/* ===== 平台介绍 /introduction/ ===== */
.page-about {
  --about-rail: 152px;
  --about-gap: clamp(24px, 3vw, 52px);
  --about-rule: rgba(192, 138, 62, 0.22);
}

.page-about .breadcrumb {
  padding: 20px 0 4px;
}

/* ---- 首屏 ---- */
.page-about .about-hero {
  position: relative;
  padding: clamp(32px, 5.5vw, 68px) 0 clamp(30px, 4.5vw, 52px);
  border-bottom: 1px solid var(--line-dark);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -140px;
  top: -180px;
  width: 480px;
  height: 480px;
  background: radial-gradient(circle, rgba(240, 217, 168, 0.15), transparent 68%);
  pointer-events: none;
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
}

.page-about .about-hero__eyebrow {
  margin: 0 0 14px;
  color: var(--copper-bright);
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.95rem, 4.4vw, 3.35rem);
  line-height: 1.2;
  letter-spacing: -0.01em;
  color: var(--white);
}

.page-about .about-hero__lead {
  margin: 0;
  max-width: 34em;
  color: var(--text-body);
  font-size: 16px;
  line-height: 1.9;
}

.page-about .about-hero__stats {
  border-left: 1px solid var(--line-dark);
  padding-left: 22px;
}

.page-about .about-stats {
  margin: 0;
  display: grid;
  gap: 12px;
}

.page-about .about-stats__row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--about-rule);
}

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

.page-about .about-stats__key {
  color: var(--graphite);
  font-size: 13px;
  letter-spacing: 0.04em;
}

.page-about .about-stats__val {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--copper-bright);
  text-align: right;
}

/* ---- 开篇图 ---- */
.page-about .about-plate {
  margin: clamp(26px, 4vw, 44px) 0 0;
}

.page-about .about-plate .media-frame {
  border: 1px solid var(--line-dark);
}

.page-about .about-inline-fig {
  margin: 30px 0 0;
}

.page-about .about-inline-fig .media-frame,
.page-about .about-split__fig .media-frame {
  border: 1px solid var(--line-dark);
}

/* ---- 正文骨架 ---- */
.page-about .about-doc {
  padding: clamp(36px, 5.5vw, 68px) 0 0;
}

.page-about .about-doc__grid {
  position: relative;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.page-about .about-rail {
  display: none;
}

.page-about .about-rail__cap {
  margin: 0 0 14px;
  font-size: 11px;
  letter-spacing: 0.2em;
  color: var(--graphite);
}

.page-about .about-rail__list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--line-dark);
}

.page-about .about-rail__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  padding: 8px 0 8px 12px;
  margin-left: -1px;
  border-left: 1px solid transparent;
  color: var(--text-dim);
  font-size: 13px;
  line-height: 1.45;
  text-decoration: none;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-rail__link:hover,
.page-about .about-rail__link:focus-visible {
  color: var(--copper-bright);
  border-left-color: var(--copper);
}

.page-about .about-rail__link[data-active="true"] {
  color: var(--white);
  border-left-color: var(--copper-bright);
}

.page-about .about-rail__num {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--copper);
}

/* ---- 章节 ---- */
.page-about .about-sec {
  padding: clamp(32px, 4.5vw, 54px) 0;
  border-top: 1px solid var(--line-dark);
  scroll-margin-top: calc(var(--header-h) + 24px);
}

.page-about .about-body > .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-body > .about-sec:last-child {
  padding-bottom: 0;
}

.page-about .about-sec__num {
  margin: 0 0 10px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--copper);
}

.page-about .about-sec__title {
  position: relative;
  margin: 0 0 24px;
  padding-bottom: 16px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.35rem, 2.6vw, 2rem);
  line-height: 1.36;
  color: var(--white);
}

.page-about .about-sec__title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: 0;
  width: 44px;
  height: 1px;
  background: var(--copper);
}

.page-about .about-sec > p,
.page-about .about-sec__body > p {
  margin: 0 0 16px;
  max-width: 38em;
  color: var(--text-body);
  font-size: 16px;
  line-height: 1.9;
}

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

.page-about .about-sec__more {
  margin: 24px 0 0;
  max-width: 38em;
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.85;
}

.page-about .about-sec__more a {
  color: var(--copper-bright);
  text-decoration: none;
  border-bottom: 1px solid var(--line-dark-strong);
  transition: border-color var(--dur) var(--ease);
}

.page-about .about-sec__more a:hover {
  border-bottom-color: var(--copper-bright);
}

/* ---- 场景三格 ---- */
.page-about .about-scenes {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line-dark);
  border: 1px solid var(--line-dark);
}

.page-about .about-scene {
  background: var(--ink-soft);
  padding: 22px 20px 24px;
}

.page-about .about-scene__no {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--copper);
}

.page-about .about-scene__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.08rem;
  line-height: 1.5;
  color: var(--white);
}

.page-about .about-scene__text {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.85;
}

/* ---- 旁注 ---- */
.page-about .about-note {
  margin: 26px 0 0;
  padding: 20px 22px;
  max-width: 44em;
  background: var(--paper);
  border-left: 2px solid var(--copper);
}

.page-about .about-note__title {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: #6B4A18;
}

.page-about .about-note p {
  margin: 0 0 8px;
  max-width: none;
  color: rgba(11, 13, 16, 0.82);
  font-size: 14.5px;
  line-height: 1.85;
}

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

/* ---- 年份时间轴 ---- */
.page-about .about-timeline {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: minmax(230px, 1fr);
  gap: 0;
  margin: 26px 0 0;
  padding-bottom: 6px;
  overflow-x: auto;
  border-top: 1px solid var(--copper);
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-node {
  position: relative;
  scroll-snap-align: start;
  padding: 26px 22px 24px 0;
  border-right: 1px solid var(--line-dark);
}

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

.page-about .about-node::before {
  content: "";
  position: absolute;
  top: -1px;
  left: 0;
  width: 40px;
  height: 2px;
  background: var(--copper-bright);
}

.page-about .about-node__time {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--copper-bright);
}

.page-about .about-node__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.05rem;
  line-height: 1.5;
  color: var(--white);
}

.page-about .about-node__text {
  margin: 0;
  max-width: none;
  color: var(--text-dim);
  font-size: 14px;
  line-height: 1.85;
}

/* ---- 服务中心 ---- */
.page-about .about-centers {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line-dark);
  border: 1px solid var(--line-dark);
}

.page-about .about-center {
  background: var(--ink-soft);
  padding: 22px 20px 24px;
  border-top: 2px solid var(--copper);
}

.page-about .about-center__city {
  margin: 0 0 8px;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--copper-bright);
}

.page-about .about-center__role {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.06rem;
  line-height: 1.5;
  color: var(--white);
}

.page-about .about-center__text {
  margin: 0;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.85;
}

/* ---- 行业模板 ---- */
.page-about .about-filter-row {
  margin: 24px 0 0;
}

.page-about .about-tpls {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line-dark);
  border: 1px solid var(--line-dark);
}

.page-about .about-tpl {
  background: var(--ink-soft);
  padding: 24px 22px 26px;
}

.page-about .about-tpl[hidden],
.page-about .about-tpl[data-visible="false"] {
  display: none;
}

.page-about .about-tpl__name {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.14rem;
  color: var(--white);
  letter-spacing: 0.02em;
}

.page-about .about-tpl__hint {
  margin: 0;
  color: var(--graphite);
  font-size: 13px;
  line-height: 1.75;
}

.page-about .about-tpl__list {
  list-style: none;
  margin: 14px 0 0;
  padding: 0;
}

.page-about .about-tpl__list li {
  position: relative;
  padding: 9px 0 9px 16px;
  color: var(--text-body);
  font-size: 14.5px;
  line-height: 1.7;
  border-bottom: 1px solid var(--about-rule);
}

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

.page-about .about-tpl__list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  width: 6px;
  height: 1px;
  background: var(--copper);
}

/* ---- 安全与合规 ---- */
.page-about .about-split {
  display: grid;
  grid-template-columns: 1fr;
  gap: 30px;
}

.page-about .about-split__text > p {
  margin: 0 0 16px;
  max-width: 38em;
  color: var(--text-body);
  font-size: 16px;
  line-height: 1.9;
}

.page-about .about-checks {
  list-style: none;
  margin: 22px 0 0;
  padding: 0;
}

.page-about .about-checks li {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  padding: 14px 0;
  border-top: 1px solid var(--line-dark);
  color: var(--text-body);
  font-size: 15px;
  line-height: 1.8;
}

.page-about .about-checks li:last-child {
  border-bottom: 1px solid var(--line-dark);
}

.page-about .about-checks__k {
  flex: none;
  min-width: 74px;
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--copper-bright);
}

.page-about .about-checks li > span:last-child {
  flex: 1 1 220px;
  min-width: 0;
}

/* ---- 上线三步 ---- */
.page-about .about-steps {
  list-style: none;
  margin: 28px 0 0;
  padding: 0;
  border-top: 1px solid var(--line-dark);
}

.page-about .about-step {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line-dark);
}

.page-about .about-step__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--copper);
}

.page-about .about-step__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.08rem;
  line-height: 1.5;
  color: var(--white);
}

.page-about .about-step__text {
  margin: 0;
  max-width: 38em;
  color: var(--text-body);
  font-size: 15px;
  line-height: 1.85;
}

/* ---- 更新节奏 ---- */
.page-about .about-cadence {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 26px 0 0;
  background: var(--line-dark);
  border: 1px solid var(--line-dark);
}

.page-about .about-cadence__item {
  background: var(--ink-soft);
  padding: 24px 22px 26px;
}

.page-about .about-cadence__v {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 1.35rem;
  letter-spacing: 0.01em;
  color: var(--copper-bright);
}

.page-about .about-cadence__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.06rem;
  line-height: 1.5;
  color: var(--white);
}

.page-about .about-cadence__text {
  margin: 0;
  max-width: none;
  color: var(--text-dim);
  font-size: 14.5px;
  line-height: 1.85;
}

/* ---- 右侧刻度 ---- */
.page-about .about-progress {
  display: none;
}

/* ---- 收尾 ---- */
.page-about .about-cta {
  margin-top: clamp(40px, 6vw, 76px);
  padding: clamp(36px, 5vw, 60px) 0;
  background: var(--ink-soft);
  border-top: 1px solid var(--copper);
}

.page-about .about-cta__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px;
}

.page-about .about-cta h2 {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.35rem, 2.4vw, 1.9rem);
  line-height: 1.36;
  color: var(--white);
}

.page-about .about-cta p {
  margin: 0;
  max-width: 34em;
  color: var(--text-dim);
  font-size: 15.5px;
  line-height: 1.85;
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---- 断点 ---- */
@media (min-width: 600px) {
  .page-about .about-scenes {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-centers {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .about-tpls {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .about-cadence {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-step {
    grid-template-columns: 52px minmax(0, 186px) minmax(0, 1fr);
    gap: 22px;
    align-items: baseline;
    padding: 26px 0;
  }
  .page-about .about-split {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
    gap: 40px;
    align-items: start;
  }
  .page-about .about-cta__inner {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    align-items: end;
    gap: 40px;
  }
  .page-about .about-cta__actions {
    justify-content: flex-end;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(228px, 0.85fr);
    gap: 56px;
    align-items: end;
  }
}

@media (min-width: 1024px) {
  .page-about .about-doc__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
  }
  .page-about .about-rail {
    display: block;
    position: sticky;
    top: calc(var(--header-h) + 28px);
    align-self: start;
  }
  .page-about .about-tpls {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .about-timeline {
    grid-auto-columns: minmax(206px, 1fr);
  }
}

@media (min-width: 1400px) {
  .page-about .about-progress {
    display: block;
    position: absolute;
    right: -30px;
    top: 0;
    bottom: 0;
    width: 1px;
    pointer-events: none;
    background-image: repeating-linear-gradient(
      180deg,
      var(--line-dark) 0 10px,
      transparent 10px 28px
    );
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-rail__link,
  .page-about .about-sec__more a {
    transition: none;
  }
}