.page-about {
  --ab-grid-line: rgba(201, 213, 209, 0.09);
  --ab-card-bg: rgba(11, 42, 30, 0.72);
  --ab-cyan-line: rgba(56, 242, 208, 0.38);
  display: block;
  color: var(--silver-100);
  font-family: var(--font-body);
  font-size: var(--fs-body);
  line-height: 1.72;
}

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

.page-about .breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 18px 0 0;
  font-size: var(--fs-cap);
  color: var(--silver-300);
}

.page-about .breadcrumbs .utility-link {
  color: var(--silver-300);
  text-decoration: none;
}

.page-about .breadcrumbs .utility-link:hover,
.page-about .breadcrumbs .utility-link:focus-visible {
  color: var(--cyan);
}

/* ---------- 首屏 ---------- */
.page-about .ab-hero {
  position: relative;
  overflow: hidden;
  padding: 20px 0 54px;
  border-bottom: 1px solid var(--line);
  background:
    radial-gradient(92% 118% at 92% -12%, rgba(20, 92, 59, 0.62), transparent 62%),
    radial-gradient(58% 78% at 0% 112%, rgba(31, 168, 150, 0.16), transparent 72%),
    linear-gradient(180deg, rgba(11, 42, 30, 0.55) 0%, rgba(6, 20, 15, 0) 100%);
}

.page-about .ab-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  opacity: 0.55;
  background-image:
    linear-gradient(var(--ab-grid-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--ab-grid-line) 1px, transparent 1px);
  background-size: 48px 48px;
  -webkit-mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
  mask-image: linear-gradient(180deg, rgba(0, 0, 0, 0.9), transparent 88%);
}

.page-about .ab-hero-inner {
  position: relative;
  display: grid;
  gap: 30px;
  padding-top: 24px;
}

.page-about .ab-hero-title {
  margin: 10px 0 18px;
  font-family: var(--font-head);
  font-size: clamp(2.3rem, 8.6vw, 4.5rem);
  font-weight: 700;
  line-height: 0.99;
  letter-spacing: 0.005em;
  color: var(--silver-100);
}

.page-about .ab-hero-title em {
  font-style: normal;
  color: var(--cyan);
}

.page-about .ab-hero-lead {
  max-width: 46ch;
  margin: 0 0 22px;
  font-size: 1.02rem;
  color: var(--silver-300);
}

.page-about .ab-hero-marks {
  display: grid;
  gap: 8px;
  margin: 0;
  padding: 16px 0 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-about .ab-hero-marks li {
  display: flex;
  gap: 10px;
  align-items: baseline;
  font-size: 0.92rem;
  color: var(--silver-300);
}

.page-about .ab-hero-marks .mono {
  color: var(--cyan);
  font-size: 0.84rem;
}

.page-about .media-frame {
  border: 1px solid var(--line);
  background: var(--ink-800);
  overflow: hidden;
  margin: 0;
}

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

.page-about .ab-hero-media {
  border-color: var(--ab-cyan-line);
  box-shadow: var(--shadow-card);
}

/* ---------- 主体布局 ---------- */
.page-about .ab-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 34px;
  padding: 44px 0 0;
}

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

.page-about .ab-index-title {
  margin: 0 0 12px;
  font-size: 0.7rem;
  letter-spacing: 0.24em;
  color: var(--cyan-dim);
}

.page-about .ab-index-list {
  display: grid;
  gap: 2px;
  margin: 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line);
}

.page-about .ab-index-link {
  display: flex;
  gap: 10px;
  align-items: baseline;
  padding: 9px 12px;
  font-size: 0.9rem;
  line-height: 1.4;
  color: var(--silver-300);
  text-decoration: none;
  transition: color var(--ease), background-color var(--ease);
}

.page-about .ab-index-num {
  font-size: 0.72rem;
  color: var(--cyan-dim);
}

.page-about .ab-index-link:hover,
.page-about .ab-index-link:focus-visible {
  color: var(--silver-100);
  background: rgba(56, 242, 208, 0.07);
}

.page-about .ab-index-link:hover .ab-index-num,
.page-about .ab-index-link:focus-visible .ab-index-num {
  color: var(--cyan);
}

/* ---------- 章节骨架 ---------- */
.page-about .ab-sec {
  padding-bottom: 64px;
  scroll-margin-top: 96px;
}

.page-about .ab-sec-head {
  display: flex;
  gap: 14px;
  align-items: baseline;
  padding-bottom: 14px;
  margin-bottom: 24px;
  border-bottom: 1px solid var(--line);
}

.page-about .ab-sec-num {
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--cyan);
}

.page-about .ab-sec-title {
  margin: 0;
  font-family: var(--font-head);
  font-size: var(--fs-h2);
  font-weight: 600;
  line-height: 1.16;
  letter-spacing: 0.01em;
  color: var(--silver-100);
}

.page-about .ab-prose p {
  max-width: 66ch;
  margin: 0 0 16px;
  color: var(--silver-300);
}

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

.page-about .ab-prose--after {
  margin-top: 20px;
}

/* ---------- 01 阶段时间线 ---------- */
.page-about .ab-phase {
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  border-left: 1px solid var(--line);
}

.page-about .ab-phase-item {
  position: relative;
  padding: 0 0 22px 30px;
}

.page-about .ab-phase-item:last-child {
  padding-bottom: 0;
}

.page-about .ab-phase-item::before {
  content: "";
  position: absolute;
  top: 8px;
  left: -4px;
  width: 7px;
  height: 7px;
  background: var(--ink-900);
  border: 1px solid var(--cyan-dim);
  transform: rotate(45deg);
}

.page-about .ab-phase-item:last-child::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .ab-phase-ver {
  display: block;
  margin-bottom: 4px;
  font-size: 0.74rem;
  letter-spacing: 0.1em;
  color: var(--cyan-dim);
}

.page-about .ab-phase-name {
  margin: 0 0 4px;
  font-family: var(--font-head);
  font-size: 1.08rem;
  font-weight: 600;
  color: var(--silver-100);
}

.page-about .ab-phase-desc {
  max-width: 60ch;
  margin: 0;
  font-size: 0.94rem;
  color: var(--silver-300);
}

/* ---------- 02 六区间刻度 ---------- */
.page-about .ab-scale {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 2px;
  margin: 4px 0 24px;
  padding: 0;
  list-style: none;
}

.page-about .ab-scale-tick {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 10px 8px 12px;
  border-top: 2px solid var(--ab-cyan-line);
  background: linear-gradient(180deg, rgba(20, 92, 59, 0.5), rgba(11, 42, 30, 0.14));
}

.page-about .ab-scale-tick b {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--cyan);
}

.page-about .ab-scale-tick:last-child {
  border-top-color: var(--cyan);
}

.page-about .ab-rules-media {
  margin-bottom: 26px;
}

.page-about .ab-rules {
  display: grid;
  gap: 14px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-rule {
  padding: 20px 20px 22px;
  background: var(--ab-card-bg);
  border: 1px solid var(--line);
  border-left: 2px solid var(--ab-cyan-line);
  transition: border-color var(--ease), background-color var(--ease), transform var(--ease);
}

.page-about .ab-rule:hover,
.page-about .ab-rule:focus-within {
  border-color: var(--ab-cyan-line);
  border-left-color: var(--cyan);
  background: rgba(20, 92, 59, 0.44);
  transform: translateY(-3px);
}

.page-about .ab-rule-title {
  margin: 12px 0 0;
  font-family: var(--font-head);
  font-size: var(--fs-h3);
  font-weight: 600;
  color: var(--silver-100);
}

.page-about .ab-rule-note {
  margin: 8px 0 0;
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--silver-300);
}

/* ---------- 03 主客场 ---------- */
.page-about .ab-hfa {
  display: grid;
  gap: 14px;
  margin: 24px 0 0;
}

.page-about .ab-hfa-card {
  padding: 22px 22px 20px;
  background: linear-gradient(135deg, rgba(20, 92, 59, 0.58), rgba(6, 20, 15, 0.62) 72%);
  border: 1px solid var(--line);
  clip-path: polygon(0 0, calc(100% - 20px) 0, 100% 20px, 100% 100%, 0 100%);
}

.page-about .ab-hfa-kicker {
  margin: 0 0 12px;
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--cyan-dim);
}

.page-about .ab-hfa-line {
  margin: 0 0 14px;
  font-size: 0.96rem;
  color: var(--silver-100);
}

.page-about .ab-hfa-meta {
  margin: 0;
  padding-top: 12px;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: var(--silver-300);
  border-top: 1px solid var(--line);
}

/* ---------- 04 球迷组织 ---------- */
.page-about .ab-stands {
  display: grid;
  gap: 24px;
}

.page-about .ab-stands-media figcaption {
  border-top: 1px solid var(--line);
}

.page-about .ab-stats {
  display: grid;
  gap: 1px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-about .ab-stats li {
  padding: 16px 16px 18px;
  background: var(--ink-900);
}

.page-about .ab-stat-num {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.5rem;
  line-height: 1.1;
  color: var(--cyan);
}

.page-about .ab-stat-label {
  display: block;
  margin-top: 6px;
  font-size: 0.82rem;
  color: var(--silver-300);
}

/* ---------- 05 协作与边界 ---------- */
.page-about .ab-roles {
  display: grid;
  gap: 14px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.page-about .ab-role {
  padding: 20px;
  background: rgba(6, 20, 15, 0.6);
  border: 1px solid var(--line);
  border-top: 2px solid var(--cyan-dim);
}

.page-about .ab-role-num {
  display: block;
  font-size: 0.74rem;
  letter-spacing: 0.2em;
  color: var(--cyan-dim);
}

.page-about .ab-role-title {
  margin: 8px 0 0;
  font-family: var(--font-head);
  font-size: var(--fs-h3);
  font-weight: 600;
  color: var(--silver-100);
}

.page-about .ab-role-desc {
  margin: 8px 0 0;
  font-size: 0.9rem;
  line-height: 1.65;
  color: var(--silver-300);
}

.page-about .ab-limits {
  margin-top: 26px;
  padding: 22px 22px 20px;
  background: rgba(244, 241, 232, 0.05);
  border: 1px solid var(--line-2);
}

.page-about .ab-limits-title {
  margin: 0 0 12px;
  font-size: 0.74rem;
  letter-spacing: 0.2em;
  color: var(--amber);
}

.page-about .ab-limits-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 9px;
}

.page-about .ab-limits-list li {
  position: relative;
  padding-left: 18px;
  font-size: 0.92rem;
  color: var(--silver-300);
}

.page-about .ab-limits-list li::before {
  content: "";
  position: absolute;
  top: 0.72em;
  left: 0;
  width: 8px;
  height: 1px;
  background: var(--amber);
}

/* ---------- 06 维护节奏 ---------- */
.page-about .ab-cadence {
  display: grid;
  gap: 1px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.page-about .ab-cadence li {
  display: grid;
  gap: 6px;
  padding: 16px 4px;
  background: var(--ink-900);
}

.page-about .ab-cadence-when {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  color: var(--cyan);
}

.page-about .ab-cadence-what {
  margin: 0;
  font-size: 0.95rem;
  color: var(--silver-300);
}

/* ---------- 尾部导航 ---------- */
.page-about .ab-next {
  padding: 4px 0 70px;
}

.page-about .ab-next-title {
  margin: 0;
  font-family: var(--font-head);
  font-size: var(--fs-h2);
  font-weight: 600;
  color: var(--silver-100);
}

.page-about .ab-next-grid {
  display: grid;
  gap: 12px;
  margin-top: 20px;
}

.page-about .ab-next-card {
  display: block;
  padding: 18px 18px 20px;
  color: var(--silver-100);
  text-decoration: none;
  border: 1px solid var(--line);
  background: rgba(11, 42, 30, 0.5);
  transition: border-color var(--ease), transform var(--ease), background-color var(--ease);
}

.page-about .ab-next-card:hover,
.page-about .ab-next-card:focus-visible {
  border-color: var(--cyan);
  background: rgba(20, 92, 59, 0.42);
  transform: translateY(-3px);
}

.page-about .ab-next-num {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--cyan-dim);
}

.page-about .ab-next-label {
  display: block;
  margin-top: 8px;
  font-family: var(--font-head);
  font-size: 1.06rem;
  font-weight: 600;
}

.page-about .ab-next-desc {
  display: block;
  margin-top: 6px;
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--silver-300);
}

/* ---------- 断点 ---------- */
@media (min-width: 640px) {
  .page-about .ab-stats {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (min-width: 760px) {
  .page-about .ab-rules {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

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

  .page-about .ab-cadence li {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 20px;
    align-items: baseline;
  }

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

@media (min-width: 900px) {
  .page-about .ab-hero {
    padding: 26px 0 64px;
  }

  .page-about .ab-hero-inner {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
    gap: 48px;
    align-items: end;
  }

  .page-about .ab-layout {
    grid-template-columns: 218px minmax(0, 1fr);
    gap: 56px;
  }

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

  .page-about .ab-stands {
    grid-template-columns: minmax(0, 0.92fr) minmax(0, 1.08fr);
    gap: 34px;
    align-items: start;
  }
}

@media (min-width: 1100px) {
  .page-about .ab-next-grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .ab-rule,
  .page-about .ab-next-card,
  .page-about .ab-index-link {
    transition: none;
  }

  .page-about .ab-rule:hover,
  .page-about .ab-rule:focus-within,
  .page-about .ab-next-card:hover,
  .page-about .ab-next-card:focus-visible {
    transform: none;
  }
}