.page-about {
  --about-rule: 1px solid var(--grid-line);
  --about-pad: clamp(56px, 9vw, 104px);
  padding-bottom: 88px;
  overflow-x: clip;
}

/* ---------- 面包屑 ---------- */
.page-about .breadcrumb {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 28px 0 32px;
  font-size: 13px;
  letter-spacing: .08em;
  color: var(--gray-rock);
}
.page-about .breadcrumb a {
  color: var(--gray-rock);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--flag-blue);
  border-bottom-color: var(--flag-blue);
}
.page-about .breadcrumb [aria-current="page"] {
  color: var(--yak-white);
}

/* ---------- 品牌封面 ---------- */
.page-about .brand-cover {
  padding-top: 6px;
}
.page-about .brand-cover::before {
  content: "";
  display: block;
  width: 104px;
  height: 3px;
  margin-bottom: 26px;
  background: linear-gradient(90deg,
    var(--flag-blue) 0 20%,
    var(--flag-white) 20% 40%,
    var(--flag-red) 40% 60%,
    var(--flag-green) 60% 80%,
    var(--flag-yellow) 80% 100%);
}
.page-about .brand-cover__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.2rem, 7.5vw, 5rem);
  line-height: .96;
  letter-spacing: -.02em;
  color: var(--yak-white);
}
.page-about .brand-cover__lede {
  max-width: 56ch;
  margin: 24px 0 0;
  font-size: clamp(1rem, 1.4vw, 1.1875rem);
  line-height: 1.9;
  color: var(--yak-white);
  opacity: .88;
}
.page-about .brand-cover__stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 22px 20px;
  margin: 40px 0 0;
  padding-top: 26px;
  border-top: var(--about-rule);
}
.page-about .brand-cover__stats .stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-width: 0;
}
.page-about .brand-cover__stats .stat__value {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  font-weight: 700;
  line-height: 1;
  color: var(--flag-white);
}
.page-about .brand-cover__stats .stat:nth-child(2) .stat__value { color: var(--flag-blue); }
.page-about .brand-cover__stats .stat:nth-child(3) .stat__value { color: var(--flag-green); }
.page-about .brand-cover__stats .stat:nth-child(4) .stat__value { color: var(--amber); }
.page-about .brand-cover__stats .stat__label {
  font-size: 12px;
  letter-spacing: .1em;
  color: var(--gray-rock);
}

/* ---------- 图片通用 ---------- */
.page-about .media-frame {
  margin: 0;
}
.page-about .media-frame img {
  width: 100%;
  height: auto;
  display: block;
}
.page-about .media-frame__caption {
  margin-top: 12px;
  font-size: 12px;
  letter-spacing: .06em;
  line-height: 1.6;
  color: var(--gray-rock);
}
.page-about .brand-cover__figure {
  margin: 44px 0 0;
}

/* ---------- 章节目录 ---------- */
.page-about .brand-index {
  position: sticky;
  top: var(--bar-h);
  z-index: 6;
  margin-top: 34px;
  background: var(--night);
  border-top: var(--about-rule);
  border-bottom: var(--about-rule);
}
.page-about .brand-index__list {
  display: flex;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}
.page-about .brand-index__list::-webkit-scrollbar { display: none; }
.page-about .brand-index__list a {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 14px 16px;
  white-space: nowrap;
  font-size: 13px;
  letter-spacing: .04em;
  color: var(--gray-rock);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}
.page-about .brand-index__list a:hover,
.page-about .brand-index__list a:focus-visible {
  color: var(--flag-white);
  border-bottom-color: var(--amber);
}
.page-about .brand-index__num {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--flag-blue);
}

/* ---------- 章节骨架 ---------- */
.page-about .brand-chapter {
  scroll-margin-top: calc(var(--bar-h) + 68px);
}
.page-about .brand-chapter:first-child {
  margin-top: clamp(36px, 5vw, 56px);
}
.page-about .brand-chapter + .brand-chapter {
  margin-top: var(--about-pad);
  padding-top: clamp(32px, 4vw, 48px);
  border-top: var(--about-rule);
}
.page-about .brand-chapter .chapter-head {
  display: flex;
  align-items: baseline;
  gap: clamp(12px, 2vw, 22px);
  margin-bottom: clamp(22px, 3vw, 34px);
}
.page-about .brand-chapter .chapter-head__index {
  font-family: var(--font-mono);
  font-size: clamp(2rem, 6vw, 3.6rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -.03em;
  color: var(--flag-blue);
  opacity: .5;
}
.page-about .brand-chapter:nth-of-type(2) .chapter-head__index { color: var(--flag-green); }
.page-about .brand-chapter:nth-of-type(3) .chapter-head__index { color: var(--amber); }
.page-about .brand-chapter:nth-of-type(4) .chapter-head__index { color: var(--flag-red); }
.page-about .brand-chapter:nth-of-type(5) .chapter-head__index { color: var(--flag-yellow); }
.page-about .brand-chapter:nth-of-type(6) .chapter-head__index { color: var(--flag-blue); }
.page-about .brand-chapter .section-title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.5rem, 3.4vw, 2.4rem);
  line-height: 1.15;
  letter-spacing: -.01em;
  color: var(--yak-white);
}
.page-about .brand-chapter__body p {
  max-width: 68ch;
  margin: 0 0 18px;
  font-size: 1rem;
  line-height: 1.9;
  color: var(--yak-white);
  opacity: .86;
}
.page-about .brand-chapter__body p:last-child { margin-bottom: 0; }

/* ---------- 时间线 ---------- */
.page-about .brand-timeline {
  position: relative;
  margin: 0;
  padding: 4px 0 4px 30px;
  list-style: none;
  border-left: 1px solid var(--grid-line);
}
.page-about .brand-timeline__item {
  position: relative;
  padding-bottom: 34px;
}
.page-about .brand-timeline__item:last-child { padding-bottom: 0; }
.page-about .brand-timeline__item::before {
  content: "";
  position: absolute;
  left: -35px;
  top: 10px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--night);
  border: 1px solid var(--grid-line);
  transition: background .25s var(--ease), border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.page-about .brand-timeline__item:hover::before,
.page-about .brand-timeline__item:focus-within::before {
  background: var(--amber);
  border-color: var(--amber);
  box-shadow: 0 0 0 5px rgba(242, 183, 5, .16);
}
.page-about .brand-timeline__year {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: clamp(1.35rem, 2.6vw, 1.75rem);
  font-weight: 700;
  line-height: 1;
  color: var(--flag-blue);
}
.page-about .brand-timeline__item:nth-child(2) .brand-timeline__year { color: var(--flag-green); }
.page-about .brand-timeline__item:nth-child(3) .brand-timeline__year { color: var(--amber); }
.page-about .brand-timeline__item:nth-child(4) .brand-timeline__year { color: var(--flag-red); }
.page-about .brand-timeline__title {
  margin: 0 0 8px;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--flag-white);
}
.page-about .brand-timeline__text {
  max-width: 62ch;
  margin: 0;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--yak-white);
  opacity: .78;
}

/* ---------- 设计手记 ---------- */
.page-about .brand-chapter__lede {
  max-width: 58ch;
  margin: 0 0 clamp(24px, 3vw, 34px);
  font-size: 1.0625rem;
  line-height: 1.85;
  color: var(--yak-white);
  opacity: .82;
}
.page-about .brand-notes {
  display: grid;
  gap: 0;
}
.page-about .brand-note {
  padding: 22px 0;
  border-top: var(--about-rule);
}
.page-about .brand-note__title {
  margin: 0 0 10px;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 700;
  color: var(--flag-white);
}
.page-about .brand-note__title::before {
  content: "";
  display: inline-block;
  width: 14px;
  height: 2px;
  margin-right: 10px;
  vertical-align: middle;
  background: var(--flag-blue);
}
.page-about .brand-note:nth-child(2) .brand-note__title::before { background: var(--flag-green); }
.page-about .brand-note:nth-child(3) .brand-note__title::before { background: var(--amber); }
.page-about .brand-note:nth-child(4) .brand-note__title::before { background: var(--flag-red); }
.page-about .brand-note p {
  margin: 0;
  max-width: 62ch;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--yak-white);
  opacity: .8;
}

/* ---------- 团队：图文交错 + 标签页 ---------- */
.page-about .brand-split {
  display: grid;
  gap: 28px;
  align-items: center;
  margin-bottom: clamp(28px, 4vw, 42px);
}
.page-about .brand-split__text p {
  max-width: 56ch;
  margin: 0 0 16px;
  font-size: 1rem;
  line-height: 1.9;
  color: var(--yak-white);
  opacity: .86;
}
.page-about .brand-split__text p:last-child { margin-bottom: 0; }
.page-about .brand-split__media { margin: 0; }

.page-about .brand-tabs .tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 22px;
}
.page-about .brand-tabs .tabs__tab {
  appearance: none;
  font-family: var(--font-body);
  font-size: 13px;
  letter-spacing: .06em;
  padding: 10px 16px;
  background: transparent;
  color: var(--gray-rock);
  border: 1px solid var(--grid-line);
  border-radius: var(--radius);
  cursor: pointer;
  transition: color .2s var(--ease), background .2s var(--ease), border-color .2s var(--ease);
}
.page-about .brand-tabs .tabs__tab:hover { color: var(--flag-white); border-color: var(--gray-rock); }
.page-about .brand-tabs .tabs__tab:focus-visible {
  outline: 2px solid var(--flag-blue);
  outline-offset: 2px;
}
.page-about .brand-tabs .tabs__tab[aria-selected="true"] {
  color: var(--night);
  background: var(--amber);
  border-color: var(--amber);
  font-weight: 700;
}
.page-about .brand-tabs .tabs__panel {
  padding-top: 18px;
  border-top: var(--about-rule);
}
.page-about .brand-tabs .tabs__panel p {
  max-width: 66ch;
  margin: 0 0 14px;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--yak-white);
  opacity: .82;
}
.page-about .brand-tabs .tabs__panel p:last-child { margin-bottom: 0; }

.page-about .brand-chapter__figure {
  margin: clamp(28px, 4vw, 42px) 0 0;
}

/* ---------- 结尾行动区 ---------- */
.page-about .brand-cta {
  margin-top: var(--about-pad);
  padding: clamp(34px, 5vw, 56px) clamp(24px, 4vw, 52px);
  background:
    linear-gradient(120deg, rgba(46, 107, 255, .16) 0%, rgba(11, 27, 58, 0) 46%),
    linear-gradient(300deg, rgba(230, 57, 70, .18) 0%, rgba(11, 27, 58, 0) 42%),
    var(--night-deep);
  border-top: 3px solid var(--flag-red);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 22px), calc(100% - 22px) 100%, 0 100%);
}
.page-about .brand-cta .section-title {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 700;
  line-height: 1.2;
  color: var(--yak-white);
}
.page-about .brand-cta p {
  max-width: 62ch;
  margin: 0 0 26px;
  font-size: .9375rem;
  line-height: 1.85;
  color: var(--yak-white);
  opacity: .84;
}
.page-about .brand-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 768px) {
  .page-about .brand-cover__stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
  .page-about .brand-index__list {
    justify-content: flex-start;
  }
}

@media (min-width: 820px) {
  .page-about .brand-notes {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .brand-note {
    padding: 26px 32px 26px 0;
  }
  .page-about .brand-note:nth-child(even) {
    padding-right: 0;
    padding-left: 32px;
    border-left: var(--about-rule);
  }
}

@media (min-width: 860px) {
  .page-about .brand-split {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    gap: clamp(32px, 5vw, 64px);
  }
  .page-about .brand-split--flip .brand-split__text { order: 2; }
  .page-about .brand-split--flip .brand-split__media { order: 1; }
}

@media (prefers-reduced-motion: reduce) {
  .page-about *,
  .page-about *::before,
  .page-about *::after {
    transition: none !important;
    animation: none !important;
  }
}
</PAGE_CSS>