/* ===== 品牌概况 · page-about ===== */
.page-about {
  --about-rail: 172px;
  --about-line: rgba(143, 163, 200, 0.22);
  --about-ink-soft: rgba(10, 22, 51, 0.78);
  --about-shell: 1240px;
  display: block;
  background: var(--night);
  color: var(--snow);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  display: flex;
  align-items: flex-end;
  min-height: clamp(520px, 74vh, 720px);
  padding: calc(var(--header-h) + 64px) 0 clamp(40px, 6vw, 72px);
  overflow: hidden;
  isolation: isolate;
}

.page-about .about-hero__media {
  position: absolute;
  inset: 0;
  z-index: -2;
}

.page-about .about-hero__media img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center 38%;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: -1;
  background:
    linear-gradient(180deg, rgba(10, 22, 51, 0.74) 0%, rgba(10, 22, 51, 0.34) 44%, rgba(10, 22, 51, 0.95) 100%),
    linear-gradient(90deg, rgba(10, 22, 51, 0.88) 0%, rgba(10, 22, 51, 0.2) 68%);
}

.page-about .about-hero__body {
  flex: 1 1 auto;
  width: 100%;
}

.page-about .breadcrumb ol {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 20px;
  padding: 0;
  list-style: none;
  font-size: 0.8125rem;
  color: var(--mist);
}

.page-about .breadcrumb li + li::before {
  content: "/";
  margin-right: 6px;
  color: var(--ridge);
}

.page-about .breadcrumb a {
  color: var(--mist);
  text-decoration: none;
}

.page-about .breadcrumb a:hover,
.page-about .breadcrumb a:focus-visible {
  color: var(--snow);
  text-decoration: underline;
}

.page-about .breadcrumb [aria-current="page"] {
  color: var(--snow);
}

.page-about .about-hero h1 {
  margin: 14px 0 20px;
  max-width: 21ch;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(2.05rem, 6vw, 3.85rem);
  line-height: 1.08;
  letter-spacing: -0.01em;
}

.page-about .about-hero__lede {
  margin: 0;
  max-width: 48ch;
  font-size: clamp(1rem, 1.5vw, 1.125rem);
  line-height: 1.8;
  color: rgba(244, 247, 255, 0.84);
}

.page-about .about-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px 24px;
  margin: 34px 0 0;
  padding-top: 24px;
  border-top: 1px solid rgba(143, 163, 200, 0.32);
}

.page-about .about-hero__facts dt {
  margin: 0 0 6px;
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--mist);
}

.page-about .about-hero__facts dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0;
  color: var(--snow);
}

.page-about .about-hero__facts div:nth-child(2) dd {
  color: var(--banner);
}

.page-about .about-hero__facts div:nth-child(1) dd {
  color: var(--jade);
}

/* ---------- 双轨布局 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  grid-template-areas:
    "index"
    "stream";
  gap: 30px;
  padding-block: 56px 80px;
  align-items: start;
}

.page-about .about-stream {
  grid-area: stream;
  min-width: 0;
}

.page-about .about-index {
  grid-area: index;
  position: sticky;
  top: var(--header-h);
  z-index: 6;
  margin-inline: calc(var(--gutter) * -1);
  padding: 10px var(--gutter);
  background: rgba(10, 22, 51, 0.94);
  border-bottom: 1px solid var(--about-line);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
}

.page-about .about-index__title {
  display: none;
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.18em;
  color: var(--mist);
}

.page-about .about-index__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

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

.page-about .about-index__list li {
  flex: 0 0 auto;
}

.page-about .about-index__list a {
  display: block;
  padding: 7px 13px;
  border-radius: 999px;
  border: 1px solid var(--about-line);
  color: var(--mist);
  font-size: 0.8125rem;
  white-space: nowrap;
  text-decoration: none;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .about-index__list a:hover {
  color: var(--snow);
  border-color: var(--ridge);
}

.page-about .about-index__list a[aria-current="location"] {
  color: var(--snow);
  border-color: var(--saffron);
  background: rgba(200, 16, 46, 0.2);
}

/* ---------- 章节面板 ---------- */
.page-about .about-section {
  position: relative;
  padding: clamp(26px, 4.6vw, 52px) clamp(20px, 3.6vw, 46px);
  border: 1px solid var(--about-line);
  border-radius: var(--radius);
  background: rgba(16, 34, 74, 0.5);
}

.page-about .about-section + .about-section {
  margin-top: clamp(22px, 3.4vw, 40px);
}

.page-about .about-section--ice {
  background: var(--ice);
  border-color: rgba(10, 22, 51, 0.08);
  color: var(--night);
}

.page-about .about-section--grid {
  background-color: rgba(16, 34, 74, 0.46);
  background-image:
    linear-gradient(rgba(143, 163, 200, 0.08) 1px, transparent 1px),
    linear-gradient(90deg, rgba(143, 163, 200, 0.08) 1px, transparent 1px);
  background-size: 46px 46px;
}

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

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

.page-about .about-rail__idx {
  margin: 0;
  font-size: clamp(1.9rem, 4vw, 2.6rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
  color: var(--saffron);
}

.page-about .about-rail__meta {
  margin: 0;
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--mist);
}

.page-about .about-section--ice .about-rail__meta {
  color: rgba(10, 22, 51, 0.52);
}

.page-about .about-copy {
  min-width: 0;
}

.page-about .about-copy h2 {
  margin: 0 0 18px;
  padding-left: 16px;
  border-left: 3px solid var(--saffron);
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.4rem, 3vw, 2rem);
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--snow);
}

.page-about .about-section--ice .about-copy h2 {
  color: var(--night);
}

.page-about .about-copy p {
  max-width: 42em;
  margin: 0 0 16px;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: rgba(244, 247, 255, 0.8);
}

.page-about .about-section--ice .about-copy p {
  color: var(--about-ink-soft);
}

.page-about .about-note {
  margin: 22px 0 0;
  padding-left: 14px;
  border-left: 2px solid var(--banner);
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-section--ice .about-note {
  color: rgba(10, 22, 51, 0.58);
}

/* ---------- 要点列表 ---------- */
.page-about .about-points {
  display: grid;
  gap: 12px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-points li {
  display: grid;
  grid-template-columns: minmax(88px, auto) minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  padding-top: 12px;
  border-top: 1px dashed var(--about-line);
}

.page-about .about-section--ice .about-points li {
  border-top-color: rgba(10, 22, 51, 0.16);
}

.page-about .about-points b {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--ember);
}

.page-about .about-points span {
  font-size: 0.875rem;
  line-height: 1.7;
  color: rgba(244, 247, 255, 0.76);
}

.page-about .about-section--ice .about-points span {
  color: var(--about-ink-soft);
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  margin: 26px 0 0;
  padding: 0 0 0 30px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 6px;
  top: 16px;
  bottom: 16px;
  width: 1px;
  background: linear-gradient(180deg, var(--saffron), var(--banner) 50%, var(--jade));
  opacity: 0.55;
}

.page-about .about-timeline__item {
  position: relative;
}

.page-about .about-timeline__dot {
  position: absolute;
  left: -30px;
  top: 18px;
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--night);
  border: 2px solid var(--saffron);
}

.page-about .about-milestone {
  border-bottom: 1px solid var(--about-line);
}

.page-about .about-milestone summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px;
  padding: 16px 0 14px;
  list-style: none;
  cursor: pointer;
}

.page-about .about-milestone summary::-webkit-details-marker {
  display: none;
}

.page-about .about-milestone summary::after {
  content: "展开";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  letter-spacing: 0.1em;
  color: var(--mist);
}

.page-about .about-milestone[open] summary::after {
  content: "收起";
  color: var(--banner);
}

.page-about .about-milestone summary:hover .about-milestone__title,
.page-about .about-milestone summary:focus-visible .about-milestone__title {
  color: var(--banner);
}

.page-about .about-milestone__ver {
  flex: 0 0 auto;
  padding: 3px 9px;
  border: 1px solid rgba(242, 183, 5, 0.5);
  border-radius: 999px;
  font-size: 0.6875rem;
  letter-spacing: 0.08em;
  color: var(--banner);
}

.page-about .about-milestone__title {
  font-size: 1rem;
  font-weight: 700;
  color: var(--snow);
  transition: color 0.2s var(--ease);
}

.page-about .about-milestone__body {
  max-width: 44em;
  margin: 0 0 18px;
  font-size: 0.875rem;
  line-height: 1.85;
  color: rgba(244, 247, 255, 0.76);
}

/* ---------- 图像与图注 ---------- */
.page-about .about-media {
  margin: 26px 0 0;
}

.page-about .about-media img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border-radius: 12px;
  background: linear-gradient(160deg, var(--layer), var(--deep));
}

.page-about .about-media--wide img {
  aspect-ratio: 10 / 7;
}

.page-about .about-media figcaption {
  margin-top: 10px;
  font-size: 0.75rem;
  line-height: 1.7;
  color: var(--mist);
}

.page-about .about-section--ice .about-media figcaption {
  color: rgba(10, 22, 51, 0.56);
}

/* ---------- 数据条 ---------- */
.page-about .about-meter {
  margin-top: 28px;
}

.page-about .about-meter__row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  align-items: baseline;
  justify-content: space-between;
  font-size: 0.875rem;
  color: var(--about-ink-soft);
}

.page-about .about-meter__value {
  font-weight: 700;
  color: var(--saffron);
}

.page-about .about-meter .meter {
  height: 8px;
  margin-top: 10px;
  border-radius: 999px;
  background: rgba(10, 22, 51, 0.14);
  overflow: hidden;
}

.page-about .about-meter__fill {
  display: block;
  height: 100%;
  width: 60%;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--banner), var(--ember));
}

.page-about .about-meter__note {
  margin: 12px 0 0;
  font-size: 0.8125rem;
  line-height: 1.75;
  color: rgba(10, 22, 51, 0.6);
}

/* ---------- 栏目贴片 ---------- */
.page-about .about-cats {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 12px;
  margin: 26px 0 24px;
  padding: 0;
  list-style: none;
}

.page-about .about-cats__item {
  padding: 14px 16px;
  border: 1px solid var(--about-line);
  border-radius: 10px;
  background: rgba(10, 22, 51, 0.5);
}

.page-about .about-cats__item p {
  margin: 10px 0 0;
  font-size: 0.8125rem;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 来源列表 ---------- */
.page-about .about-sources {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 14px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .about-sources__item {
  padding: 16px 18px;
  border-left: 3px solid var(--jade);
  border-radius: 0 10px 10px 0;
  background: rgba(10, 22, 51, 0.06);
}

.page-about .about-sources__item:nth-child(2) {
  border-left-color: var(--banner);
}

.page-about .about-sources__item:nth-child(3) {
  border-left-color: var(--ember);
}

.page-about .about-sources__item:nth-child(4) {
  border-left-color: var(--saffron);
}

.page-about .about-sources__item h3 {
  margin: 0 0 8px;
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--night);
}

.page-about .about-sources__item p {
  margin: 0;
  max-width: 40em;
  font-size: 0.8125rem;
  line-height: 1.75;
  color: var(--about-ink-soft);
}

/* ---------- 结尾 ---------- */
.page-about .about-next {
  margin-top: clamp(28px, 4vw, 48px);
  padding: clamp(28px, 4.4vw, 52px) clamp(20px, 3.6vw, 46px);
  border-radius: var(--radius);
  border: 1px solid rgba(200, 16, 46, 0.4);
  background:
    radial-gradient(120% 140% at 0% 0%, rgba(200, 16, 46, 0.28) 0%, rgba(10, 22, 51, 0) 58%),
    rgba(16, 34, 74, 0.6);
}

.page-about .about-next__title {
  margin: 0 0 12px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(1.35rem, 2.8vw, 1.85rem);
  line-height: 1.3;
  color: var(--snow);
}

.page-about .about-next__lede {
  margin: 0;
  max-width: 40em;
  font-size: 0.9375rem;
  line-height: 1.8;
  color: rgba(244, 247, 255, 0.78);
}

.page-about .about-next__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-next__foot {
  margin: 20px 0 0;
  font-size: 0.8125rem;
  color: var(--mist);
}

.page-about .about-next__foot a {
  color: var(--banner);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-next__foot a:hover {
  color: var(--snow);
}

/* ---------- 窄屏细节 ---------- */
@media (max-width: 519px) {
  .page-about .about-points li {
    grid-template-columns: minmax(0, 1fr);
    gap: 6px;
  }

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

  .page-about .about-hero__facts {
    gap: 16px;
  }
}

/* ---------- 平板与桌面 ---------- */
@media (min-width: 720px) {
  .page-about .about-grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: 22px 36px;
  }

  .page-about .about-rail {
    flex-direction: column;
    align-items: flex-start;
    gap: 10px;
    padding-top: 4px;
  }

  .page-about .about-rail__meta {
    writing-mode: horizontal-tb;
  }

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

  .page-about .about-hero__facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (min-width: 980px) {
  .page-about .about-layout {
    grid-template-columns: minmax(0, 1fr) 216px;
    grid-template-areas: "stream index";
    gap: 68px;
    padding-block: 76px 104px;
  }

  .page-about .about-index {
    position: sticky;
    top: calc(var(--header-h) + 28px);
    margin-inline: 0;
    padding: 0;
    background: none;
    border-bottom: 0;
    -webkit-backdrop-filter: none;
    backdrop-filter: none;
  }

  .page-about .about-index__title {
    display: block;
  }

  .page-about .about-index__list {
    display: grid;
    gap: 2px;
    overflow: visible;
  }

  .page-about .about-index__list a {
    padding: 9px 14px;
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    background: none;
    font-size: 0.875rem;
  }

  .page-about .about-index__list a:hover {
    background: rgba(27, 58, 107, 0.42);
  }

  .page-about .about-index__list a[aria-current="location"] {
    border-left-color: var(--saffron);
    background: rgba(200, 16, 46, 0.14);
  }

  .page-about .about-rail__idx {
    font-size: 2.75rem;
  }
}