 7px);
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--navy-900);
  border: 2px solid var(--amber);
  transition: background var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .timeline__item:hover{
  border-color: var(--line-strong);
}
.page-about .timeline__item:hover::before{
  background: var(--amber);
}
.page-about .timeline__meta{
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 0 0 10px;
}
.page-about .timeline__note{
  font-size: var(--fs-12);
  color: var(--gray);
  letter-spacing: .04em;
}
.page-about .timeline__title{
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.35;
  letter-spacing: -.01em;
  color: var(--mist);
}
.page-about .timeline__text{
  margin: 10px 0 0;
  color: var(--gray);
  font-size: var(--fs-16);
}

/* ---------- 折叠面板 ---------- */
.page-about .panel{
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px dashed var(--line);
}
.page-about .panel__summary{
  display: flex;
  align-items: center;
  gap: 9px;
  cursor: pointer;
  list-style: none;
  font-size: var(--fs-14);
  color: var(--cyan);
  transition: color var(--dur) var(--ease);
}
.page-about .panel__summary::-webkit-details-marker{ display: none; }
.page-about .panel__summary::before{
  content: "";
  flex: none;
  width: 7px;
  height: 7px;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg) translate(-1px, -1px);
  transition: transform var(--dur) var(--ease);
}
.page-about .panel[open] .panel__summary::before{
  transform: rotate(-135deg) translate(-2px, -2px);
}
.page-about .panel__summary:hover{ color: var(--mist); }
.page-about .panel__body{
  padding-top: 10px;
}
.page-about .panel__body p{
  margin: 0;
  font-size: var(--fs-14);
  color: var(--gray);
  line-height: 1.75;
}

/* ---------- 02 分类 ---------- */
.page-about .about-split{
  display: grid;
  gap: clamp(22px, 3.4vw, 36px);
  margin-top: clamp(22px, 3.4vw, 34px);
}
.page-about .cat-tree{
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(240px, 100%), 1fr));
  gap: 10px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.page-about .cat-tree__item{
  position: relative;
  display: flex;
  gap: 12px;
  padding: 14px 16px 14px 18px;
  border-radius: var(--r-md);
  background: var(--about-soft);
  border: 1px solid transparent;
  border-left: 2px solid rgba(124,108,255,.55);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}
.page-about .cat-tree__item:hover{
  background: rgba(124,108,255,.09);
  border-color: rgba(124,108,255,.4);
  border-left-color: var(--violet);
}
.page-about .cat-tree__idx{
  flex: none;
  font-size: var(--fs-12);
  color: var(--violet);
  padding-top: 3px;
  letter-spacing: .06em;
}
.page-about .cat-tree__name{
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-16);
  color: var(--mist);
  letter-spacing: -.01em;
}
.page-about .cat-tree__desc{
  margin: 6px 0 0;
  font-size: var(--fs-14);
  line-height: 1.7;
  color: var(--gray);
}
.page-about .about-split__media{
  margin: 0;
}

.page-about .about-note{
  margin-top: clamp(20px, 3vw, 30px);
  padding: clamp(16px, 2.4vw, 22px);
  border-radius: var(--r-lg);
  background: linear-gradient(120deg, rgba(53,227,178,.10), rgba(59,201,255,.06));
  border: 1px solid rgba(53,227,178,.24);
}
.page-about .about-note__text{
  margin: 0;
  color: var(--mist);
  font-size: var(--fs-16);
}
.page-about .about-note__copy{
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin: 14px 0 0;
}
.page-about .about-note__label{
  font-size: var(--fs-12);
  letter-spacing: .08em;
  color: var(--gray);
}
.page-about .copy-chip{
  padding: 6px 14px;
  border-radius: var(--r-pill);
  border: 1px solid rgba(53,227,178,.45);
  background: transparent;
  color: var(--mint);
  font-size: var(--fs-14);
  letter-spacing: .04em;
  cursor: pointer;
  transition: background var(--dur) var(--ease), transform var(--dur) var(--ease);
}
.page-about .copy-chip:hover{ background: rgba(53,227,178,.14); }
.page-about .copy-chip:active{ transform: translateY(2px); }
.page-about .copy-chip[data-copied="true"]{
  background: var(--mint);
  color: var(--navy-900);
  border-color: var(--mint);
}

.page-about .about-statline{
  margin: clamp(18px, 2.6vw, 26px) 0 0;
  font-size: var(--fs-16);
  color: var(--gray);
  line-height: 1.75;
}
.page-about .about-statline__num{
  color: var(--cyan);
  font-weight: 700;
  margin-right: 4px;
}

/* ---------- 03 节奏 ---------- */
.page-about .cadence{
  display: grid;
  gap: 14px;
  margin-top: clamp(22px, 3.4vw, 34px);
}
.page-about .cadence__item{
  position: relative;
  padding: clamp(18px, 2.6vw, 24px);
  border-radius: var(--r-lg);
  background: var(--navy-800);
  border: 1px solid var(--line);
  overflow: hidden;
}
.page-about .cadence__item::after{
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 3px;
  background: var(--cyan);
  opacity: .8;
}
.page-about .cadence__item--mint::after{ background: var(--mint); }
.page-about .cadence__head{ margin: 0; }
.page-about .cadence__value{
  display: inline-block;
  font-size: var(--fs-20);
  font-weight: 700;
  color: var(--cyan);
  letter-spacing: .02em;
}
.page-about .cadence__item--mint .cadence__value{ color: var(--mint); }
.page-about .cadence__title{
  margin: 8px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-16);
  color: var(--mist);
  letter-spacing: -.01em;
}
.page-about .cadence__text{
  margin: 8px 0 0;
  font-size: var(--fs-14);
  color: var(--gray);
  line-height: 1.75;
}

/* ---------- 04 屏幕区间 ---------- */
.page-about .screen-range{
  display: grid;
  gap: 0;
  margin: clamp(22px, 3.4vw, 34px) 0 0;
  padding: 0;
  list-style: none;
}
.page-about .screen-range__item{
  padding: 16px 0;
  border-bottom: 1px dashed var(--line);
  display: grid;
  gap: 6px;
}
.page-about .screen-range__bar{
  display: block;
  width: var(--w, 50%);
  height: 4px;
  border-radius: var(--r-pill);
  background: linear-gradient(90deg, var(--amber), rgba(255,194,75,.25));
  margin-bottom: 6px;
}
.page-about .screen-range__w{
  font-size: var(--fs-14);
  color: var(--amber);
  letter-spacing: .04em;
}
.page-about .screen-range__desc{
  margin: 0;
  font-size: var(--fs-14);
  color: var(--gray);
  line-height: 1.7;
}

/* ---------- 05 场景 ---------- */
.page-about .about-scenes{
  display: grid;
  gap: 14px;
  margin-top: clamp(22px, 3.4vw, 34px);
}
.page-about .about-scene{
  padding: clamp(18px, 2.6vw, 24px);
  border-radius: var(--r-lg);
  background: var(--navy-800);
  border: 1px solid var(--line);
  border-top: 3px solid var(--orange);
  display: grid;
  gap: 8px;
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .about-scene--violet{ border-top-color: var(--violet); }
.page-about .about-scene--mint{ border-top-color: var(--mint); }
.page-about .about-scene:hover{
  transform: translateY(-2px);
  border-color: var(--line-strong);
}
.page-about .about-scene__num{
  font-size: var(--fs-12);
  letter-spacing: .08em;
  color: var(--gray);
}
.page-about .about-scene__title{
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: var(--fs-20);
  line-height: 1.35;
  color: var(--mist);
  letter-spacing: -.01em;
}
.page-about .about-scene__text{
  margin: 0;
  font-size: var(--fs-14);
  color: var(--gray);
  line-height: 1.75;
}
.page-about .about-scene__link{
  margin-top: 4px;
  font-size: var(--fs-14);
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(59,201,255,.35);
  padding-bottom: 2px;
  justify-self: start;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}
.page-about .about-scene__link:hover{
  color: var(--mist);
  border-color: var(--mist);
}

.page-about .about-tail{
  margin: clamp(22px, 3.4vw, 32px) 0 0;
  font-size: var(--fs-16);
  color: var(--gray);
  line-height: 1.8;
}
.page-about .about-tail a{
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(59,201,255,.32);
}
.page-about .about-tail a:hover{
  color: var(--mist);
  border-color: var(--mist);
}

/* ---------- 响应式 ---------- */
@media (min-width: 760px){
  .page-about .cadence{
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-scenes{
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-scene{ align-content: start; }
}

@media (min-width: 900px){
  .page-about .about-hero{
    grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr);
    align-items: center;
  }
  .page-about .about-timeline-wrap{
    grid-template-columns: minmax(0, 290px) minmax(0, 1fr);
    align-items: start;
  }
  .page-about .about-timeline-figure{
    position: sticky;
    top: 96px;
  }
}

@media (min-width: 1024px){
  .page-about .about-step{
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(20px, 3vw, 40px);
  }
  .page-about .about-step__num{
    position: sticky;
    top: 96px;
  }
  .page-about .about-step__body{
    max-width: 860px;
  }
  .page-about .about-split{
    grid-template-columns: minmax(0, 1.32fr) minmax(0, 1fr);
    align-items: start;
  }
}

@media (min-width: 1180px){
  .page-about .about-hero{
    padding: 56px 60px;
  }
}

@media (prefers-reduced-motion: reduce){
  .page-about .timeline__item,
  .page-about .about-scene,
  .page-about .about-index__link,
  .page-about .copy-chip,
  .page-about .panel__summary::before{
    transition: none;
  }
  .page-about .about-scene:hover{
    transform: none;
  }
}
</style>

.page-about {
  --w: 1rem;
}