.page-about {
  --about-rail-w: 236px;
  --about-gap: 52px;
  --about-goldline: rgba(201, 138, 46, 0.3);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  padding: 26px 0 34px;
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero .page-head__title {
  margin: 10px 0 0;
  max-width: 20em;
  color: var(--text);
  letter-spacing: 0.03em;
}

.page-about .about-hero .page-head__lead {
  max-width: 62ch;
  color: var(--text-dim);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 30px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  overflow: hidden;
}

.page-about .about-stat {
  padding: 18px 16px 16px;
  background: linear-gradient(158deg, rgba(44, 58, 115, 0.5), rgba(14, 20, 48, 0.9));
}

.page-about .about-stat__num {
  display: block;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: 0.02em;
  color: var(--mane-300);
}

.page-about .about-stat__label {
  display: block;
  margin-top: 7px;
  font-size: 13px;
  line-height: 1.5;
  color: var(--text-dim);
}

/* ---------- 布局：左栏正文 + 右栏索引 ---------- */
.page-about .about-layout {
  display: block;
  padding-top: 34px;
}

.page-about .about-rail {
  margin: 0 0 30px;
  overflow-x: auto;
  overflow-y: hidden;
  -webkit-overflow-scrolling: touch;
  border-bottom: 1px solid var(--line);
}

.page-about .about-index__title {
  display: none;
}

.page-about .about-index__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0 0 12px;
  list-style: none;
  min-width: max-content;
}

.page-about .about-index__link {
  display: inline-flex;
  align-items: baseline;
  gap: 6px;
  padding: 7px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--text-dim);
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s ease, border-color 0.2s ease, background 0.2s ease;
}

.page-about .about-index__num {
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--steel-200);
}

.page-about .about-index__link:hover,
.page-about .about-index__link:focus-visible {
  color: var(--text);
  border-color: var(--line-strong);
  background: var(--glass);
}

.page-about .about-index__link[aria-current="true"] {
  color: var(--amber-300);
  border-color: rgba(255, 138, 30, 0.55);
  background: rgba(255, 138, 30, 0.1);
}

.page-about .about-index__link[aria-current="true"] .about-index__num {
  color: var(--amber-500);
}

/* ---------- 章节骨架 ---------- */
.page-about .about-block {
  padding: 38px 0 44px;
  border-top: 1px solid var(--line);
  scroll-margin-top: 96px;
}

.page-about .about-block:first-child {
  border-top: 0;
  padding-top: 4px;
}

.page-about .section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.page-about .section-head__title {
  margin: 0;
  font-size: 23px;
  line-height: 1.35;
  letter-spacing: 0.02em;
  color: var(--text);
}

.page-about .section-head__index {
  flex: none;
  font-size: 13px;
  letter-spacing: 0.18em;
  color: var(--steel-200);
}

.page-about .about-lead {
  margin-top: 20px;
  max-width: 62ch;
}

.page-about .about-lead p {
  margin: 0;
  font-size: 16px;
  line-height: 1.82;
  color: var(--text-dim);
}

.page-about .about-lead a {
  color: var(--amber-300);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 182, 92, 0.4);
}

.page-about .about-lead a:hover {
  color: var(--amber-500);
  border-bottom-color: var(--amber-500);
}

.page-about .media-frame {
  margin: 24px 0 0;
  border-radius: var(--radius-m);
  overflow: hidden;
}

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

/* ---------- 时间轴 ---------- */
.page-about .about-timeline {
  position: relative;
  margin: 26px 0 0;
  padding: 0 0 0 26px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 12px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--mane-500), var(--amber-500) 48%, var(--steel-400));
  opacity: 0.7;
}

.page-about .about-timeline > li {
  position: relative;
  padding: 0 0 22px;
}

.page-about .about-timeline > li:last-child {
  padding-bottom: 0;
}

.page-about .about-timeline > li::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 6px;
  width: 11px;
  height: 11px;
  border-radius: 3px;
  background: var(--ink-900);
  border: 1px solid var(--mane-500);
  box-shadow: 0 0 0 4px rgba(201, 138, 46, 0.12);
}

.page-about .tl-year {
  display: inline-block;
  margin-bottom: 6px;
  font-size: 13px;
  letter-spacing: 0.16em;
  color: var(--amber-300);
}

.page-about .tl-title {
  margin: 0 0 6px;
  font-size: 17.5px;
  line-height: 1.45;
  color: var(--text);
}

.page-about .tl-text {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-dim);
}

.page-about .tl-text a {
  color: var(--amber-300);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 182, 92, 0.4);
}

/* ---------- 人群卡 ---------- */
.page-about .persona-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .persona {
  position: relative;
  padding: 18px 18px 18px 22px;
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  background: var(--glass);
}

.page-about .persona::before {
  content: "";
  position: absolute;
  left: 0;
  top: 18px;
  bottom: 18px;
  width: 2px;
  border-radius: 2px;
  background: var(--mane-500);
}

.page-about .persona__no {
  display: block;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--steel-200);
}

.page-about .persona__title {
  margin: 8px 0 7px;
  font-size: 17.5px;
  line-height: 1.45;
  color: var(--text);
}

.page-about .persona__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.76;
  color: var(--text-dim);
}

.page-about .persona__text a {
  color: var(--amber-300);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 182, 92, 0.4);
}

.page-about .persona .tag-list {
  margin-top: 12px;
}

/* ---------- 三段式图文 ---------- */
.page-about .about-split {
  margin-top: 20px;
}

.page-about .about-split .media-frame {
  margin-top: 18px;
}

/* ---------- 版本轨道 ---------- */
.page-about .track-stack {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .track {
  padding: 17px 18px 16px;
  border: 1px solid var(--line);
  border-left: 3px solid var(--mane-500);
  border-radius: var(--radius-m);
  background: linear-gradient(120deg, rgba(44, 58, 115, 0.42), rgba(27, 36, 80, 0.9));
  transition: background 0.22s ease, box-shadow 0.22s ease, border-left-color 0.22s ease;
}

.page-about .track--stable {
  border-left-color: var(--amber-500);
}

.page-about .track--compat {
  border-left-color: var(--steel-400);
}

.page-about .track:hover,
.page-about .track:focus-within {
  background: linear-gradient(120deg, rgba(44, 58, 115, 0.72), rgba(27, 36, 80, 0.95));
  box-shadow: 0 0 0 1px var(--line-strong);
}

.page-about .track:hover {
  border-left-color: var(--amber-500);
}

.page-about .track--compat:hover {
  border-left-color: var(--amber-300);
}

.page-about .track__head {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  gap: 10px;
}

.page-about .track__name {
  margin: 0;
  font-size: 18.5px;
  line-height: 1.4;
  color: var(--text);
}

.page-about .track__code {
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--steel-200);
}

.page-about .track__text {
  margin: 9px 0 0;
  max-width: 62ch;
  font-size: 15px;
  line-height: 1.74;
  color: var(--text-dim);
}

.page-about .track__note {
  margin: 10px 0 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--mane-300);
  transition: color 0.22s ease;
}

.page-about .track:hover .track__note {
  color: var(--amber-300);
}

/* ---------- 四象限团队 ---------- */
.page-about .team-bento {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-top: 24px;
}

.page-about .team-cell {
  position: relative;
  padding: 20px 18px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-m);
  background: linear-gradient(155deg, rgba(44, 58, 115, 0.55), rgba(14, 20, 48, 0.92));
}

.page-about .team-cell::after {
  content: "";
  position: absolute;
  right: 16px;
  top: 16px;
  width: 20px;
  height: 20px;
  border-top: 1px solid var(--line-strong);
  border-right: 1px solid var(--line-strong);
  opacity: 0.65;
}

.page-about .team-cell__no {
  display: block;
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--mane-300);
}

.page-about .team-cell__name {
  margin: 9px 0 8px;
  font-size: 18px;
  line-height: 1.4;
  color: var(--text);
}

.page-about .team-cell__text {
  margin: 0;
  font-size: 14.8px;
  line-height: 1.74;
  color: var(--text-dim);
}

/* ---------- 合作三段 ---------- */
.page-about .eco-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .eco-item {
  padding-left: 16px;
  border-left: 1px solid var(--line-strong);
}

.page-about .eco-item__k {
  display: block;
  margin-bottom: 8px;
  font-size: 11.5px;
  letter-spacing: 0.16em;
  color: var(--amber-300);
}

.page-about .eco-item__t {
  margin: 0 0 8px;
  font-size: 17.5px;
  line-height: 1.4;
  color: var(--text);
}

.page-about .eco-item__d {
  margin: 0;
  font-size: 15px;
  line-height: 1.74;
  color: var(--text-dim);
}

/* ---------- 陕西 ---------- */
.page-about .shaanxi {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 22px;
}

.page-about .shaanxi .media-frame {
  margin: 0;
  border: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(44, 58, 115, 0.3), rgba(14, 20, 48, 0.8));
}

.page-about .shaanxi__lead {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.82;
  color: var(--text-dim);
}

.page-about .shaanxi__list {
  margin: 16px 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 10px;
}

.page-about .shaanxi__list li {
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text);
  padding-left: 0;
}

.page-about .shaanxi__k {
  display: inline-block;
  min-width: 82px;
  margin-right: 8px;
  font-size: 11.5px;
  letter-spacing: 0.14em;
  color: var(--steel-200);
}

.page-about .shaanxi__more {
  margin: 16px 0 0;
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--text-dim);
}

.page-about .shaanxi__more a {
  color: var(--amber-300);
  text-decoration: none;
  border-bottom: 1px solid rgba(255, 182, 92, 0.4);
}

/* ---------- 原则与问答 ---------- */
.page-about .principle-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .principle {
  padding: 16px 18px;
  border: 1px solid var(--about-goldline);
  border-left: 3px solid var(--mane-500);
  border-radius: var(--radius-m);
  background: rgba(201, 138, 46, 0.08);
}

.page-about .principle__t {
  margin: 0 0 7px;
  font-size: 17px;
  line-height: 1.45;
  color: var(--mane-300);
}

.page-about .principle__d {
  margin: 0;
  font-size: 14.8px;
  line-height: 1.76;
  color: var(--text-dim);
}

.page-about .qa-list {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .qa-item {
  padding: 16px 0;
  border-top: 1px solid var(--line);
}

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

.page-about .qa-item__q {
  margin: 0 0 8px;
  font-size: 16.5px;
  line-height: 1.5;
  color: var(--text);
}

.page-about .qa-item__a {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.78;
  color: var(--text-dim);
}

/* ---------- 结尾入口 ---------- */
.page-about .about-cta {
  margin-top: 30px;
  padding: 26px 22px 24px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-l);
  background: linear-gradient(135deg, rgba(201, 138, 46, 0.17), rgba(44, 58, 115, 0.52) 56%, rgba(14, 20, 48, 0.94));
}

.page-about .about-cta__title {
  margin: 0 0 9px;
  font-size: 20px;
  line-height: 1.45;
  color: var(--text);
  letter-spacing: 0.02em;
}

.page-about .about-cta__text {
  margin: 0 0 18px;
  max-width: 62ch;
  font-size: 14.8px;
  line-height: 1.74;
  color: var(--text-dim);
}

.page-about .about-cta__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

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

/* ---------- 中屏 ---------- */
@media (min-width: 700px) {
  .page-about .about-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-stat__num {
    font-size: 28px;
  }

  .page-about .section-head__title {
    font-size: 27px;
  }

  .page-about .persona-list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .team-bento {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .page-about .eco-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
  }

  .page-about .principle-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 大屏：左窄栏正文 + 右侧跟随索引 ---------- */
@media (min-width: 1000px) {
  .page-about .about-hero {
    padding: 34px 0 40px;
  }

  .page-about .about-hero .page-head__title {
    font-size: 40px;
    line-height: 1.24;
  }

  .page-about .about-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) var(--about-rail-w);
    gap: var(--about-gap);
    align-items: start;
    padding-top: 40px;
  }

  .page-about .about-rail {
    position: sticky;
    top: 104px;
    margin: 0;
    overflow: visible;
    border-bottom: 0;
    order: 2;
  }

  .page-about .about-index {
    padding: 18px 16px;
    border: 1px solid var(--line);
    border-radius: var(--radius-m);
    background: linear-gradient(170deg, rgba(44, 58, 115, 0.42), rgba(14, 20, 48, 0.85));
  }

  .page-about .about-index__title {
    display: block;
    margin: 0 0 12px;
    font-size: 11.5px;
    letter-spacing: 0.2em;
    color: var(--steel-200);
  }

  .page-about .about-index__list {
    flex-direction: column;
    gap: 2px;
    min-width: 0;
    padding: 0;
  }

  .page-about .about-index__link {
    display: flex;
    width: 100%;
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0 var(--radius-s) var(--radius-s) 0;
    padding: 9px 10px;
    font-size: 14px;
    white-space: normal;
  }

  .page-about .about-index__link[aria-current="true"] {
    background: rgba(255, 138, 30, 0.09);
    border-left-width: 2px;
  }

  .page-about .about-block {
    padding: 46px 0 52px;
  }

  .page-about .section-head__title {
    font-size: 30px;
  }

  .page-about .about-split {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.02fr);
    gap: 34px;
    align-items: center;
  }

  .page-about .about-split .about-lead {
    margin-top: 0;
  }

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

  .page-about .shaanxi {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr);
    gap: 34px;
    align-items: center;
  }

  .page-about .track-stack {
    gap: 14px;
  }

  .page-about .about-cta {
    padding: 32px 30px 28px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero .page-head__title {
    font-size: 44px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .track,
  .page-about .track__note,
  .page-about .about-index__link {
    transition: none;
  }
}