.page-about {
  --about-rail: 214px;
  --about-gap: 48px;
  --about-fig-radius: 20px;
  display: block;
  background: var(--void);
  color: var(--ink);
}

/* ── 首屏 ────────────────────────────────── */
.page-about .about-hero {
  position: relative;
  overflow: hidden;
  padding-block: clamp(40px, 8vw, 96px) clamp(44px, 7vw, 88px);
  background:
    radial-gradient(120% 90% at 88% 6%, rgba(139, 92, 246, 0.30), transparent 62%),
    radial-gradient(90% 70% at 4% 96%, rgba(255, 107, 44, 0.16), transparent 66%),
    var(--void);
  border-bottom: 1px solid var(--line);
}

.page-about .about-hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
  opacity: 0.34;
  pointer-events: none;
}

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

.page-about .about-hero-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg, rgba(5, 10, 26, 0.42) 0%, rgba(5, 10, 26, 0.82) 62%, var(--void) 100%);
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 72px;
  z-index: 1;
  background: linear-gradient(100deg, var(--orange) 0%, var(--violet) 44%, transparent 74%);
  opacity: 0.14;
  pointer-events: none;
}

.page-about .about-hero-inner {
  position: relative;
  z-index: 2;
}

.page-about .about-hero .breadcrumb {
  margin-bottom: 22px;
}

.page-about .about-h1 {
  margin: 14px 0 0;
  font-size: clamp(30px, 6.2vw, 62px);
  line-height: 1.16;
  letter-spacing: -0.01em;
  font-weight: 800;
  max-width: 20ch;
}

.page-about .about-lede {
  margin: 20px 0 0;
  max-width: 46em;
  font-size: clamp(15px, 1.4vw, 17px);
  line-height: 1.85;
  color: var(--muted);
}

/* 首屏数字 */
.page-about .about-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: clamp(28px, 5vw, 46px);
  max-width: 900px;
}

.page-about .about-stat {
  position: relative;
  padding: 14px 14px 14px 18px;
  border-left: 2px solid var(--line);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  background: rgba(18, 34, 77, 0.46);
  transition: border-color 0.18s var(--ease-out), background 0.18s var(--ease-out);
}

.page-about .about-stat:hover,
.page-about .about-stat:focus-within {
  border-left-color: var(--orange);
  background: rgba(18, 34, 77, 0.72);
}

.page-about .about-stat-num {
  display: block;
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: 0.04em;
  color: var(--orange);
}

.page-about .about-stat-label {
  display: block;
  margin-top: 4px;
  font-size: 13px;
  color: var(--ink);
}

.page-about .about-stat-note {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--muted);
}

@media (hover: hover) and (pointer: fine) {
  .page-about .about-stat-note {
    opacity: 0;
    transform: translateY(-3px);
    transition: opacity 0.18s var(--ease-out), transform 0.18s var(--ease-out);
  }

  .page-about .about-stat:hover .about-stat-note,
  .page-about .about-stat:focus-within .about-stat-note {
    opacity: 1;
    transform: none;
  }
}

/* ── 两栏正文骨架 ────────────────────────── */
.page-about .about-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(28px, 5vw, 44px);
  padding-block: clamp(40px, 7vw, 90px);
}

/* 章节索引 */
.page-about .about-index-title {
  margin: 0 0 10px;
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--violet);
}

.page-about .about-index ol {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: none;
}

.page-about .about-index ol::-webkit-scrollbar {
  display: none;
}

.page-about .about-index a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 6px 13px;
  border: 1px solid var(--line);
  border-radius: var(--pill);
  color: var(--muted);
  font-size: 13px;
  line-height: 1.4;
  text-decoration: none;
  white-space: nowrap;
  transition: color 0.18s var(--ease-out), border-color 0.18s var(--ease-out), background 0.18s var(--ease-out);
}

.page-about .about-index a .mono {
  color: var(--orange);
  font-size: 11px;
  letter-spacing: 0.06em;
}

.page-about .about-index a:hover,
.page-about .about-index a:focus-visible {
  color: var(--ink);
  border-color: var(--orange);
}

/* ── 章节通用 ────────────────────────────── */
.page-about .about-section {
  padding-block: clamp(30px, 5vw, 52px);
  border-top: 1px solid var(--line);
}

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

.page-about .about-section-head {
  display: flex;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .about-num {
  flex: none;
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--orange);
}

.page-about .about-h2 {
  margin: 0;
  font-size: clamp(21px, 3.2vw, 32px);
  line-height: 1.3;
  letter-spacing: -0.01em;
  font-weight: 800;
}

.page-about .about-copy p {
  margin: 0 0 15px;
  max-width: 42em;
  font-size: 15px;
  line-height: 1.9;
  color: var(--ink);
}

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

.page-about .about-copy a {
  color: var(--orange);
  text-decoration: underline;
  text-underline-offset: 3px;
}

.page-about .about-copy a:hover {
  color: var(--orange-hi);
}

.page-about .about-quote {
  margin: 26px 0 0;
  padding: 2px 0 2px 20px;
  border-left: 3px solid var(--orange);
  font-size: clamp(17px, 2.4vw, 23px);
  font-weight: 500;
  line-height: 1.65;
  color: var(--ink);
  letter-spacing: -0.005em;
}

/* ── 三条主线 ────────────────────────────── */
.page-about .about-lines {
  margin: 22px 0 24px;
  padding: 0;
  list-style: none;
}

.page-about .about-line {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 14px;
  align-items: start;
  padding: 20px 0;
  border-top: 1px solid var(--line);
  transition: background 0.18s var(--ease-out);
}

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

.page-about .about-line-num {
  font-size: clamp(22px, 3vw, 28px);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: 0.04em;
  color: var(--violet);
  transition: color 0.18s var(--ease-out);
}

.page-about .about-line:hover .about-line-num {
  color: var(--orange);
}

.page-about .about-line h3 {
  margin: 0 0 8px;
  font-size: 16px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--ink);
}

.page-about .about-line p {
  margin: 0;
  font-size: 14.5px;
  line-height: 1.85;
  color: var(--muted);
}

/* ── 团队 ────────────────────────────────── */
.page-about .about-team {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 22px;
  margin-top: 22px;
}

.page-about .about-team-fig {
  margin: 0;
  border-radius: var(--about-fig-radius);
  overflow: hidden;
  background: var(--panel);
  border: 1px solid var(--line);
}

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

.page-about .about-team-fig figcaption {
  padding: 10px 14px 12px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.page-about .about-team-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-team-list li {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 2.1fr);
  gap: 10px 14px;
  align-items: baseline;
  padding: 14px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-team-list li:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-team-tag {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--green);
}

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

/* ── 版本时间线 ──────────────────────────── */
.page-about .about-timeline {
  position: relative;
  margin: 24px 0 0;
  padding: 6px 0 0 30px;
  list-style: none;
}

.page-about .about-timeline::before {
  content: "";
  position: absolute;
  left: 9px;
  top: 12px;
  bottom: 16px;
  width: 2px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--orange) 0%, var(--violet) 52%, rgba(57, 255, 136, 0.55) 100%);
}

.page-about .about-tl {
  position: relative;
  padding-bottom: 14px;
  border-radius: var(--radius-md);
}

.page-about .about-tl::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 10px;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--void);
  border: 2px solid var(--orange);
  transition: box-shadow 0.18s var(--ease-out), border-color 0.18s var(--ease-out);
}

.page-about .about-tl[open]::before,
.page-about .about-tl details[open] + * ,
.page-about .about-tl:has(details[open])::before {
  border-color: var(--green);
  box-shadow: 0 0 0 4px rgba(57, 255, 136, 0.14);
}

.page-about .about-tl details {
  background: rgba(18, 34, 77, 0.40);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  transition: border-color 0.18s var(--ease-out), background 0.18s var(--ease-out);
}

.page-about .about-tl details:hover {
  border-color: rgba(255, 107, 44, 0.55);
  background: rgba(18, 34, 77, 0.66);
}

.page-about .about-tl summary {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
  padding: 14px 16px;
  cursor: pointer;
  list-style: none;
}

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

.page-about .about-tl summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 16px;
  line-height: 1;
  color: var(--orange);
}

.page-about .about-tl details[open] summary::after {
  content: "−";
  color: var(--green);
}

.page-about .about-tl-ver {
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--orange);
}

.page-about .about-tl-name {
  font-size: 16px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-tl details p {
  margin: 0;
  padding: 0 16px 16px;
  font-size: 14px;
  line-height: 1.85;
  color: var(--muted);
}

.page-about .about-version-fig {
  margin: 26px 0 0;
  border-radius: var(--about-fig-radius);
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--panel);
}

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

.page-about .about-version-fig figcaption {
  padding: 10px 14px 12px;
  font-size: 12px;
  line-height: 1.6;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

/* ── 更新节奏 ────────────────────────────── */
.page-about .about-cadence {
  margin: 22px 0 18px;
  padding: 0;
}

.page-about .about-cad-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 4px;
  padding: 13px 0;
  border-top: 1px solid var(--line);
}

.page-about .about-cad-row:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .about-cad-row dt {
  font-size: 14px;
  font-weight: 700;
  color: var(--ink);
}

.page-about .about-cad-row dt::before {
  content: "▍";
  margin-right: 6px;
  color: var(--green);
}

.page-about .about-cad-row dd {
  margin: 0;
  padding-left: 16px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--muted);
}

/* ── 联系与服务 ──────────────────────────── */
.page-about .about-contact-list {
  margin: 22px 0 0;
  padding: 18px 18px 6px;
  list-style: none;
  border: 1px solid var(--line);
  border-left: 3px solid var(--orange);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  background: rgba(18, 34, 77, 0.42);
}

.page-about .about-contact-list li {
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 10px;
  align-items: baseline;
  padding-bottom: 12px;
}

.page-about .about-contact-key {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--violet);
}

.page-about .about-contact-val {
  font-size: 14px;
  line-height: 1.7;
  color: var(--ink);
  word-break: break-word;
}

.page-about .about-cta {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.page-about .about-topwrap {
  margin: 28px 0 0;
}

.page-about .about-top {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--muted);
  text-decoration: none;
  border-bottom: 1px solid var(--line);
  padding-bottom: 2px;
  transition: color 0.18s var(--ease-out), border-color 0.18s var(--ease-out);
}

.page-about .about-top:hover {
  color: var(--orange);
  border-color: var(--orange);
}

/* ── 平板及以上 ──────────────────────────── */
@media (min-width: 640px) {
  .page-about .about-team-list li {
    grid-template-columns: 74px minmax(0, 1fr);
  }

  .page-about .about-cad-row {
    grid-template-columns: 110px minmax(0, 1fr);
    align-items: baseline;
    gap: 16px;
  }

  .page-about .about-cad-row dd {
    padding-left: 0;
  }
}

@media (min-width: 860px) {
  .page-about .about-team {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 1fr);
    gap: 26px;
    align-items: start;
  }

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

/* ── 桌面：粘性章节索引 ──────────────────── */
@media (min-width: 1000px) {
  .page-about .about-layout {
    grid-template-columns: var(--about-rail) minmax(0, 1fr);
    gap: var(--about-gap);
    align-items: start;
  }

  .page-about .about-rail {
    position: sticky;
    top: 96px;
    align-self: start;
  }

  .page-about .about-index {
    border-left: 1px solid var(--line);
    padding-left: 16px;
  }

  .page-about .about-index ol {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-about .about-index a {
    white-space: normal;
    border-color: transparent;
    border-radius: var(--radius-sm);
    padding: 8px 10px;
    font-size: 13.5px;
    line-height: 1.5;
  }

  .page-about .about-index a:hover,
  .page-about .about-index a:focus-visible {
    background: var(--card);
    border-color: transparent;
    color: var(--ink);
  }

  .page-about .about-h1 {
    max-width: 24ch;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-stat,
  .page-about .about-stat-note,
  .page-about .about-index a,
  .page-about .about-line-num,
  .page-about .about-tl details,
  .page-about .about-top {
    transition: none;
  }
}