.page-about {
  padding-block: clamp(1.25rem, 4vw, 2.4rem) clamp(2rem, 6vw, 4rem);
}

.page-about .about-crumb {
  margin-bottom: clamp(1rem, 3vw, 1.6rem);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  display: grid;
  gap: clamp(1.1rem, 3vw, 1.8rem);
  padding: clamp(1.1rem, 3vw, 1.9rem);
  border: 1px solid var(--line);
  background:
    radial-gradient(130% 150% at 100% 0%, rgba(44, 63, 121, 0.58), transparent 62%),
    linear-gradient(162deg, rgba(27, 42, 91, 0.92), rgba(16, 26, 58, 0.78));
  overflow: hidden;
}

.page-about .about-hero::before,
.page-about .about-hero::after {
  content: "";
  position: absolute;
  width: 20px;
  height: 20px;
  border: 0 solid var(--gold);
  pointer-events: none;
}

.page-about .about-hero::before {
  top: 0;
  left: 0;
  border-top-width: 2px;
  border-left-width: 2px;
}

.page-about .about-hero::after {
  right: 0;
  bottom: 0;
  border-right-width: 2px;
  border-bottom-width: 2px;
}

.page-about .about-hero-copy {
  min-width: 0;
}

.page-about .about-hero-kicker {
  margin: 0 0 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  color: var(--gold);
}

.page-about .about-hero h1 {
  margin: 0 0 1rem;
  font-size: clamp(1.7rem, 5.2vw, 2.9rem);
  line-height: 1.14;
  letter-spacing: -0.025em;
  font-weight: 800;
  color: var(--paper);
}

.page-about .about-hero-lede {
  margin: 0 0 1.25rem;
  max-width: 46ch;
  font-size: clamp(0.95rem, 2.3vw, 1.04rem);
  line-height: 1.85;
  color: rgba(244, 246, 251, 0.82);
}

.page-about .about-hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.15rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--line-soft);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.07em;
  color: var(--steel);
}

.page-about .about-hero-visual {
  margin: 0;
  min-width: 0;
}

.page-about .about-hero-visual img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  object-fit: cover;
}

.page-about .about-hero-visual figcaption {
  margin-top: 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.07em;
  color: var(--steel);
}

/* ---------- 章节索引 ---------- */
.page-about .about-chapters {
  margin-top: clamp(1.4rem, 4vw, 2.4rem);
  padding: 0.6rem 0;
  border-top: 1px solid var(--line-soft);
  border-bottom: 1px solid var(--line-soft);
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.page-about .about-chapters-list {
  display: flex;
  flex-wrap: nowrap;
  gap: 0.35rem 1.4rem;
  margin: 0;
  padding: 0 0.2rem;
  list-style: none;
  min-width: max-content;
}

.page-about .about-chapters-list a {
  display: inline-flex;
  align-items: baseline;
  gap: 0.45rem;
  padding: 0.2rem 0;
  font-size: 0.82rem;
  color: var(--steel);
  text-decoration: none;
  white-space: nowrap;
  border-bottom: 1px solid transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease);
}

.page-about .about-chapters-list a:hover,
.page-about .about-chapters-list a:focus-visible {
  color: var(--gold);
  border-bottom-color: var(--gold);
}

.page-about .about-chapters-list span {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--gold);
}

/* ---------- 章节头 ---------- */
.page-about .about-sec {
  margin-top: clamp(2rem, 6vw, 3.6rem);
  scroll-margin-top: 5.5rem;
}

.page-about .about-sec-head {
  display: flex;
  align-items: flex-start;
  gap: 0.9rem;
  padding-top: 1rem;
  margin-bottom: clamp(1.1rem, 3vw, 1.6rem);
  border-top: 1px solid var(--line);
}

.page-about .about-sec-num {
  flex: 0 0 auto;
  font-family: var(--font-mono);
  font-size: clamp(1.6rem, 4.6vw, 2.5rem);
  line-height: 1;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--gold);
}

.page-about .about-sec-headtext {
  min-width: 0;
  padding-top: 0.1rem;
}

.page-about .about-sec-title {
  margin: 0;
  font-size: clamp(1.1rem, 3.1vw, 1.5rem);
  line-height: 1.28;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-about .about-sec-lede {
  margin: 0.5rem 0 0;
  max-width: 62ch;
  font-size: 0.92rem;
  line-height: 1.8;
  color: rgba(244, 246, 251, 0.74);
}

/* ---------- 01 分层结构 ---------- */
.page-about .about-tiers {
  display: grid;
  gap: 0.8rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-tier {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.9rem;
  align-items: start;
  padding: 0.9rem 1rem;
  background: var(--glass);
  border: 1px solid var(--line-soft);
  border-left: 2px solid var(--gold);
}

.page-about .about-tier:nth-child(2) {
  border-left-color: var(--celadon);
  background: rgba(27, 42, 91, 0.55);
}

.page-about .about-tier:nth-child(3) {
  border-left-color: var(--steel);
}

.page-about .about-tier-main {
  min-width: 0;
}

.page-about .about-tier-step {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  color: var(--gold);
  padding-top: 0.28rem;
}

.page-about .about-tier:nth-child(2) .about-tier-step {
  color: var(--celadon-2);
}

.page-about .about-tier:nth-child(3) .about-tier-step {
  color: var(--steel);
}

.page-about .about-tier-title {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.55rem;
  margin: 0 0 0.35rem;
  font-size: 1rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-tier-count {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  font-weight: 400;
  letter-spacing: 0.05em;
  color: var(--celadon-2);
  padding: 0.1rem 0.42rem;
  border: 1px solid rgba(79, 168, 138, 0.42);
  border-radius: var(--radius);
}

.page-about .about-tier-text {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.78;
  color: rgba(244, 246, 251, 0.76);
}

/* ---------- 图片容器 ---------- */
.page-about .about-figure {
  margin: 1.15rem 0 0;
}

.page-about .about-figure--lead {
  margin: 0 0 1.2rem;
}

.page-about .about-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  object-fit: cover;
}

.page-about .about-figure figcaption {
  margin-top: 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  color: var(--steel);
}

/* ---------- 02 版本 ---------- */
.page-about .about-version-scope {
  margin-top: 0.4rem;
}

.page-about .about-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin: 0 0 1rem;
}

.page-about .about-filter .filter-btn {
  appearance: none;
  cursor: pointer;
  padding: 0.36rem 0.72rem;
  background: transparent;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.73rem;
  letter-spacing: 0.06em;
  color: var(--steel);
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-filter .filter-btn:hover,
.page-about .about-filter .filter-btn:focus-visible {
  color: var(--gold-2);
  border-color: var(--gold-2);
}

.page-about .about-filter .filter-btn[aria-pressed="true"] {
  color: var(--ink);
  background: var(--gold);
  border-color: var(--gold);
}

.page-about .about-version-list {
  display: grid;
  gap: 0.85rem;
}

.page-about .about-version {
  padding: 1.05rem 1.1rem;
  background: var(--ink-2);
  border: 1px solid var(--line-soft);
  border-radius: var(--radius);
  transition: transform var(--dur) var(--ease), border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-version:nth-child(even) {
  background: var(--glass);
  border-color: var(--line);
}

.page-about .about-version:hover,
.page-about .about-version:focus-within {
  transform: translateY(-4px);
  border-color: var(--gold);
}

.page-about .about-version-tag {
  display: inline-block;
  margin-bottom: 0.5rem;
  padding-bottom: 0.14rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.1em;
  color: var(--gold);
  border-bottom: 1px solid rgba(232, 181, 60, 0.45);
}

.page-about .about-version-title {
  margin: 0 0 0.45rem;
  font-size: 1rem;
  line-height: 1.4;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-version-text {
  margin: 0;
  font-size: 0.89rem;
  line-height: 1.78;
  color: rgba(244, 246, 251, 0.75);
}

/* ---------- 03 更新记录 ---------- */
.page-about .about-log {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-log-item {
  display: grid;
  gap: 0.3rem;
  padding: 0.9rem 0;
  border-top: 1px solid var(--line-soft);
}

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

.page-about .about-log-when {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  color: var(--celadon-2);
}

.page-about .about-log-body {
  min-width: 0;
}

.page-about .about-log-title {
  margin: 0 0 0.28rem;
  font-size: 0.97rem;
  line-height: 1.42;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-log-text {
  margin: 0;
  font-size: 0.89rem;
  line-height: 1.78;
  color: rgba(244, 246, 251, 0.75);
}

.page-about .about-inline-note {
  margin: 1.1rem 0 0;
  font-size: 0.86rem;
  line-height: 1.8;
  color: var(--steel);
}

.page-about .about-link {
  color: var(--gold-2);
  text-decoration: none;
  border-bottom: 1px solid rgba(246, 217, 138, 0.42);
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

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

/* ---------- 04 覆盖 ---------- */
.page-about .about-coverage {
  display: grid;
  gap: 1.15rem;
  padding: clamp(1rem, 3vw, 1.5rem);
  border: 1px solid var(--line);
  background: linear-gradient(135deg, rgba(44, 63, 121, 0.52), rgba(27, 42, 91, 0.34));
}

.page-about .about-coverage-stat {
  min-width: 0;
}

.page-about .about-coverage-num {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(2.9rem, 9vw, 4.3rem);
  line-height: 1;
  font-weight: 700;
  letter-spacing: -0.035em;
  color: var(--gold);
}

.page-about .about-coverage-unit {
  display: block;
  margin-top: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  letter-spacing: 0.11em;
  color: var(--steel);
}

.page-about .about-coverage-text p {
  margin: 0 0 0.7rem;
  font-size: 0.9rem;
  line-height: 1.8;
  color: rgba(244, 246, 251, 0.78);
}

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

/* ---------- 05 团队 ---------- */
.page-about .about-team {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-team-row {
  display: grid;
  gap: 0.3rem;
  padding: 0.85rem 0;
  border-top: 1px solid var(--line-soft);
}

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

.page-about .about-team-name {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.07em;
  color: var(--gold-2);
}

.page-about .about-team-row p {
  margin: 0;
  font-size: 0.9rem;
  line-height: 1.78;
  color: rgba(244, 246, 251, 0.76);
}

/* ---------- 06 备案 ---------- */
.page-about .about-filing {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1.4rem;
  padding: 0.95rem 1.05rem;
  border: 1px dashed var(--line);
  font-family: var(--font-mono);
  font-size: 0.77rem;
  letter-spacing: 0.08em;
  color: var(--steel);
}

/* ---------- 续读入口 ---------- */
.page-about .about-next {
  margin-top: clamp(2rem, 6vw, 3.2rem);
  padding-top: 1.2rem;
  border-top: 1px solid var(--line);
}

.page-about .about-next-title {
  margin: 0 0 0.9rem;
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  color: var(--steel);
}

.page-about .about-next-list {
  display: grid;
  gap: 0.5rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .about-next-list a {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.15rem 0.6rem;
  padding: 0.7rem 0.85rem;
  text-decoration: none;
  border-left: 2px solid var(--line);
  transition: border-color var(--dur) var(--ease), background var(--dur) var(--ease);
}

.page-about .about-next-list a:hover,
.page-about .about-next-list a:focus-visible {
  border-left-color: var(--gold);
  background: var(--glass);
}

.page-about .about-next-idx {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--gold);
}

.page-about .about-next-name {
  font-size: 0.94rem;
  font-weight: 700;
  color: var(--paper);
}

.page-about .about-next-desc {
  flex: 1 1 100%;
  font-size: 0.82rem;
  line-height: 1.7;
  color: var(--steel);
}

/* ---------- 桌面增强 ---------- */
@media (min-width: 760px) {
  .page-about .about-coverage {
    grid-template-columns: 0.42fr 0.58fr;
    align-items: center;
  }

  .page-about .about-log-item {
    grid-template-columns: 5.2rem 1fr;
    gap: 1.1rem;
    align-items: baseline;
  }

  .page-about .about-team-row {
    grid-template-columns: 8.5rem 1fr;
    gap: 1.2rem;
    align-items: baseline;
  }

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

@media (min-width: 900px) {
  .page-about .about-hero {
    grid-template-columns: 1.15fr 0.85fr;
    align-items: center;
  }

  .page-about .about-version-list {
    grid-template-columns: repeat(12, minmax(0, 1fr));
  }

  .page-about .about-version:nth-child(1) {
    grid-column: span 5;
  }

  .page-about .about-version:nth-child(2) {
    grid-column: span 7;
  }

  .page-about .about-version:nth-child(3) {
    grid-column: span 7;
  }

  .page-about .about-version:nth-child(4) {
    grid-column: span 5;
  }

  .page-about .about-tiers {
    grid-template-columns: 1fr;
  }
}

@media (min-width: 1080px) {
  .page-about .about-tier {
    padding: 1rem 1.15rem;
  }

  .page-about .about-tier-text,
  .page-about .about-version-text,
  .page-about .about-log-text,
  .page-about .about-team-row p {
    font-size: 0.92rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .about-version,
  .page-about .about-next-list a,
  .page-about .about-chapters-list a,
  .page-about .about-filter .filter-btn {
    transition: none;
  }

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

```