.page-about {
  --about-num-w: 88px;
  --about-measure: 34em;
  --about-hair: rgba(42, 92, 65, 0.62);
  background: var(--field);
  color: var(--paper);
}

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

/* ---------- 封面首屏 ---------- */
.page-about .about-cover {
  position: relative;
  padding: clamp(22px, 5vw, 44px) 0 clamp(40px, 7vw, 76px);
  background:
    radial-gradient(120% 90% at 88% -10%, rgba(233, 255, 77, 0.12), transparent 58%),
    linear-gradient(172deg, var(--stand) 0%, var(--field) 82%);
  overflow: hidden;
}

.page-about .about-cover::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--line) 30%, var(--line) 70%, transparent);
}

.page-about .about-cover__inner {
  display: grid;
  gap: 32px;
}

.page-about .about-cover__eyebrow {
  margin: 22px 0 0;
  color: var(--signal);
}

.page-about .about-cover__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(29px, 8vw, 60px);
  line-height: 1.16;
  letter-spacing: -0.02em;
  text-wrap: balance;
}

.page-about .about-cover__lede {
  margin: 20px 0 0;
  max-width: var(--about-measure);
  font-size: 16px;
  line-height: 1.85;
  color: var(--cool);
}

.page-about .about-cover__stats {
  display: grid;
  gap: 1px;
  background: var(--hair);
  border: 1px solid var(--hair);
  border-radius: var(--radius-card);
  overflow: hidden;
}

.page-about .about-cover__stat {
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 15px 18px;
  background: var(--stand);
}

.page-about .about-cover__stat-num {
  flex: none;
  min-width: 3.4em;
  font-family: var(--font-mono);
  font-size: 25px;
  font-weight: 600;
  line-height: 1.1;
  color: var(--signal);
  letter-spacing: -0.02em;
}

.page-about .about-cover__stat:last-child .about-cover__stat-num {
  color: var(--orange);
}

.page-about .about-cover__stat-label {
  font-size: 13px;
  line-height: 1.55;
  color: var(--cool);
}

/* ---------- 章节长卷 ---------- */
.page-about .chapter {
  position: relative;
  padding: clamp(46px, 9vw, 100px) 0;
  scroll-margin-top: 24px;
  border-top: 1px solid var(--about-hair);
}

.page-about .chapter--band {
  background: var(--stand);
}

.page-about .chapter--turf {
  background: linear-gradient(180deg, var(--stand) 0%, var(--turf) 46%, var(--stand) 100%);
}

.page-about .chapter--close {
  background:
    radial-gradient(90% 120% at 12% 0%, rgba(233, 255, 77, 0.10), transparent 62%),
    var(--stand);
}

.page-about .chapter__grid {
  display: grid;
  gap: 26px;
}

.page-about .chapter__aside {
  display: flex;
  align-items: flex-start;
}

.page-about .chapter__num {
  display: block;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(42px, 12vw, 76px);
  line-height: 0.86;
  letter-spacing: -0.04em;
  color: rgba(245, 243, 234, 0.10);
  -webkit-text-stroke: 1px var(--line);
  user-select: none;
}

.page-about .chapter__body {
  max-width: var(--about-measure);
}

.page-about .chapter__kicker {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--signal);
}

.page-about .chapter__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(23px, 5.6vw, 36px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .chapter__text p {
  margin: 16px 0 0;
  font-size: 16px;
  line-height: 1.85;
  color: var(--cool);
}

.page-about .chapter__text--tail {
  margin: 22px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--cool);
}

.page-about .chapter__link {
  color: var(--signal);
  text-decoration: none;
  border-bottom: 1px solid rgba(233, 255, 77, 0.45);
  padding-bottom: 1px;
}

.page-about .chapter__link:hover,
.page-about .chapter__link:focus-visible {
  border-bottom-color: var(--signal);
}

.page-about .about-quote {
  margin: 28px 0 0;
  padding: 2px 0 2px 18px;
  border-left: 3px solid var(--signal);
  font-family: var(--font-display);
  font-size: clamp(17px, 4.2vw, 21px);
  line-height: 1.72;
  color: var(--paper);
}

/* ---------- 图片容器 ---------- */
.page-about .media-frame {
  margin: 0;
  overflow: hidden;
  border-radius: var(--radius-media);
  border: 1px solid var(--hair);
  background: var(--turf);
}

.page-about .chapter__media .media-frame,
.page-about .chapter__media {
  margin: 0;
}

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

.page-about .media-frame--tall img {
  aspect-ratio: 4 / 5;
}

.page-about .media-frame--wide img {
  aspect-ratio: 2 / 1;
}

.page-about .media-frame__caption {
  padding: 12px 16px 14px;
  font-family: var(--font-mono);
  font-size: 11px;
  line-height: 1.6;
  letter-spacing: 0.02em;
  color: var(--mist);
  background: rgba(6, 23, 15, 0.55);
}

.page-about .chapter__wide {
  margin: 32px 0 0;
}

/* ---------- 四步法 ---------- */
.page-about .steps {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .step {
  position: relative;
  padding: 18px 16px 17px;
  border: 1px solid var(--hair);
  border-radius: var(--radius-card);
  background: rgba(20, 67, 44, 0.42);
  transition: border-color 0.24s var(--ease), transform 0.24s var(--ease), background 0.24s var(--ease);
}

.page-about .step:hover,
.page-about .step:focus-within {
  border-color: var(--signal);
  background: rgba(20, 67, 44, 0.72);
  transform: translateY(-4px);
}

.page-about .step__num {
  display: inline-flex;
  align-items: center;
  height: 26px;
  padding: 0 12px;
  border-radius: var(--radius-pill);
  background: rgba(233, 255, 77, 0.14);
  color: var(--signal);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
}

.page-about .step:last-child .step__num {
  background: var(--orange);
  color: #14100c;
}

.page-about .step__title {
  margin: 12px 0 0;
  font-family: var(--font-display);
  font-size: 19px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .step__text {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--cool);
}

.page-about .step__note {
  margin: 10px 0 0;
  padding-top: 10px;
  border-top: 1px dashed var(--hair);
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 时间线 ---------- */
.page-about .timeline {
  list-style: none;
  position: relative;
  margin: 36px 0 0;
  padding: 0;
  display: grid;
  gap: 26px;
}

.page-about .timeline::before {
  content: "";
  position: absolute;
  left: 7px;
  top: 8px;
  bottom: 10px;
  width: 1px;
  background: var(--line);
}

.page-about .timeline__item {
  position: relative;
  padding-left: 32px;
}

.page-about .timeline__dot {
  position: absolute;
  left: 0;
  top: 5px;
  width: 15px;
  height: 15px;
  border-radius: 50%;
  border: 1px solid var(--line);
  background: var(--stand);
}

.page-about .timeline__item--now .timeline__dot {
  background: var(--signal);
  border-color: var(--signal);
  box-shadow: 0 0 0 5px rgba(233, 255, 77, 0.14);
}

.page-about .timeline__title {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--paper);
}

.page-about .timeline__item--now .timeline__title {
  color: var(--signal);
}

.page-about .timeline__text {
  margin: 8px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--cool);
}

/* ---------- 使用场景拼贴 ---------- */
.page-about .use-grid {
  margin: 28px 0 0;
  display: grid;
  gap: 14px;
}

.page-about .use-card {
  display: flex;
  flex-direction: column;
  gap: 10px;
  padding: 20px 18px;
  border: 1px solid var(--hair);
  border-radius: var(--radius-card);
  background: linear-gradient(158deg, rgba(20, 67, 44, 0.86), rgba(11, 42, 28, 0.94));
}

.page-about .use-card--lead {
  border-color: rgba(233, 255, 77, 0.34);
  background: linear-gradient(158deg, rgba(20, 67, 44, 0.96), rgba(6, 23, 15, 0.96));
}

.page-about .use-card__title {
  margin: 0;
  font-family: var(--font-display);
  font-size: 20px;
  font-weight: 700;
  line-height: 1.4;
  color: var(--paper);
}

.page-about .use-card__text {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--cool);
}

.page-about .use-card__meta {
  margin: 0;
  padding-top: 10px;
  border-top: 1px solid var(--hair);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--mist);
}

/* ---------- 收尾 ---------- */
.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 28px 0 0;
}

/* ---------- 右侧点状目录 ---------- */
.page-about .about-toc {
  display: none;
}

@media (min-width: 760px) {
  .page-about .about-cover__inner {
    gap: 36px;
  }

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

  .page-about .about-cover__stat {
    flex-direction: column;
    gap: 8px;
  }

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

  .page-about .use-card--lead {
    grid-row: span 2;
    justify-content: center;
  }
}

@media (min-width: 860px) {
  .page-about .chapter__grid {
    grid-template-columns: var(--about-num-w) minmax(0, 1fr);
    column-gap: 32px;
    align-items: start;
  }

  .page-about .chapter__body {
    max-width: none;
  }

  .page-about .chapter__text p,
  .page-about .chapter__title,
  .page-about .about-quote,
  .page-about .chapter__text--tail {
    max-width: var(--about-measure);
  }

  .page-about .steps {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 10px;
  }

  .page-about .timeline {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 24px;
  }

  .page-about .timeline::before {
    left: 8px;
    right: 8px;
    top: 7px;
    bottom: auto;
    width: auto;
    height: 1px;
  }

  .page-about .timeline__item {
    padding: 34px 0 0;
  }

  .page-about .timeline__dot {
    top: 0;
  }
}

@media (hover: hover) and (min-width: 860px) {
  .page-about .step__note {
    margin: 0;
    max-height: 0;
    padding-top: 0;
    border-top-color: transparent;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.24s var(--ease), opacity 0.24s var(--ease),
      margin 0.24s var(--ease), padding 0.24s var(--ease);
  }

  .page-about .step:hover .step__note,
  .page-about .step:focus-within .step__note {
    margin: 10px 0 0;
    max-height: 9em;
    padding-top: 10px;
    border-top-color: var(--hair);
    opacity: 1;
  }
}

@media (min-width: 1080px) {
  .page-about {
    --about-num-w: 104px;
  }

  .page-about .chapter__grid--media {
    grid-template-columns: var(--about-num-w) minmax(0, 34em) minmax(0, 1fr);
    column-gap: clamp(28px, 3vw, 48px);
  }

  .page-about .chapter__media {
    position: sticky;
    top: 40px;
  }

  .page-about .media-frame--slant {
    transform: rotate(-2.5deg);
    transform-origin: 50% 50%;
  }
}

@media (min-width: 1200px) {
  .page-about .about-toc {
    display: block;
    position: fixed;
    right: 12px;
    top: 50%;
    transform: translateY(-50%);
    z-index: 6;
  }

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

  .page-about .about-toc__link {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    text-decoration: none;
  }

  .page-about .about-toc__link::before {
    content: "";
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--mist);
    transition: width 0.24s var(--ease), height 0.24s var(--ease), background 0.24s var(--ease);
  }

  .page-about .about-toc__link:hover::before,
  .page-about .about-toc__link:focus-visible::before,
  .page-about .about-toc__link.is-active::before {
    width: 10px;
    height: 10px;
    background: var(--signal);
  }

  .page-about .about-toc__label {
    position: absolute;
    right: 44px;
    white-space: nowrap;
    padding: 4px 11px;
    border-radius: var(--radius-pill);
    border: 1px solid var(--line);
    background: var(--stand);
    color: var(--paper);
    font-family: var(--font-mono);
    font-size: 11px;
    letter-spacing: 0.08em;
    opacity: 0;
    transform: translateX(6px);
    pointer-events: none;
    transition: opacity 0.2s var(--ease), transform 0.2s var(--ease);
  }

  .page-about .about-toc__link:hover .about-toc__label,
  .page-about .about-toc__link:focus-visible .about-toc__label {
    opacity: 1;
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .step,
  .page-about .step__note,
  .page-about .about-toc__link::before,
  .page-about .about-toc__label {
    transition: none;
  }

  .page-about .step:hover,
  .page-about .step:focus-within {
    transform: none;
  }
}

.page-about {
  --hair: transparent;
}