.page-about {
  --pa-gap: clamp(18px, 3vw, 34px);
  --pa-rule: 1px solid var(--deep-500);
  --pa-rule-soft: 1px solid var(--deep-700);
}

.page-about .pa-num {
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--amber);
}

.page-about .pa-link {
  display: inline-block;
  margin-top: 18px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--amber);
  text-decoration: none;
  border-bottom: 1px solid rgba(244, 167, 60, 0.4);
  padding-bottom: 2px;
  transition: border-color var(--dur) var(--ease), color var(--dur) var(--ease);
}

.page-about .pa-link:hover,
.page-about .pa-link:focus-visible {
  color: var(--silver-100);
  border-bottom-color: var(--amber);
}

/* 首屏 */
.page-about .pa-hero {
  padding-block: clamp(26px, 5vw, 56px) clamp(30px, 5vw, 62px);
  border-bottom: var(--pa-rule-soft);
}

.page-about .pa-hero__grid {
  display: grid;
  gap: var(--pa-gap);
  margin-top: clamp(20px, 3.4vw, 36px);
}

.page-about .pa-hero__title {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.85rem, 4.6vw, 3.05rem);
  line-height: 1.12;
  letter-spacing: 0.01em;
  color: var(--silver-100);
  margin: 0 0 18px;
  max-width: 22ch;
}

.page-about .pa-hero__facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px 18px;
  margin: 28px 0 0;
}

.page-about .pa-stat {
  border-left: 2px solid var(--deep-500);
  padding-left: 12px;
  transition: border-color var(--dur) var(--ease);
}

.page-about .pa-stat:hover {
  border-left-color: var(--amber);
}

.page-about .pa-stat__value {
  display: block;
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 1.32rem;
  letter-spacing: 0.01em;
  color: var(--amber);
}

.page-about .pa-stat__label {
  display: block;
  margin-top: 4px;
  font-size: 0.78rem;
  color: var(--silver-300);
}

.page-about .pa-hero__figure {
  margin: 0;
}

/* 时间线 */
.page-about .pa-track-section__lede {
  margin-top: 12px;
}

.page-about .pa-track {
  list-style: none;
  margin: clamp(26px, 4vw, 44px) 0 0;
  padding: 0 0 0 16px;
  border-left: var(--pa-rule);
  display: flex;
  flex-direction: column;
  gap: clamp(18px, 3vw, 30px);
}

.page-about .pa-track__row {
  position: relative;
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 12px;
}

.page-about .pa-track__row::before {
  content: "";
  position: absolute;
  left: -21px;
  top: 16px;
  width: 9px;
  height: 9px;
  background: var(--deep-900);
  border: 1px solid var(--amber);
}

.page-about .pa-track__mark {
  padding-top: 10px;
}

.page-about .pa-track__num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.92rem;
  color: var(--amber);
  letter-spacing: 0.02em;
}

.page-about .pa-track__year {
  display: block;
  margin-top: 3px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.02em;
  color: var(--silver-300);
}

.page-about .pa-stage {
  border: var(--pa-rule);
  background: var(--deep-950);
  box-shadow: var(--shadow);
  transition: border-color var(--dur) var(--ease);
}

.page-about .pa-stage:hover {
  border-color: var(--amber);
}

.page-about .pa-stage > summary {
  list-style: none;
  cursor: pointer;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 6px 14px;
  padding: 16px 18px;
}

.page-about .pa-stage > summary::-webkit-details-marker {
  display: none;
}

.page-about .pa-stage > summary::after {
  content: "+";
  margin-left: auto;
  font-family: var(--font-mono);
  font-weight: 600;
  color: var(--amber);
}

.page-about .pa-stage[open] > summary::after {
  content: "\2212";
}

.page-about .pa-stage__title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--silver-100);
}

.page-about .pa-stage__sum {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--silver-300);
}

.page-about .pa-stage__body {
  padding: 14px 18px 18px;
  border-top: var(--pa-rule-soft);
  background: var(--deep-900);
}

.page-about .pa-stage__body p {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.8;
  color: var(--silver-300);
  max-width: 68ch;
}

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

/* 岗位分工 */
.page-about .pa-role-grid {
  display: grid;
  gap: 16px;
  margin-top: clamp(22px, 3.4vw, 36px);
}

.page-about .pa-role {
  border: var(--pa-rule);
  background: var(--deep-900);
  padding: 20px 18px;
  position: relative;
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .pa-role::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 26px;
  height: 2px;
  background: var(--amber);
}

.page-about .pa-role:hover {
  border-color: var(--amber);
  background: var(--deep-700);
}

.page-about .pa-role__num {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.04em;
  color: var(--silver-300);
}

.page-about .pa-role__name {
  margin: 10px 0 4px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.12rem;
  color: var(--silver-100);
}

.page-about .pa-role__count {
  margin: 0 0 14px;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.82rem;
  color: var(--amber);
}

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

.page-about .pa-role__list li {
  position: relative;
  padding-left: 16px;
  margin-bottom: 9px;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  line-height: 1.7;
  color: var(--silver-300);
}

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

.page-about .pa-role__list li:last-child {
  margin-bottom: 0;
}

.page-about .pa-roles__note {
  margin-top: 20px;
  padding-left: 14px;
  border-left: 2px solid var(--deep-500);
  max-width: 74ch;
}

/* 版本沿革 */
.page-about .pa-archive__grid {
  display: grid;
  gap: var(--pa-gap);
  align-items: start;
}

.page-about .pa-archive__figure {
  margin: 0;
}

.page-about .wdg-prose {
  margin: 0 0 14px;
}

.page-about .wdg-prose:last-of-type {
  margin-bottom: 0;
}

/* 老用户回访 */
.page-about .pa-pairs {
  margin-top: clamp(22px, 3.4vw, 34px);
  border-top: var(--pa-rule);
}

.page-about .pa-pair {
  display: grid;
  gap: 6px;
  padding: 18px 0;
  border-bottom: var(--pa-rule-soft);
}

.page-about .pa-pair__name {
  margin: 0;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--amber);
}

.page-about .pa-pair__desc,
.page-about .pa-pair__fix {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.86rem;
  line-height: 1.75;
  color: var(--silver-300);
}

.page-about .pa-pair__fix {
  position: relative;
  padding-left: 16px;
  color: var(--silver-100);
}

.page-about .pa-pair__fix::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.75em;
  width: 9px;
  height: 1px;
  background: var(--green);
}

.page-about .pa-feedback__foot {
  margin-top: 26px;
  padding-left: 16px;
  border-left: 1px solid var(--deep-500);
}

/* 六项标准 */
.page-about .pa-criteria {
  list-style: none;
  margin: clamp(22px, 3.4vw, 36px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
  border-top: var(--pa-rule);
}

.page-about .pa-criteria__item {
  padding: 18px 0;
  border-bottom: var(--pa-rule-soft);
  position: relative;
}

.page-about .pa-criteria__num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--amber);
  letter-spacing: 0.04em;
}

.page-about .pa-criteria__name {
  margin: 8px 0 6px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.02rem;
  color: var(--silver-100);
}

.page-about .pa-criteria__item p {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.83rem;
  line-height: 1.75;
  color: var(--silver-300);
}

/* 兼容性清单 */
.page-about .pa-compat__grid {
  display: grid;
  gap: var(--pa-gap);
}

.page-about .pa-compat__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 22px;
}

/* 读者构成 */
.page-about .pa-reach__grid {
  display: grid;
  gap: var(--pa-gap);
  margin-top: clamp(22px, 3.4vw, 36px);
  align-items: start;
}

.page-about .pa-reach__figure {
  margin: 0;
}

.page-about .pa-reach__stat {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.page-about .pa-reach__value {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.3rem, 6vw, 3.4rem);
  line-height: 1;
  color: var(--amber);
}

.page-about .pa-reach__unit {
  font-family: var(--font-mono);
  font-size: 0.86rem;
  color: var(--silver-300);
}

.page-about .pa-reach__data > p {
  margin: 14px 0 0;
  font-family: var(--font-mono);
  font-size: 0.87rem;
  line-height: 1.8;
  color: var(--silver-300);
  max-width: 60ch;
}

.page-about .pa-reach__bar {
  position: relative;
  margin-top: 22px;
  height: 40px;
  border: var(--pa-rule);
  background: var(--deep-950);
  display: flex;
  align-items: center;
}

.page-about .pa-reach__fill {
  position: absolute;
  top: 1px;
  bottom: 1px;
  left: 1px;
  width: 31%;
  background: linear-gradient(90deg, rgba(244, 167, 60, 0.85), rgba(244, 167, 60, 0.16));
}

.page-about .pa-reach__bar-text {
  position: relative;
  padding-left: 14px;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--silver-100);
}

.page-about .pa-reach__data .wdg-note {
  margin-top: 18px;
  max-width: 62ch;
}

/* 下一步 */
.page-about .pa-next__grid {
  display: grid;
  gap: 14px;
  margin-top: clamp(22px, 3.4vw, 34px);
}

.page-about .pa-next__card {
  display: block;
  border: var(--pa-rule);
  background: var(--deep-900);
  padding: 20px 18px;
  text-decoration: none;
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-about .pa-next__card:hover,
.page-about .pa-next__card:focus-visible {
  border-color: var(--amber);
  background: var(--deep-700);
}

.page-about .pa-next__num {
  display: block;
  font-family: var(--font-mono);
  font-weight: 600;
  font-size: 0.78rem;
  color: var(--amber);
  letter-spacing: 0.04em;
}

.page-about .pa-next__title {
  margin: 10px 0 8px;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--silver-100);
}

.page-about .pa-next__card p {
  margin: 0;
  font-family: var(--font-mono);
  font-size: 0.83rem;
  line-height: 1.75;
  color: var(--silver-300);
}

/* 图片响应式兜底 */
.page-about .wdg-figure__media img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  object-fit: cover;
}

@media (min-width: 640px) {
  .page-about .pa-role-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .pa-next__grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
  .page-about .pa-criteria {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    column-gap: 26px;
  }
  .page-about .pa-pair {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.3fr);
    column-gap: 22px;
    align-items: baseline;
  }
  .page-about .pa-pair__fix {
    grid-column: 2;
  }
}

@media (min-width: 860px) {
  .page-about .pa-hero__grid {
    grid-template-columns: minmax(0, 1.02fr) minmax(0, 0.98fr);
    align-items: start;
  }
  .page-about .pa-archive__grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 0.75fr);
  }
  .page-about .pa-compat__grid {
    grid-template-columns: minmax(0, 0.9fr) minmax(0, 1.4fr);
  }
  .page-about .pa-reach__grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 0.85fr);
  }
}

@media (min-width: 960px) {
  .page-about .pa-track__row {
    grid-template-columns: 104px minmax(0, 1fr);
    gap: 24px;
  }
  .page-about .pa-track__row::before {
    left: -21px;
    top: 18px;
  }
  .page-about .pa-role-grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .pa-criteria {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .pa-next__grid {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 420px) {
  .page-about .pa-hero__facts {
    grid-template-columns: 1fr;
  }
  .page-about .pa-track__row {
    grid-template-columns: 48px minmax(0, 1fr);
    gap: 10px;
  }
  .page-about .pa-stage > summary {
    padding: 14px 14px;
  }
  .page-about .pa-stage__body {
    padding: 12px 14px 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .pa-stage,
  .page-about .pa-role,
  .page-about .pa-next__card,
  .page-about .pa-stat,
  .page-about .pa-link {
    transition: none;
  }
}