.page-about {
  --about-rail: 230px;
  --flow-pad: clamp(20px, 3vw, 38px);
  color: var(--c-on-dark);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding-top: clamp(24px, 4vw, 48px);
}

.page-about .about-hero__inner {
  display: grid;
  gap: 14px;
}

.page-about h1 {
  margin: 0;
  max-width: 16em;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(29px, 5vw, 52px);
  line-height: 1.34;
  letter-spacing: .045em;
  color: var(--c-paper);
}

.page-about .about-hero__lead {
  margin: 6px 0 0;
  max-width: 44em;
  font-size: clamp(15px, 1.5vw, 17px);
  line-height: 1.95;
  color: var(--c-on-dark);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 18px;
  margin: clamp(10px, 2vw, 22px) 0 0;
}

.page-about .about-hero__facts > div {
  padding: 8px 0 8px 14px;
  border-left: 2px solid var(--c-brass);
}

.page-about .about-hero__facts dt {
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .16em;
  color: var(--c-brass);
}

.page-about .about-hero__facts dd {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.7;
  color: var(--c-paper);
}

.page-about .about-hero__figure {
  position: relative;
  margin: clamp(26px, 4vw, 50px) 0 0;
}

.page-about .about-hero__figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  border-top: 1px solid var(--c-line);
  border-bottom: 1px solid var(--c-line);
}

/* ---------- 主体双栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: clamp(30px, 4vw, 44px);
  padding-block: clamp(44px, 6vw, 88px);
}

.page-about .about-rail {
  align-self: start;
}

.page-about .about-rail__inner {
  position: static;
}

.page-about .about-rail__quote {
  margin: 0 0 26px;
  padding-left: 18px;
  border-left: 2px solid var(--c-cinnabar);
  font-family: var(--font-serif);
  font-size: 17.5px;
  line-height: 1.8;
  letter-spacing: .035em;
  color: var(--c-paper);
}

.page-about .about-rail__toc ol {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--c-line);
}

.page-about .about-rail__toc li + li {
  border-top: 1px dashed var(--c-line-soft);
}

.page-about .about-rail__toc a {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 11px 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--c-on-dark-dim);
  text-decoration: none;
  transition: color var(--dur) var(--ease), padding-left var(--dur) var(--ease);
}

.page-about .about-rail__toc a:hover,
.page-about .about-rail__toc a:focus-visible {
  padding-left: 5px;
  color: var(--c-brass-hi);
}

.page-about .about-rail__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .12em;
  color: var(--c-brass);
}

/* ---------- 连续画布与刻度 ---------- */
.page-about .about-flow {
  min-width: 0;
  position: relative;
  padding-left: var(--flow-pad);
  border-left: 1px solid var(--c-line-soft);
}

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

.page-about .about-sec + .about-sec {
  margin-top: clamp(44px, 6vw, 78px);
}

.page-about .about-sec::before {
  content: "";
  position: absolute;
  top: .6em;
  left: calc(-1 * var(--flow-pad) - 1px);
  width: calc(var(--flow-pad) - 8px);
  max-width: 26px;
  height: 2px;
  background: var(--c-brass);
}

.page-about .about-sec__head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 16px;
}

.page-about .about-sec__head h2 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: clamp(21px, 2.7vw, 30px);
  line-height: 1.45;
  letter-spacing: .04em;
  color: var(--c-paper);
}

.page-about .about-sec__body > p {
  margin: 0 0 18px;
  max-width: 46em;
  font-size: clamp(15px, 1.4vw, 16.5px);
  line-height: 1.95;
  color: var(--c-on-dark);
}

.page-about .about-sec__body a {
  color: var(--c-brass-hi);
  text-decoration: underline;
  text-decoration-color: rgba(201, 160, 80, .45);
  text-underline-offset: 3px;
}

.page-about .about-sec__body a:hover {
  text-decoration-color: var(--c-brass-hi);
}

.page-about .rule-list {
  margin: 4px 0 6px;
}

.page-about .rule-item {
  margin-bottom: 14px;
}

/* ---------- 院落示意 ---------- */
.page-about .about-map {
  margin: 6px 0 28px;
}

.page-about .about-map svg {
  display: block;
  width: 100%;
  max-width: 460px;
  height: auto;
}

.page-about .about-map text {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .1em;
  fill: #EDE4D3;
}

.page-about .about-map text.about-map__sub {
  font-size: 10px;
  letter-spacing: .12em;
  fill: rgba(237, 228, 211, .58);
}

.page-about .about-map figcaption {
  margin-top: 12px;
  max-width: 460px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.85;
  letter-spacing: .05em;
  color: var(--c-on-dark-dim);
}

/* ---------- 折叠条目 ---------- */
.page-about .about-folds {
  margin-top: 20px;
  border-top: 1px solid var(--c-line);
}

.page-about .about-fold {
  border-bottom: 1px solid var(--c-line-soft);
}

.page-about .about-fold summary {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 16px 2px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-fold summary::after {
  content: "＋";
  margin-left: auto;
  flex: none;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--c-brass);
}

.page-about .about-fold[open] summary::after {
  content: "－";
}

.page-about .about-fold__tag {
  flex: none;
  padding: 3px 7px;
  border: 1px solid rgba(201, 107, 92, .5);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .18em;
  color: var(--c-cinnabar-lt);
}

.page-about .about-fold__name {
  font-family: var(--font-serif);
  font-size: 16.5px;
  letter-spacing: .03em;
  color: var(--c-paper);
}

.page-about .about-fold__body {
  padding: 2px 0 20px 4px;
}

.page-about .about-fold__body p {
  margin: 0 0 10px;
  max-width: 42em;
  font-size: 15px;
  line-height: 1.9;
  color: var(--c-on-dark);
}

/* ---------- 节奏表 ---------- */
.page-about .about-cadence {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  margin: 6px 0 26px;
  border-top: 1px solid var(--c-line);
}

.page-about .about-cadence dt {
  padding: 15px 10px 15px 0;
  border-bottom: 1px solid var(--c-line-soft);
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.7;
  letter-spacing: .14em;
  color: var(--c-brass);
}

.page-about .about-cadence dd {
  margin: 0;
  padding: 15px 0;
  border-bottom: 1px solid var(--c-line-soft);
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-on-dark);
}

/* ---------- 配图 ---------- */
.page-about .about-figure {
  margin: 26px 0 0;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  height: auto;
  border: 1px solid var(--c-line);
}

.page-about .about-figure__cap {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.8;
  letter-spacing: .05em;
  color: var(--c-on-dark-dim);
}

/* ---------- 版本数字 ---------- */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 8px 0 24px;
  padding: 0;
  list-style: none;
  background: var(--c-line-soft);
  border: 1px solid var(--c-line-soft);
}

.page-about .about-stats__item {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 16px;
  background: var(--c-ink);
}

.page-about .about-stats__num {
  font-family: var(--font-serif);
  font-size: clamp(27px, 3.4vw, 40px);
  line-height: 1;
  letter-spacing: .02em;
  color: var(--c-brass);
}

.page-about .about-stats__label {
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--c-on-dark-dim);
}

/* ---------- 联系信息 ---------- */
.page-about .about-contact {
  display: grid;
  margin: 8px 0 20px;
  border-top: 1px solid var(--c-line);
}

.page-about .about-contact__row {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 10px 14px;
  padding: 13px 0;
  border-bottom: 1px solid var(--c-line-soft);
}

.page-about .about-contact__k {
  font-family: var(--font-mono);
  font-size: 11.5px;
  line-height: 1.8;
  letter-spacing: .14em;
  color: var(--c-brass);
}

.page-about .about-contact__v {
  font-size: 15px;
  line-height: 1.8;
  color: var(--c-paper);
  overflow-wrap: anywhere;
}

.page-about .about-cta {
  margin: clamp(26px, 4vw, 40px) 0 0;
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .about-hero__lead {
    font-size: 17px;
  }

  .page-about .about-cadence {
    grid-template-columns: 116px minmax(0, 1fr);
  }

  .page-about .about-contact__row {
    grid-template-columns: 108px minmax(0, 1fr);
    align-items: baseline;
  }
}

@media (min-width: 760px) {
  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 20px;
  }

  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

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

  .page-about .about-rail__inner {
    position: sticky;
    top: calc(var(--header-h) + 32px);
  }

  .page-about .about-sec__body > p {
    max-width: 44em;
  }
}

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