.page-about {
  --about-line: linear-gradient(90deg, var(--vermilion), var(--gold) 32%, var(--turquoise) 62%, var(--neon));
  --about-card: rgba(247, 243, 234, 0.05);
  --about-card-line: rgba(247, 243, 234, 0.16);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
}

/* ---------- 悬浮章节索引 ---------- */
.page-about .about-rail {
  display: none;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  background: var(--night);
  color: var(--paper);
  padding-block: clamp(40px, 7vw, 84px) clamp(36px, 6vw, 72px);
}

.page-about .about-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(120% 90% at 8% -12%, rgba(122, 63, 242, 0.42), transparent 58%),
    radial-gradient(90% 72% at 94% 4%, rgba(41, 224, 214, 0.22), transparent 62%),
    radial-gradient(84% 84% at 58% 116%, rgba(201, 58, 43, 0.28), transparent 66%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 3px;
  background: linear-gradient(
    90deg,
    var(--vermilion) 0 20%,
    var(--gold) 20% 40%,
    var(--turquoise) 40% 62%,
    var(--neon) 62% 82%,
    var(--cyan) 82% 100%
  );
}

.page-about .about-hero__grid {
  position: relative;
  z-index: 1;
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 56px);
}

.page-about .about-hero h1 {
  margin: 0.3em 0 0.55em;
  font-family: var(--font-serif);
  font-size: clamp(2rem, 5.4vw, 3.7rem);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: 0.005em;
  color: var(--paper);
}

@supports ((-webkit-background-clip: text) or (background-clip: text)) {
  .page-about .about-hero h1 {
    background: linear-gradient(100deg, var(--gold) 4%, var(--paper) 46%, var(--cyan) 96%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
  }
}

.page-about .about-hero__intro {
  max-width: 40ch;
  margin: 0;
  font-size: clamp(0.96rem, 1.6vw, 1.08rem);
  line-height: 1.78;
  color: rgba(247, 243, 234, 0.84);
}

.page-about .about-hero .breadcrumb {
  margin-bottom: 18px;
  font-size: 0.78rem;
  color: var(--sand);
}

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

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

.page-about .about-hero .eyebrow {
  color: var(--gold);
}

.page-about .about-hero__aside {
  border-top: 1px solid var(--hair);
  padding-top: 18px;
}

.page-about .about-hero__aside-label {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.16em;
  color: var(--cyan);
}

.page-about .about-hero__levels {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .about-hero__levels li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 9px 0;
  border-bottom: 1px dashed rgba(247, 243, 234, 0.16);
  font-family: var(--font-serif);
  font-size: 1.04rem;
  color: var(--paper);
}

.page-about .about-hero__levels li span {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  color: var(--gold);
}

.page-about .about-hero__aside-note {
  margin: 14px 0 0;
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--sand);
}

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

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  position: relative;
  padding-block: clamp(52px, 8vw, 104px);
}

.page-about .about-section--paper {
  background: var(--paper);
  color: var(--ink);
}

.page-about .about-h2 {
  margin: 0.35em 0 0.7em;
  font-family: var(--font-serif);
  font-size: clamp(1.5rem, 3.2vw, 2.3rem);
  line-height: 1.24;
  color: var(--ink);
}

.page-about .about-split {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 48px);
}

.page-about .about-split__note {
  border-top: 3px solid var(--vermilion);
  padding-top: 16px;
}

.page-about .about-note__kicker {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  color: var(--vermilion);
}

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

.page-about .about-note__list li {
  display: grid;
  grid-template-columns: 62px minmax(0, 1fr);
  gap: 10px;
  font-size: 0.86rem;
  line-height: 1.6;
  color: var(--ink);
}

.page-about .about-note__list li span {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--turquoise);
  padding-top: 3px;
}

.page-about .about-note__tail {
  margin: 16px 0 0;
  font-size: 0.84rem;
  line-height: 1.7;
  color: rgba(26, 18, 38, 0.72);
}

.page-about .about-note__tail a {
  color: var(--vermilion);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

/* ---------- 品牌起点 ---------- */
.page-about .about-origin__figure {
  margin: 0 0 clamp(28px, 4.5vw, 52px);
}

.page-about .media-frame {
  overflow: hidden;
  clip-path: polygon(var(--cut) 0, 100% 0, 100% 100%, calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
}

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

/* ---------- 层级卡片 ---------- */
.page-about .about-levels {
  background: var(--night);
  color: var(--paper);
  overflow: hidden;
}

.page-about .about-levels::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(80% 60% at 100% 0%, rgba(122, 63, 242, 0.24), transparent 60%),
    radial-gradient(70% 70% at 0% 100%, rgba(31, 138, 122, 0.22), transparent 62%);
}

.page-about .about-levels > .container {
  position: relative;
  z-index: 1;
}

.page-about .about-levels .section-head__title {
  color: var(--paper);
}

.page-about .about-levels .section-head__note {
  color: var(--sand);
}

.page-about .about-levels__lede {
  max-width: 62ch;
  margin: 0 0 clamp(26px, 4vw, 44px);
  font-size: 1rem;
  line-height: 1.8;
  color: rgba(247, 243, 234, 0.82);
}

.page-about .level-track {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: min(78vw, 292px);
  gap: 16px;
  overflow-x: auto;
  overscroll-behavior-x: contain;
  scroll-snap-type: x mandatory;
  padding-bottom: 16px;
  scrollbar-width: thin;
  scrollbar-color: var(--neon) rgba(247, 243, 234, 0.1);
}

.page-about .level-track::-webkit-scrollbar {
  height: 6px;
}

.page-about .level-track::-webkit-scrollbar-track {
  background: rgba(247, 243, 234, 0.1);
}

.page-about .level-track::-webkit-scrollbar-thumb {
  background: var(--neon);
}

.page-about .level-card {
  --level-accent: var(--turquoise);
  position: relative;
  scroll-snap-align: start;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 26px 20px 18px;
  background: var(--about-card);
  border: 1px solid var(--about-card-line);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
  transition: transform 0.32s var(--ease), box-shadow 0.32s var(--ease), border-color 0.32s var(--ease);
}

.page-about .level-card::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 52px;
  height: 3px;
  background: var(--level-accent);
}

.page-about .level-card:nth-child(2) { --level-accent: var(--cyan); }
.page-about .level-card:nth-child(3) { --level-accent: var(--gold); }
.page-about .level-card:nth-child(4) { --level-accent: var(--vermilion); }
.page-about .level-card:nth-child(5) { --level-accent: var(--neon); }

.page-about .level-card:hover {
  transform: translateY(-4px);
  border-color: rgba(122, 63, 242, 0.6);
  box-shadow: inset 0 0 0 1px rgba(122, 63, 242, 0.45), inset 0 0 12px rgba(122, 63, 242, 0.28);
}

.page-about .level-card__no {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.16em;
  color: var(--level-accent);
}

.page-about .level-card__name {
  margin: 0;
  font-family: var(--font-serif);
  font-size: 1.5rem;
  letter-spacing: 0.04em;
  color: var(--paper);
}

.page-about .level-card__lede {
  margin: 0;
  font-size: 0.88rem;
  line-height: 1.7;
  color: rgba(247, 243, 234, 0.76);
}

.page-about .level-card__more {
  margin-top: auto;
  border-top: 1px dashed rgba(247, 243, 234, 0.18);
  padding-top: 10px;
}

.page-about .level-card__more > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--cyan);
  padding: 4px 0;
}

.page-about .level-card__more > summary::-webkit-details-marker {
  display: none;
}

.page-about .level-card__more > summary::after {
  content: "＋";
  font-size: 0.9rem;
  line-height: 1;
  color: var(--gold);
}

.page-about .level-card__more[open] > summary::after {
  content: "－";
}

.page-about .level-card__more > summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 3px;
}

.page-about .level-card__detail {
  padding-top: 8px;
  font-size: 0.84rem;
  line-height: 1.72;
  color: rgba(247, 243, 234, 0.8);
}

.page-about .level-card__detail p {
  margin: 0 0 10px;
}

.page-about .level-card__detail ul {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 6px;
}

.page-about .level-card__detail li {
  position: relative;
  padding-left: 14px;
  font-size: 0.8rem;
  color: rgba(247, 243, 234, 0.68);
}

.page-about .level-card__detail li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.62em;
  width: 7px;
  height: 1px;
  background: var(--level-accent);
}

.page-about .about-levels__foot {
  margin: clamp(22px, 3.5vw, 36px) 0 0;
  font-size: 0.88rem;
  line-height: 1.75;
  color: rgba(247, 243, 234, 0.72);
}

.page-about .about-levels__foot a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

/* ---------- 段位分数 ---------- */
.page-about .about-score {
  border-top: 1px solid var(--hair-dark);
}

.page-about .about-score__lede {
  margin: 0 0 clamp(22px, 3.5vw, 34px);
  font-size: 1rem;
  line-height: 1.82;
  color: rgba(26, 18, 38, 0.84);
}

.page-about .about-score__tabs .tabs__list {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  border-bottom: 1px solid var(--hair-dark);
  padding-bottom: 10px;
  margin-bottom: 16px;
}

.page-about .about-score__tabs .tab {
  font-family: var(--font-sans);
  font-size: 0.86rem;
  padding: 8px 14px;
  border: 1px solid var(--hair-dark);
  background: transparent;
  color: var(--ink);
  cursor: pointer;
  clip-path: polygon(8px 0, 100% 0, 100% 100%, 0 100%, 0 8px);
  transition: background 0.28s var(--ease), color 0.28s var(--ease), border-color 0.28s var(--ease);
}

.page-about .about-score__tabs .tab[aria-selected="true"] {
  background: var(--night);
  border-color: var(--night);
  color: var(--paper);
}

.page-about .about-score__tabs .tab:hover {
  border-color: var(--neon);
}

.page-about .about-score__tabs .tab:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-about .about-score__tabs .tab-panel {
  font-size: 0.94rem;
  line-height: 1.82;
  color: rgba(26, 18, 38, 0.84);
}

.page-about .about-score__tabs .tab-panel p {
  margin: 0;
}

.page-about .about-score__note {
  border-top-color: var(--neon);
}

.page-about .about-score__note .media-frame {
  margin: 0 0 18px;
}

.page-about .score-facts {
  margin: 0;
  display: grid;
  gap: 10px;
}

.page-about .score-facts > div {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 10px;
  padding-bottom: 9px;
  border-bottom: 1px dashed var(--hair-dark);
}

.page-about .score-facts dt {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  color: var(--turquoise);
  padding-top: 3px;
}

.page-about .score-facts dd {
  margin: 0;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--ink);
}

/* ---------- 场地清单 ---------- */
.page-about .about-clist {
  background: linear-gradient(168deg, var(--turquoise-deep) 0%, #0A3A36 52%, var(--night) 100%);
  color: var(--paper);
  overflow: hidden;
}

.page-about .about-clist .section-head__title {
  color: var(--paper);
}

.page-about .about-clist .section-head__note {
  color: var(--gold);
}

.page-about .about-clist__body {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(24px, 4vw, 44px);
}

.page-about .about-clist__main p {
  margin: 0 0 16px;
  font-size: 0.98rem;
  line-height: 1.84;
  color: rgba(247, 243, 234, 0.86);
}

.page-about .about-clist__main a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

.page-about .city-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .city-list li {
  display: grid;
  grid-template-columns: 74px minmax(0, 1fr);
  gap: 12px;
  align-items: baseline;
  padding: 11px 0;
  border-bottom: 1px dashed rgba(247, 243, 234, 0.18);
}

.page-about .city-list li span {
  font-family: var(--font-serif);
  font-size: 1.04rem;
  color: var(--gold);
}

.page-about .city-list li em {
  font-style: normal;
  font-size: 0.82rem;
  line-height: 1.6;
  color: rgba(247, 243, 234, 0.72);
}

.page-about .about-clist__texture {
  margin: clamp(28px, 4.5vw, 52px) 0 0;
  opacity: 0.5;
}

/* ---------- 使用场景 ---------- */
.page-about .scope-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 0;
  border-top: 1px solid var(--hair-dark);
}

.page-about .scope-item {
  padding: clamp(20px, 3.4vw, 34px) 0;
  border-bottom: 1px solid var(--hair-dark);
}

.page-about .scope-item__tag {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.2em;
  color: var(--vermilion);
}

.page-about .scope-item__title {
  margin: 0 0 10px;
  font-family: var(--font-serif);
  font-size: 1.28rem;
  color: var(--ink);
}

.page-about .scope-item__text {
  margin: 0;
  max-width: 46ch;
  font-size: 0.92rem;
  line-height: 1.82;
  color: rgba(26, 18, 38, 0.78);
}

/* ---------- 收束 ---------- */
.page-about .about-cta {
  margin-top: clamp(40px, 6vw, 72px);
  padding: clamp(26px, 4vw, 44px);
  background: var(--night);
  color: var(--paper);
  clip-path: polygon(var(--cut) 0, 100% 0, 100% calc(100% - var(--cut)), calc(100% - var(--cut)) 100%, 0 100%, 0 var(--cut));
  position: relative;
  overflow: hidden;
}

.page-about .about-cta::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background:
    radial-gradient(70% 90% at 0% 0%, rgba(217, 164, 65, 0.22), transparent 60%),
    radial-gradient(70% 90% at 100% 100%, rgba(122, 63, 242, 0.28), transparent 62%);
}

.page-about .about-cta > * {
  position: relative;
  z-index: 1;
}

.page-about .about-cta__title {
  margin: 0 0 12px;
  font-family: var(--font-serif);
  font-size: clamp(1.3rem, 2.6vw, 1.9rem);
  color: var(--paper);
}

.page-about .about-cta__text {
  margin: 0 0 22px;
  max-width: 56ch;
  font-size: 0.94rem;
  line-height: 1.82;
  color: rgba(247, 243, 234, 0.82);
}

.page-about .about-cta__text a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-cta__links .btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .scope-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 0 clamp(18px, 3vw, 34px);
  }

  .page-about .scope-item {
    border-bottom: 1px solid var(--hair-dark);
  }

  .page-about .about-clist__body {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.9fr);
  }
}

@media (min-width: 960px) {
  .page-about .about-hero__grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(250px, 0.72fr);
    align-items: end;
  }

  .page-about .about-split {
    grid-template-columns: minmax(0, 1.85fr) minmax(240px, 0.78fr);
    align-items: start;
  }

  .page-about .about-score__body {
    grid-template-columns: minmax(0, 1.7fr) minmax(280px, 0.82fr);
  }

  .page-about .level-track {
    grid-auto-columns: minmax(0, 1fr);
    overflow-x: auto;
  }

  .page-about .about-hero__vertical {
    display: block;
    position: absolute;
    left: clamp(10px, 1.6vw, 22px);
    top: clamp(44px, 7vw, 88px);
    writing-mode: vertical-rl;
    font-family: var(--font-mono);
    font-size: 0.68rem;
    letter-spacing: 0.38em;
    color: rgba(167, 156, 140, 0.7);
    pointer-events: none;
  }

  .page-about .about-hero {
    padding-left: clamp(38px, 5vw, 66px);
  }
}

@media (min-width: 1280px) {
  .page-about .about-rail {
    display: flex;
    flex-direction: column;
    gap: 4px;
    position: fixed;
    right: 18px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 4;
    padding: 12px 8px;
    background: rgba(18, 12, 30, 0.82);
    border-left: 2px solid var(--vermilion);
    backdrop-filter: blur(4px);
  }

  .page-about .about-rail a {
    font-size: 0.7rem;
    line-height: 1.4;
    letter-spacing: 0.06em;
    color: rgba(247, 243, 234, 0.7);
    text-decoration: none;
    padding: 5px 2px;
    transition: color 0.28s var(--ease);
  }

  .page-about .about-rail a:hover,
  .page-about .about-rail a:focus-visible {
    color: var(--cyan);
  }

  .page-about .about-rail a:focus-visible {
    outline: 2px solid var(--cyan);
    outline-offset: 2px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .level-card,
  .page-about .about-score__tabs .tab,
  .page-about .about-rail a {
    transition: none;
  }

  .page-about .level-card:hover {
    transform: none;
  }
}