.page-about {
  --about-rail: 300px;
  --about-wine-wash: rgba(142, 31, 69, 0.38);
  --about-teal-wash: rgba(14, 59, 58, 0.58);
  display: block;
  color: var(--text);
  overflow-x: hidden;
}

.page-about img {
  max-width: 100%;
  height: auto;
}

.page-about h2 {
  font-family: var(--font-display);
  font-size: clamp(25px, 4vw, 36px);
  font-weight: 900;
  line-height: 1.26;
  letter-spacing: -0.01em;
  margin: 0 0 18px;
  color: var(--text);
}

.page-about h3 {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--text);
}

/* 面包屑 */
.page-about .breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  padding-block: clamp(20px, 3.4vw, 32px) 0;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
}

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

.page-about .breadcrumb a:hover {
  text-decoration: underline;
}

/* 首屏 */
.page-about .about-hero {
  padding-block: clamp(18px, 3.6vw, 34px) clamp(32px, 5.5vw, 60px);
}

.page-about .about-hero__title {
  margin: 14px 0 22px;
  max-width: 18ch;
}

.page-about .about-hero__lede {
  max-width: 56ch;
  margin: 0;
  font-size: clamp(16px, 1.9vw, 18px);
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: clamp(30px, 5vw, 48px) 0 0;
  padding: 1px;
  background: var(--line-muted);
  border-radius: 20px 4px 20px 4px;
  overflow: hidden;
}

.page-about .about-stats__item {
  padding: 16px 18px 18px;
  background: rgba(26, 16, 56, 0.92);
}

.page-about .about-stats dt {
  margin: 0 0 7px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--muted);
}

.page-about .about-stats dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(19px, 2.8vw, 25px);
  letter-spacing: 0.02em;
  color: var(--cyan);
}

/* 通栏横幅 */
.page-about .about-banner {
  margin: 0;
  border-radius: clamp(24px, 4vw, 48px) 8px clamp(24px, 4vw, 48px) 8px;
  overflow: hidden;
}

/* 双栏叙事 */
.page-about .about-body {
  padding-block: clamp(48px, 8vw, 100px) clamp(40px, 6vw, 80px);
}

.page-about .about-body__title {
  max-width: 22ch;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-body__grid {
  display: grid;
  gap: clamp(34px, 6vw, 68px);
}

/* 阶段编年带 */
.page-about .about-rail__list {
  list-style: none;
  margin: 18px 0 0;
  padding: 0 0 0 26px;
  position: relative;
}

.page-about .about-rail__list::before {
  content: "";
  position: absolute;
  left: 5px;
  top: 8px;
  bottom: 12px;
  width: 1px;
  background: linear-gradient(180deg, var(--violet), var(--cyan));
  opacity: 0.55;
}

.page-about .about-rail__item {
  position: relative;
  padding-bottom: 26px;
}

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

.page-about .about-rail__item::before {
  content: "";
  position: absolute;
  left: -26px;
  top: 9px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--ink);
  border: 1px solid var(--cyan);
  box-shadow: 0 0 0 3px rgba(52, 231, 228, 0.1);
}

.page-about .about-rail__item:hover::before,
.page-about .about-rail__item:focus-within::before {
  background: var(--cyan);
  box-shadow: 0 0 14px rgba(52, 231, 228, 0.6);
}

.page-about .about-rail__time {
  margin: 0 0 5px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--muted);
}

.page-about .about-rail__name {
  margin: 0 0 6px;
  font-size: 16.5px;
  line-height: 1.4;
}

.page-about .about-rail__note {
  margin: 0;
  font-size: 13.5px;
  line-height: 1.75;
  color: var(--muted);
  max-height: 0;
  opacity: 0;
  overflow: hidden;
  transition: max-height 0.34s var(--ease), opacity 0.3s var(--ease);
}

.page-about .about-rail__item:hover .about-rail__note,
.page-about .about-rail__item:focus-within .about-rail__note {
  max-height: 6.5em;
  opacity: 1;
}

/* 分段切换 */
.page-about .about-switch {
  position: relative;
}

.page-about .about-switch__input {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: 0;
  opacity: 0;
  pointer-events: none;
}

.page-about .about-switch__bar {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line-muted);
  transition: box-shadow 0.2s var(--ease);
}

.page-about .about-switch__input:focus-visible ~ .about-switch__bar {
  box-shadow: 0 2px 0 var(--orange);
}

.page-about .about-switch__tab {
  display: inline-block;
  padding: 8px 15px;
  font-size: 13px;
  letter-spacing: 0.06em;
  color: var(--muted);
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: color 0.25s var(--ease), border-color 0.25s var(--ease), background-color 0.25s var(--ease);
}

.page-about .about-switch__tab:hover {
  color: var(--text);
  border-color: var(--line-cyan);
}

.page-about #about-sw-1:checked ~ .about-switch__bar label[for="about-sw-1"],
.page-about #about-sw-2:checked ~ .about-switch__bar label[for="about-sw-2"],
.page-about #about-sw-3:checked ~ .about-switch__bar label[for="about-sw-3"] {
  color: var(--ink);
  background: var(--cyan);
  border-color: var(--cyan);
  font-weight: 600;
}

.page-about .about-switch__panels {
  padding-top: clamp(22px, 3.5vw, 32px);
}

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

.page-about #about-sw-1:checked ~ .about-switch__panels > #about-panel-1,
.page-about #about-sw-2:checked ~ .about-switch__panels > #about-panel-2,
.page-about #about-sw-3:checked ~ .about-switch__panels > #about-panel-3 {
  display: block;
  animation: about-panel-in 0.4s var(--ease) both;
}

@keyframes about-panel-in {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.page-about .about-switch__panel p {
  max-width: 62ch;
  margin: 0 0 1.15em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

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

.page-about .about-switch__panel strong {
  color: var(--text);
  font-weight: 600;
}

.page-about .about-switch__figure {
  margin: 22px 0 20px;
  border-radius: 28px 8px 28px 8px;
  overflow: hidden;
}

.page-about .about-link {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid var(--line-cyan);
  padding-bottom: 1px;
}

.page-about .about-link:hover {
  color: var(--text);
  border-color: var(--cyan);
}

/* 灯带 */
.page-about .about-band {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  padding-block: clamp(16px, 3vw, 26px);
}

.page-about .about-band::before,
.page-about .about-band::after {
  content: "";
  height: 1px;
  flex: 1 1 0;
  background: linear-gradient(90deg, transparent, var(--violet), var(--cyan), transparent);
  opacity: 0.6;
}

.page-about .about-band__text {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  color: var(--cyan);
  text-align: center;
}

/* 房间分类 */
.page-about .about-rooms {
  padding-block: clamp(48px, 7vw, 96px);
  background: linear-gradient(155deg, var(--about-wine-wash), rgba(11, 7, 24, 0) 68%);
  border-top: 1px solid var(--line-muted);
  border-bottom: 1px solid var(--line-muted);
}

.page-about .about-rooms__head {
  max-width: 700px;
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-rooms__lede {
  margin: 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

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

.page-about .about-room {
  padding: 22px 20px 24px;
  background: rgba(26, 16, 56, 0.78);
  border: 1px solid var(--line-violet);
  border-radius: 24px 6px 24px 6px;
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease), transform 0.3s var(--ease);
}

.page-about .about-room:hover,
.page-about .about-room:focus-within {
  border-color: var(--cyan);
  box-shadow: var(--glow-cyan);
  transform: translateY(-3px);
}

.page-about .about-room__index {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.1em;
  color: var(--cyan);
}

.page-about .about-room__name {
  margin: 0 0 6px;
  font-size: 20px;
}

.page-about .about-room__meta {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.04em;
  color: var(--gold);
}

.page-about .about-room__desc {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* 段位 */
.page-about .about-ranks {
  padding-block: clamp(48px, 7vw, 96px);
  background: linear-gradient(200deg, var(--about-teal-wash), rgba(11, 7, 24, 0) 72%);
}

.page-about .about-ranks__grid {
  display: grid;
  gap: clamp(28px, 5vw, 56px);
  align-items: center;
}

.page-about .about-ranks__copy p {
  max-width: 58ch;
  margin: 0 0 1.1em;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-ranks__tiers {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
  margin: 24px 0 20px;
  padding: 0;
}

.page-about .about-ranks__tier {
  padding: 6px 13px;
  border: 1px solid var(--line-cyan);
  border-radius: var(--radius-pill);
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .about-ranks__more {
  margin: 0;
  font-size: 15px;
}

.page-about .about-ranks__figure {
  margin: 0;
  border-radius: 46% 54% 42% 58% / 56% 44% 56% 44%;
  overflow: hidden;
  box-shadow: 0 0 60px rgba(123, 77, 255, 0.22);
}

/* 上手路径 */
.page-about .about-start {
  padding-block: clamp(48px, 7vw, 96px);
}

.page-about .about-start__lede {
  max-width: 54ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-start__steps {
  list-style: none;
  margin: clamp(26px, 4vw, 44px) 0 0;
  padding: 0;
  display: grid;
  gap: 16px;
}

.page-about .about-start__step {
  padding: 24px 22px;
  background: rgba(26, 16, 56, 0.6);
  border: 1px solid var(--line-muted);
  border-left: 2px solid var(--line-cyan);
  border-radius: 4px 24px 4px 24px;
}

.page-about .about-start__num {
  display: block;
  margin-bottom: 12px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-about .about-start__step h3 {
  margin: 0 0 10px;
  font-size: 17.5px;
  line-height: 1.45;
}

.page-about .about-start__step p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.78;
  color: var(--muted);
}

.page-about .about-start__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: clamp(26px, 4vw, 40px);
}

/* 收尾主张 */
.page-about .about-sign {
  padding-block: 0 clamp(56px, 8vw, 104px);
}

.page-about .about-sign__inner {
  padding: clamp(28px, 5vw, 52px);
  border: 1px solid var(--line-violet);
  border-radius: clamp(28px, 4vw, 44px) 8px clamp(28px, 4vw, 44px) 8px;
  background:
    radial-gradient(120% 140% at 10% 0%, rgba(123, 77, 255, 0.3), rgba(11, 7, 24, 0) 62%),
    rgba(26, 16, 56, 0.66);
}

.page-about .about-sign__line {
  margin: 0 0 14px;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(23px, 4vw, 34px);
  letter-spacing: -0.01em;
  color: var(--text);
  text-shadow: 0 0 18px rgba(123, 77, 255, 0.45);
}

.page-about .about-sign__text {
  max-width: 54ch;
  margin: 0 0 22px;
  font-size: 15px;
  line-height: 1.8;
  color: var(--muted);
}

/* 断点 */
@media (min-width: 700px) {
  .page-about .about-rooms__list {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }
}

@media (min-width: 720px) {
  .page-about .about-stats {
    grid-template-columns: repeat(5, minmax(0, 1fr));
  }
}

@media (min-width: 860px) {
  .page-about .about-start__steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 20px;
  }
}

@media (min-width: 900px) {
  .page-about .about-ranks__grid {
    grid-template-columns: minmax(0, 1fr) 360px;
  }
}

@media (min-width: 960px) {
  .page-about .about-body__grid {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 132px;
  }
}

@media (min-width: 1080px) {
  .page-about .about-rooms__list {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-room:nth-child(even) {
    margin-top: 18px;
  }
}

@media (max-width: 959px) {
  .page-about .about-rail__note {
    max-height: none;
    opacity: 1;
  }
}

@media (max-width: 480px) {
  .page-about .about-stats__item {
    padding: 14px 14px 16px;
  }

  .page-about .about-ranks__figure {
    border-radius: 32px 8px 32px 8px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-room:hover,
  .page-about .about-room:focus-within {
    transform: none;
  }

  .page-about #about-sw-1:checked ~ .about-switch__panels > #about-panel-1,
  .page-about #about-sw-2:checked ~ .about-switch__panels > #about-panel-2,
  .page-about #about-sw-3:checked ~ .about-switch__panels > #about-panel-3 {
    animation: about-panel-fade 0.12s linear both;
  }

  .page-about .about-rail__note {
    transition: opacity 0.12s linear;
  }
}

@keyframes about-panel-fade {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}