.page-about {
  --about-rail-w: 152px;
  --about-gap: clamp(18px, 3.2vw, 44px);
  --about-space: clamp(56px, 8vw, 112px);
  color: var(--paper-mist);
}

.page-about h1 {
  margin: 14px 0 0;
  font-size: clamp(1.85rem, 5.1vw, 3.5rem);
  font-weight: 900;
  line-height: 1.14;
  letter-spacing: -0.012em;
  color: var(--paper-mist);
}

.page-about h2 {
  margin: 0 0 16px;
  font-size: clamp(1.3rem, 2.6vw, 1.95rem);
  font-weight: 700;
  line-height: 1.36;
  color: var(--paper-mist);
}

.page-about h3 {
  margin: 0 0 8px;
  font-weight: 700;
  color: var(--paper-mist);
}

.page-about .num {
  font-family: var(--font-mono);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.015em;
  color: var(--electric-yellow);
}

.page-about .num[title] {
  cursor: help;
  border-bottom: 1px dashed rgba(53, 224, 200, 0.55);
}

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  padding: clamp(22px, 3.6vw, 44px) 0 clamp(44px, 6.4vw, 88px);
  border-bottom: var(--line);
}

.page-about .about-hero__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(26px, 4vw, 52px);
  align-items: end;
}

.page-about .about-lede {
  margin: 20px 0 0;
  max-width: 58ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--muted-slate);
}

.page-about .about-stats {
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(126px, 1fr));
  gap: 1px;
  background: var(--grid-line);
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-stats li {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 14px 16px 16px;
  background: var(--ink-layer);
}

.page-about .about-stat__num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2.15rem);
  font-weight: 600;
  line-height: 1;
  color: var(--electric-yellow);
  letter-spacing: -0.02em;
}

.page-about .about-stat__label {
  font-size: 0.75rem;
  line-height: 1.55;
  color: var(--muted-slate);
}

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

.page-about .figure__frame {
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  background: var(--ink-layer);
  overflow: hidden;
}

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

.page-about .figure__caption {
  margin-top: 10px;
  font-size: 0.76rem;
  line-height: 1.7;
  color: var(--muted-slate);
}

/* ---------- 题签 ---------- */

.page-about .about-plate {
  padding: clamp(40px, 6vw, 80px) 0 0;
}

.page-about .about-plate__inner {
  max-width: 62ch;
  padding: 2px 0 2px clamp(16px, 2.4vw, 30px);
  border-left: 1px solid var(--cyan-signal);
}

.page-about .about-plate__text {
  margin: 0;
  font-family: var(--font-serif);
  font-size: clamp(1.12rem, 2.3vw, 1.6rem);
  line-height: 1.62;
  color: var(--paper-mist);
}

.page-about .about-plate__sub {
  margin: 14px 0 0;
  font-size: 0.88rem;
  line-height: 1.78;
  color: var(--muted-slate);
}

/* ---------- 通用章节 ---------- */

.page-about .about-section {
  margin-top: var(--about-space);
}

.page-about .about-rail-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(16px, 3vw, 40px);
}

.page-about .about-rail__label {
  display: block;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--grid-line);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.26em;
  color: var(--cyan-signal);
}

.page-about .about-main p {
  margin: 0 0 18px;
  max-width: 72ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--paper-mist);
}

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

.page-about .about-main a,
.page-about .about-report__body a {
  color: var(--cyan-signal);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.page-about .about-main a:hover,
.page-about .about-report__body a:hover {
  color: var(--focus-ring);
}

.page-about .about-origin__figure {
  margin: 26px 0 28px;
  max-width: 660px;
}

.page-about .about-origin__figure .figure__frame {
  border-left: 1px solid var(--cyan-signal);
}

/* ---------- 整理方法 ---------- */

.page-about .about-method__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
  align-items: start;
}

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

.page-about .about-method__figure .figure__frame {
  border-top: 2px solid var(--cyan-signal);
}

.page-about .about-method__body p {
  margin: 0 0 18px;
  max-width: 70ch;
  font-size: 1rem;
  line-height: 1.8;
  color: var(--paper-mist);
}

.page-about .about-method__body a {
  color: var(--cyan-signal);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}

.page-about .about-method__body a:hover {
  color: var(--focus-ring);
}

.page-about .caliber-fold {
  margin-top: 26px;
  border-top: 1px solid var(--grid-line);
  border-bottom: 1px solid var(--grid-line);
}

.page-about .caliber-fold__summary {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 13px 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  color: var(--cyan-signal);
}

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

.page-about .caliber-fold__summary::before {
  content: "+";
  flex: none;
  width: 1em;
  color: var(--muted-slate);
}

.page-about .caliber-fold[open] .caliber-fold__summary::before {
  content: "−";
  color: var(--cyan-signal);
}

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

.page-about .about-fields {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 11px;
}

.page-about .about-fields li {
  position: relative;
  padding-left: 18px;
  max-width: 68ch;
  font-size: 0.9rem;
  line-height: 1.76;
  color: var(--muted-slate);
}

.page-about .about-fields li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.76em;
  width: 7px;
  height: 1px;
  background: var(--cyan-signal);
}

/* ---------- 团队分工 ---------- */

.page-about .about-roles {
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 1px;
  background: var(--grid-line);
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  overflow: hidden;
}

.page-about .about-roles li {
  display: grid;
  gap: 7px;
  padding: 16px 18px;
  background: var(--ink-layer);
}

.page-about .about-roles__name {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  color: var(--cyan-signal);
}

.page-about .about-roles__desc {
  font-size: 0.88rem;
  line-height: 1.75;
  color: var(--muted-slate);
}

/* ---------- 口径阶段 ---------- */

.page-about .about-phase-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 22px 0 0;
}

.page-about .about-phase-nav a {
  display: inline-block;
  padding: 6px 12px;
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.06em;
  color: var(--muted-slate);
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .about-phase-nav a:hover,
.page-about .about-phase-nav a:focus-visible {
  border-color: var(--cyan-signal);
  color: var(--cyan-signal);
}

.page-about .about-track {
  position: relative;
  margin: 30px 0 0;
  padding: 0 0 0 clamp(18px, 3vw, 40px);
  list-style: none;
}

.page-about .about-track::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(
    180deg,
    rgba(53, 224, 200, 0) 0%,
    rgba(53, 224, 200, 0.85) 10%,
    rgba(53, 224, 200, 0.85) 88%,
    rgba(53, 224, 200, 0) 100%
  );
  opacity: 0.6;
}

.page-about .phase {
  position: relative;
  padding: 0 0 clamp(26px, 4vw, 44px);
  scroll-margin-top: 96px;
}

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

.page-about .phase::before {
  content: "";
  position: absolute;
  left: calc(-1 * clamp(18px, 3vw, 40px));
  top: 8px;
  width: 9px;
  height: 9px;
  border: 1px solid var(--cyan-signal);
  border-radius: 50%;
  background: var(--ink-base);
  transform: translateX(-50%);
}

.page-about .phase:target::before {
  background: var(--cyan-signal);
}

.page-about .phase:target {
  background: linear-gradient(90deg, rgba(53, 224, 200, 0.09), rgba(53, 224, 200, 0) 72%);
  border-radius: var(--radius);
}

.page-about .phase__index {
  display: block;
  margin-bottom: 7px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.22em;
  color: var(--cyan-signal);
}

.page-about .phase__title {
  font-size: clamp(1.05rem, 1.9vw, 1.32rem);
  line-height: 1.4;
}

.page-about .phase__text {
  margin: 0;
  max-width: 70ch;
  font-size: 0.94rem;
  line-height: 1.8;
  color: var(--muted-slate);
}

/* ---------- 来源与纠错 ---------- */

.page-about .about-report__grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(20px, 3vw, 40px);
  align-items: start;
  padding-top: clamp(24px, 3.4vw, 42px);
  border-top: 1px solid var(--grid-line);
}

.page-about .about-report__body p {
  margin: 0 0 16px;
  max-width: 70ch;
  font-size: 0.96rem;
  line-height: 1.8;
  color: var(--paper-mist);
}

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

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

.page-about .about-report__actions .btn {
  text-decoration: none;
}

/* ---------- 断点 ---------- */

@media (min-width: 720px) {
  .page-about .about-roles {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 860px) {
  .page-about .about-rail-grid {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
    gap: var(--about-gap);
  }

  .page-about .about-rail__label {
    padding: 2px 0 0 12px;
    border-bottom: 0;
    border-left: 1px solid var(--grid-line);
    writing-mode: vertical-rl;
    letter-spacing: 0.34em;
  }
}

@media (min-width: 900px) {
  .page-about .about-method__grid {
    grid-template-columns: minmax(0, 0.74fr) minmax(0, 1.26fr);
  }

  .page-about .about-report__grid {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  }

  .page-about .about-report__actions {
    justify-content: flex-end;
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.12fr) minmax(0, 0.88fr);
  }
}

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