.page-about {
  --about-rail: 210px;
  --about-anchor-top: 110px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding: clamp(34px, 6vw, 74px) 0 clamp(28px, 5vw, 52px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(90deg, rgba(42, 48, 70, .55) 1px, transparent 1px),
    linear-gradient(180deg, rgba(42, 48, 70, .55) 1px, transparent 1px);
  background-size: 72px 72px;
  opacity: .22;
  -webkit-mask-image: radial-gradient(115% 85% at 16% 0%, #000 0%, transparent 72%);
  mask-image: radial-gradient(115% 85% at 16% 0%, #000 0%, transparent 72%);
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  display: grid;
  gap: clamp(26px, 4vw, 44px);
}

.page-about .about-title {
  font-size: clamp(30px, 6.4vw, 76px);
  font-weight: 900;
  line-height: 1.07;
  letter-spacing: .035em;
  margin: 14px 0 20px;
  max-width: 20ch;
}

.page-about .about-lede {
  max-width: 60ch;
  margin: 0;
  font-size: 16px;
  line-height: 1.82;
  color: var(--text);
}

.page-about .about-hero-side {
  display: grid;
  gap: 14px;
  padding: 22px 20px;
  background: linear-gradient(158deg, rgba(22, 26, 42, .92), rgba(13, 16, 27, .92));
  border: 1px solid var(--line);
  clip-path: polygon(0 0, 100% 0, 100% calc(100% - 24px), calc(100% - 24px) 100%, 0 100%);
}

.page-about .side-line {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .side-line:last-child {
  padding-bottom: 0;
  border-bottom: 0;
}

.page-about .side-key {
  font-size: var(--fs-11);
  letter-spacing: .2em;
  color: var(--muted);
}

.page-about .side-val {
  font-size: 15px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: .02em;
}

/* ---------- 首屏横图 ---------- */
.page-about .about-cover {
  margin: 0 0 clamp(44px, 7vw, 86px);
}

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

/* ---------- 主体两栏 ---------- */
.page-about .about-body {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
  padding-bottom: clamp(48px, 8vw, 96px);
}

.page-about .about-index {
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.page-about .about-index-label {
  margin: 0 0 12px;
  font-size: var(--fs-11);
  letter-spacing: .24em;
  color: var(--muted);
}

.page-about .about-index-list {
  display: flex;
  gap: 18px;
  margin: 0;
  padding: 0 0 8px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .about-index-list a {
  display: inline-flex;
  align-items: baseline;
  gap: 7px;
  padding: 6px 0;
  font-size: 13px;
  color: var(--muted);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 1px solid transparent;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-index-list a:hover,
.page-about .about-index-list a:focus-visible {
  color: var(--purple-soft);
  border-bottom-color: var(--purple);
}

.page-about .idx-num {
  color: var(--purple-soft);
  font-size: var(--fs-11);
  letter-spacing: .14em;
}

/* ---------- 章节 ---------- */
.page-about .about-sec {
  scroll-margin-top: var(--about-anchor-top);
}

.page-about .about-sec + .about-sec {
  margin-top: clamp(38px, 5vw, 62px);
  padding-top: clamp(30px, 4.5vw, 52px);
  border-top: 1px solid var(--line-soft);
}

.page-about .about-sec-title {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin: 0 0 18px;
  font-size: clamp(20px, 3.1vw, 34px);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: .045em;
}

.page-about .sec-num {
  flex: none;
  font-size: var(--fs-11);
  letter-spacing: .22em;
  font-weight: 600;
  color: var(--purple-soft);
}

.page-about .about-sec:target .about-sec-title {
  color: var(--purple-soft);
}

.page-about .about-sub-title {
  margin: clamp(28px, 4vw, 40px) 0 4px;
  font-size: var(--fs-18);
  font-weight: 700;
  letter-spacing: .05em;
  color: var(--muted);
}

.page-about .about-sec p {
  max-width: 66ch;
  margin: 0 0 14px;
  font-size: 15px;
  line-height: 1.82;
  color: var(--text);
}

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

.page-about .about-note {
  color: var(--muted) !important;
  font-size: 14px !important;
}

/* ---------- 不做清单 ---------- */
.page-about .about-not {
  display: grid;
  gap: 18px;
  margin: 24px 0 0;
  padding: 0 0 0 18px;
  list-style: none;
  border-left: 2px solid var(--line);
}

.page-about .about-not li {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  grid-template-areas:
    "mark title"
    ".    desc";
  gap: 5px 10px;
  align-items: baseline;
}

.page-about .not-mark {
  grid-area: mark;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.6;
  color: var(--red);
}

.page-about .not-title {
  grid-area: title;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: .03em;
  color: var(--text);
}

.page-about .not-desc {
  grid-area: desc;
  font-size: 14px;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 年龄组标签页 ---------- */
.page-about .about-tabs {
  margin-top: 26px;
}

.page-about .about-tabs .tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  padding: 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-tabs .tab {
  appearance: none;
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  border-radius: 0;
  padding: 10px 18px 9px;
  font: inherit;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: .12em;
  color: var(--muted);
  cursor: pointer;
  transition: color .2s var(--ease), border-color .2s var(--ease);
}

.page-about .about-tabs .tab:hover {
  color: var(--purple-soft);
}

.page-about .about-tabs .tab[aria-selected="true"] {
  color: var(--text);
  border-bottom-color: var(--purple);
}

.page-about .about-tabs .tab:focus-visible {
  outline: 2px solid var(--purple-soft);
  outline-offset: 2px;
}

.page-about .about-tabs .tabpanel {
  padding-top: 18px;
}

.page-about .about-tabs .tabpanel[hidden] {
  display: none;
}

.page-about .about-tabs .tabpanel p {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--text);
}

.page-about .about-tabs .tag {
  margin-right: 6px;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  position: relative;
  margin: 22px 0 0;
  padding: 0 0 0 28px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 8px;
  width: 1px;
  background: linear-gradient(180deg, var(--purple) 0%, rgba(0, 240, 200, .55) 100%);
}

.page-about .tl-item {
  position: relative;
  padding-bottom: 24px;
}

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

.page-about .tl-dot {
  position: absolute;
  left: -28px;
  top: 7px;
  width: 11px;
  height: 11px;
  background: var(--ink);
  border: 2px solid var(--purple);
  transform: rotate(45deg);
}

.page-about .tl-dot--live {
  border-color: var(--cyan);
  box-shadow: 0 0 0 4px rgba(0, 240, 200, .12);
}

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

.page-about .tl-year {
  margin: 0;
  font-size: var(--fs-11);
  letter-spacing: .2em;
  color: var(--purple-soft);
}

.page-about .tl-item--live .tl-year {
  color: var(--cyan);
}

.page-about .tl-title {
  margin: 0;
  font-size: var(--fs-18);
  font-weight: 700;
  letter-spacing: .03em;
  color: var(--text);
}

.page-about .tl-desc {
  margin: 2px 0 0;
  max-width: 58ch;
  font-size: 14px;
  line-height: 1.78;
  color: var(--muted);
}

/* ---------- 工作流 ---------- */
.page-about .about-flow {
  display: grid;
  gap: clamp(22px, 3vw, 34px);
  margin-top: 26px;
}

.page-about .flow-figure {
  margin: 0;
}

.page-about .flow-steps {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .flow-step {
  display: grid;
  grid-template-columns: 54px minmax(0, 1fr);
  gap: 16px;
  padding: 18px 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .flow-step:first-child {
  padding-top: 4px;
  border-top: 1px solid var(--purple);
}

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

.page-about .flow-step-num {
  font-size: 24px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: .04em;
  color: var(--purple-soft);
  padding-top: 2px;
}

.page-about .flow-step-body p {
  margin: 0;
}

.page-about .flow-step-title {
  margin: 0 0 6px !important;
  font-size: var(--fs-18) !important;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--text);
}

.page-about .about-band-media {
  margin: clamp(28px, 4vw, 44px) 0 0;
}

/* ---------- 统计边界 ---------- */
.page-about .about-boundary {
  display: grid;
  margin-top: 24px;
  border-top: 1px solid var(--line);
}

.page-about .boundary-col {
  padding: 20px 0;
}

.page-about .boundary-col + .boundary-col {
  border-top: 1px solid var(--line-soft);
}

.page-about .boundary-head {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 14px;
  font-size: var(--fs-11);
  letter-spacing: .24em;
  color: var(--muted);
}

.page-about .boundary-head::before {
  content: "";
  width: 18px;
  height: 2px;
  background: var(--purple);
}

.page-about .boundary-col--out .boundary-head::before {
  background: var(--grid);
}

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

.page-about .boundary-list li {
  position: relative;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.72;
  color: var(--text);
}

.page-about .boundary-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .64em;
  width: 6px;
  height: 6px;
  background: var(--purple);
  transform: rotate(45deg);
}

.page-about .boundary-col--out .boundary-list li {
  color: var(--muted);
}

.page-about .boundary-col--out .boundary-list li::before {
  background: var(--grid);
}

/* ---------- 纠错 ---------- */
.page-about .about-fix {
  display: grid;
  gap: 0;
  margin: 24px 0 18px;
  padding: 0;
  list-style: none;
}

.page-about .about-fix li {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr);
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--line-soft);
}

.page-about .about-fix li:first-child {
  border-top: 1px solid var(--purple);
}

.page-about .fix-step {
  font-size: var(--fs-13);
  font-weight: 600;
  letter-spacing: .16em;
  color: var(--purple-soft);
  padding-top: 3px;
}

.page-about .fix-body p {
  margin: 0;
}

.page-about .fix-title {
  margin: 0 0 5px !important;
  font-size: 15px !important;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--text);
}

/* ---------- 运营与协作 ---------- */
.page-about .about-channels {
  display: grid;
  gap: 0;
  margin: 22px 0 18px;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .about-channels li {
  display: grid;
  gap: 3px;
  padding: 13px 0;
  border-bottom: 1px solid var(--line-soft);
}

.page-about .ch-key {
  font-size: var(--fs-11);
  letter-spacing: .22em;
  color: var(--muted);
}

.page-about .ch-val {
  font-size: 15px;
  line-height: 1.6;
  color: var(--text);
  overflow-wrap: anywhere;
}

.page-about .about-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 900px) {
  .page-about .about-hero-inner {
    grid-template-columns: minmax(0, 1.6fr) minmax(240px, .85fr);
    align-items: end;
    gap: clamp(36px, 5vw, 82px);
  }

  .page-about .about-hero-side {
    transform: translateY(-18px);
  }
}

@media (min-width: 960px) {
  .page-about .about-body {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: clamp(34px, 5vw, 76px);
    align-items: start;
  }

  .page-about .about-index {
    position: sticky;
    top: var(--about-anchor-top);
    padding-top: 18px;
  }

  .page-about .about-index-list {
    flex-direction: column;
    gap: 0;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-index-list li {
    border-bottom: 1px solid var(--line-soft);
  }

  .page-about .about-index-list a {
    display: flex;
    width: 100%;
    padding: 10px 0;
    white-space: normal;
    line-height: 1.5;
    border-bottom: 0;
  }
}

@media (min-width: 760px) {
  .page-about .about-boundary {
    grid-template-columns: 1fr 1fr;
  }

  .page-about .boundary-col {
    padding: 24px 0 8px;
  }

  .page-about .boundary-col + .boundary-col {
    border-top: 0;
    border-left: 1px solid var(--line);
    padding-left: clamp(22px, 3.5vw, 42px);
  }
}

@media (min-width: 860px) {
  .page-about .about-flow {
    grid-template-columns: minmax(200px, 290px) minmax(0, 1fr);
    align-items: start;
    gap: clamp(26px, 3.5vw, 46px);
  }

  .page-about .flow-figure {
    position: sticky;
    top: var(--about-anchor-top);
  }
}

@media (max-width: 599px) {
  .page-about .flow-step {
    grid-template-columns: 40px minmax(0, 1fr);
    gap: 12px;
  }

  .page-about .flow-step-num {
    font-size: 20px;
  }

  .page-about .about-fix li {
    grid-template-columns: 36px minmax(0, 1fr);
    gap: 10px;
  }

  .page-about .about-links .btn {
    width: 100%;
    text-align: center;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-index-list a,
  .page-about .about-tabs .tab {
    transition: none;
  }
}