.page-about {
  --about-hair: rgba(20, 16, 15, .12);
  --about-hair-light: rgba(247, 242, 234, .18);
  --about-rail-w: 190px;
  background: var(--paper);
  color: var(--ink);
  overflow-x: hidden;
}

.page-about .yy-breadcrumb {
  padding-top: clamp(14px, 2.6vw, 26px);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(18px, 3.4vw, 38px) 0 clamp(30px, 5vw, 60px);
  border-bottom: var(--hair);
}

.page-about .about-hero__inner {
  display: grid;
  gap: clamp(22px, 4vw, 44px);
  align-items: start;
}

.page-about .about-hero__frame {
  position: relative;
  aspect-ratio: 14 / 9;
  overflow: hidden;
  border: var(--hair);
  background: linear-gradient(135deg, var(--violet) 0%, var(--danxia) 54%, var(--sand) 100%);
  box-shadow: var(--shadow-2);
}

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

.page-about .about-hero__title {
  margin: clamp(10px, 1.6vw, 18px) 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(28px, 6.4vw, 56px);
  line-height: 1.16;
  letter-spacing: .06em;
}

.page-about .about-hero__lede {
  margin: clamp(14px, 2vw, 22px) 0 0;
  max-width: 34em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  margin: clamp(22px, 3.2vw, 36px) 0 0;
  border-top: var(--hair);
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column-reverse;
  padding: clamp(12px, 2vw, 18px) clamp(8px, 1.6vw, 18px) 4px 0;
  border-right: var(--hair);
}

.page-about .about-stats__item:last-child {
  border-right: 0;
  padding-right: 0;
}

.page-about .about-stats__num {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(24px, 4.4vw, 40px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--ink);
}

.page-about .about-stats__num small {
  font-size: .42em;
  font-weight: 400;
  margin-left: 3px;
  letter-spacing: .04em;
  color: var(--muted);
}

.page-about .about-stats__label {
  margin: 0 0 9px;
  font-size: 12px;
  letter-spacing: .18em;
  color: var(--muted);
}

/* ---------- 分栏主体 ---------- */
.page-about .about-body {
  display: grid;
  gap: clamp(18px, 3vw, 34px);
  padding: clamp(24px, 4vw, 46px) 0 0;
}

.page-about .about-col {
  display: grid;
  gap: 0;
  min-width: 0;
}

/* 章节导轨 */
.page-about .about-rail {
  border-bottom: var(--hair);
}

.page-about .about-rail__label {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: .28em;
  color: var(--muted);
}

.page-about .about-rail__list {
  display: flex;
  gap: 20px;
  margin: 0;
  padding: 0 0 10px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .about-rail__item {
  flex: 0 0 auto;
}

.page-about .about-rail__link {
  display: block;
  padding-top: 9px;
  border-top: 2px solid transparent;
  text-decoration: none;
  color: var(--muted);
  white-space: nowrap;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--ink);
}

.page-about .about-rail__link[aria-current="true"] {
  color: var(--danxia);
  border-top-color: var(--danxia);
}

.page-about .about-rail__code {
  display: block;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .08em;
}

.page-about .about-rail__text {
  display: block;
  margin-top: 3px;
  font-size: 13px;
  letter-spacing: .06em;
}

/* ---------- 章节通用 ---------- */
.page-about .about-section {
  padding: clamp(28px, 4.4vw, 54px) 0;
  border-bottom: var(--hair);
}

.page-about .about-section:last-of-type {
  border-bottom: 0;
}

.page-about .about-section__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(20px, 3.4vw, 33px);
  line-height: 1.34;
  letter-spacing: .09em;
  max-width: 22em;
}

.page-about .about-section__text {
  margin: 16px 0 0;
  max-width: 34em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-inline-link {
  color: var(--danxia);
  text-decoration: none;
  border-bottom: 1px solid rgba(179, 58, 36, .38);
  padding-bottom: 1px;
}

.page-about .about-inline-link:hover,
.page-about .about-inline-link:focus-visible {
  border-bottom-color: var(--danxia);
}

.page-about .about-inline-link--light {
  color: var(--sand-light);
  border-bottom-color: rgba(241, 217, 166, .45);
}

.page-about .about-inline-link--light:hover,
.page-about .about-inline-link--light:focus-visible {
  border-bottom-color: var(--sand-light);
}

/* ---------- 阶段时间轴 ---------- */
.page-about .about-stages {
  margin: clamp(22px, 3.2vw, 36px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-stages__item {
  position: relative;
  padding: 0 0 clamp(22px, 3vw, 34px) clamp(20px, 3vw, 30px);
  border-left: 1px solid var(--about-hair);
}

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

.page-about .about-stages__item::before {
  content: "";
  position: absolute;
  left: -4px;
  top: 8px;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--sand);
  box-shadow: 0 0 0 4px var(--paper);
}

.page-about .about-stages__item:first-child::before {
  background: var(--danxia);
}

.page-about .about-stages__code {
  display: inline-block;
  padding: 2px 8px;
  border: var(--hair);
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .12em;
  color: var(--danxia);
}

.page-about .about-stages__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(16px, 1.9vw, 20px);
  letter-spacing: .05em;
  line-height: 1.5;
}

.page-about .about-stages__text {
  margin: 10px 0 0;
  max-width: 34em;
  font-size: clamp(14.5px, 1.4vw, 16px);
  line-height: 1.9;
  color: var(--ink);
}

/* ---------- 会员等级 ---------- */
.page-about .about-tiers {
  margin-top: clamp(22px, 3.2vw, 34px);
  border-top: var(--hair);
}

.page-about .about-tier {
  border-bottom: var(--hair);
}

.page-about .about-tier__head {
  margin: 0;
}

.page-about .about-tier__trigger {
  display: flex;
  align-items: center;
  gap: clamp(10px, 2vw, 18px);
  width: 100%;
  padding: clamp(13px, 1.9vw, 19px) 0;
  background: none;
  border: 0;
  text-align: left;
  font: inherit;
  color: inherit;
  cursor: pointer;
}

.page-about .about-tier__trigger:focus-visible {
  outline: 2px solid var(--neon);
  outline-offset: 3px;
}

.page-about .about-tier__bar {
  flex: 0 0 auto;
  display: block;
  width: 52px;
  height: 8px;
  background-image: linear-gradient(90deg, var(--danxia-deep) 0%, var(--danxia) 46%, var(--sand) 100%);
  background-size: 400% 100%;
  background-repeat: no-repeat;
}

.page-about .about-tier--1 .about-tier__bar { background-position: 0% 50%; }
.page-about .about-tier--2 .about-tier__bar { background-position: 34% 50%; }
.page-about .about-tier--3 .about-tier__bar { background-position: 67% 50%; }
.page-about .about-tier--4 .about-tier__bar { background-position: 100% 50%; }

.page-about .about-tier__name {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(17px, 2.1vw, 22px);
  letter-spacing: .12em;
}

.page-about .about-tier__tag {
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .14em;
  color: var(--muted);
  border: var(--hair);
  padding: 3px 8px;
}

.page-about .about-tier__mark {
  position: relative;
  flex: 0 0 auto;
  width: 18px;
  height: 18px;
  margin-left: auto;
}

.page-about .about-tier__mark::before,
.page-about .about-tier__mark::after {
  content: "";
  position: absolute;
  background: var(--ink);
}

.page-about .about-tier__mark::before {
  left: 3px;
  top: 8px;
  width: 12px;
  height: 1px;
}

.page-about .about-tier__mark::after {
  left: 8px;
  top: 3px;
  width: 1px;
  height: 12px;
  transition: transform .22s var(--ease);
}

.page-about .about-tier__trigger[aria-expanded="true"] .about-tier__mark::after {
  transform: scaleY(0);
}

.page-about .about-tier__panel {
  padding: 0 0 clamp(16px, 2.4vw, 24px);
}

.page-about .about-tier__panel p {
  margin: 0;
  max-width: 34em;
  font-size: clamp(14.5px, 1.4vw, 16px);
  line-height: 1.9;
  color: var(--ink);
}

.page-about .about-tier-figure {
  margin: clamp(22px, 3.2vw, 34px) 0 0;
  max-width: 460px;
}

.page-about .about-tier-figure__frame {
  aspect-ratio: 1 / 1;
  overflow: hidden;
  border: var(--hair);
  background: linear-gradient(160deg, var(--stone) 0%, var(--sand-light) 100%);
  transition: transform .22s var(--ease), border-color .22s var(--ease);
}

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

.page-about .about-tier-figure:hover .about-tier-figure__frame {
  transform: translateY(-2px);
  border-color: var(--danxia);
}

/* ---------- 场地形态 ---------- */
.page-about .about-venues {
  display: grid;
  gap: clamp(14px, 2vw, 20px);
  margin-top: clamp(22px, 3.2vw, 34px);
}

.page-about .about-venue {
  padding: clamp(15px, 2.2vw, 22px);
  border: var(--hair);
  background: var(--paper);
  box-shadow: var(--shadow-1);
  transition: transform .22s var(--ease), border-color .22s var(--ease);
}

.page-about .about-venue:hover {
  transform: translateY(-2px);
  border-color: var(--danxia);
}

.page-about .about-venue__plan {
  padding: 10px;
  margin-bottom: 14px;
  background: var(--sand-light);
  color: var(--ink);
}

.page-about .about-venue__plan svg {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .about-venue__name {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(17px, 2vw, 21px);
  letter-spacing: .12em;
}

.page-about .about-venue__scene {
  margin: 10px 0 0;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .08em;
  color: var(--danxia);
}

.page-about .about-venue__text {
  margin: 10px 0 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--ink);
}

.page-about .about-venue-figure {
  margin: clamp(24px, 3.4vw, 38px) 0 0;
}

.page-about .about-venue-figure__frame {
  aspect-ratio: 3 / 2;
  overflow: hidden;
  border: var(--hair);
  background: linear-gradient(120deg, var(--ink-deep) 0%, var(--danxia-deep) 100%);
}

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

/* ---------- 合作生态深色块 ---------- */
.page-about .about-panel--dark {
  margin-top: clamp(22px, 3.2vw, 34px);
  padding: clamp(20px, 3.2vw, 40px);
  background: var(--ink-deep);
  color: var(--paper-a80);
  border: var(--hair-light, 1px solid rgba(247, 242, 234, .18));
}

.page-about .about-panel__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(17px, 2.2vw, 22px);
  letter-spacing: .12em;
  color: var(--paper);
}

.page-about .about-panel__text {
  margin: 14px 0 0;
  max-width: 36em;
  font-size: clamp(14.5px, 1.4vw, 16px);
  line-height: 1.9;
  color: var(--paper-a80);
}

.page-about .about-sectors {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: clamp(16px, 2.4vw, 24px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-sectors__item {
  padding: 5px 11px;
  border: 1px solid var(--about-hair-light);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--sand-light);
}

.page-about .about-panel__stats {
  display: flex;
  flex-wrap: wrap;
  gap: clamp(18px, 3vw, 44px);
  margin-top: clamp(18px, 2.8vw, 30px);
  padding-top: clamp(16px, 2.4vw, 26px);
  border-top: 1px solid var(--about-hair-light);
}

.page-about .about-panel__stat-num {
  display: block;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(26px, 4vw, 42px);
  line-height: 1;
  letter-spacing: -.02em;
  color: var(--sand);
}

.page-about .about-panel__stat-label {
  display: block;
  margin-top: 9px;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--paper-a60);
}

/* ---------- 服务中心 ---------- */
.page-about .about-duties {
  margin: clamp(20px, 3vw, 30px) 0 0;
  padding: 0;
  list-style: none;
  border-top: var(--hair);
}

.page-about .about-duties__item {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 10px;
  align-items: start;
  padding: 13px 0;
  border-bottom: var(--hair);
}

.page-about .about-duties__item:last-child {
  border-bottom: 0;
}

.page-about .about-duties__num {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--danxia);
  padding-top: 5px;
}

.page-about .about-duties__text {
  font-size: clamp(14.5px, 1.4vw, 16px);
  line-height: 1.85;
}

/* ---------- 年度节奏 ---------- */
.page-about .about-facts {
  display: grid;
  gap: clamp(14px, 2vw, 20px);
  margin: clamp(22px, 3.2vw, 34px) 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-facts__item {
  padding-top: 14px;
  border-top: 2px solid var(--stone);
}

.page-about .about-facts__item:first-child {
  border-top-color: var(--danxia);
}

.page-about .about-facts__label {
  display: block;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--muted);
}

.page-about .about-facts__value {
  display: block;
  margin-top: 10px;
  font-family: var(--font-display);
  font-weight: 300;
  font-size: clamp(21px, 2.8vw, 28px);
  letter-spacing: -.01em;
  line-height: 1.2;
  color: var(--ink);
}

.page-about .about-facts__note {
  display: block;
  margin-top: 8px;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 页末等级条 ---------- */
.page-about .about-ladder {
  margin-top: clamp(26px, 4vw, 46px);
  padding: clamp(20px, 3vw, 34px) 0 0;
  border-top: var(--hair);
}

.page-about .about-ladder__title {
  margin: 0 0 18px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(15px, 1.7vw, 18px);
  letter-spacing: .14em;
}

.page-about .about-ladder__bar {
  height: 6px;
  background: linear-gradient(90deg, var(--danxia-deep) 0%, var(--danxia) 46%, var(--sand) 100%);
}

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

.page-about .about-ladder__item {
  padding: 12px 0;
  border-top: var(--hair);
}

.page-about .about-ladder__name {
  display: block;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 15px;
  letter-spacing: .14em;
}

.page-about .about-ladder__desc {
  display: block;
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .16em;
  color: var(--muted);
}

/* ---------- 反馈条 ---------- */
.page-about .about-feedback {
  margin-top: clamp(26px, 4vw, 46px);
  margin-bottom: clamp(30px, 5vw, 60px);
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .about-venues {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-ladder__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__inner {
    grid-template-columns: 42fr 58fr;
    gap: clamp(28px, 4vw, 56px);
  }
}

@media (min-width: 1000px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: clamp(34px, 5vw, 76px);
  }

  .page-about .about-rail {
    position: sticky;
    top: 92px;
    align-self: start;
    border-bottom: 0;
  }

  .page-about .about-rail__list {
    position: relative;
    flex-direction: column;
    gap: 0;
    padding: 0 0 0 18px;
    overflow: visible;
  }

  .page-about .about-rail__list::before {
    content: "";
    position: absolute;
    left: 3px;
    top: 10px;
    bottom: 10px;
    width: 1px;
    background: var(--about-hair);
  }

  .page-about .about-rail__link {
    position: relative;
    padding: 9px 0;
    border-top: 0;
  }

  .page-about .about-rail__link::before {
    content: "";
    position: absolute;
    left: -18px;
    top: 15px;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--stone);
    transition: background .2s var(--ease), box-shadow .2s var(--ease);
  }

  .page-about .about-rail__link[aria-current="true"]::before {
    background: var(--danxia);
    box-shadow: 0 0 0 3px rgba(179, 58, 36, .18);
  }

  .page-about .about-tier__panel p {
    padding-left: clamp(62px, 8vw, 82px);
  }

  .page-about .about-tier__panel {
    padding-bottom: clamp(18px, 2.6vw, 26px);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-venue,
  .page-about .about-tier-figure__frame,
  .page-about .about-tier__mark::after,
  .page-about .about-rail__link,
  .page-about .about-rail__link::before {
    transition: none;
  }

  .page-about .about-venue:hover,
  .page-about .about-tier-figure:hover .about-tier-figure__frame {
    transform: none;
  }
}

.page-about {
  --hair-light: currentColor;
}