.page-about {
  --about-num: clamp(2.2rem, 6vw, 4rem);
  --about-line: 1px solid var(--line);
  display: block;
  overflow-x: hidden;
  padding-bottom: 72px;
}

.page-about h2 {
  font-size: clamp(1.5rem, 3.4vw, 2.3rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.14;
  color: var(--head);
  margin: 0 0 14px;
  max-width: 24ch;
}

.page-about h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--head);
  margin: 0 0 8px;
}

.page-about p {
  max-width: 68ch;
  line-height: 1.75;
  color: var(--text);
  overflow-wrap: break-word;
}

.page-about a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid rgba(79, 227, 208, 0.4);
}

.page-about a:hover {
  border-bottom-color: var(--cyan);
}

/* ---------- 首屏 ---------- */
.page-about .about-hero {
  border-top: var(--about-line);
  padding: 28px 0 40px;
}

.page-about .about-hero-grid {
  display: grid;
  gap: 30px;
  grid-template-columns: minmax(0, 1fr);
  align-items: start;
}

.page-about .about-hero-num {
  font-family: var(--mono);
  font-size: var(--about-num);
  font-weight: 200;
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--mid);
  margin: 0 0 12px;
}

.page-about .about-hero h1 {
  font-size: clamp(2rem, 5.6vw, 4rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.05;
  color: var(--head);
  margin: 0 0 18px;
  max-width: 20ch;
}

.page-about .about-hero .lede {
  font-size: 1.0625rem;
  line-height: 1.75;
  color: var(--text);
  max-width: 60ch;
  margin: 0;
}

.page-about .about-slash {
  display: block;
  width: min(280px, 70%);
  height: auto;
  margin: 22px 0 24px;
  opacity: 0.85;
}

.page-about .about-hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.page-about .about-facts {
  display: grid;
  gap: 16px;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin: 0;
  padding: 20px;
  background: var(--panel);
  border: 2px solid var(--line);
  box-shadow: var(--shadow);
}

.page-about .about-fact dt {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  color: var(--mid);
}

.page-about .about-fact dd {
  margin: 6px 0 0;
  font-family: var(--mono);
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--head);
  letter-spacing: -0.01em;
}

/* ---------- 章节骨架 ---------- */
.page-about .about-section {
  border-top: var(--about-line);
  padding: 42px 0;
}

.page-about .about-section-grid {
  display: grid;
  gap: 18px;
  grid-template-columns: minmax(0, 1fr);
}

.page-about .sec-num {
  font-family: var(--mono);
  font-size: var(--about-num);
  font-weight: 200;
  line-height: 0.9;
  letter-spacing: -0.03em;
  color: var(--mid);
  margin: 0;
}

/* ---------- 用途条 ---------- */
.page-about .about-usecases {
  display: grid;
  gap: 14px;
  margin: 26px 0;
}

.page-about .about-usecase {
  border-left: 3px solid var(--orange);
  background: linear-gradient(90deg, rgba(255, 138, 61, 0.08), transparent 70%);
  padding: 12px 16px;
}

.page-about .about-usecase:nth-child(2) {
  border-left-color: var(--cyan);
  background: linear-gradient(90deg, rgba(79, 227, 208, 0.08), transparent 70%);
}

.page-about .about-usecase:nth-child(3) {
  border-left-color: var(--clay);
  background: linear-gradient(90deg, rgba(216, 195, 160, 0.1), transparent 70%);
}

.page-about .about-usecase p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.7;
}

.page-about .about-usecase-title {
  font-weight: 600;
  color: var(--head);
  margin-bottom: 4px !important;
}

/* ---------- 四类内容卡片 ---------- */
.page-about .about-cards {
  display: grid;
  gap: 16px;
  grid-template-columns: minmax(0, 1fr);
  margin: 24px 0 26px;
}

.page-about .about-card {
  background: var(--panel);
  border: 2px solid var(--line);
  box-shadow: var(--shadow);
  padding: 20px;
  transition: transform 200ms ease-out, border-color 200ms ease-out;
}

.page-about .about-card:hover,
.page-about .about-card:focus-within {
  transform: translateY(-2px);
  border-color: var(--cyan);
}

.page-about .about-card p {
  font-size: 0.95rem;
  line-height: 1.7;
  margin: 0 0 12px;
}

.page-about .about-tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.18em;
  color: var(--clay);
  background: rgba(216, 195, 160, 0.12);
  border: 1px solid rgba(216, 195, 160, 0.3);
  padding: 3px 8px;
  margin: 0 0 12px;
}

.page-about .about-link {
  font-size: 0.9rem;
  font-family: var(--mono);
  letter-spacing: 0.04em;
}

/* ---------- 校对步骤 ---------- */
.page-about .about-steps {
  display: grid;
  gap: 18px;
  margin: 26px 0 0;
}

.page-about .about-step {
  border-left: 3px solid var(--cyan);
  padding: 6px 0 6px 18px;
  background: linear-gradient(90deg, rgba(79, 227, 208, 0.07), transparent 65%);
}

.page-about .about-step:nth-child(2) {
  border-left-color: var(--orange);
  background: linear-gradient(90deg, rgba(255, 138, 61, 0.07), transparent 65%);
}

.page-about .about-step:nth-child(3) {
  border-left-color: var(--clay);
  background: linear-gradient(90deg, rgba(216, 195, 160, 0.09), transparent 65%);
}

.page-about .about-step-num {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.18em;
  color: var(--mid);
  margin: 0 0 6px;
}

.page-about .about-step p {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ---------- 图片 ---------- */
.page-about .about-media {
  margin: 28px 0 0;
}

.page-about .media-frame {
  border: 2px solid var(--line);
  background: var(--panel);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.page-about .media-frame img {
  display: block;
  width: 100%;
  height: auto;
  max-width: 100%;
  object-fit: cover;
}

.page-about .media-caption {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.08em;
  color: var(--mid);
  margin-top: 10px;
}

/* ---------- 团队分组 ---------- */
.page-about .tabs {
  margin: 22px 0 0;
}

.page-about .tab-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-about .tab {
  font: inherit;
  font-size: 0.9rem;
  color: var(--text);
  background: var(--panel);
  border: 2px solid var(--line);
  padding: 9px 14px;
  cursor: pointer;
  transition: border-color 180ms ease-out, color 180ms ease-out, transform 180ms ease-out;
}

.page-about .tab:hover {
  transform: translateY(-2px);
  border-color: var(--cyan);
  color: var(--head);
}

.page-about .tab[aria-selected="true"] {
  border-color: var(--orange);
  color: var(--head);
  background: var(--panel-2);
}

.page-about .tab:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.page-about .tab-panel {
  padding: 18px 0 0;
  border-top: var(--about-line);
  margin-top: 16px;
}

.page-about .tab-panel p {
  font-size: 0.98rem;
  margin: 0 0 12px;
}

.page-about .about-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
}

.page-about .about-list li {
  position: relative;
  padding-left: 18px;
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--text);
}

.page-about .about-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 8px;
  height: 2px;
  background: var(--cyan);
}

/* ---------- 占比条 ---------- */
.page-about .about-meters {
  margin: 30px 0 0;
  padding: 20px;
  background: var(--panel);
  border: 2px solid var(--line);
}

.page-about .about-meter-row {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 12px;
  margin-bottom: 8px;
}

.page-about .about-meter-label {
  font-size: 0.85rem;
  color: var(--text);
}

.page-about .about-meter-value {
  font-size: 1.05rem;
  color: var(--head);
}

.page-about .about-meter {
  display: block;
  height: 10px;
  background: var(--panel-2);
  border: 1px solid var(--line);
  margin-bottom: 18px;
}

.page-about .about-meter > span {
  display: block;
  height: 100%;
  width: var(--w);
  background: var(--cyan);
}

.page-about .about-meter.is-concede > span {
  background: var(--orange);
}

.page-about .about-meters .about-meter:last-child {
  margin-bottom: 0;
}

/* ---------- 时间线 ---------- */
.page-about .about-timeline {
  list-style: none;
  margin: 26px 0 0;
  padding: 0 0 0 26px;
  border-left: 1px solid var(--line);
  display: grid;
  gap: 26px;
}

.page-about .about-node {
  position: relative;
  padding: 2px 0 2px 4px;
}

.page-about .about-node::before {
  content: "";
  position: absolute;
  left: -33px;
  top: 8px;
  width: 11px;
  height: 11px;
  background: var(--panel);
  border: 2px solid var(--clay);
  transition: background-color 200ms ease-out, border-color 200ms ease-out;
}

.page-about .about-node:hover::before,
.page-about .about-node:focus-within::before {
  background: var(--cyan);
  border-color: var(--cyan);
}

.page-about .about-node--now::before {
  border-color: var(--cyan);
  background: var(--cyan);
  box-shadow: 0 0 0 5px rgba(79, 227, 208, 0.16);
}

.page-about .about-node-year {
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.2em;
  color: var(--clay);
  margin: 0 0 6px;
}

.page-about .about-node--now .about-node-year {
  color: var(--cyan);
}

.page-about .about-node p:last-child {
  margin: 0;
  font-size: 0.95rem;
  line-height: 1.72;
}

/* ---------- 公告块 ---------- */
.page-about .notice {
  margin: 26px 0 0;
  font-size: 0.9rem;
  line-height: 1.75;
  color: var(--text);
}

/* ---------- 结尾引导 ---------- */
.page-about .about-cta {
  border-top: var(--about-line);
  padding: 44px 0 0;
}

.page-about .about-cta p {
  margin: 0 0 22px;
}

/* ---------- 响应式 ---------- */
@media (min-width: 640px) {
  .page-about .about-cards {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

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

@media (min-width: 900px) {
  .page-about .about-hero-grid {
    grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr);
    gap: 44px;
  }

  .page-about .about-section {
    padding: 54px 0;
  }

  .page-about .about-section-grid {
    grid-template-columns: 96px minmax(0, 1fr);
    gap: 34px;
  }

  .page-about .about-facts {
    grid-template-columns: minmax(0, 1fr);
  }

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

  .page-about .about-steps {
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }

  .page-about .sec-num {
    padding-top: 4px;
  }
}

@media (min-width: 1180px) {
  .page-about .about-hero-num {
    font-size: 4.4rem;
  }
}

.page-about {
  --w: 1rem;
}