.page-about {
  display: block;
  --about-rule: rgba(214, 167, 71, .22);
}

/* ===== 首屏 ===== */
.page-about .about-hero {
  position: relative;
  padding-top: clamp(22px, 4vw, 44px);
  padding-bottom: clamp(40px, 6vw, 76px);
  overflow: hidden;
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image: linear-gradient(to right, rgba(154, 166, 199, .16) 1px, transparent 1px);
  background-size: 96px 100%;
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--about-rule) 22%, var(--about-rule) 78%, transparent);
}

.page-about .about-hero > .container {
  position: relative;
  z-index: 1;
}

.page-about .hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 5vw, 52px);
  margin-top: 26px;
}

@media (min-width: 900px) {
  .page-about .hero-grid {
    grid-template-columns: minmax(0, 1.06fr) minmax(0, .94fr);
    align-items: end;
    gap: 60px;
  }
}

.page-about .hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 20px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: .16em;
  color: var(--gold);
}

.page-about .hero-eyebrow .mono-index {
  color: var(--gold-hi);
  letter-spacing: .08em;
}

.page-about .hero-text h1 {
  margin: 0 0 22px;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(29px, 5vw, 54px);
  line-height: 1.16;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-about .hero-lede {
  margin: 0 0 34px;
  max-width: 33em;
  font-size: clamp(16px, 1.7vw, 17.5px);
  line-height: 1.9;
  color: var(--text);
}

.page-about .hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 22px;
  padding-top: 24px;
  border-top: 1px solid var(--about-rule);
}

@media (min-width: 620px) {
  .page-about .hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

.page-about .hero-stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}

.page-about .hero-stat-num {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(26px, 3.4vw, 34px);
  line-height: 1;
  color: var(--gold-hi);
  letter-spacing: -0.01em;
}

.page-about .hero-stat-cap {
  font-family: var(--font-mono);
  font-size: 12px;
  line-height: 1.5;
  letter-spacing: .02em;
  color: var(--mist);
}

.page-about .hero-media {
  position: relative;
}

.page-about .hero-media::before {
  content: "";
  position: absolute;
  top: 0;
  left: -16px;
  width: 1px;
  height: 62%;
  background: linear-gradient(to bottom, var(--gold), rgba(214, 167, 71, 0));
}

@media (max-width: 899px) {
  .page-about .hero-media::before {
    display: none;
  }
}

.page-about .media-frame {
  margin: 0;
}

.page-about .chapter-media {
  margin-bottom: 30px;
}

.page-about .chapter-media--narrow {
  max-width: 560px;
}

/* ===== 双栏主体 ===== */
.page-about .about-shell {
  padding-bottom: clamp(56px, 8vw, 104px);
}

.page-about .about-body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(30px, 5vw, 56px);
  padding-top: clamp(44px, 6vw, 76px);
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: 208px minmax(0, 1fr);
    gap: 68px;
    align-items: start;
  }
}

/* ===== 左侧索引 ===== */
.page-about .idx-title {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .2em;
  color: var(--mist);
}

.page-about .idx-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid rgba(154, 166, 199, .22);
}

.page-about .idx-link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  margin-left: -1px;
  padding: 9px 0 9px 16px;
  border-left: 1px solid transparent;
  font-size: 14px;
  line-height: 1.5;
  color: var(--mist);
  text-decoration: none;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .idx-link:hover,
.page-about .idx-link:focus-visible {
  color: var(--gold-hi);
  border-left-color: var(--gold);
}

.page-about .idx-link:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: 3px;
}

.page-about .idx-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .06em;
  color: var(--gold);
}

@media (min-width: 960px) {
  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 26px);
    align-self: start;
  }
}

@media (max-width: 959px) {
  .page-about .idx-list {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 18px;
    border-left: 0;
    border-bottom: 1px solid rgba(154, 166, 199, .22);
    padding-bottom: 14px;
  }

  .page-about .idx-link {
    margin-left: 0;
    padding: 4px 0;
    border-left: 0;
  }

  .page-about .idx-link:hover,
  .page-about .idx-link:focus-visible {
    border-left-color: transparent;
  }
}

/* ===== 章节 ===== */
.page-about .about-flow {
  min-width: 0;
}

.page-about .about-chapter {
  padding: clamp(34px, 5vw, 58px) 0;
  border-top: 1px solid rgba(154, 166, 199, .18);
  scroll-margin-top: calc(var(--header-h) + 28px);
}

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

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

.page-about .about-chapter:target .chapter-title {
  color: var(--gold-hi);
}

.page-about .chapter-head {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}

.page-about .chapter-head::after {
  content: "";
  flex: 1;
  height: 1px;
  background: linear-gradient(to right, var(--about-rule), rgba(214, 167, 71, 0));
}

.page-about .chapter-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: clamp(15px, 1.8vw, 19px);
  font-weight: 500;
  letter-spacing: .05em;
  color: var(--gold);
}

.page-about .chapter-title {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 900;
  font-size: clamp(23px, 3.2vw, 38px);
  line-height: 1.22;
  letter-spacing: -0.02em;
  color: var(--paper);
  transition: color .25s var(--ease);
}

.page-about .chapter-body p {
  max-width: 38em;
  margin: 0 0 18px;
  font-size: 16.5px;
  line-height: 1.9;
  color: var(--text);
}

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

.page-about .cat-note {
  margin-top: 28px;
}

/* ===== 类目刻度 ===== */
.page-about .cat-scale {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid rgba(154, 166, 199, .18);
}

.page-about .cat-cell {
  position: relative;
  padding: 16px 0 16px 20px;
  border-bottom: 1px solid rgba(154, 166, 199, .18);
  transition: background-color .2s var(--ease);
}

.page-about .cat-cell::before {
  content: "";
  position: absolute;
  left: 0;
  top: 27px;
  width: 9px;
  height: 1px;
  background: var(--gold);
  opacity: .65;
}

.page-about .cat-cell:hover {
  background-color: rgba(42, 58, 120, .22);
}

.page-about .cat-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.page-about .cat-num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .06em;
  color: var(--gold);
}

.page-about .cat-name {
  font-family: var(--font-serif);
  font-size: 17px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .cat-desc {
  margin: 6px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

@media (min-width: 760px) {
  .page-about .cat-scale {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 48px;
    border-top: 0;
  }

  .page-about .cat-cell {
    border-top: 1px solid rgba(154, 166, 199, .18);
  }
}

/* ===== 团队分工表 ===== */
.page-about .team-table {
  margin-top: 30px;
  border-top: 1px solid var(--about-rule);
}

.page-about .team-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 4px 18px;
  align-items: baseline;
  padding: 14px 0;
  border-bottom: 1px solid rgba(154, 166, 199, .18);
}

.page-about .team-role {
  font-family: var(--font-mono);
  font-size: 13.5px;
  letter-spacing: .03em;
  color: var(--paper);
}

.page-about .team-scope {
  grid-column: 1 / -1;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
}

.page-about .team-size {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--celadon);
  text-align: right;
  white-space: nowrap;
}

.page-about .team-row--head .team-role,
.page-about .team-row--head .team-scope,
.page-about .team-row--head .team-size {
  font-size: 11.5px;
  letter-spacing: .18em;
  color: var(--mist);
  opacity: .8;
}

.page-about .team-row--head .team-scope {
  display: none;
}

@media (min-width: 700px) {
  .page-about .team-row {
    grid-template-columns: 132px minmax(0, 1fr) 82px;
    gap: 0 22px;
  }

  .page-about .team-scope {
    grid-column: auto;
  }

  .page-about .team-row--head .team-scope {
    display: block;
  }
}

/* ===== 团队展开 ===== */
.page-about .team-more {
  margin-top: 26px;
  border: 1px solid rgba(154, 166, 199, .22);
  border-radius: var(--radius-sm);
  background: rgba(42, 58, 120, .18);
  overflow: hidden;
}

.page-about .team-more > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 15px 18px;
  cursor: pointer;
  list-style: none;
  font-size: 15px;
  font-weight: 500;
  color: var(--paper);
  transition: background-color .2s var(--ease);
}

.page-about .team-more > summary::-webkit-details-marker {
  display: none;
}

.page-about .team-more > summary:hover {
  background: rgba(42, 58, 120, .4);
}

.page-about .team-more > summary::after {
  content: "+";
  flex: none;
  font-family: var(--font-mono);
  font-size: 17px;
  line-height: 1;
  color: var(--gold);
}

.page-about .team-more[open] > summary::after {
  content: "–";
}

.page-about .team-more > summary:focus-visible {
  outline: 2px solid var(--coral);
  outline-offset: -2px;
}

.page-about .team-more-body {
  padding: 4px 18px 18px;
  border-top: 1px solid rgba(154, 166, 199, .18);
}

.page-about .team-more-body p {
  margin: 14px 0 0;
  max-width: 38em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

/* ===== 更新节奏 ===== */
.page-about .rhythm {
  margin-top: 28px;
  border-top: 1px solid var(--about-rule);
}

.page-about .rhythm-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 6px;
  padding: 18px 0;
  border-bottom: 1px solid rgba(154, 166, 199, .18);
}

@media (min-width: 640px) {
  .page-about .rhythm-row {
    grid-template-columns: 148px minmax(0, 1fr);
    gap: 26px;
    align-items: baseline;
  }
}

.page-about .rhythm-mark {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: .05em;
  color: var(--celadon);
}

.page-about .rhythm-text {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

/* ===== 联系区块 ===== */
.page-about .about-contact {
  position: relative;
  margin-top: clamp(36px, 5vw, 56px);
  padding: clamp(26px, 4vw, 42px);
  border: 1px solid var(--about-rule);
  border-radius: var(--radius);
  background: linear-gradient(140deg, rgba(22, 32, 74, .95), rgba(11, 18, 48, .95));
  overflow: hidden;
}

.page-about .about-contact::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 92px;
  height: 3px;
  background: var(--coral);
}

.page-about .contact-lead {
  margin: 0 0 20px;
  font-family: var(--font-serif);
  font-size: clamp(17px, 2vw, 20px);
  font-weight: 700;
  color: var(--paper);
}

.page-about .contact-list {
  list-style: none;
  margin: 0 0 28px;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .contact-list li {
  position: relative;
  padding-left: 20px;
  max-width: 42em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--mist);
}

.page-about .contact-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .78em;
  width: 8px;
  height: 1px;
  background: var(--gold);
}

.page-about .contact-list strong {
  color: var(--paper);
  font-weight: 600;
}

.page-about .contact-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 14px;
}

@media (prefers-reduced-motion: reduce) {
  .page-about .idx-link,
  .page-about .cat-cell,
  .page-about .team-more > summary,
  .page-about .chapter-title {
    transition: none;
  }
}