.page-about {
  --about-rail-w: 216px;
  --about-gap: clamp(28px, 4.5vw, 62px);
  --about-sec-pad: clamp(38px, 5.5vw, 70px);
  --about-cell-low: rgba(53, 224, 200, 0.16);
  --about-cell-mid: rgba(53, 224, 200, 0.46);
  --about-cell-high: rgba(198, 255, 61, 0.82);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(84px, 11vw, 146px) clamp(40px, 5.5vw, 74px);
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, var(--ink-0) 0%, var(--ink-3) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  top: -34%;
  right: -14%;
  width: min(560px, 72vw);
  aspect-ratio: 1 / 1;
  background: radial-gradient(circle, rgba(198, 255, 61, 0.10), transparent 66%);
  pointer-events: none;
}

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

.page-about .breadcrumbs {
  margin-bottom: clamp(26px, 4vw, 44px);
}

.page-about .about-hero__kicker {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 18px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--teal);
}

.page-about .about-hero__kicker::before {
  content: "";
  width: 24px;
  height: 2px;
  background: var(--lime);
}

.page-about .about-hero__title {
  margin: 0 0 22px;
  max-width: 21ch;
  font-size: clamp(29px, 5.2vw, 58px);
  line-height: 1.15;
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--snow);
}

.page-about .about-hero__lead {
  margin: 0 0 clamp(32px, 4.5vw, 52px);
  max-width: 63ch;
  font-size: clamp(15.5px, 1.9vw, 17.5px);
  line-height: 1.8;
  color: var(--mute);
}

.page-about .about-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  border: 1px solid var(--line);
  background: var(--line);
}

.page-about .about-fact {
  background: var(--ink-1);
  padding: 18px 16px 20px;
  display: grid;
  align-content: start;
  gap: 7px;
}

.page-about .about-fact__value {
  font-family: var(--font-mono);
  font-size: clamp(22px, 3.1vw, 33px);
  font-weight: 700;
  line-height: 1;
  letter-spacing: 0.02em;
  color: var(--lime);
}

.page-about .about-fact__label {
  font-size: 12.8px;
  line-height: 1.55;
  color: var(--mute);
}

/* ---------- 骨架：左索引 + 右内容 ---------- */
.page-about .about-sheet {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--about-gap);
  padding-block: clamp(36px, 5.5vw, 70px) clamp(60px, 8vw, 110px);
}

.page-about .about-index__title {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--mute);
}

.page-about .about-index__list {
  list-style: none;
  margin: 0;
  padding: 0 0 8px;
  display: flex;
  gap: 8px;
  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__link {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 13px;
  border: 1px solid var(--line);
  color: var(--mute);
  font-size: 13.2px;
  line-height: 1.4;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease), background 0.2s var(--ease);
}

.page-about .about-index__link .chapter-index__no {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  color: var(--teal);
}

.page-about .about-index__link:hover {
  color: var(--snow);
  border-color: var(--line-2);
}

.page-about .about-index__link.is-active {
  color: var(--snow);
  border-color: var(--lime);
  background: rgba(198, 255, 61, 0.07);
}

.page-about .about-index__link.is-active .chapter-index__no {
  color: var(--lime);
}

/* ---------- 章节 ---------- */
.page-about .about-flow > .about-sec:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .about-sec {
  padding-block: var(--about-sec-pad);
  border-top: 1px solid var(--line);
  scroll-margin-top: calc(var(--hdr) + 26px);
}

.page-about .about-sec__head {
  margin-bottom: 18px;
}

.page-about .about-sec__no {
  display: block;
  margin-bottom: 9px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.18em;
  color: var(--lime);
}

.page-about .about-sec__title {
  margin: 0;
  padding-left: 16px;
  border-left: 3px solid var(--lime);
  font-size: clamp(21px, 3vw, 31px);
  line-height: 1.32;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--snow);
}

.page-about .about-sec__lead {
  margin: 0 0 30px;
  max-width: 66ch;
  font-size: 15.6px;
  line-height: 1.82;
  color: var(--mute);
}

/* ---------- 01 主线 ---------- */
.page-about .about-pillars {
  border-top: 1px solid var(--line);
}

.page-about .about-pillar {
  display: grid;
  gap: 6px;
  padding: 20px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-pillar__name {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  font-size: 16.5px;
  font-weight: 700;
  color: var(--snow);
}

.page-about .about-pillar__dot {
  width: 8px;
  height: 8px;
  flex: 0 0 auto;
  background: var(--lime);
}

.page-about .about-pillar__text {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mute);
}

/* ---------- 图片容器 ---------- */
.page-about .about-shot {
  margin: 0 0 30px;
  border: 1px solid var(--line);
  background: var(--ink-1);
  overflow: hidden;
}

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

.page-about .about-shot .media-frame__caption {
  padding: 12px 16px;
  font-size: 12.6px;
  line-height: 1.6;
  color: var(--mute);
  border-top: 1px solid var(--line);
}

/* ---------- 02 流程 ---------- */
.page-about .about-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

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

.page-about .about-step__sum {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 18px 4px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-step__sum:focus-visible {
  outline: 2px solid var(--lime);
  outline-offset: 2px;
}

.page-about .about-step__no {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--lime);
}

.page-about .about-step__name {
  flex: 1 1 auto;
  font-size: 16.8px;
  font-weight: 700;
  color: var(--snow);
}

.page-about .about-step__hint {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--teal);
}

.page-about .about-step__hint::after {
  content: " +";
}

.page-about .about-step[open] .about-step__hint::after {
  content: " −";
}

.page-about .about-step__body {
  max-width: 68ch;
  padding: 0 4px 22px 42px;
  font-size: 15px;
  line-height: 1.82;
  color: var(--mute);
}

/* ---------- 03 收藏入口 ---------- */
.page-about .about-entries {
  display: grid;
  grid-template-columns: 1fr;
  gap: 26px 32px;
}

.page-about .about-entry {
  padding-top: 16px;
  border-top: 2px solid var(--teal);
}

.page-about .about-entry__no {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.18em;
  color: var(--teal);
}

.page-about .about-entry__title {
  margin: 0 0 10px;
  font-size: 17px;
  line-height: 1.45;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-entry__text {
  margin: 0;
  font-size: 14.8px;
  line-height: 1.78;
  color: var(--mute);
}

.page-about .about-note {
  margin: 30px 0 0;
  max-width: 64ch;
  padding-left: 16px;
  border-left: 2px solid var(--lime);
  font-size: 15px;
  line-height: 1.82;
  color: var(--mute);
}

.page-about .about-links {
  display: flex;
  flex-wrap: wrap;
  gap: 12px 28px;
  margin: 24px 0 0;
}

.page-about .about-link {
  display: inline-block;
  font-size: 14.4px;
  line-height: 1.6;
  color: var(--teal);
  text-decoration: none;
  border-bottom: 1px solid rgba(53, 224, 200, 0.35);
  padding-bottom: 2px;
  transition: color 0.2s var(--ease), border-color 0.2s var(--ease);
}

.page-about .about-link:hover,
.page-about .about-link:focus-visible {
  color: var(--lime);
  border-color: var(--lime);
}

.page-about .about-links .about-link::after {
  content: " →";
}

/* ---------- 04 代际 ---------- */
.page-about .about-gens {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  margin-bottom: 34px;
}

.page-about .about-gen {
  display: grid;
  align-content: start;
  gap: 12px;
  padding: 24px 22px 26px;
  background: var(--ink-2);
  border: 1px solid var(--line);
  transition: border-color 0.22s var(--ease), box-shadow 0.22s var(--ease), background 0.22s var(--ease);
}

.page-about .about-gen:hover,
.page-about .about-gen:focus-within {
  border-color: var(--line-2);
  box-shadow: var(--shadow-1);
}

.page-about .about-gen__tag {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--mute);
}

.page-about .about-gen__title {
  margin: 0;
  font-size: 17.5px;
  line-height: 1.42;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-gen__text {
  margin: 0;
  font-size: 14.6px;
  line-height: 1.8;
  color: var(--mute);
}

.page-about .about-gen__fix {
  margin: 0;
  padding-top: 12px;
  border-top: 1px dashed var(--line);
  font-size: 13.6px;
  line-height: 1.7;
  color: var(--teal);
}

.page-about .about-gen--now {
  border-color: rgba(255, 106, 43, 0.55);
  background: linear-gradient(180deg, rgba(255, 106, 43, 0.10), rgba(17, 20, 23, 0.94));
}

.page-about .about-gen--now:hover,
.page-about .about-gen--now:focus-within {
  border-color: var(--orange);
}

.page-about .about-gen--now .about-gen__tag {
  color: var(--orange);
}

/* ---------- 04 归档矩阵 ---------- */
.page-about .about-matrix-block {
  margin-top: 30px;
}

.page-about .about-matrix__cap {
  margin: 0 0 14px;
  font-size: 13.4px;
  line-height: 1.65;
  color: var(--mute);
}

.page-about .about-matrix {
  display: grid;
  gap: 5px;
  padding: 16px 14px;
  border: 1px solid var(--line);
  background: var(--ink-1);
  overflow-x: auto;
}

.page-about .about-matrix__row {
  display: grid;
  grid-template-columns: 56px repeat(12, minmax(10px, 1fr));
  gap: 4px;
  align-items: center;
  min-width: 320px;
}

.page-about .about-matrix__season {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--mute);
  white-space: nowrap;
}

.page-about .about-cell {
  display: block;
  aspect-ratio: 2 / 1;
  border-radius: 1px;
  background: var(--ink-3);
  transition: outline-color 0.16s var(--ease);
}

.page-about .about-cell--low {
  background: var(--about-cell-low);
}

.page-about .about-cell--mid {
  background: var(--about-cell-mid);
}

.page-about .about-cell--high {
  background: var(--about-cell-high);
}

.page-about .about-cell:hover {
  outline: 1px solid var(--lime);
  outline-offset: 1px;
}

.page-about .about-legend {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 10px 24px;
  margin: 16px 0 0;
  padding: 0;
}

.page-about .about-legend__item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 12.6px;
  color: var(--mute);
}

.page-about .about-legend__swatch {
  display: block;
  width: 14px;
  height: 8px;
  border-radius: 1px;
}

.page-about .about-legend__swatch--low {
  background: var(--about-cell-low);
}

.page-about .about-legend__swatch--mid {
  background: var(--about-cell-mid);
}

.page-about .about-legend__swatch--high {
  background: var(--about-cell-high);
}

/* ---------- 05 团队 ---------- */
.page-about .about-teams {
  list-style: none;
  margin: 0;
  padding: 0;
  border-top: 1px solid var(--line);
}

.page-about .about-team {
  display: grid;
  gap: 8px;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}

.page-about .about-team__name {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0;
  font-size: 17px;
  font-weight: 800;
  color: var(--snow);
}

.page-about .about-team__name::before {
  content: "";
  width: 4px;
  height: 18px;
  flex: 0 0 auto;
  background: var(--teal);
}

.page-about .about-team__text {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.82;
  color: var(--mute);
}

/* ---------- 06 站点信息 ---------- */
.page-about .about-info {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  margin: 0 0 28px;
  border: 1px solid var(--line);
  background: var(--line);
}

.page-about .about-info > div {
  display: grid;
  gap: 5px;
  padding: 15px 18px 17px;
  background: var(--ink-1);
}

.page-about .about-info dt {
  font-family: var(--font-mono);
  font-size: 10.8px;
  letter-spacing: 0.16em;
  color: var(--mute);
}

.page-about .about-info dd {
  margin: 0;
  font-size: 15px;
  line-height: 1.6;
  color: var(--snow);
  word-break: break-word;
}

.page-about .about-info + .about-note a {
  margin: 0 2px;
}

/* ---------- 平板 ---------- */
@media (min-width: 700px) {
  .page-about .about-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .page-about .about-fact {
    padding: 22px 18px 24px;
  }

  .page-about .about-pillar {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.55fr);
    gap: 6px 28px;
    align-items: baseline;
  }

  .page-about .about-pillar__text {
    margin-top: 0;
  }

  .page-about .about-entries {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-about .about-team {
    grid-template-columns: 170px minmax(0, 1fr);
    gap: 8px 26px;
    align-items: start;
  }

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

  .page-about .about-gens {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 桌面：左侧索引固定 ---------- */
@media (min-width: 1040px) {
  .page-about .about-sheet {
    grid-template-columns: var(--about-rail-w) minmax(0, 1fr);
  }

  .page-about .about-index {
    align-self: start;
    position: sticky;
    top: calc(var(--hdr-sm) + 26px);
  }

  .page-about .about-index__list {
    display: block;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-index__list > li + li {
    margin-top: 2px;
  }

  .page-about .about-index__link {
    white-space: normal;
    padding: 9px 0 9px 15px;
    border: 0;
    border-left: 2px solid transparent;
    background: none;
    font-size: 13.6px;
  }

  .page-about .about-index__link:hover {
    border-left-color: var(--line-2);
  }

  .page-about .about-index__link.is-active {
    border-left-color: var(--lime);
    background: linear-gradient(90deg, rgba(198, 255, 61, 0.08), transparent 78%);
  }

  .page-about .about-matrix__row {
    grid-template-columns: 64px repeat(12, minmax(16px, 1fr));
  }
}

@media (min-width: 1320px) {
  .page-about .about-hero__lead {
    font-size: 18px;
  }
}

@media (max-width: 600px) {
  .page-about .about-step__body {
    padding-left: 4px;
  }

  .page-about .about-matrix {
    padding: 14px 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-gen,
  .page-about .about-index__link,
  .page-about .about-cell,
  .page-about .about-link {
    transition: none;
  }
}