.page-about {
  --about-ver1: var(--cyan);
  --about-ver2: var(--purple-light);
  --about-ver3: var(--amber);
  --about-gutter: 20px;
}

.page-about .about-top {
  padding-top: var(--s-3);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  margin-top: var(--s-3);
  padding-block: var(--s-6) var(--s-5);
  border-top: 2px solid var(--line);
  border-bottom: 2px solid var(--line);
  background:
    radial-gradient(120% 150% at 8% 0%, rgba(108, 59, 255, .30) 0%, rgba(7, 11, 34, 0) 58%),
    radial-gradient(90% 130% at 96% 10%, rgba(47, 225, 214, .13) 0%, rgba(7, 11, 34, 0) 62%),
    var(--ink-900);
  overflow: hidden;
}

.page-about .about-hero__inner {
  display: grid;
  gap: var(--s-4);
}

.page-about .about-hero__title {
  margin: var(--s-2) 0 var(--s-3);
  font-size: clamp(2rem, 5.4vw, 3.6rem);
  font-weight: 900;
  line-height: 1.16;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .about-hero .lede {
  margin: 0;
  color: var(--muted);
}

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

.page-about .about-stats > li {
  background: var(--ink-800);
  padding: var(--s-3) var(--s-2);
  display: grid;
  gap: 6px;
  align-content: start;
}

.page-about .stat-num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 3.4vw, 2.1rem);
  font-weight: 700;
  line-height: 1.1;
  color: var(--amber);
}

.page-about .about-stats > li:nth-child(2n) .stat-num {
  color: var(--cyan);
}

.page-about .stat-label {
  font-size: 13px;
  line-height: 1.6;
  color: var(--muted);
}

@media (min-width: 760px) {
  .page-about .about-hero__inner {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
    gap: var(--s-6);
  }
}

/* ---------- 两列骨架 ---------- */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--s-4);
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--about-gutter);
  padding-block: var(--s-5) var(--s-6);
}

.page-about .about-stream {
  min-width: 0;
}

/* ---------- 柱式索引 ---------- */
.page-about .about-index .pillar-index__list {
  display: flex;
  gap: var(--s-1);
  overflow-x: auto;
  list-style: none;
  margin: 0;
  padding: 0 0 var(--s-1);
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-about .about-index .pillar-index__link {
  display: flex;
  align-items: baseline;
  gap: 8px;
  white-space: nowrap;
  padding: 8px 10px;
  border: 2px solid transparent;
  border-radius: 2px;
  font-size: 14px;
  color: var(--muted);
  text-decoration: none;
  transition: color 180ms ease-out, border-color 180ms ease-out, background 180ms ease-out;
}

.page-about .about-index .pillar-index__link:hover {
  color: var(--text);
  border-color: var(--line);
}

.page-about .about-index .pillar-index__link[aria-current="true"] {
  color: var(--amber);
  border-color: var(--amber);
  background: rgba(255, 184, 77, .08);
}

.page-about .pillar-index__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--purple-light);
}

@media (min-width: 1040px) {
  .page-about .about-layout {
    grid-template-columns: 200px minmax(0, 1fr);
    gap: var(--s-6);
    align-items: start;
    padding-inline: var(--s-5);
  }

  .page-about .about-index {
    position: sticky;
    top: 88px;
    align-self: start;
  }

  .page-about .about-index .pillar-index__list {
    flex-direction: column;
    overflow: visible;
  }

  .page-about .about-index .pillar-index__link {
    white-space: normal;
  }
}

/* ---------- 章节 ---------- */
.page-about .section {
  padding-block: var(--s-5);
  border-top: 2px solid var(--line);
}

.page-about .section:first-child {
  border-top: 0;
  padding-top: 0;
}

.page-about .spread {
  display: grid;
  gap: var(--s-3);
}

.page-about .spread__side {
  display: grid;
  gap: var(--s-2);
  align-content: start;
}

.page-about .section__num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(2rem, 5vw, 3rem);
  font-weight: 700;
  line-height: 1;
  color: var(--purple);
  opacity: .9;
}

.page-about .spread__phrase {
  margin: 0;
  padding-left: 12px;
  border-left: 2px solid var(--amber);
  font-size: 15px;
  line-height: 1.7;
  color: var(--muted);
}

.page-about .section__title {
  margin: 0 0 var(--s-2);
  font-size: clamp(1.5rem, 3.2vw, 2.05rem);
  font-weight: 800;
  line-height: 1.3;
  letter-spacing: -0.01em;
  color: var(--text);
}

.page-about .spread__body p {
  margin: 0 0 1.2em;
  line-height: 1.8;
}

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

@media (min-width: 900px) {
  .page-about .spread {
    grid-template-columns: minmax(0, 4fr) minmax(0, 8fr);
    gap: var(--s-6);
    align-items: start;
  }
}

/* ---------- 团队方阵 ---------- */
.page-about .team-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 2px;
  margin: var(--s-4) 0 0;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .team-card {
  background: var(--ink-800);
  padding: var(--s-3);
  display: grid;
  gap: 8px;
  align-content: start;
  border-left: 4px solid transparent;
  transition: border-color 180ms ease-out, background 180ms ease-out, transform 180ms ease-out;
}

.page-about .team-card:hover {
  background: var(--ink-700);
  border-left-color: var(--cyan);
  transform: translateX(2px);
}

.page-about .team-card:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
  border-left-color: var(--cyan);
}

.page-about .team-card__idx {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--purple-light);
}

.page-about .team-card__title {
  margin: 0;
  font-size: 17px;
  font-weight: 700;
  line-height: 1.45;
  color: var(--text);
}

.page-about .team-card__desc {
  margin: 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

@media (min-width: 640px) {
  .page-about .team-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1180px) {
  .page-about .team-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

/* ---------- 版本时间轴 ---------- */
.page-about .version-steps {
  margin: var(--s-4) 0 0;
}

.page-about .version-steps .steps__list {
  display: flex;
  gap: 2px;
  background: var(--line);
  border: 2px solid var(--line);
  border-bottom: 0;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-about .version-steps .steps__item {
  flex: 1 0 auto;
  min-width: 132px;
  display: grid;
  gap: 4px;
  text-align: left;
  background: var(--ink-800);
  border: 0;
  border-bottom: 3px solid transparent;
  color: var(--muted);
  font: inherit;
  padding: var(--s-2) var(--s-3);
  cursor: pointer;
  transition: color 180ms ease-out, background 180ms ease-out, border-color 180ms ease-out;
}

.page-about .version-steps .steps__item:hover {
  color: var(--text);
  background: var(--ink-700);
}

.page-about .version-steps .steps__item[aria-selected="true"] {
  background: var(--ink-700);
  color: var(--text);
  border-bottom-color: var(--amber);
}

.page-about .version-steps .steps__num {
  font-family: var(--font-mono);
  font-size: 1.35rem;
  font-weight: 700;
  line-height: 1;
}

.page-about .version-steps .steps__item[data-ver="v1"] .steps__num { color: var(--about-ver1); }
.page-about .version-steps .steps__item[data-ver="v2"] .steps__num { color: var(--about-ver2); }
.page-about .version-steps .steps__item[data-ver="v3"] .steps__num { color: var(--about-ver3); }

.page-about .version-steps .steps__name {
  font-size: 13px;
  letter-spacing: .02em;
}

.page-about .version-steps .steps__panel {
  background: var(--ink-800);
  border: 2px solid var(--line);
  border-top: 0;
  padding: var(--s-3);
}

.page-about .version-steps .steps__panel > p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text);
}

.page-about .ver-meta {
  margin: var(--s-3) 0 0;
  display: grid;
  gap: 2px;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-about .ver-meta__row {
  display: grid;
  gap: 4px;
  background: var(--ink-900);
  padding: 10px var(--s-2);
}

.page-about .ver-meta dt {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--muted);
}

.page-about .ver-meta dd {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: var(--text);
}

@media (min-width: 640px) {
  .page-about .ver-meta__row {
    grid-template-columns: 88px minmax(0, 1fr);
    align-items: baseline;
    gap: var(--s-2);
  }
}

/* ---------- 四道流程 ---------- */
.page-about .flow {
  list-style: none;
  counter-reset: about-flow;
  margin: var(--s-4) 0 0;
  padding: 0;
  display: grid;
  gap: var(--s-2);
}

.page-about .flow__item {
  counter-increment: about-flow;
  position: relative;
  background: var(--ink-800);
  border: 2px solid var(--line);
  border-radius: 2px;
  padding: var(--s-3) var(--s-3) var(--s-3) calc(var(--s-3) + 58px);
  transition: border-color 180ms ease-out;
}

.page-about .flow__item:hover {
  border-color: var(--purple);
}

.page-about .flow__item::before {
  content: "0" counter(about-flow);
  position: absolute;
  left: var(--s-3);
  top: var(--s-3);
  font-family: var(--font-mono);
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1.2;
  color: var(--cyan);
}

.page-about .flow__title {
  margin: 0 0 6px;
  font-size: 16px;
  font-weight: 700;
  color: var(--text);
}

.page-about .flow__item p {
  margin: 0;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

@media (min-width: 900px) {
  .page-about .flow {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: var(--s-3);
  }
}

/* ---------- 图片 ---------- */
.page-about .figure {
  margin: var(--s-4) 0 0;
}

.page-about .figure__media {
  border: 2px solid var(--line);
  border-radius: 2px;
  background: var(--ink-800);
  overflow: hidden;
}

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

.page-about .figure__cap {
  margin-top: 10px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

/* ---------- 收束行动 ---------- */
.page-about .about-cta {
  margin-top: var(--s-5);
  padding: var(--s-3);
}

.page-about .about-cta .panel__label {
  margin: 0 0 var(--s-2);
  letter-spacing: .14em;
  color: var(--amber);
}

.page-about .about-cta .panel__title {
  margin: 0 0 var(--s-2);
  font-size: clamp(1.25rem, 2.6vw, 1.6rem);
  font-weight: 800;
  color: var(--text);
}

.page-about .about-cta__body {
  margin: 0 0 var(--s-3);
  font-size: 15px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-cta__links {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-2);
}

@media (max-width: 560px) {
  .page-about .about-cta__links {
    flex-direction: column;
  }

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

/* ---------- 动效降级 ---------- */
@media (prefers-reduced-motion: reduce) {
  .page-about .team-card,
  .page-about .flow__item,
  .page-about .version-steps .steps__item,
  .page-about .about-index .pillar-index__link {
    transition: color 160ms linear, background-color 160ms linear;
    transform: none;
  }

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