.page-about {
  --about-gap: clamp(48px, 8vw, 96px);
  --about-notch: 22px;
  --about-dash: repeating-linear-gradient(180deg, var(--stone) 0 5px, transparent 5px 11px);
}

/* ---------- 面包屑 ---------- */
.page-about .about-crumb {
  padding-top: 20px;
  padding-bottom: 10px;
}

/* ---------- 首屏框景 ---------- */
.page-about .about-hero {
  padding-top: 8px;
  padding-bottom: clamp(28px, 5vw, 48px);
}

.page-about .hero-frame {
  position: relative;
  background: var(--white);
  padding: 34px 20px 30px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - var(--about-notch)), calc(100% - var(--about-notch)) 100%, 0 100%);
  box-shadow: 0 0 0 1px var(--stone);
  overflow: hidden;
}

.page-about .hero-frame::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 9px;
  background-image: repeating-linear-gradient(90deg, var(--stone) 0 1px, transparent 1px 13px);
  opacity: .95;
}

.page-about .hero-frame::after {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 6px;
  height: 46%;
  background: linear-gradient(180deg, var(--sky), var(--glacier));
}

.page-about .hero-main {
  padding-left: 10px;
}

.page-about .hero-kicker {
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--sky-deep);
  margin: 6px 0 14px;
}

.page-about .about-hero h1 {
  font-size: clamp(28px, 7.2vw, 54px);
  line-height: 1.14;
  font-weight: 900;
  letter-spacing: -.015em;
  color: var(--ink);
  margin: 0 0 18px;
  max-width: 22ch;
}

.page-about .about-hero .lede {
  font-size: 17px;
  line-height: 1.75;
  color: var(--ink);
  max-width: 54ch;
  margin: 0 0 24px;
}

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

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 30px;
  padding-top: 24px;
  border-top: 1px dashed var(--stone);
  padding-left: 10px;
}

.page-about .hero-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 14px;
  background: var(--mist);
  border-left: 3px solid var(--sky);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: clamp(26px, 6vw, 36px);
  font-weight: 700;
  line-height: 1;
  color: var(--indigo);
  letter-spacing: -.02em;
}

.page-about .stat-unit {
  font-size: .55em;
  margin-left: 2px;
  color: var(--sky-deep);
}

.page-about .stat-label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--ink);
  opacity: .82;
}

/* ---------- 轨道 + 正文 ---------- */
.page-about .about-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 30px;
  padding-bottom: var(--about-gap);
}

.page-about .about-rail {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding-bottom: 18px;
  border-bottom: 1px dashed var(--stone);
}

.page-about .rail-title {
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--flag-deep);
  margin: 0;
}

.page-about .year-scale {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 2px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.page-about .year-scale::-webkit-scrollbar {
  display: none;
}

.page-about .year-item {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 5px;
  padding: 12px 14px 10px;
  min-width: 84px;
  background: var(--white);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%);
}

.page-about .year-tick {
  position: absolute;
  left: 14px;
  top: 6px;
  width: 14px;
  height: 2px;
  background: var(--gold);
}

.page-about .year-num {
  font-size: 14px;
  font-weight: 700;
  color: var(--indigo);
  letter-spacing: .02em;
}

.page-about .year-label {
  font-size: 11px;
  color: var(--ink);
  opacity: .66;
  white-space: nowrap;
}

.page-about .about-rail .status-panel {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 12px 14px;
  background: var(--indigo);
  color: var(--paper);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 12px), calc(100% - 12px) 100%, 0 100%);
}

.page-about .panel-cap {
  font-size: 10px;
  letter-spacing: .18em;
  color: var(--gold);
}

.page-about .panel-count {
  font-size: 13px;
  line-height: 1.4;
}

/* ---------- 章节通用 ---------- */
.page-about .about-sec {
  padding-top: clamp(36px, 6vw, 62px);
  padding-bottom: clamp(36px, 6vw, 62px);
  border-top: 1px dashed var(--stone);
}

.page-about .about-sec:first-child {
  border-top: 0;
  padding-top: 6px;
}

.page-about .about-sec .section-head {
  margin-bottom: 28px;
}

.page-about .about-sec .sec-num {
  color: var(--flag-deep);
  font-size: 13px;
  letter-spacing: .16em;
}

.page-about .about-sec h2 {
  font-size: clamp(22px, 4.6vw, 34px);
  line-height: 1.22;
  font-weight: 800;
  color: var(--ink);
  margin: 8px 0 10px;
}

.page-about .sec-sub {
  font-size: 15px;
  line-height: 1.72;
  color: var(--ink);
  opacity: .78;
  margin: 0;
  max-width: 58ch;
}

.page-about .about-sec h3 {
  font-size: 17px;
  font-weight: 800;
  color: var(--indigo);
  margin: 0 0 8px;
}

.page-about .about-sec p {
  font-size: 16px;
  line-height: 1.76;
  color: var(--ink);
  margin: 0 0 14px;
}

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

.page-about .about-sec a {
  color: var(--sky-deep);
}

/* ---------- 01 时间轴 ---------- */
.page-about .timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  position: relative;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 10px;
  bottom: 10px;
  width: 1px;
  background-image: repeating-linear-gradient(180deg, var(--stone) 0 6px, transparent 6px 13px);
}

.page-about .tl-item {
  position: relative;
  padding-left: 32px;
  padding-bottom: 18px;
}

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

.page-about .tl-dot {
  position: absolute;
  left: 0;
  top: 12px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--flag);
  box-shadow: 0 0 0 4px var(--paper);
}

.page-about .tl-body {
  background: var(--white);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 16px), calc(100% - 16px) 100%, 0 100%);
  box-shadow: 0 0 0 1px var(--stone);
  padding: 16px 18px;
}

.page-about .tl-body[open] {
  box-shadow: 0 0 0 1px var(--sky);
}

.page-about .tl-summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  cursor: pointer;
  list-style: none;
  position: relative;
  padding-right: 26px;
}

.page-about .tl-summary::-webkit-details-marker {
  display: none;
}

.page-about .tl-summary:focus-visible {
  outline: 2px solid var(--flag);
  outline-offset: 4px;
}

.page-about .tl-year {
  font-size: 15px;
  font-weight: 700;
  color: var(--flag-deep);
  letter-spacing: .02em;
}

.page-about .tl-title {
  flex: 1 1 12ch;
  font-size: 16px;
  font-weight: 800;
  color: var(--ink);
  line-height: 1.45;
}

.page-about .tl-mark {
  position: absolute;
  right: 0;
  top: 50%;
  width: 13px;
  height: 13px;
  margin-top: -6px;
  border-radius: 50%;
  border: 1px solid var(--stone);
}

.page-about .tl-mark::before,
.page-about .tl-mark::after {
  content: "";
  position: absolute;
  left: 3px;
  top: 5px;
  width: 5px;
  height: 1px;
  background: var(--ink);
}

.page-about .tl-mark::after {
  transform: rotate(90deg);
  transition: transform 180ms var(--ease);
}

.page-about .tl-body[open] .tl-mark::after {
  transform: rotate(0deg);
}

.page-about .tl-content {
  padding-top: 14px;
}

.page-about .tl-figure {
  margin: 16px 0 0;
}

/* ---------- 02 价值主张 ---------- */
.page-about .belief-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
}

.page-about .belief-card {
  position: relative;
  background: var(--white);
  padding: 24px 20px 22px;
  border-top: 3px solid var(--sky);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
  box-shadow: 0 0 0 1px var(--stone);
}

.page-about .belief-card:nth-child(2) {
  border-top-color: var(--flag);
}

.page-about .belief-card:nth-child(3) {
  border-top-color: var(--gold);
}

.page-about .belief-index {
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--sky-deep);
  margin: 0 0 10px;
}

.page-about .belief-card p:not(.belief-index) {
  font-size: 15px;
  line-height: 1.74;
  margin: 0;
}

/* ---------- 03 产品线 ---------- */
.page-about .lines-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
}

.page-about .lines-copy p {
  font-size: 16px;
  line-height: 1.78;
}

.page-about .lines-link {
  margin-top: 20px;
}

.page-about .lines-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--stone);
  box-shadow: 0 0 0 1px var(--stone);
}

.page-about .line-item {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 12px;
  padding: 18px 16px;
  background: var(--white);
}

.page-about .line-item:nth-child(even) {
  background: var(--mist);
}

.page-about .line-idx {
  font-size: 13px;
  font-weight: 700;
  color: var(--flag-deep);
  padding-top: 3px;
}

.page-about .line-item h3 {
  margin-bottom: 6px;
}

.page-about .line-item p {
  font-size: 14px;
  line-height: 1.7;
  margin: 0;
  opacity: .88;
}

/* ---------- 04 团队 ---------- */
.page-about .team-banner {
  margin: 0 0 22px;
}

.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
}

.page-about .team-card {
  background: var(--indigo);
  color: var(--paper);
  padding: 22px 20px;
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 18px), calc(100% - 18px) 100%, 0 100%);
}

.page-about .team-card .stat-num {
  display: block;
  color: var(--gold);
  margin-bottom: 6px;
}

.page-about .team-card .stat-label {
  display: block;
  font-size: 13px;
  color: var(--mist);
  margin-bottom: 12px;
}

.page-about .team-card p {
  font-size: 14px;
  line-height: 1.72;
  color: var(--paper);
  opacity: .88;
  margin: 0;
}

.page-about .team-note {
  margin-top: 22px;
  padding: 16px 18px;
  border-left: 3px solid var(--glacier);
  background: var(--mist);
  font-size: 15px;
  line-height: 1.72;
  color: var(--ink);
}

/* ---------- 05 品质 ---------- */
.page-about .quality-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.page-about .quality-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 10px;
}

.page-about .quality-item {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding: 16px 16px;
  background: var(--white);
  box-shadow: inset 3px 0 0 var(--sky);
}

.page-about .quality-item:nth-child(2) {
  box-shadow: inset 3px 0 0 var(--glacier);
}

.page-about .quality-item:nth-child(3) {
  box-shadow: inset 3px 0 0 var(--gold);
}

.page-about .quality-item:nth-child(4) {
  box-shadow: inset 3px 0 0 var(--flag);
}

.page-about .q-key {
  font-size: 20px;
  font-weight: 700;
  color: var(--indigo);
  line-height: 1.2;
  letter-spacing: -.01em;
}

.page-about .q-text {
  font-size: 15px;
  line-height: 1.68;
  color: var(--ink);
}

.page-about .quality-media {
  margin: 0;
}

.page-about .credit-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 18px;
  margin-top: 26px;
}

.page-about .credit-card {
  padding: 22px 20px;
  background: var(--paper);
  border: 1px dashed var(--stone);
  clip-path: polygon(0 0, calc(100% - 18px) 0, 100% 18px, 100% 100%, 0 100%);
}

.page-about .credit-card p {
  font-size: 15px;
  line-height: 1.74;
  margin: 0;
}

/* ---------- 06 反馈 ---------- */
.page-about .feedback-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 26px;
  align-items: start;
}

.page-about .feedback-figure {
  margin: 0;
  padding: 20px 18px 14px;
  background: var(--white);
  box-shadow: 0 0 0 1px var(--stone);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 20px), calc(100% - 20px) 100%, 0 100%);
}

.page-about .fb-chart {
  display: block;
  width: 100%;
  height: auto;
}

.page-about .fb-axis {
  stroke: var(--stone);
  stroke-width: 1;
}

.page-about .fb-bar--before {
  fill: var(--stone);
}

.page-about .fb-bar--after {
  fill: var(--flag);
}

.page-about .fb-cap {
  font-family: var(--font-mono);
  font-size: 12px;
  fill: var(--ink);
}

.page-about .fb-val {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 700;
  fill: var(--indigo);
}

.page-about .feedback-figure figcaption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.6;
  color: var(--ink);
  opacity: .7;
}

.page-about .about-closer {
  margin-top: 30px;
  padding: 26px 20px;
  background: var(--mist);
  border-left: 4px solid var(--sky);
}

.page-about .closer-line {
  font-size: 16px;
  line-height: 1.76;
  margin: 0 0 18px;
  max-width: 60ch;
}

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

/* ---------- 图片容器兜底 ---------- */
.page-about .media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

/* ---------- 平板 ---------- */
@media (min-width: 720px) {
  .page-about .about-sec h2 {
    font-size: clamp(26px, 3.4vw, 34px);
  }

  .page-about .timeline::before {
    left: 6px;
  }

  .page-about .belief-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    align-items: start;
  }

  .page-about .belief-card:nth-child(2) {
    margin-top: 26px;
  }

  .page-about .belief-card:nth-child(3) {
    margin-top: 52px;
  }

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

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

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

/* ---------- 桌面 ---------- */
@media (min-width: 900px) {
  .page-about .hero-frame {
    display: grid;
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 44px;
    padding: 58px 48px 52px;
  }

  .page-about .hero-main {
    padding-left: 14px;
  }

  .page-about .hero-stats {
    margin-top: 0;
    padding-top: 0;
    border-top: 0;
    border-left: 1px dashed var(--stone);
    padding-left: 28px;
    align-content: start;
  }

  .page-about .about-shell {
    grid-template-columns: 128px minmax(0, 1fr);
    gap: 48px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
    align-self: start;
    border-bottom: 0;
    padding-bottom: 0;
  }

  .page-about .year-scale {
    flex-direction: column;
    gap: 6px;
    overflow: visible;
  }

  .page-about .year-item {
    min-width: 0;
    padding: 10px 12px 9px;
  }

  .page-about .year-tick {
    left: 12px;
    top: 5px;
    width: 18px;
  }

  .page-about .tl-item {
    padding-left: 40px;
  }

  .page-about .timeline::before {
    left: 8px;
  }

  .page-about .tl-dot {
    top: 14px;
    width: 15px;
    height: 15px;
  }

  .page-about .lines-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.1fr);
    gap: 40px;
  }

  .page-about .quality-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 34px;
  }

  .page-about .feedback-grid {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
    gap: 40px;
  }

  .page-about .about-closer {
    padding: 30px 34px;
  }
}

@media (min-width: 1120px) {
  .page-about .about-shell {
    grid-template-columns: 140px minmax(0, 1fr);
    gap: 64px;
  }

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

@media (prefers-reduced-motion: reduce) {
  .page-about .tl-mark::after {
    transition: none;
  }
}