.page-about {
  --ab-rule: rgba(230, 233, 239, 0.13);
  --ab-rule-2: rgba(230, 233, 239, 0.26);
  --ab-celadon-soft: rgba(63, 169, 142, 0.4);
  background: var(--c-ink);
  color: var(--c-text);
  overflow-x: hidden;
}

.page-about .about-context {
  padding-top: 22px;
  padding-bottom: 4px;
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding: clamp(34px, 5.5vw, 74px) 0 clamp(40px, 6vw, 76px);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-hero-band {
  position: absolute;
  inset: -22% -12% auto -12%;
  height: 82%;
  background: linear-gradient(115deg, rgba(255, 122, 41, 0.17) 0%, rgba(255, 122, 41, 0.05) 36%, rgba(255, 122, 41, 0) 62%);
  clip-path: polygon(0 0, 100% 0, 100% 24%, 0 78%);
  z-index: -1;
  pointer-events: none;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  right: -10%;
  bottom: -34%;
  width: 48%;
  height: 78%;
  background: radial-gradient(circle at 50% 50%, rgba(63, 169, 142, 0.2), rgba(63, 169, 142, 0) 68%);
  z-index: -1;
  pointer-events: none;
}

.page-about .about-hero-grid {
  display: grid;
  gap: clamp(26px, 4vw, 56px);
  align-items: center;
}

.page-about .about-kicker {
  margin: 0 0 16px;
  font-size: 12.5px;
  letter-spacing: 0.2em;
  color: var(--c-signal);
  text-transform: uppercase;
}

.page-about .about-hero h1 {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(29px, 4.6vw, 45px);
  line-height: 1.2;
  letter-spacing: -0.01em;
  max-width: 16em;
}

.page-about .about-lede {
  margin: 0 0 28px;
  font-size: clamp(16px, 1.5vw, 17.5px);
  line-height: 1.85;
  color: var(--c-text);
  max-width: 36em;
}

.page-about .about-hero-facts {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0;
  max-width: 38em;
}

.page-about .about-hero-facts li {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 11px 0;
  border-top: 1px solid var(--ab-rule);
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.03em;
  line-height: 1.65;
  color: var(--c-muted);
}

.page-about .about-hero-facts li::before {
  content: "";
  flex: none;
  width: 6px;
  height: 6px;
  background: var(--c-celadon);
  transform: rotate(45deg) translateY(-1px);
}

.page-about .about-hero-figure {
  position: relative;
  margin: 0;
  padding: 10px;
  background: var(--c-plate);
  border: 1px solid var(--ab-rule-2);
  box-shadow: var(--shadow);
}

.page-about .about-hero-figure::before {
  content: "";
  position: absolute;
  left: -1px;
  top: -1px;
  width: 42px;
  height: 4px;
  background: var(--c-celadon);
}

.page-about .about-hero-figure img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 2 / 1;
  object-fit: cover;
}

/* ---------- 章节索引 ---------- */
.page-about .about-index {
  background: var(--c-plate);
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-index-inner {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px 18px;
  padding-top: 12px;
  padding-bottom: 12px;
}

.page-about .about-index-label {
  font-size: 11.5px;
  letter-spacing: 0.22em;
  color: var(--c-muted);
}

.page-about .about-index-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.page-about .about-index .toc-link {
  display: inline-block;
  padding: 6px 12px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  color: var(--c-muted);
  text-decoration: none;
  border: 1px solid transparent;
  border-radius: var(--radius);
  transition: color 0.24s var(--ease), border-color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .about-index .toc-link:hover,
.page-about .about-index .toc-link:focus-visible {
  color: var(--c-text);
  border-color: var(--ab-rule-2);
}

.page-about .about-index .toc-link.is-active {
  color: var(--c-celadon);
  border-color: var(--ab-celadon-soft);
  background: rgba(63, 169, 142, 0.1);
}

/* ---------- 通用章节 ---------- */
.page-about .section {
  padding: clamp(48px, 6.5vw, 96px) 0;
  border-bottom: 1px solid var(--ab-rule);
  scroll-margin-top: 90px;
}

.page-about .section:last-of-type {
  border-bottom: 0;
}

.page-about .section-label {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 18px;
  font-size: 12px;
  letter-spacing: 0.2em;
  color: var(--c-signal);
}

.page-about .section-label::after {
  content: "";
  flex: none;
  width: clamp(60px, 12vw, 150px);
  height: 1px;
  background: var(--ab-rule-2);
}

.page-about .section-title {
  margin: 0 0 18px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: clamp(23px, 3.2vw, 32px);
  line-height: 1.32;
  letter-spacing: -0.005em;
}

.page-about .about-intro {
  margin: 0 0 10px;
  max-width: 44em;
  font-size: 16px;
  line-height: 1.85;
  color: var(--c-muted);
}

.page-about .about-quote {
  margin: 0 0 30px;
  padding-left: clamp(16px, 3vw, 28px);
  border-left: 3px solid var(--c-signal);
  font-family: var(--font-head);
  font-size: clamp(19px, 2.6vw, 27px);
  font-weight: 600;
  line-height: 1.6;
  color: var(--c-text);
}

.page-about .prose p {
  margin: 0 0 18px;
  font-size: 16px;
  line-height: 1.9;
  color: var(--c-text);
}

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

/* ---------- 能力档案盒 ---------- */
.page-about .about-caps {
  display: grid;
  gap: 18px;
  margin-top: 34px;
}

.page-about .archive-card.about-cap {
  position: relative;
  padding: 24px 22px 26px;
  background: var(--c-plate);
  border: 1px solid var(--ab-rule);
  border-radius: var(--radius);
  transition: border-color 0.24s var(--ease), background-color 0.24s var(--ease);
}

.page-about .archive-card.about-cap:hover,
.page-about .archive-card.about-cap:focus-within {
  border-color: var(--ab-celadon-soft);
  background: var(--c-plate-2);
}

.page-about .about-cap .card-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.page-about .about-cap .card-index {
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.16em;
  color: var(--c-celadon);
}

.page-about .about-cap .card-title {
  margin: 0;
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 600;
  line-height: 1.45;
  color: var(--c-text);
}

.page-about .about-cap .card-divider {
  height: 1px;
  margin: 16px 0 14px;
  background: var(--ab-rule);
}

.page-about .about-cap p {
  margin: 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-text);
}

.page-about .about-cap a {
  color: var(--c-celadon);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-celadon-soft);
  transition: color 0.2s var(--ease);
}

.page-about .about-cap a:hover,
.page-about .about-cap a:focus-visible {
  color: var(--c-text);
}

.page-about .about-cap-more {
  margin-top: 12px;
  font-size: 14px;
  line-height: 1.8;
  color: var(--c-muted);
}

@media (hover: hover) and (min-width: 900px) {
  .page-about .about-cap-more {
    max-height: 0;
    margin-top: 0;
    opacity: 0;
    overflow: hidden;
    transition: max-height 0.3s var(--ease), opacity 0.22s var(--ease), margin-top 0.3s var(--ease);
  }
  .page-about .archive-card.about-cap:hover .about-cap-more,
  .page-about .archive-card.about-cap:focus-within .about-cap-more {
    max-height: 240px;
    margin-top: 12px;
    opacity: 1;
  }
}

/* ---------- 服务范围 ---------- */
.page-about .about-coverage {
  display: grid;
  gap: clamp(28px, 4vw, 52px);
  align-items: start;
}

.page-about .about-tiers {
  list-style: none;
  margin: 30px 0 0;
  padding: 0;
  display: grid;
  gap: 14px;
}

.page-about .about-tier {
  display: flex;
  gap: 16px;
  padding: 20px 22px;
  background: var(--c-plate);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.page-about .about-tier.is-core {
  border-left: 3px solid var(--c-celadon);
}

.page-about .about-tier.is-mid {
  border-left: 3px solid var(--ab-celadon-soft);
}

.page-about .about-tier.is-far {
  border-left: 3px solid var(--ab-rule-2);
}

.page-about .about-tier-num {
  flex: none;
  padding-top: 4px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-celadon);
}

.page-about .about-tier.is-far .about-tier-num {
  color: var(--c-muted);
}

.page-about .about-tier-body h3 {
  margin: 0 0 8px;
  font-family: var(--font-head);
  font-size: 17px;
  font-weight: 600;
  color: var(--c-text);
}

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

.page-about .about-coverage-figure {
  margin: 0;
  padding: 10px;
  background: var(--c-plate);
  border: 1px solid var(--ab-rule-2);
}

.page-about .about-coverage-figure .figure-media {
  position: relative;
  overflow: hidden;
  background: radial-gradient(circle at 50% 48%, rgba(63, 169, 142, 0.2), rgba(14, 27, 51, 0) 64%), var(--c-ink);
}

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

.page-about .about-coverage-figure .figure-caption {
  padding: 14px 4px 4px;
  font-size: 13px;
  line-height: 1.75;
  color: var(--c-muted);
}

/* ---------- 运营节奏 ---------- */
.page-about .about-rhythm-figure {
  margin: 30px 0 0;
}

.page-about .about-rhythm-figure .figure-media {
  overflow: hidden;
  border: 1px solid var(--ab-rule-2);
  background: var(--c-plate);
}

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

.page-about .about-rhythm-figure .figure-caption {
  padding: 12px 2px 0;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.03em;
  line-height: 1.75;
  color: var(--c-muted);
}

.page-about .about-rhythm {
  margin-top: 30px;
  padding-left: 22px;
  border-left: 1px solid var(--ab-rule-2);
}

.page-about .about-step {
  position: relative;
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-step:last-child {
  border-bottom: 0;
}

.page-about .about-step > summary {
  position: relative;
  padding: 16px 32px 16px 0;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-head);
  font-size: 15.5px;
  font-weight: 600;
  line-height: 1.7;
  color: var(--c-text);
}

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

.page-about .about-step > summary::before {
  content: "";
  position: absolute;
  left: -27px;
  top: 24px;
  width: 9px;
  height: 9px;
  background: var(--c-plate);
  border: 1.5px solid var(--c-celadon);
  transform: rotate(45deg);
}

.page-about .about-step > summary::after {
  content: "";
  position: absolute;
  right: 4px;
  top: 22px;
  width: 8px;
  height: 8px;
  border-right: 1.5px solid var(--c-muted);
  border-bottom: 1.5px solid var(--c-muted);
  transform: rotate(45deg);
  transition: transform 0.22s var(--ease);
}

.page-about .about-step[open] > summary::after {
  transform: rotate(-135deg);
}

.page-about .about-step > summary:focus-visible {
  outline: 2px solid var(--c-celadon);
  outline-offset: 3px;
}

.page-about .about-step-when {
  display: inline-block;
  margin-right: 10px;
  padding: 2px 9px;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--c-celadon);
  border: 1px solid var(--ab-celadon-soft);
  border-radius: var(--radius);
}

.page-about .about-step .panel-body {
  padding: 0 0 18px;
}

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

.page-about .about-step .panel-body a {
  color: var(--c-celadon);
  text-decoration: none;
  border-bottom: 1px solid var(--ab-celadon-soft);
}

.page-about .about-step .panel-body a:hover,
.page-about .about-step .panel-body a:focus-visible {
  color: var(--c-text);
}

/* ---------- 合作对接 ---------- */
.page-about .about-coop {
  display: grid;
  gap: clamp(24px, 3.5vw, 46px);
  margin-top: 34px;
}

.page-about .about-coop-list {
  border-top: 1px solid var(--ab-rule);
}

.page-about .about-coop-item {
  padding: 24px 0;
  border-bottom: 1px solid var(--ab-rule);
}

.page-about .about-coop-code {
  display: block;
  margin-bottom: 10px;
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--c-celadon);
}

.page-about .about-coop-item h3 {
  margin: 0 0 10px;
  font-family: var(--font-head);
  font-size: 18px;
  font-weight: 600;
  color: var(--c-text);
}

.page-about .about-coop-item p {
  margin: 0;
  max-width: 48em;
  font-size: 15px;
  line-height: 1.85;
  color: var(--c-muted);
}

.page-about .about-coop-start {
  padding: 26px 24px 28px;
  background: var(--c-plate);
  border: 1px solid var(--ab-rule-2);
  border-top: 3px solid var(--c-signal);
  border-radius: var(--radius);
}

.page-about .about-coop-start h3 {
  margin: 0 0 20px;
  font-family: var(--font-head);
  font-size: 19px;
  font-weight: 600;
  color: var(--c-text);
}

.page-about .about-start-list {
  list-style: none;
  margin: 0 0 26px;
  padding: 0;
  display: grid;
  gap: 15px;
}

.page-about .about-start-list li {
  display: grid;
  grid-template-columns: 26px minmax(0, 1fr);
  gap: 12px;
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--c-muted);
}

.page-about .about-start-list .mono {
  font-size: 12.5px;
  letter-spacing: 0.12em;
  color: var(--c-celadon);
  padding-top: 2px;
}

.page-about .about-coop-start .btn {
  display: block;
  box-sizing: border-box;
  width: 100%;
  text-align: center;
}

/* ---------- 响应式 ---------- */
@media (min-width: 720px) {
  .page-about .about-caps {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 22px;
  }
}

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  }
}

@media (min-width: 960px) {
  .page-about .about-coverage {
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 0.92fr);
  }
  .page-about .about-coop {
    grid-template-columns: minmax(0, 1.35fr) minmax(0, 0.65fr);
    align-items: start;
  }
}

@media (min-width: 1080px) {
  .page-about .about-caps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
  .page-about .archive-card.about-cap:last-child {
    grid-column: 1 / -1;
  }
  .page-about .archive-card.about-cap:last-child p {
    max-width: 88ch;
  }
}

@media (max-width: 639px) {
  .page-about .about-rhythm {
    padding-left: 18px;
  }
  .page-about .about-step > summary::before {
    left: -23px;
  }
  .page-about .about-quote {
    padding-left: 16px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .archive-card.about-cap,
  .page-about .about-index .toc-link,
  .page-about .about-step > summary::after,
  .page-about .about-cap-more {
    transition: none;
  }
}
</main>