.page-about {
  background: var(--color-surface);
}

/* ---------- 页头 ---------- */
.page-about .about-intro {
  position: relative;
  overflow: hidden;
  padding: var(--space-6) 0 var(--space-6);
  background:
    radial-gradient(120% 90% at 94% -18%, var(--color-highlight) 0%, transparent 58%),
    radial-gradient(80% 70% at -6% 4%, var(--color-primary-soft) 0%, transparent 60%),
    var(--color-surface);
}

.page-about .about-intro__grid {
  display: grid;
  gap: var(--space-6);
  margin-top: var(--space-6);
}

@media (min-width: 960px) {
  .page-about .about-intro__grid {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
    gap: var(--space-8);
    align-items: start;
  }
}

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

.page-about .about-intro__title {
  margin: var(--space-3) 0 0;
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

@media (min-width: 780px) {
  .page-about .about-intro__title {
    font-size: var(--text-3xl);
  }
}

.page-about .about-intro__lede {
  margin: var(--space-4) 0 0;
  font-size: var(--text-lg);
  line-height: 1.62;
  color: var(--color-ink-soft);
}

.page-about .about-intro__aside {
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  background: linear-gradient(158deg, var(--color-surface-alt) 0%, var(--color-primary-soft) 100%);
  box-shadow: var(--shadow-1);
}

.page-about .about-intro__aside-title {
  margin: 0 0 var(--space-3);
  font-family: var(--font-heading);
  font-size: var(--text-base);
  font-weight: var(--weight-heading);
  color: var(--color-primary);
}

.page-about .about-notes {
  display: grid;
  gap: var(--space-3);
  margin: 0;
}

.page-about .about-notes__row {
  display: grid;
  gap: 4px;
}

.page-about .about-notes dt {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-ink-muted);
}

.page-about .about-notes dd {
  margin: 0;
  font-size: var(--text-sm);
  line-height: 1.7;
  color: var(--color-ink);
}

/* ---------- 章节轨道 ---------- */
.page-about .about-rail {
  position: sticky;
  top: 0;
  z-index: 4;
  padding: var(--space-2) 0;
  background: color-mix(in srgb, var(--color-surface) 92%, transparent);
  backdrop-filter: blur(10px);
  border-top: var(--border-thin) solid var(--color-line);
  border-bottom: var(--border-thin) solid var(--color-line);
}

.page-about .about-rail__list {
  display: flex;
  gap: var(--space-1);
  margin: 0;
  padding: 0 0 4px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-rail__list::-webkit-scrollbar {
  display: none;
}

.page-about .about-rail__link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: var(--radius-pill);
  font-size: var(--text-sm);
  color: var(--color-ink-soft);
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 200ms ease, color 200ms ease;
}

.page-about .about-rail__link:hover {
  background: var(--color-primary-soft);
  color: var(--color-primary);
}

.page-about .about-rail__link:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

.page-about .about-rail__link[aria-current] {
  background: var(--color-primary-soft);
  color: var(--color-primary);
  font-weight: var(--weight-heading);
}

.page-about .about-rail__num {
  font-size: var(--text-xs);
  color: var(--color-accent);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-chapter {
  padding-bottom: var(--section-y);
}

.page-about .about-chapter:first-of-type {
  padding-top: var(--space-8);
}

.page-about .about-chapter--last {
  padding-top: var(--section-y);
}

.page-about .about-chapter__grid {
  display: grid;
  gap: var(--space-4);
}

@media (min-width: 900px) {
  .page-about .about-chapter__grid {
    grid-template-columns: 168px minmax(0, 1fr);
    gap: var(--space-8);
    align-items: start;
  }

  .page-about .about-chapter__mark {
    position: sticky;
    top: calc(var(--space-8) + var(--space-4));
  }
}

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

.page-about .about-chapter__body {
  display: grid;
  gap: var(--space-3);
  max-width: var(--measure);
  align-content: start;
}

.page-about .about-chapter__body > * {
  margin: 0;
}

.page-about .about-chapter__body--wide {
  max-width: 100%;
}

.page-about .about-chapter__title {
  font-family: var(--font-heading);
  font-size: var(--text-xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-ink);
}

@media (min-width: 780px) {
  .page-about .about-chapter__title {
    font-size: var(--text-2xl);
  }
}

.page-about .about-chapter__body p {
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-ink);
}

.page-about .about-chapter__body a {
  color: var(--color-primary);
  text-underline-offset: 3px;
}

.page-about .about-chapter__body a:hover {
  color: var(--color-accent);
}

.page-about .about-chapter__body a:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
  border-radius: 4px;
}

/* ---------- 引文块 ---------- */
.page-about .about-quote {
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  background: linear-gradient(135deg, var(--color-primary-soft) 0%, var(--color-highlight) 100%);
}

.page-about .about-quote p {
  font-size: var(--text-lg);
  line-height: 1.6;
  color: var(--color-ink);
}

/* ---------- 图片位 ---------- */
.page-about .about-media {
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: var(--color-surface-deep);
}

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

/* ---------- 团队分工 ---------- */
.page-about .about-method {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 900px) {
  .page-about .about-method {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
    gap: var(--space-8);
    align-items: start;
  }
}

.page-about .about-roles {
  display: grid;
  gap: var(--space-4);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-role {
  display: grid;
  gap: 6px;
  padding-left: var(--space-3);
  border-left: 3px solid var(--color-primary-soft);
  transition: border-color 200ms ease;
}

.page-about .about-role:hover {
  border-left-color: var(--color-accent);
}

.page-about .about-role__tag {
  font-size: var(--text-xs);
  letter-spacing: 0.06em;
  color: var(--color-accent);
}

.page-about .about-role__title {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  color: var(--color-ink);
}

.page-about .about-role__text {
  font-size: var(--text-base);
  line-height: 1.72;
  color: var(--color-ink-soft);
}

/* ---------- 深色数字区 ---------- */
.page-about .about-now {
  position: relative;
  overflow: hidden;
  padding: var(--section-y-lg) 0;
  background: var(--color-contrast-surface);
  color: var(--color-contrast-ink);
}

.page-about .about-now::before {
  content: "";
  position: absolute;
  top: -32%;
  right: -12%;
  width: 620px;
  height: 620px;
  background: radial-gradient(circle, color-mix(in srgb, var(--color-accent) 46%, transparent) 0%, transparent 68%);
  pointer-events: none;
}

.page-about .about-now > .container {
  position: relative;
}

.page-about .about-now__kicker {
  margin: 0;
  font-size: var(--text-xs);
  letter-spacing: 0.14em;
  color: var(--color-contrast-accent);
}

.page-about .about-now__title {
  margin: var(--space-3) 0 0;
  font-family: var(--font-heading);
  font-size: var(--text-2xl);
  font-weight: var(--weight-heading);
  line-height: var(--leading-heading);
  letter-spacing: var(--tracking-heading);
  color: var(--color-contrast-ink);
}

.page-about .about-now__lede {
  margin: var(--space-3) 0 0;
  max-width: var(--measure);
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: color-mix(in srgb, var(--color-contrast-ink) 82%, transparent);
}

.page-about .about-figures {
  display: grid;
  gap: var(--space-4);
  margin-top: var(--space-6);
}

@media (min-width: 880px) {
  .page-about .about-figures {
    grid-template-columns: repeat(12, minmax(0, 1fr));
    gap: var(--space-6) var(--space-4);
  }

  .page-about .about-figure:nth-child(1) {
    grid-column: span 7;
  }

  .page-about .about-figure:nth-child(2) {
    grid-column: span 5;
  }

  .page-about .about-figure:nth-child(3) {
    grid-column: span 5;
  }

  .page-about .about-figure:nth-child(4) {
    grid-column: span 7;
  }

  .page-about .about-figure:nth-child(5) {
    grid-column: span 12;
  }
}

.page-about .about-figure {
  display: grid;
  gap: var(--space-1);
  padding-top: var(--space-3);
  border-top: var(--border-thin) solid var(--color-contrast-line);
  transition: transform 220ms ease;
}

.page-about .about-figure:hover {
  transform: translateY(-2px);
}

.page-about .about-figure__value {
  font-family: var(--font-mono);
  font-size: var(--text-figure);
  font-weight: var(--weight-heading);
  line-height: 1;
  font-variant-numeric: tabular-nums;
  color: var(--color-contrast-accent);
}

.page-about .about-figure__unit {
  font-size: var(--text-lg);
  margin-left: 4px;
}

.page-about .about-figure__label {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: var(--weight-heading);
  color: var(--color-contrast-ink);
}

.page-about .about-figure__text {
  font-size: var(--text-sm);
  line-height: 1.72;
  color: color-mix(in srgb, var(--color-contrast-ink) 76%, transparent);
}

.page-about .about-now__cta {
  display: grid;
  gap: var(--space-3);
  margin-top: var(--space-8);
  padding-top: var(--space-4);
  border-top: var(--border-thin) solid var(--color-contrast-line);
}

@media (min-width: 820px) {
  .page-about .about-now__cta {
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    gap: var(--space-6);
  }
}

.page-about .about-now__cta p {
  margin: 0;
  font-size: var(--text-base);
  line-height: var(--leading-body);
  color: var(--color-contrast-ink);
}

.page-about .about-now__actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

/* ---------- 协作与下一步 ---------- */
.page-about .about-pair {
  display: grid;
  gap: var(--space-3);
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-pair li {
  padding: var(--space-3);
  border-radius: var(--radius-md);
  background: var(--color-surface-alt);
  font-size: var(--text-base);
  line-height: 1.72;
  color: var(--color-ink);
}

.page-about .about-pair__key {
  display: block;
  margin-bottom: 4px;
  font-size: var(--text-xs);
  letter-spacing: 0.08em;
  color: var(--color-primary);
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-2);
}

.page-about .about-totop {
  margin-top: var(--space-4);
}

/* ---------- 窄屏收束 ---------- */
@media (max-width: 520px) {
  .page-about .about-intro__aside {
    padding: var(--space-3);
  }

  .page-about .about-figure__value {
    font-size: var(--text-2xl);
  }

  .page-about .about-now__actions .btn,
  .page-about .about-cta .btn {
    width: 100%;
    justify-content: center;
  }
}