.page-about {
  --about-stage-line: 6px;
  --about-soft: rgba(244, 239, 228, .74);
  display: block;
  background: var(--ink-0);
  color: var(--bone);
}

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

.page-about a {
  color: var(--flag-blue);
}

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

/* ---------- 通用章节头 ---------- */
.page-about .about-head {
  max-width: 46ch;
  margin-bottom: clamp(26px, 4vw, 46px);
}

.page-about .about-head__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(26px, 4.4vw, 44px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  margin: 10px 0 0;
  color: var(--bone);
}

.page-about .about-head__note {
  margin: 14px 0 0;
  font-size: 17px;
  line-height: 1.9;
  color: var(--about-soft);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  padding: clamp(28px, 4vw, 46px) 0 clamp(48px, 7vw, 92px);
  overflow: hidden;
  border-bottom: var(--line) solid var(--rock);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  width: 10px;
  background: var(--flag-v);
  opacity: .85;
}

.page-about .breadcrumb {
  font-family: var(--font-mono);
  font-size: 13px;
  color: rgba(244, 239, 228, .6);
  margin-bottom: clamp(20px, 3vw, 34px);
}

.page-about .about-hero__grid {
  display: grid;
  gap: clamp(28px, 4vw, 44px);
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(34px, 7.4vw, 78px);
  line-height: 1.04;
  letter-spacing: -0.025em;
  margin: 12px 0 0;
  color: var(--bone);
}

.page-about .about-hero__lede {
  margin: clamp(18px, 2.6vw, 28px) 0 0;
  font-size: 17px;
  line-height: 1.9;
  color: rgba(244, 239, 228, .82);
  max-width: 42ch;
}

.page-about .about-hero__entry {
  border: var(--line) solid var(--rock);
  background: var(--ink-1);
  box-shadow: var(--shadow);
  padding: 16px 16px 6px;
}

.page-about .about-hero__entry-title {
  font-size: 12px;
  letter-spacing: .14em;
  color: var(--gold);
  margin: 0 0 12px;
  text-transform: uppercase;
}

.page-about .about-entry {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "k t"
    "k d";
  gap: 2px 12px;
  align-items: baseline;
  padding: 12px 10px;
  border-top: 2px solid var(--rock);
  text-decoration: none;
  color: var(--bone);
  transition: background .2s ease, transform .2s ease;
}

.page-about .about-entry:first-of-type {
  border-top: 0;
}

.page-about .about-entry:hover,
.page-about .about-entry:focus-visible {
  background: rgba(233, 178, 60, .1);
  transform: translateX(2px);
  color: var(--bone);
}

.page-about .about-entry__k {
  grid-area: k;
  font-size: 13px;
  color: var(--clay);
}

.page-about .about-entry__t {
  grid-area: t;
  font-size: 16px;
  font-weight: 700;
}

.page-about .about-entry__d {
  grid-area: d;
  font-size: 13px;
  line-height: 1.7;
  color: rgba(244, 239, 228, .64);
}

.page-about .about-hero__facts {
  list-style: none;
  margin: clamp(30px, 5vw, 52px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 2px;
  background: var(--rock);
  border: var(--line) solid var(--rock);
}

.page-about .about-fact {
  background: var(--ink-0);
  padding: 16px 14px;
}

.page-about .about-fact__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(22px, 3.6vw, 34px);
  line-height: 1.1;
  color: var(--gold);
}

.page-about .about-fact__label {
  display: block;
  margin-top: 6px;
  font-size: 13px;
  color: var(--about-soft);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  padding: clamp(52px, 8vw, 108px) 0;
  background: var(--ink-1);
  border-bottom: var(--line) solid var(--rock);
  overflow: hidden;
}

.page-about .about-timeline__bg {
  position: absolute;
  inset: 0;
  opacity: .2;
  pointer-events: none;
}

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

.page-about .about-timeline__inner {
  position: relative;
}

.page-about .timeline {
  display: grid;
  gap: clamp(22px, 3.5vw, 48px);
}

.page-about .timeline__rail ol {
  list-style: none;
  margin: 0;
  padding: 0 0 10px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .timeline__rail a {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 9px 14px;
  border: 2px solid var(--rock);
  text-decoration: none;
  color: rgba(244, 239, 228, .7);
  white-space: nowrap;
  transition: border-color .2s ease, background .2s ease, color .2s ease;
}

.page-about .timeline__rail a:hover,
.page-about .timeline__rail a:focus-visible {
  border-color: var(--gold);
  background: rgba(233, 178, 60, .1);
  color: var(--bone);
}

.page-about .timeline__yr {
  font-size: 14px;
  color: var(--gold);
}

.page-about .timeline__nm {
  font-size: 13px;
}

.page-about .timeline__stages {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: clamp(18px, 2.6vw, 30px);
}

.page-about .stage {
  position: relative;
  padding: clamp(20px, 3vw, 30px) clamp(18px, 3vw, 30px) clamp(20px, 3vw, 30px) clamp(26px, 3.4vw, 38px);
  background: var(--ink-0);
  border: var(--line) solid var(--rock);
  box-shadow: var(--shadow-sm);
  scroll-margin-top: 100px;
}

.page-about .stage::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: var(--about-stage-line);
  background: var(--clay);
}

.page-about .stage:nth-child(even)::before {
  background: var(--flag-green);
}

.page-about .stage:target {
  border-color: var(--gold);
  box-shadow: 8px 8px 0 rgba(233, 178, 60, .3);
}

.page-about .stage__year {
  margin: 0;
  font-size: clamp(26px, 3.6vw, 40px);
  line-height: 1;
  color: var(--gold);
  letter-spacing: -0.02em;
}

.page-about .stage__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(19px, 2.4vw, 25px);
  line-height: 1.3;
  color: var(--bone);
}

.page-about .stage__text {
  margin: 10px 0 0;
  font-size: 17px;
  line-height: 1.9;
  color: var(--about-soft);
  max-width: 46ch;
}

/* ---------- 服务对象 ---------- */
.page-about .about-audience {
  background: var(--ink-2);
  padding: clamp(52px, 8vw, 108px) 0;
  border-bottom: var(--line) solid var(--rock);
}

.page-about .audience-grid {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 18px;
}

.page-about .audience-card {
  position: relative;
  padding: 22px 20px 18px 26px;
  background: rgba(21, 15, 46, .74);
  border-left: 6px solid var(--clay);
  box-shadow: var(--shadow-sm);
}

.page-about .audience-card:nth-child(2) {
  border-left-color: var(--flag-blue);
}

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

.page-about .audience-card:nth-child(4) {
  border-left-color: var(--flag-green);
}

.page-about .audience-card__num {
  margin: 0;
  font-size: 13px;
  letter-spacing: .16em;
  color: var(--gold);
}

.page-about .audience-card__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 19px;
  line-height: 1.35;
  color: var(--bone);
}

.page-about .audience-card__text {
  margin: 10px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(244, 239, 228, .8);
}

.page-about .audience-card__go {
  margin: 14px 0 0;
  font-size: 14px;
  font-family: var(--font-mono);
}

/* ---------- 内容体系 ---------- */
.page-about .about-system {
  background: var(--ink-0);
  padding: clamp(52px, 8vw, 108px) 0;
  border-bottom: var(--line) solid var(--rock);
}

.page-about .system-grid {
  display: grid;
  gap: clamp(28px, 4vw, 56px);
  align-items: center;
}

.page-about .system-chart {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
}

.page-about .about-fan {
  width: min(100%, 320px);
  height: auto;
  filter: drop-shadow(8px 8px 0 rgba(0, 0, 0, .5));
}

.page-about .system-chart__cap {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--about-soft);
  margin: 0;
}

.page-about .system-body__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(19px, 2.4vw, 25px);
  line-height: 1.32;
  color: var(--bone);
}

.page-about .system-body__title + .system-body__text {
  margin-top: 0;
}

.page-about .system-body__text {
  margin: 0 0 clamp(26px, 3.4vw, 40px);
  font-size: 17px;
  line-height: 1.9;
  color: var(--about-soft);
  max-width: 46ch;
}

.page-about .system-chips {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: -14px 0 clamp(26px, 3.4vw, 40px);
  padding: 0;
}

.page-about .chip {
  font-family: var(--font-mono);
  font-size: 13px;
  padding: 5px 11px;
  border: 2px solid var(--rock);
  color: rgba(244, 239, 228, .86);
}

.page-about .chip:nth-child(3n+1) {
  border-color: var(--flag-blue);
}

.page-about .chip:nth-child(3n+2) {
  border-color: var(--flag-green);
}

.page-about .chip:nth-child(3n) {
  border-color: var(--clay);
}

.page-about .system-downloads {
  margin-top: clamp(38px, 5vw, 68px);
  display: grid;
  gap: clamp(22px, 3.4vw, 40px);
  padding-top: clamp(28px, 4vw, 46px);
  border-top: var(--line) solid var(--rock);
}

.page-about .system-figure {
  margin: 0;
}

.page-about .system-figure img {
  width: 100%;
  border: var(--line) solid var(--rock);
  box-shadow: var(--shadow);
  object-fit: cover;
}

.page-about .system-figure__cap {
  margin: 12px 0 0;
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--about-soft);
}

.page-about .download-panel__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(20px, 2.6vw, 27px);
  line-height: 1.3;
  color: var(--bone);
}

.page-about .download-panel__text {
  margin: 0 0 20px;
  font-size: 17px;
  line-height: 1.9;
  color: var(--about-soft);
  max-width: 44ch;
}

.page-about .download-list {
  list-style: none;
  margin: 0 0 24px;
  padding: 0;
  display: grid;
  gap: 2px;
  background: var(--rock);
  border: var(--line) solid var(--rock);
}

.page-about .download-item {
  background: #16333A;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 16px;
}

.page-about .download-item__num {
  font-size: clamp(20px, 2.6vw, 26px);
  color: var(--gold);
}

.page-about .download-item__label {
  font-size: 15px;
  color: rgba(244, 239, 228, .84);
}

.page-about .download-panel__go {
  margin: 0;
}

/* ---------- 团队 ---------- */
.page-about .about-team {
  background: var(--bone);
  color: var(--ink-0);
  padding: clamp(52px, 8vw, 108px) 0;
  border-bottom: var(--line) solid var(--rock);
}

.page-about .about-team .about-head__title {
  color: var(--ink-0);
}

.page-about .about-team .about-head__note {
  color: rgba(21, 15, 46, .74);
}

.page-about .about-team .eyebrow {
  color: var(--clay);
}

.page-about .team-blocks {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.page-about .team-block {
  position: relative;
  padding: 20px 20px 18px;
  color: var(--bone);
  transition: transform .24s ease, box-shadow .24s ease;
}

.page-about .team-block--content {
  background: var(--clay);
}

.page-about .team-block--tech {
  background: var(--flag-blue);
}

.page-about .team-block--support {
  background: var(--flag-green);
}

.page-about .team-block--community {
  background: #6E8B58;
}

.page-about .team-block__num {
  margin: 0;
  font-size: clamp(30px, 4.4vw, 44px);
  line-height: 1;
  color: rgba(244, 239, 228, .96);
  letter-spacing: -0.02em;
}

.page-about .team-block__role {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 19px;
  color: #fff;
}

.page-about .team-block__desc {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .9);
}

.page-about .team-block__extra {
  display: block;
  margin: 0;
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  font-size: 14px;
  line-height: 1.75;
  color: rgba(255, 255, 255, .95);
  transition: max-height .28s ease, opacity .28s ease, margin-top .28s ease;
}

.page-about .team-block:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 0 rgba(21, 15, 46, .3);
}

.page-about .team-block:hover .team-block__extra,
.page-about .team-block:focus-within .team-block__extra {
  max-height: 12em;
  opacity: 1;
  margin-top: 10px;
}

.page-about .team-figure {
  margin: clamp(30px, 4.4vw, 56px) 0 0;
}

.page-about .team-figure img {
  width: 100%;
  border: var(--line) solid var(--ink-0);
  box-shadow: var(--shadow);
  object-fit: cover;
}

.page-about .team-figure__cap {
  margin: 12px 0 0;
  font-size: 12px;
  letter-spacing: .08em;
  color: rgba(21, 15, 46, .6);
}

.page-about .team-trust {
  margin-top: clamp(26px, 3.6vw, 42px);
  display: grid;
  gap: 14px;
  padding-left: 18px;
  border-left: 6px solid var(--gold);
}

.page-about .team-trust__text {
  margin: 0;
  font-size: 16px;
  line-height: 1.85;
  color: rgba(21, 15, 46, .82);
  max-width: 62ch;
}

/* ---------- 四条理由 ---------- */
.page-about .about-reasons {
  background: var(--ink-0);
  padding: clamp(52px, 8vw, 108px) 0;
  border-bottom: var(--line) solid var(--rock);
}

.page-about .reason-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: var(--line) solid var(--rock);
}

.page-about .reason {
  position: relative;
  padding: 22px 0 22px 20px;
  border-bottom: 2px solid var(--rock);
}

.page-about .reason::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 6px;
  background: var(--flag-blue);
}

.page-about .reason:nth-child(2)::before {
  background: var(--flag-green);
}

.page-about .reason:nth-child(3)::before {
  background: var(--gold);
}

.page-about .reason:nth-child(4)::before {
  background: var(--clay);
}

.page-about .reason__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(19px, 2.3vw, 24px);
  line-height: 1.3;
  color: var(--bone);
}

.page-about .reason__text {
  margin: 0;
  font-size: 17px;
  line-height: 1.9;
  color: var(--about-soft);
  max-width: 60ch;
}

/* ---------- 继续了解 ---------- */
.page-about .about-next {
  background: var(--ink-1);
  padding: clamp(52px, 8vw, 108px) 0;
}

.page-about .next-grid {
  display: grid;
  gap: 16px;
}

.page-about .next-card {
  display: block;
  padding: 24px 20px;
  background: var(--ink-0);
  border: var(--line) solid var(--rock);
  box-shadow: var(--shadow-sm);
  text-decoration: none;
  color: var(--bone);
  transition: transform .24s ease, box-shadow .24s ease, border-color .24s ease;
}

.page-about .next-card:hover,
.page-about .next-card:focus-visible {
  transform: translate(-2px, -2px);
  box-shadow: var(--shadow);
  border-color: var(--gold);
  color: var(--bone);
}

.page-about .next-card__k {
  margin: 0;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--gold);
}

.page-about .next-card__t {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: 22px;
  line-height: 1.25;
  color: var(--bone);
}

.page-about .next-card__d {
  margin: 10px 0 16px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--about-soft);
}

.page-about .next-card__a {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 14px;
  color: var(--gold);
}

/* ---------- 响应式 ---------- */
@media (min-width: 700px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .audience-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }

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

@media (min-width: 880px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(300px, .85fr);
    align-items: start;
  }

  .page-about .system-grid {
    grid-template-columns: minmax(0, .9fr) minmax(0, 1.1fr);
  }

  .page-about .system-downloads {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    align-items: center;
  }

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

@media (min-width: 900px) {
  .page-about .timeline {
    grid-template-columns: 214px minmax(0, 1fr);
    align-items: start;
  }

  .page-about .timeline__rail {
    position: sticky;
    top: 92px;
    align-self: start;
  }

  .page-about .timeline__rail ol {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .timeline__rail a {
    border: 0;
    border-left: 3px solid transparent;
    padding: 12px 14px;
    margin-left: -3px;
    white-space: normal;
  }

  .page-about .timeline__rail a:hover,
  .page-about .timeline__rail a:focus-visible {
    border-left-color: var(--gold);
  }

  .page-about .audience-grid {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: 22px;
  }

  .page-about .audience-card:nth-child(1) {
    grid-column: 1 / 7;
  }

  .page-about .audience-card:nth-child(2) {
    grid-column: 8 / 13;
    margin-top: 52px;
  }

  .page-about .audience-card:nth-child(3) {
    grid-column: 2 / 8;
    margin-top: 26px;
  }

  .page-about .audience-card:nth-child(4) {
    grid-column: 8 / 13;
    margin-top: 78px;
  }

  .page-about .team-blocks {
    flex-direction: row;
    align-items: flex-start;
    gap: 8px;
  }

  .page-about .team-block--content {
    flex: 1.7 1 0;
  }

  .page-about .team-block--tech {
    flex: 1.28 1 0;
    margin-top: 26px;
  }

  .page-about .team-block--support {
    flex: 1 1 0;
    margin-top: 52px;
  }

  .page-about .team-block--community {
    flex: 1 1 0;
    margin-top: 78px;
  }

  .page-about .reason {
    display: grid;
    grid-template-columns: minmax(180px, 260px) minmax(0, 1fr);
    gap: 8px 28px;
    align-items: baseline;
    padding: 26px 0 26px 24px;
  }

  .page-about .reason__title {
    margin-bottom: 0;
  }
}

@media (max-width: 899px) {
  .page-about .team-block__extra {
    max-height: none;
    opacity: 1;
    margin-top: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }

  .page-about .team-block:hover {
    transform: none;
  }

  .page-about .next-card:hover,
  .page-about .next-card:focus-visible {
    transform: none;
  }
}