.page-about {
  --about-rule: rgba(243, 238, 230, 0.16);
  --about-soft: rgba(243, 238, 230, 0.62);
  --about-track: 36px;
  background: var(--ink);
  color: var(--paper);
  padding-bottom: clamp(40px, 6vw, 88px);
  overflow-x: hidden;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: clamp(24px, 4vw, 56px) 0 clamp(24px, 3vw, 40px);
  border-bottom: 1px solid var(--about-rule);
  background-image: repeating-linear-gradient(
    90deg,
    rgba(243, 238, 230, 0.045) 0 1px,
    transparent 1px 78px
  );
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3.5vw, 46px);
  align-items: start;
  margin-top: clamp(18px, 2.4vw, 28px);
}

.page-about .about-hero__copy h1 {
  margin: 10px 0 0;
  font-family: var(--f-display);
  font-size: clamp(2rem, 5.4vw, 3.4rem);
  line-height: 1.06;
  letter-spacing: -0.02em;
  font-weight: 800;
}

.page-about .about-hero__lead {
  margin: 16px 0 0;
  max-width: 46ch;
  font-size: 16px;
  line-height: 1.75;
  color: var(--about-soft);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

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

.page-about .about-shot img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
  border: 1px solid var(--about-rule);
  background: var(--char);
}

.page-about .about-shot--hero img {
  aspect-ratio: 11 / 7;
  filter: saturate(0.72) contrast(1.04);
}

.page-about .about-shot--wide img {
  aspect-ratio: 2 / 1;
  margin-top: clamp(20px, 3vw, 32px);
}

.page-about .about-shot--square img {
  aspect-ratio: 3 / 2;
  margin-top: clamp(20px, 3vw, 32px);
}

.page-about .about-shot__cap {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--about-soft);
}

/* ---------- 数字条 ---------- */
.page-about .about-stats {
  list-style: none;
  margin: clamp(26px, 4vw, 44px) 0 0;
  padding: 18px 0 0;
  border-top: 1px solid var(--about-rule);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 2px;
  border-left: 2px solid var(--crimson);
  padding-left: 10px;
}

.page-about .about-stats__num {
  font-size: clamp(20px, 2.6vw, 28px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--paper);
  font-variant-numeric: tabular-nums;
}

.page-about .about-stats__label {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--about-soft);
}

/* ---------- 主体双栏 ---------- */
.page-about .about-body {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(24px, 3vw, 44px);
  padding-top: clamp(28px, 4vw, 52px);
}

.page-about .about-spy {
  border-left: 4px solid var(--crimson);
  padding-left: 16px;
}

.page-about .about-spy__title {
  margin: 0 0 10px;
  color: var(--amber);
}

.page-about .about-spy__nav {
  display: flex;
  flex-direction: column;
}

.page-about .about-spy__link {
  display: block;
  padding: 9px 0;
  font-size: 13.5px;
  line-height: 1.4;
  color: var(--about-soft);
  text-decoration: none;
  border-bottom: 1px dashed var(--about-rule);
  transition: color var(--speed) ease, padding-left var(--speed) ease;
}

.page-about .about-spy__link:hover,
.page-about .about-spy__link:focus-visible {
  color: var(--paper);
  padding-left: 6px;
}

.page-about .about-spy__link.is-current {
  color: var(--amber);
  font-weight: 700;
}

.page-about .about-spy__note {
  margin: 14px 0 0;
  line-height: 1.6;
}

/* ---------- 章节纸张 ---------- */
.page-about .about-sec {
  position: relative;
  padding: clamp(22px, 3.2vw, 42px);
  margin-bottom: clamp(20px, 2.6vw, 32px);
  background: var(--char);
  border: 1px solid var(--about-rule);
  box-shadow: 7px 7px 0 rgba(0, 0, 0, 0.42);
}

.page-about .about-sec--paper {
  --about-rule: rgba(13, 13, 15, 0.16);
  --about-soft: rgba(13, 13, 15, 0.66);
  background: var(--paper);
  color: var(--ink);
  box-shadow: 7px 7px 0 rgba(0, 0, 0, 0.34);
}

.page-about .about-sec__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px 14px;
  padding-bottom: 14px;
  margin-bottom: 22px;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-sec__no {
  font-size: 12px;
  letter-spacing: 0.12em;
  background: var(--crimson);
  color: var(--paper);
  padding: 4px 8px;
  line-height: 1;
}

.page-about .about-sec__head h2 {
  margin: 0;
  font-family: var(--f-display);
  font-size: clamp(1.3rem, 2.6vw, 1.95rem);
  line-height: 1.15;
  letter-spacing: -0.015em;
  font-weight: 800;
}

.page-about .about-sec__sub {
  flex: 1 0 100%;
  margin: 0;
  font-size: 14px;
  line-height: 1.65;
  color: var(--about-soft);
  max-width: 60ch;
}

/* ---------- 发展线 ---------- */
.page-about .about-timeline {
  position: relative;
  list-style: none;
  margin: 0;
  padding: 0 0 0 var(--about-track);
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 10px;
  top: 12px;
  bottom: 12px;
  width: 4px;
  background: linear-gradient(180deg, var(--crimson) 0%, var(--red) 55%, var(--crimson) 100%);
}

.page-about .about-node {
  position: relative;
  border-bottom: 1px dashed var(--about-rule);
}

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

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: -30px;
  top: 19px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 3px var(--paper);
  transition: transform var(--speed) ease;
}

.page-about .about-node:hover::before,
.page-about .about-node details[open]::before {
  transform: scale(1.25);
}

.page-about .about-node summary {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr) auto;
  gap: 6px 14px;
  align-items: baseline;
  padding: 15px 0;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-node__year {
  font-size: 15px;
  font-weight: 700;
  color: var(--crimson);
  font-variant-numeric: tabular-nums;
}

.page-about .about-node__title {
  font-family: var(--f-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.35;
}

.page-about .about-node__hint::after {
  content: "展开";
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--about-soft);
}

.page-about .about-node details[open] .about-node__hint::after {
  content: "收起";
  color: var(--crimson);
}

.page-about .about-node__body {
  margin: 0 0 16px;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--about-soft);
}

/* ---------- 团队分工 ---------- */
.page-about .about-roster {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-roster__row {
  position: relative;
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 2px 16px;
  padding: 18px 14px;
  border-bottom: 1px dashed var(--about-rule);
  transition: background var(--speed) ease;
}

.page-about .about-roster__row::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--red);
  transform: scaleY(0);
  transform-origin: top center;
  transition: transform var(--speed) ease;
}

.page-about .about-roster__row:hover {
  background: rgba(243, 238, 230, 0.05);
}

.page-about .about-roster__row:hover::before {
  transform: scaleY(1);
}

.page-about .about-roster__num {
  grid-row: span 2;
  font-size: clamp(26px, 3.2vw, 34px);
  font-weight: 700;
  line-height: 1;
  color: var(--amber);
  font-variant-numeric: tabular-nums;
}

.page-about .about-roster__role {
  font-family: var(--f-display);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page-about .about-roster__duty {
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-soft);
}

/* ---------- 流程 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.page-about .about-steps__item {
  padding: 18px 16px 20px;
  border: 1px solid var(--about-rule);
  border-top: 3px solid var(--crimson);
  background: rgba(13, 13, 15, 0.035);
}

.page-about .about-steps__no {
  display: inline-block;
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--crimson);
}

.page-about .about-steps__item h3 {
  margin: 8px 0 6px;
  font-family: var(--f-display);
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .about-steps__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-soft);
}

/* ---------- 三条内容线 ---------- */
.page-about .about-lines {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .about-lines__item {
  padding: 20px 0;
  border-top: 1px solid var(--about-rule);
}

.page-about .about-lines__item:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-lines__head {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.page-about .about-lines__head h3 {
  margin: 0;
  font-family: var(--f-display);
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.01em;
}

.page-about .about-lines__item p {
  margin: 8px 0 0;
  max-width: 60ch;
  font-size: 14px;
  line-height: 1.7;
  color: var(--about-soft);
}

.page-about .about-lines__link {
  display: inline-block;
  margin-top: 10px;
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 2px;
  transition: color var(--speed) ease, border-color var(--speed) ease;
}

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

/* ---------- 社群互校 ---------- */
.page-about .about-community {
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
}

.page-about .about-community__stat {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 14px 0;
  border-bottom: 1px solid var(--about-rule);
}

.page-about .about-community__num {
  font-size: clamp(30px, 4vw, 42px);
  font-weight: 700;
  line-height: 1;
  color: var(--crimson);
  font-variant-numeric: tabular-nums;
}

.page-about .about-community__label {
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--about-soft);
}

.page-about .about-community__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.8;
}

/* ---------- 通用小件 ---------- */
.page-about .about-note {
  margin: 18px 0 0;
  line-height: 1.7;
}

.page-about .about-inline-link {
  color: inherit;
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color var(--speed) ease;
}

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

/* ---------- 结尾 ---------- */
.page-about .about-cta {
  padding: clamp(24px, 3.4vw, 44px);
  background: var(--crimson);
  color: var(--paper);
  border: 1px solid rgba(243, 238, 230, 0.2);
  box-shadow: 7px 7px 0 rgba(0, 0, 0, 0.34);
}

.page-about .about-cta h2 {
  margin: 0;
  font-family: var(--f-display);
  font-size: clamp(1.35rem, 2.8vw, 2rem);
  line-height: 1.15;
  letter-spacing: -0.015em;
  font-weight: 800;
}

.page-about .about-cta p {
  margin: 10px 0 0;
  font-size: 15px;
  line-height: 1.7;
  color: rgba(243, 238, 230, 0.82);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

.page-about .about-cta .m-btn--line {
  color: var(--paper);
  border-color: rgba(243, 238, 230, 0.6);
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

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

  .page-about .about-community__text {
    grid-column: 1 / -1;
  }
}

@media (min-width: 760px) {
  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .about-roster__row:nth-child(even) {
    margin-left: 34px;
  }

  .page-about .about-node__body {
    padding-left: 78px;
    margin-top: -4px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero__grid {
    grid-template-columns: 1.12fr 0.88fr;
  }

  .page-about .about-stats {
    grid-template-columns: repeat(6, minmax(0, 1fr));
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: 218px minmax(0, 1fr);
    gap: clamp(32px, 4vw, 56px);
  }

  .page-about .about-spy {
    position: sticky;
    top: 24px;
    align-self: start;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-spy__link,
  .page-about .about-roster__row,
  .page-about .about-roster__row::before,
  .page-about .about-node::before,
  .page-about .about-lines__link {
    transition: none;
  }
}