/* ===== 平台介绍页 /introduction/ ===== */

.page-about {
  margin: 1.5rem 0 4rem;
}

.page-about .crumbs {
  margin-bottom: 1.25rem;
}

/* ---------- 首屏 ---------- */
.page-about .about-head {
  max-width: 52rem;
}

.page-about .about-head .sec-kicker {
  margin: 0 0 .65rem;
}

.page-about .about-head .page-title {
  margin: 0;
}

.page-about .about-lead {
  margin: 1.1rem 0 0;
  max-width: 40em;
  font-size: clamp(1rem, 0.95rem + 0.3vw, 1.125rem);
  line-height: 1.95;
  color: var(--glass-white);
  opacity: 0.9;
}

.page-about .about-facts {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 1.4rem 0 0;
  border-top: 1px solid var(--line-soft);
  display: flex;
  flex-wrap: wrap;
  gap: 1.15rem 2.5rem;
}

.page-about .about-facts li {
  display: flex;
  flex-direction: column;
  gap: 0.22rem;
}

.page-about .about-facts__num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(1.5rem, 1.2rem + 1.2vw, 1.875rem);
  font-weight: 700;
  line-height: 1;
  color: var(--gold-hi);
  letter-spacing: -0.02em;
}

.page-about .about-facts__lbl {
  font-size: var(--fs-14);
  color: var(--gray-gold);
}

/* ---------- 配图容器 ---------- */
.page-about .about-visual {
  margin: 2.25rem 0 2.75rem;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--deep-vermilion);
}

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

.page-about .about-visual--mid {
  margin: 2rem 0 1.25rem;
}

/* ---------- 左索引 + 右连续画布 ---------- */
.page-about .about-body {
  display: grid;
  gap: 2rem;
}

.page-about .stage-rail {
  border-top: 1px solid var(--line);
  padding-top: 1rem;
}

.page-about .stage-rail__title {
  margin: 0 0 0.7rem;
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--gray-gold);
}

.page-about .stage-nav {
  list-style: none;
  margin: 0;
  padding: 0 0 0.35rem;
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .stage-nav li {
  flex: none;
}

.page-about .stage-nav a {
  display: block;
  white-space: nowrap;
  padding: 0.45rem 0.8rem;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  font-size: var(--fs-14);
  color: var(--gray-gold);
  text-decoration: none;
  transition: color 0.25s ease, border-color 0.25s ease, background-color 0.25s ease;
}

.page-about .stage-nav a:hover,
.page-about .stage-nav a:focus-visible {
  color: var(--gold-hi);
  border-color: var(--gold);
  background: var(--glass-1);
}

.page-about .stage-nav__num {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--copper);
  margin-right: 0.35rem;
}

.page-about .stage-nav a:hover .stage-nav__num,
.page-about .stage-nav a:focus-visible .stage-nav__num {
  color: var(--neon);
}

/* ---------- 章节与金色刻度线 ---------- */
.page-about .stage {
  position: relative;
  padding: 0 0 2.5rem;
}

.page-about .stage:not(:first-child)::before {
  content: "";
  display: block;
  height: 1px;
  width: 22%;
  max-width: 260px;
  margin-bottom: 2.25rem;
  background: linear-gradient(90deg, rgba(224, 169, 59, 0.78), rgba(224, 169, 59, 0));
  transition: width 0.6s ease;
}

.page-about .stage:nth-child(2)::before { width: 28%; }
.page-about .stage:nth-child(3)::before { width: 36%; }
.page-about .stage:nth-child(4)::before { width: 44%; }
.page-about .stage:nth-child(5)::before { width: 52%; }
.page-about .stage:nth-child(6)::before { width: 60%; }
.page-about .stage:nth-child(7)::before { width: 68%; }

.page-about .stage-title {
  position: relative;
  margin: 0 0 1rem;
  padding-left: 1rem;
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 1.05rem + 1.15vw, 1.875rem);
  font-weight: 800;
  line-height: 1.35;
  letter-spacing: -0.01em;
  color: var(--gold-hi);
}

.page-about .stage-title::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.3em;
  bottom: 0.3em;
  width: 3px;
  border-radius: 1px;
  background: var(--neon);
  box-shadow: 0 0 10px var(--neon-mist);
}

.page-about .prose {
  max-width: 40em;
}

.page-about .prose p {
  margin: 0 0 1.05em;
  line-height: 1.95;
  color: var(--glass-white);
  opacity: 0.88;
}

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

.page-about .stage-note {
  max-width: 44em;
  margin: 1.6rem 0 0;
  padding: 0.9rem 1.1rem;
  border-left: 2px solid var(--gold);
  background: var(--glass-2);
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--gray-gold);
}

/* ---------- 房间分类 ---------- */
.page-about .room-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--line-soft);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .room-item {
  background: var(--ink);
  padding: 1.15rem 1.1rem 1.25rem;
  transition: background-color 0.3s ease;
}

.page-about .room-item:hover {
  background: var(--deep-vermilion);
}

.page-about .room-item h3 {
  margin: 0 0 0.4rem;
  font-family: var(--font-display);
  font-size: var(--fs-18);
  letter-spacing: 0.01em;
  color: var(--gold);
}

.page-about .room-item p {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.8;
  color: var(--glass-white);
  opacity: 0.82;
}

/* ---------- 三阶段时间线 ---------- */
.page-about .phase-track {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  position: relative;
}

.page-about .phase {
  position: relative;
  padding: 0 0 1.75rem 2rem;
}

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

.page-about .phase::before {
  content: "";
  position: absolute;
  left: 1px;
  top: 0.38rem;
  width: 11px;
  height: 11px;
  box-sizing: border-box;
  transform: rotate(45deg);
  background: var(--ink);
  border: 2px solid var(--gold);
}

.page-about .phase:last-child::before {
  border-color: var(--neon);
  box-shadow: 0 0 14px var(--neon-mist);
}

.page-about .phase:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 6px;
  top: 1.7rem;
  bottom: 0.4rem;
  width: 1px;
  background: linear-gradient(180deg, rgba(224, 169, 59, 0.5), rgba(224, 169, 59, 0.06));
}

.page-about .phase__name {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-size: var(--fs-18);
  color: var(--gold-hi);
}

.page-about .phase__desc {
  margin: 0;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--glass-white);
  opacity: 0.82;
}

/* ---------- 团队分工 ---------- */
.page-about .team-wrap {
  display: grid;
  gap: 1.5rem;
  margin-top: 1.6rem;
  align-items: center;
}

.page-about .team-figure {
  margin: 0;
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--deep-vermilion);
}

.page-about .team-legend {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
}

.page-about .team-legend li {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.12rem 0.6rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid rgba(110, 74, 33, 0.45);
  transition: border-color 0.25s ease;
}

.page-about .team-legend li:hover {
  border-bottom-color: var(--gold);
}

.page-about .team-legend__swatch {
  width: 10px;
  height: 10px;
  flex: none;
  border-radius: 2px;
}

.page-about .team-legend__swatch--tech { background: var(--gold); }
.page-about .team-legend__swatch--cs { background: var(--neon); }
.page-about .team-legend__swatch--ct { background: rgba(246, 240, 231, 0.6); }
.page-about .team-legend__swatch--ds { background: var(--copper); }

.page-about .team-legend__role {
  font-size: var(--fs-16);
  font-weight: 600;
  color: var(--glass-white);
}

.page-about .team-legend__num {
  margin-left: auto;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--fs-18);
  color: var(--gold-hi);
}

.page-about .team-legend__desc {
  flex-basis: 100%;
  padding-left: 1.4rem;
  font-size: var(--fs-14);
  line-height: 1.75;
  color: var(--gray-gold);
}

/* ---------- 服务约定 ---------- */
.page-about .promise-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  display: grid;
  gap: 1.2rem;
}

.page-about .promise-list li {
  display: grid;
  grid-template-columns: 2.4rem minmax(0, 1fr);
  gap: 0.9rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line-soft);
}

.page-about .promise-list__num {
  font-family: var(--font-mono);
  font-size: var(--fs-14);
  letter-spacing: 0.08em;
  color: var(--neon);
  padding-top: 0.15rem;
}

.page-about .promise-list__title {
  margin: 0 0 0.3rem;
  font-family: var(--font-display);
  font-size: var(--fs-16);
  color: var(--gold-hi);
}

.page-about .promise-list p {
  margin: 0;
  max-width: 40em;
  font-size: var(--fs-14);
  line-height: 1.85;
  color: var(--glass-white);
  opacity: 0.84;
}

/* ---------- 页尾行动区 ---------- */
.page-about .about-cta {
  position: relative;
  overflow: hidden;
  margin-top: 3rem;
  padding: 1.75rem 1.35rem 1.85rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: linear-gradient(150deg, rgba(69, 18, 26, 0.9), rgba(26, 10, 16, 0.92));
}

.page-about .about-cta::after {
  content: "";
  position: absolute;
  right: -44px;
  top: -44px;
  width: 150px;
  height: 150px;
  border: 1px solid rgba(224, 169, 59, 0.22);
  transform: rotate(45deg);
  pointer-events: none;
}

.page-about .about-cta__title {
  margin: 0 0 0.6rem;
  font-family: var(--font-display);
  font-size: clamp(1.15rem, 1rem + 0.6vw, 1.375rem);
  color: var(--gold-hi);
}

.page-about .about-cta__text {
  margin: 0 0 1.4rem;
  max-width: 40em;
  font-size: var(--fs-14);
  line-height: 1.9;
  color: var(--glass-white);
  opacity: 0.86;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.7rem;
}

.page-about .about-cta__foot {
  margin: 1.2rem 0 0;
  font-size: var(--fs-14);
  color: var(--gray-gold);
}

.page-about .about-cta__foot a {
  color: var(--neon);
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .room-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .about-cta {
    padding: 2.25rem 2rem 2.35rem;
  }
}

@media (min-width: 800px) {
  .page-about .team-wrap {
    grid-template-columns: minmax(0, 0.85fr) minmax(0, 1.15fr);
    gap: 2.25rem;
  }
}

@media (min-width: 1080px) {
  .page-about .about-body {
    grid-template-columns: 172px minmax(0, 1fr);
    gap: 3.5rem;
    align-items: start;
    margin-top: 0.5rem;
  }

  .page-about .stage-rail {
    position: sticky;
    top: calc(var(--topbar-h) + 2rem);
  }

  .page-about .stage-nav {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .stage-nav li {
    border-bottom: 1px solid rgba(110, 74, 33, 0.35);
  }

  .page-about .stage-nav a {
    border: none;
    border-left: 2px solid transparent;
    border-radius: 0;
    padding: 0.65rem 0 0.65rem 0.85rem;
    white-space: normal;
    line-height: 1.5;
  }

  .page-about .stage-nav a:hover,
  .page-about .stage-nav a:focus-visible {
    border-left-color: var(--neon);
    background: linear-gradient(90deg, var(--neon-mist), rgba(56, 225, 212, 0) 72%);
    color: var(--gold-hi);
  }

  .page-about .stage {
    padding-bottom: 3.25rem;
  }

  .page-about .room-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-cta {
    margin-top: 1rem;
  }
}

@media (min-width: 1360px) {
  .page-about .about-body {
    grid-template-columns: 196px minmax(0, 1fr);
  }
}
<<<END>>>