.page-about {
  --arc-line: rgba(122, 75, 50, 0.28);
  --arc-line-soft: rgba(122, 75, 50, 0.14);
  --arc-gold-line: rgba(217, 164, 65, 0.32);
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  overflow-x: hidden;
}

.page-about .arc-wrap {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 clamp(18px, 4vw, 40px);
  box-sizing: border-box;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-title);
  color: var(--ink);
}

.page-about a {
  color: var(--cinnabar);
}

.page-about a:focus-visible,
.page-about button:focus-visible {
  outline: 2px solid var(--cinnabar);
  outline-offset: 3px;
}

/* 面包屑 */
.page-about .arc-crumb {
  border-bottom: var(--line);
  background: var(--paper);
}

.page-about .arc-crumb ol {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0;
  list-style: none;
  margin: 0;
  padding: 12px 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--umber);
}

.page-about .arc-crumb li {
  display: flex;
  align-items: center;
}

.page-about .arc-crumb li + li::before {
  content: "/";
  margin: 0 8px;
  color: var(--mist);
}

.page-about .arc-crumb a {
  color: var(--umber);
  text-decoration: none;
  border-bottom: 1px solid var(--arc-line);
  transition: color var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}

.page-about .arc-crumb a:hover {
  color: var(--cinnabar);
  border-color: var(--cinnabar);
}

/* 首屏 */
.page-about .arc-hero {
  position: relative;
  padding: clamp(30px, 5vw, 62px) 0 clamp(36px, 6vw, 72px);
  background: var(--paper);
  overflow: hidden;
}

.page-about .arc-hero::before {
  content: "档案";
  position: absolute;
  right: -0.12em;
  top: -0.28em;
  font-family: var(--font-title);
  font-weight: 900;
  font-size: clamp(7rem, 24vw, 18rem);
  line-height: 1;
  letter-spacing: 0.06em;
  color: rgba(181, 58, 45, 0.055);
  pointer-events: none;
}

.page-about .arc-hero-grid {
  position: relative;
  display: grid;
  gap: clamp(26px, 5vw, 50px);
}

.page-about .arc-kicker {
  display: flex;
  align-items: center;
  gap: 14px;
  margin: 0 0 clamp(16px, 3vw, 24px);
}

.page-about .arc-mono {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--umber);
  border: 1px solid var(--arc-line);
  background: rgba(255, 249, 239, 0.7);
  padding: 5px 10px;
}

.page-about .arc-seal {
  writing-mode: vertical-rl;
  font-family: var(--font-title);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.3em;
  color: var(--cinnabar);
  border: 2px solid var(--cinnabar);
  padding: 8px 4px;
}

.page-about .arc-hero h1 {
  margin: 0 0 clamp(16px, 3vw, 24px);
  font-size: clamp(2rem, 6.4vw, 4rem);
  font-weight: 900;
  line-height: 1.12;
  letter-spacing: 0.04em;
}

.page-about .arc-lede {
  max-width: 36em;
  margin: 0 0 clamp(24px, 4vw, 34px);
  font-size: clamp(15px, 1.6vw, 17px);
  color: #4A382F;
}

.page-about .arc-hero-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px 18px;
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .arc-hero-stats li {
  border-top: 2px solid var(--cinnabar);
  padding-top: 9px;
}

.page-about .arc-stat-v {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(20px, 2.6vw, 27px);
  font-weight: 700;
  line-height: 1.2;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.page-about .arc-stat-k {
  display: block;
  margin-top: 2px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--umber);
}

.page-about .arc-hero-index {
  background: var(--card);
  border: var(--line-strong);
  box-shadow: 7px 7px 0 rgba(122, 75, 50, 0.12);
  padding: 16px 16px 20px;
}

.page-about .arc-index-title {
  margin: 0 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.18em;
  color: var(--umber);
  text-transform: uppercase;
}

.page-about .arc-hero-index ol {
  list-style: none;
  margin: 0;
  padding: 0;
}

.page-about .arc-hero-index li + li {
  border-top: 1px dashed var(--arc-line);
}

.page-about .arc-hero-index a {
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 10px 4px;
  font-size: 14px;
  color: var(--ink);
  text-decoration: none;
  transition: background-color var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}

.page-about .arc-hero-index a:hover {
  background: rgba(217, 164, 65, 0.16);
  color: var(--cinnabar);
}

.page-about .arc-year {
  flex: none;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--cinnabar);
}

/* 章节通用 */
.page-about .arc-sec {
  padding: clamp(42px, 7vw, 84px) 0;
}

.page-about .arc-head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: clamp(20px, 3vw, 30px);
}

.page-about .arc-num {
  flex: none;
  margin-top: 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.2;
  letter-spacing: 0.1em;
  color: var(--cinnabar);
  border: 1px solid var(--cinnabar);
  padding: 3px 7px;
}

.page-about .arc-head h2 {
  margin: 0;
  font-size: clamp(1.45rem, 3.6vw, 2.25rem);
  font-weight: 800;
  line-height: 1.28;
  letter-spacing: 0.03em;
}

.page-about .arc-intro {
  max-width: 46em;
  margin: 0 0 clamp(22px, 3vw, 32px);
  color: #4A382F;
}

.page-about h3 {
  margin: 0 0 8px;
  font-size: 1.06rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.page-about .arc-figure {
  margin: 0;
}

.page-about .arc-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border: var(--line-strong);
  background: var(--gold-pale);
  object-fit: cover;
}

.page-about .arc-figure figcaption {
  margin-top: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.05em;
  color: var(--umber);
}

/* 起点 */
.page-about .arc-origin {
  border-top: var(--line);
}

.page-about .arc-origin-grid {
  display: grid;
  gap: clamp(20px, 4vw, 40px);
}

.page-about .arc-origin-text p {
  margin: 0 0 14px;
  font-size: 15px;
  color: #3A2C24;
}

.page-about .arc-check {
  list-style: none;
  margin: 18px 0 0;
  padding: 0;
}

.page-about .arc-check li {
  position: relative;
  padding-left: 22px;
  margin-bottom: 10px;
  font-size: 14.5px;
  line-height: 1.7;
}

.page-about .arc-check li::before {
  content: "◆";
  position: absolute;
  left: 0;
  top: 2px;
  font-size: 10px;
  color: var(--gold);
}

/* 时间线 */
.page-about .arc-stages {
  background: var(--ink);
  color: var(--paper);
  border-top: 1px solid var(--arc-gold-line);
  border-bottom: 1px solid var(--arc-gold-line);
}

.page-about .arc-stages .arc-head h2 {
  color: var(--paper);
}

.page-about .arc-stages .arc-num {
  color: var(--gold);
  border-color: var(--gold);
}

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

.page-about .arc-stage {
  position: relative;
  padding-bottom: 20px;
}

.page-about .arc-stage:last-child {
  padding-bottom: 0;
}

.page-about .arc-stage-year {
  display: inline-block;
  margin-bottom: 10px;
  padding: 2px 9px;
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--gold);
  border: 1px solid var(--arc-gold-line);
}

.page-about .arc-stage.is-current .arc-stage-year {
  color: var(--orange);
  border-color: var(--orange);
}

.page-about .arc-stage-body {
  background: rgba(255, 249, 239, 0.055);
  border: 1px solid var(--arc-gold-line);
  padding: clamp(16px, 2.6vw, 24px);
}

.page-about .arc-stage-body h3 {
  color: var(--paper);
}

.page-about .arc-stage-body > p {
  margin: 0 0 12px;
  font-size: 14.5px;
  line-height: 1.75;
  color: rgba(247, 240, 227, 0.82);
}

/* 可展开内容组 */
.page-about .fold-group {
  margin-top: 4px;
}

.page-about .fold-item {
  border-top: 1px solid var(--arc-line-soft);
}

.page-about .fold-trigger {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 11px 0;
  background: none;
  border: 0;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--umber);
  transition: color var(--dur-fast) var(--ease);
}

.page-about .fold-trigger::after {
  content: "+";
  flex: none;
  font-size: 16px;
  line-height: 1;
  color: var(--cinnabar);
}

.page-about .fold-trigger[aria-expanded="true"]::after {
  content: "–";
}

.page-about .fold-trigger:hover {
  color: var(--cinnabar);
}

.page-about .fold-panel {
  padding: 0 0 14px;
  font-size: 14px;
  line-height: 1.75;
  color: #4A382F;
}

.page-about .fold-panel[hidden] {
  display: none;
}

.page-about .fold-panel p {
  margin: 0;
}

.page-about .fold-panel a {
  color: var(--cinnabar);
}

.page-about .arc-stages .fold-item {
  border-top-color: rgba(217, 164, 65, 0.25);
}

.page-about .arc-stages .fold-trigger {
  color: rgba(240, 217, 168, 0.78);
}

.page-about .arc-stages .fold-trigger::after,
.page-about .arc-stages .fold-trigger:hover {
  color: var(--gold);
}

.page-about .arc-stages .fold-panel {
  color: rgba(247, 240, 227, 0.78);
}

.page-about .arc-stages .fold-panel a {
  color: var(--gold-pale);
}

/* 业务协同 */
.page-about .arc-synergy {
  border-top: var(--line);
}

.page-about .arc-syn-grid {
  display: grid;
  gap: 14px;
}

.page-about .arc-syn-card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: clamp(16px, 2.4vw, 22px);
  background: var(--card);
  border: var(--line-strong);
  transition: transform var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease);
}

.page-about .arc-syn-card:hover {
  transform: translateY(-3px);
  box-shadow: 4px 6px 0 rgba(122, 75, 50, 0.14);
}

.page-about .arc-syn-card h3 {
  font-size: 1rem;
}

.page-about .arc-syn-card p {
  margin: 0;
  font-size: 14px;
  line-height: 1.7;
  color: #4A382F;
}

.page-about .arc-syn-card--lead {
  padding: 0;
  overflow: hidden;
  background: var(--card);
}

.page-about .arc-syn-card--lead img {
  display: block;
  width: 100%;
  height: clamp(190px, 26vw, 280px);
  object-fit: cover;
  background: var(--gold-pale);
}

.page-about .arc-syn-body {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: clamp(14px, 2.2vw, 22px);
}

.page-about .arc-tag {
  align-self: flex-start;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  padding: 3px 9px;
  background: var(--gold-pale);
  color: var(--umber);
}

.page-about .arc-tag--red {
  background: var(--cinnabar);
  color: var(--card);
}

.page-about .arc-tag--green {
  background: #DCE5DA;
  color: var(--celadon-deep);
}

.page-about .arc-tag--gold {
  background: var(--gold);
  color: var(--ink);
}

.page-about .arc-link {
  align-self: flex-start;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--cinnabar);
  text-decoration: none;
  border-bottom: 1px solid var(--cinnabar);
  padding-bottom: 1px;
}

.page-about .arc-link:hover {
  color: var(--ink);
  border-color: var(--ink);
}

/* 团队 */
.page-about .arc-team {
  background: var(--card);
  border-top: var(--line);
  border-bottom: var(--line);
}

.page-about .arc-team-grid {
  display: grid;
  gap: clamp(22px, 4vw, 40px);
}

.page-about .arc-team-copy p {
  margin: 0 0 16px;
  font-size: 15px;
  color: #3A2C24;
}

.page-about .arc-team-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
  margin: 0 0 20px;
  padding: 0;
}

.page-about .arc-stat {
  display: flex;
  flex-direction: column-reverse;
  gap: 2px;
  padding-top: 10px;
  border-top: 2px solid var(--gold);
}

.page-about .arc-stat dt {
  font-size: 12px;
  line-height: 1.5;
  color: var(--umber);
}

.page-about .arc-stat dd {
  margin: 0;
  font-family: var(--font-mono);
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 700;
  line-height: 1.1;
  color: var(--cinnabar);
}

/* 流程 */
.page-about .arc-flow {
  background: var(--paper);
}

.page-about .arc-flow-list {
  list-style: none;
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
}

.page-about .arc-flow-step {
  background: var(--card);
  border: var(--line);
  border-top: 3px solid var(--cinnabar);
  padding: 16px 14px 8px;
}

.page-about .arc-flow-step h3 {
  font-size: 15px;
}

.page-about .arc-flow-step > p {
  margin: 0 0 8px;
  font-size: 13.5px;
  line-height: 1.7;
  color: #4A382F;
}

.page-about .arc-flow-num {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.16em;
  color: var(--gold);
}

/* 荣誉 */
.page-about .arc-honor {
  background: linear-gradient(180deg, var(--paper) 0%, #F2E6D1 100%);
  border-top: var(--line);
}

.page-about .arc-seal-list {
  list-style: none;
  display: grid;
  gap: 22px;
  margin: 0;
  padding: 0;
}

.page-about .arc-seal-list li {
  display: flex;
  align-items: flex-start;
  gap: 16px;
}

.page-about .arc-badge {
  flex: none;
  width: 96px;
  height: 96px;
  border-radius: 50%;
  border: 2px solid var(--cinnabar);
  color: var(--cinnabar);
  display: grid;
  place-items: center;
  text-align: center;
  padding: 10px;
  font-family: var(--font-title);
  font-size: 11.5px;
  font-weight: 700;
  line-height: 1.4;
  letter-spacing: 0.03em;
}

.page-about .arc-seal-list p {
  margin: 0;
  padding-top: 6px;
  font-size: 14px;
  line-height: 1.75;
  color: #3A2C24;
}

/* 行动区 */
.page-about .arc-cta {
  background: var(--cinnabar);
  color: var(--paper);
  padding: clamp(40px, 6vw, 72px) 0;
}

.page-about .arc-cta h2 {
  margin: 0 0 12px;
  color: var(--paper);
  font-size: clamp(1.4rem, 3.4vw, 2.1rem);
  font-weight: 800;
  letter-spacing: 0.03em;
}

.page-about .arc-cta p {
  max-width: 44em;
  margin: 0;
  font-size: 14.5px;
  line-height: 1.8;
  color: rgba(247, 240, 227, 0.9);
}

.page-about .arc-cta-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 22px 0 16px;
}

.page-about .arc-btn {
  display: inline-block;
  padding: 11px 22px;
  font-family: var(--font-title);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-decoration: none;
  border: 1px solid var(--paper);
  transition: background-color var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease), border-color var(--dur-fast) var(--ease);
}

.page-about .arc-btn--solid {
  background: var(--paper);
  color: var(--cinnabar);
  border-color: var(--paper);
}

.page-about .arc-btn--solid:hover {
  background: var(--ink);
  color: var(--paper);
  border-color: var(--ink);
}

.page-about .arc-btn--line {
  color: var(--paper);
  background: transparent;
  border-color: rgba(247, 240, 227, 0.7);
}

.page-about .arc-btn--line:hover {
  background: rgba(247, 240, 227, 0.16);
  border-color: var(--paper);
}

.page-about .arc-cta-note {
  font-size: 13px;
  color: rgba(247, 240, 227, 0.85);
}

.page-about .arc-cta-note a {
  color: var(--gold-pale);
  text-decoration: underline;
}

/* 断点 */
@media (min-width: 760px) {
  .page-about .arc-hero-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

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

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

  .page-about .arc-seal-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 26px;
  }

  .page-about .arc-seal-list li {
    flex-direction: column;
    gap: 12px;
  }

  .page-about .arc-seal-list p {
    padding-top: 0;
  }
}

@media (min-width: 880px) {
  .page-about .arc-hero {
    background: linear-gradient(105deg, var(--paper) 0 58%, #F0E3CB 58% 100%);
  }

  .page-about .arc-hero-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(280px, 0.85fr);
    align-items: start;
  }

  .page-about .arc-origin-grid {
    grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
    align-items: start;
  }

  .page-about .arc-team-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
    align-items: start;
  }

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

  .page-about .arc-syn-card--lead {
    grid-column: span 2;
    grid-row: span 2;
  }

  .page-about .arc-syn-card--lead img {
    height: clamp(240px, 30vw, 340px);
  }

  .page-about .arc-stage {
    display: grid;
    grid-template-columns: 118px minmax(0, 1fr);
    gap: 30px;
    padding-bottom: 26px;
  }

  .page-about .arc-stage::before {
    content: "";
    position: absolute;
    left: 133px;
    top: 12px;
    bottom: 0;
    width: 1px;
    background: rgba(217, 164, 65, 0.32);
  }

  .page-about .arc-stage::after {
    content: "";
    position: absolute;
    left: 128px;
    top: 8px;
    width: 11px;
    height: 11px;
    border-radius: 50%;
    background: var(--gold);
    box-shadow: 0 0 0 4px var(--ink);
  }

  .page-about .arc-stage.is-current::after {
    background: var(--orange);
  }

  .page-about .arc-stage:last-child {
    padding-bottom: 0;
  }

  .page-about .arc-stage:last-child::before {
    display: none;
  }

  .page-about .arc-stage-year {
    justify-self: end;
    text-align: right;
    margin: 0;
    padding: 0;
    border: 0;
    font-size: clamp(19px, 2.1vw, 25px);
    line-height: 1.3;
  }
}

@media (min-width: 1080px) {
  .page-about .arc-flow-list {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-about .arc-syn-card,
  .page-about .arc-btn,
  .page-about .arc-hero-index a {
    transition: none;
  }

  .page-about .arc-syn-card:hover {
    transform: none;
  }
}