.page-about {
  --about-index-w: 176px;
  --about-prose: 68ch;
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  padding: clamp(28px, 5vw, 64px) 0 clamp(26px, 4vw, 46px);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(27px, 4.4vw, 50px);
  line-height: 1.24;
  color: var(--cream);
  margin: 14px 0 0;
  max-width: 24em;
}

.page-about .about-hero__lede {
  margin: clamp(16px, 2.4vw, 26px) 0 0;
  max-width: 62ch;
  font-size: clamp(15.5px, 1.5vw, 17px);
  line-height: 1.85;
  color: var(--mute-2);
}

.page-about .about-hero__rule {
  height: 2px;
  margin-top: clamp(26px, 4vw, 44px);
  background: linear-gradient(
    90deg,
    var(--flame) 0 96px,
    var(--ice) 96px 176px,
    var(--line) 176px 100%
  );
}

/* ===== 折页式主体骨架 ===== */
.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 4vw, 56px);
  padding: clamp(34px, 5vw, 72px) 0 clamp(56px, 8vw, 112px);
}

.page-about .chap-index {
  align-self: start;
}

.page-about .chap-index__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--mute);
  text-transform: uppercase;
}

.page-about .chap-index__list {
  list-style: none;
  margin: 0;
  padding: 14px 0 0;
  border-top: 1px solid var(--line);
  display: flex;
  flex-wrap: wrap;
  gap: 6px 20px;
}

.page-about .chap-index__link {
  position: relative;
  display: block;
  padding-left: 20px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.9;
  letter-spacing: 0.04em;
  color: var(--mute);
  text-decoration: none;
  transition: color 180ms ease;
}

.page-about .chap-index__link::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.95em;
  width: 10px;
  height: 1px;
  background: var(--line);
  transition: width 180ms ease, background 180ms ease;
}

.page-about .chap-index__link:hover,
.page-about .chap-index__link:focus-visible,
.page-about .chap-index__link.is-current {
  color: var(--cream);
}

.page-about .chap-index__link:hover::before,
.page-about .chap-index__link:focus-visible::before,
.page-about .chap-index__link.is-current::before {
  width: 14px;
  background: var(--clay);
}

/* ===== 正文流 ===== */
.page-about .about-flow {
  display: flex;
  flex-direction: column;
  gap: clamp(44px, 6vw, 84px);
  min-width: 0;
}

.page-about .sec {
  scroll-margin-top: calc(var(--head-h) + 28px);
  max-width: var(--about-prose);
}

.page-about .sec__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--clay);
}

.page-about .sec__title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(23px, 3vw, 33px);
  line-height: 1.32;
  color: var(--cream);
  margin: 10px 0 0;
}

.page-about .sec__body {
  margin-top: 18px;
}

.page-about .sec__body p {
  margin: 0 0 16px;
  font-size: 16.5px;
  line-height: 1.86;
  color: var(--mute-2);
}

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

.page-about .sec__body a {
  color: var(--ice);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 168, 232, 0.42);
  transition: color 160ms ease, border-color 160ms ease;
}

.page-about .sec__body a:hover,
.page-about .sec__body a:focus-visible {
  color: var(--ice-soft);
  border-bottom-color: var(--ice-soft);
}

/* ===== 米白引用区 ===== */
.page-about .note {
  position: relative;
  max-width: var(--about-prose);
  background: var(--cream);
  border-left: 3px solid var(--moss);
  padding: clamp(24px, 3.4vw, 40px) clamp(22px, 3.4vw, 44px);
}

.page-about .note__mark {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 26px;
  line-height: 1;
  color: var(--moss);
}

.page-about .note p:last-child {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(17px, 2.1vw, 23px);
  line-height: 1.62;
  color: #1D2227;
}

/* ===== 制作流程步骤条 ===== */
.page-about .flow-steps {
  list-style: none;
  margin: 24px 0 0;
  padding: 0 0 0 clamp(18px, 2.4vw, 26px);
  border-left: 1px solid var(--line);
}

.page-about .flow-step {
  position: relative;
  padding-bottom: clamp(22px, 2.8vw, 32px);
  outline: none;
}

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

.page-about .flow-step::before {
  content: "";
  position: absolute;
  left: calc(clamp(18px, 2.4vw, 26px) * -1 - 4px);
  top: 7px;
  width: 7px;
  height: 7px;
  background: var(--flame);
  transform: rotate(45deg);
}

.page-about .flow-step__head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0;
}

.page-about .flow-step__no {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.1em;
  color: var(--flame);
}

.page-about .flow-step__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--cream);
}

.page-about .flow-step__text {
  margin: 8px 0 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--mute-2);
}

.page-about .flow-step__out {
  margin: 10px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--ice-soft);
}

.page-about .flow-step__tag {
  display: inline-block;
  margin-right: 8px;
  padding: 1px 7px;
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--moss);
  background: rgba(92, 122, 87, 0.16);
}

/* ===== 团队分工 ===== */
.page-about .team-list {
  margin: 0;
}

.page-about .team-item {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-top: 1px solid var(--line);
}

.page-about .team-item:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .team-item dt {
  display: flex;
  align-items: baseline;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--cream);
}

.page-about .team-item__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--clay);
}

.page-about .team-item dd {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.8;
  color: var(--mute-2);
}

/* ===== 协作生态节点 ===== */
.page-about .eco__list {
  list-style: none;
  margin: 22px 0 0;
  padding: 0 0 0 clamp(18px, 2.4vw, 26px);
  border-left: 1px solid var(--line);
  display: grid;
  gap: 14px;
}

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

.page-about .eco__node::before {
  content: "";
  position: absolute;
  left: calc(clamp(18px, 2.4vw, 26px) * -1);
  top: 22px;
  width: clamp(18px, 2.4vw, 26px);
  height: 1px;
  background: var(--line);
}

.page-about .eco__det {
  border: 1px solid var(--line);
  background: var(--slate);
  transition: border-color 160ms ease;
}

.page-about .eco__sum {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
  outline: none;
}

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

.page-about .eco__name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 17px;
  color: var(--cream);
}

.page-about .eco__plus {
  position: relative;
  margin-left: auto;
  width: 12px;
  height: 12px;
  flex: none;
}

.page-about .eco__plus::before,
.page-about .eco__plus::after {
  content: "";
  position: absolute;
  top: 50%;
  left: 0;
  width: 12px;
  height: 1px;
  background: var(--mute);
  transition: transform 200ms ease, background 200ms ease;
}

.page-about .eco__plus::after {
  transform: rotate(90deg);
}

.page-about .eco__det[open] .eco__plus::after {
  transform: rotate(0deg);
}

.page-about .eco__det[open] .eco__plus::before,
.page-about .eco__det[open] .eco__plus::after {
  background: var(--lime);
}

.page-about .eco__sum:hover,
.page-about .eco__sum:focus-visible {
  border-color: var(--mute);
  background: #2B3138;
}

.page-about .eco__det[open] {
  border-color: var(--lime);
}

.page-about .eco__det[open] > .eco__sum {
  background: #2B3138;
}

.page-about .eco__desc {
  margin: 0;
  padding: 0 16px 16px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute-2);
  border-top: 1px solid var(--line);
  padding-top: 14px;
}

/* ===== 版本记录 ===== */
.page-about .ver-board {
  margin: 22px 0 0;
  padding: clamp(20px, 2.6vw, 30px);
  background: var(--slate);
  border: 1px solid var(--line);
  display: grid;
  gap: 20px;
}

.page-about .ver-board__num {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.page-about .ver-board__num .num {
  font-family: var(--font-num);
  font-weight: 900;
  font-size: clamp(56px, 9vw, 96px);
  line-height: 0.92;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}

.page-about .ver-board__cap {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.12em;
  color: var(--mute);
}

.page-about .ver-board__list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .ver-board__list li {
  padding-top: 14px;
  border-top: 1px solid var(--line);
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute-2);
}

.page-about .ver-board__k {
  display: block;
  margin-bottom: 3px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ice);
}

/* ===== 配图 ===== */
.page-about .about-figure {
  margin: clamp(24px, 3.4vw, 36px) 0 clamp(22px, 3vw, 32px);
  max-width: 100%;
}

.page-about .about-figure .figure__img,
.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
  border: 1px solid var(--line);
}

.page-about .about-figure--small {
  max-width: 420px;
}

.page-about .about-figure .figure__cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: var(--mute);
}

/* ===== 结尾动作 ===== */
.page-about .sec--next {
  padding-top: clamp(22px, 3vw, 34px);
  border-top: 1px solid var(--line);
}

.page-about .sec__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 26px 0 0;
}

/* ===== 响应式 ===== */
@media (min-width: 768px) {
  .page-about .ver-board {
    grid-template-columns: minmax(160px, 0.7fr) minmax(0, 1.6fr);
    align-items: start;
    gap: 32px;
  }

  .page-about .team-item {
    grid-template-columns: minmax(140px, 0.6fr) minmax(0, 1.8fr);
    gap: 22px;
    align-items: baseline;
  }
}

@media (min-width: 900px) {
  .page-about .flow-step__out {
    max-height: 0;
    opacity: 0;
    overflow: hidden;
    margin-top: 0;
    transition: max-height 260ms ease, opacity 200ms ease, margin-top 260ms ease;
  }

  .page-about .flow-step:hover .flow-step__out,
  .page-about .flow-step:focus-within .flow-step__out {
    max-height: 220px;
    opacity: 1;
    margin-top: 10px;
  }
}

@media (min-width: 1024px) {
  .page-about .about-body {
    grid-template-columns: var(--about-index-w) minmax(0, 1fr);
    gap: clamp(44px, 6vw, 88px);
  }

  .page-about .chap-index {
    position: sticky;
    top: calc(var(--head-h) + 24px);
  }

  .page-about .chap-index__list {
    flex-direction: column;
    flex-wrap: nowrap;
    gap: 2px;
  }
}

@media (min-width: 1400px) {
  .page-about .ver-board__num .num {
    font-size: 108px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .chap-index__link,
  .page-about .chap-index__link::before,
  .page-about .eco__det,
  .page-about .eco__sum,
  .page-about .eco__plus::before,
  .page-about .eco__plus::after,
  .page-about .flow-step__out,
  .page-about .sec__body a {
    transition: none !important;
  }
}
<<<END>>>