/* ============================================================
   站点介绍页 · page-about
   作用域限定：.page-about
   ============================================================ */

.page-about {
  --about-radius: 16px;
  --about-hair: 1px solid var(--line);
  background: var(--silver);
  color: var(--ink);
  font-family: var(--font-body);
  line-height: 1.85;
}

.page-about .container {
  width: 100%;
  max-width: 1320px;
  margin: 0 auto;
  padding: 0 20px;
}

.page-about h1,
.page-about h2,
.page-about h3 {
  font-family: var(--font-display);
  color: var(--ink);
  line-height: 1.2;
  letter-spacing: -0.015em;
  margin: 0;
}

.page-about h2 {
  font-size: clamp(1.6rem, 4.4vw, 2.5rem);
  font-weight: 800;
}

.page-about h3 {
  font-size: 1.06rem;
  font-weight: 700;
}

.page-about p {
  margin: 0 0 1em;
  font-size: 1rem;
  color: var(--ink-2);
}

.page-about .mono {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
}

.page-about .eyebrow {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--blue);
  margin: 0 0 14px;
}

.page-about .annotation {
  font-size: 0.7rem;
  letter-spacing: 0.3em;
  color: var(--ink-2);
  margin: 0 0 14px;
}

.page-about .glass {
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(127, 163, 255, 0.45);
  border-radius: var(--about-radius);
  backdrop-filter: blur(8px);
  box-shadow: var(--shadow-soft);
}

.page-about .tag {
  display: inline-flex;
  align-items: center;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--mist);
  color: var(--ink-2);
  white-space: nowrap;
}

.page-about .tag--green {
  background: var(--green);
  color: var(--white);
}

.page-about .tag--orange {
  background: var(--orange);
  color: var(--deep);
}

.page-about .tag--amber {
  background: var(--amber);
  color: var(--deep);
}

.page-about .dot {
  display: inline-block;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  margin-right: 10px;
  flex: 0 0 auto;
  transform: translateY(-1px);
}

.page-about .dot--green { background: var(--green); }

/* ---------- 首屏 ---------- */

.page-about .about-hero {
  position: relative;
  padding: 24px 0 56px;
  background:
    radial-gradient(120% 80% at 88% 0%, rgba(28, 78, 216, 0.14), transparent 62%),
    linear-gradient(180deg, var(--silver) 0%, var(--mist) 100%);
  overflow: hidden;
}

.page-about .about-hero::after {
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--circuit), transparent);
  opacity: 0.7;
}

.page-about .breadcrumbs {
  font-size: 0.78rem;
  color: var(--ink-2);
  display: flex;
  gap: 8px;
  align-items: center;
  margin-bottom: 34px;
}

.page-about .breadcrumbs a {
  color: var(--ink-2);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  padding-bottom: 1px;
}

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

.page-about .about-hero__layout {
  display: grid;
  gap: 32px;
}

.page-about .about-hero h1 {
  font-size: clamp(2.4rem, 9vw, 4.4rem);
  font-weight: 900;
  letter-spacing: -0.03em;
  margin-bottom: 22px;
  position: relative;
}

.page-about .about-hero h1::before {
  content: "";
  position: absolute;
  left: -14px;
  top: 0.18em;
  bottom: 0.1em;
  width: 5px;
  border-radius: 3px;
  background: linear-gradient(180deg, var(--blue), var(--circuit));
}

.page-about .about-hero__lede {
  font-size: 1.02rem;
  max-width: 46ch;
  color: var(--ink-2);
}

.page-about .about-hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.page-about .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 0 20px;
  border-radius: 999px;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform 0.18s var(--ease), box-shadow 0.18s var(--ease), border-color 0.18s var(--ease);
}

.page-about .btn--primary {
  background: var(--deep);
  color: var(--white);
  box-shadow: var(--shadow-soft);
}

.page-about .btn--ghost {
  background: rgba(255, 255, 255, 0.7);
  border-color: var(--line);
  color: var(--ink);
}

.page-about .btn:hover {
  transform: translateY(-2px);
}

.page-about .about-hero__index {
  padding: 22px 20px;
}

.page-about .toc {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 2px;
}

.page-about .toc a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px 8px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--ink);
  font-size: 0.92rem;
  transition: background 0.18s var(--ease), color 0.18s var(--ease);
}

.page-about .toc a:hover,
.page-about .toc a:focus-visible {
  background: rgba(28, 78, 216, 0.08);
  color: var(--blue);
}

.page-about .toc .mono {
  font-size: 0.72rem;
  color: var(--blue);
  min-width: 22px;
  letter-spacing: 0.06em;
}

.page-about .about-hero__index-note {
  margin: 16px 0 0;
  padding-top: 14px;
  border-top: 1px dashed var(--line);
  font-size: 0.78rem;
  color: var(--ink-2);
}

/* ---------- 通用章节 ---------- */

.page-about .about-origin,
.page-about .about-method,
.page-about .about-people,
.page-about .about-edge {
  padding: 64px 0;
  background: var(--silver);
}

.page-about .about-stages,
.page-about .about-coverage {
  padding: 64px 0;
  background: var(--mist);
}

.page-about .about-quality {
  padding: 64px 0;
  background: var(--warm);
}

.page-about .section-head {
  max-width: 62ch;
  margin-bottom: 36px;
}

.page-about .section-head__note {
  margin-top: 12px;
  color: var(--ink-2);
}

/* ---------- 01 起点与定位 ---------- */

.page-about .origin-grid {
  display: grid;
  gap: 30px;
}

.page-about .origin-main h2 {
  margin-bottom: 20px;
}

.page-about .origin-main p {
  max-width: 60ch;
}

.page-about .origin-notes {
  display: grid;
  gap: 14px;
  margin-top: 26px;
}

.page-about .note-card {
  border-left: 3px solid var(--circuit);
  background: var(--white);
  border-radius: 0 var(--about-radius) var(--about-radius) 0;
  padding: 16px 18px;
}

.page-about .note-card p {
  margin: 10px 0 0;
  font-size: 0.92rem;
}

.page-about .origin-side {
  padding: 24px 20px;
  align-self: start;
}

.page-about .side-facts {
  margin: 0;
  display: grid;
  gap: 16px;
}

.page-about .side-facts dt {
  font-size: 0.78rem;
  letter-spacing: 0.1em;
  color: var(--blue);
  margin-bottom: 4px;
}

.page-about .side-facts dd {
  margin: 0;
  font-size: 0.9rem;
  color: var(--ink-2);
}

/* ---------- 02 阶段演进 ---------- */

.page-about .stage-track {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 34px;
}

.page-about .stage-node {
  position: relative;
  padding-left: 22px;
  border-left: 2px solid var(--line);
}

.page-about .stage-node::before {
  content: "";
  position: absolute;
  left: -8px;
  top: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--white);
  border: 3px solid var(--blue);
}

.page-about .stage-node--now::before {
  border-color: var(--orange);
  box-shadow: 0 0 0 4px rgba(255, 122, 47, 0.16);
}

.page-about .stage-node__year {
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  color: var(--blue);
  margin: 0 0 6px;
}

.page-about .stage-node h3 {
  margin-bottom: 8px;
}

.page-about .stage-node p {
  font-size: 0.92rem;
  margin-bottom: 10px;
}

.page-about .stage-node__stat {
  display: inline-block;
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--white);
  border: 1px solid var(--line);
  color: var(--deep);
}

/* ---------- 03 选型方法 ---------- */

.page-about .method-grid {
  display: grid;
  gap: 32px;
}

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

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

.page-about .media-frame--4x3 img { aspect-ratio: 4 / 3; }
.page-about .media-frame--21x9 img { aspect-ratio: 21 / 9; }

.page-about .method-media__caption {
  margin-top: 12px;
  font-size: 0.8rem;
  color: var(--ink-2);
  line-height: 1.7;
}

.page-about .method-intro {
  max-width: 56ch;
}

.page-about .method-steps {
  list-style: none;
  margin: 26px 0 0;
  padding: 0;
  display: grid;
  gap: 4px;
  counter-reset: none;
}

.page-about .method-steps li {
  display: grid;
  grid-template-columns: 46px 1fr;
  gap: 14px;
  padding: 16px 0;
  border-top: 1px solid var(--line);
}

.page-about .method-steps li:last-child {
  border-bottom: 1px solid var(--line);
}

.page-about .method-steps__num {
  font-size: 0.8rem;
  letter-spacing: 0.12em;
  color: var(--blue);
  padding-top: 4px;
}

.page-about .method-steps h3 {
  margin-bottom: 6px;
}

.page-about .method-steps p {
  margin: 0;
  font-size: 0.92rem;
}

.page-about .method-foot {
  margin-top: 22px;
  font-size: 0.9rem;
  padding: 14px 18px;
  border-radius: var(--radius-sm);
  background: var(--mist);
  color: var(--ink-2);
}

.page-about .method-foot a,
.page-about .cov-note a,
.page-about .edge-links a {
  color: var(--orange-ink);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
  padding-bottom: 1px;
}

.page-about .method-foot a:hover,
.page-about .cov-note a:hover,
.page-about .edge-links a:hover {
  color: var(--blue);
}

/* ---------- 04 质控与回访 ---------- */

.page-about .quality-grid {
  display: grid;
  gap: 30px;
}

.page-about .quality-lead p {
  max-width: 56ch;
}

.page-about .quality-check {
  list-style: none;
  margin: 20px 0 0;
  padding: 0;
  display: grid;
  gap: 12px;
}

.page-about .quality-check li {
  display: flex;
  align-items: flex-start;
  font-size: 0.92rem;
  color: var(--ink-2);
}

.page-about .quality-timeline {
  display: grid;
  gap: 16px;
}

.page-about .quality-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-left: 4px solid var(--amber);
  border-radius: var(--radius-sm);
  padding: 20px 20px 18px;
}

.page-about .quality-card--alt {
  border-left-color: var(--orange);
}

.page-about .quality-card h3 {
  margin: 12px 0 8px;
}

.page-about .quality-card p {
  font-size: 0.92rem;
  margin-bottom: 8px;
}

.page-about .quality-card__note {
  margin-bottom: 0;
  font-size: 0.8rem;
  color: var(--ink-2);
  padding-top: 8px;
  border-top: 1px dashed var(--line);
}

/* ---------- 05 人员结构 ---------- */

.page-about .people-grid {
  display: grid;
  gap: 28px;
}

.page-about .people-stats {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin: 26px 0 18px;
}

.page-about .stat-block {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 16px 14px;
  display: grid;
  gap: 6px;
}

.page-about .stat-block__num {
  font-size: clamp(1.3rem, 4vw, 1.7rem);
  font-weight: 700;
  color: var(--blue);
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.page-about .stat-block__label {
  font-size: 0.76rem;
  color: var(--ink-2);
  line-height: 1.5;
}

.page-about .people-foot {
  font-size: 0.8rem;
  color: var(--ink-2);
  border-top: 1px dashed var(--line);
  padding-top: 12px;
  margin-bottom: 0;
}

/* ---------- 06 城区覆盖 ---------- */

.page-about .cov-media {
  margin: 0 0 26px;
}

.page-about .cov-table-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--about-radius);
  background: var(--white);
}

.page-about .cov-table {
  width: 100%;
  min-width: 540px;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.page-about .cov-table caption {
  text-align: left;
}

.page-about .cov-table thead th {
  text-align: left;
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  color: var(--ink-2);
  font-weight: 600;
  padding: 14px 16px;
  background: var(--mist);
  border-bottom: 1px solid var(--line);
  white-space: nowrap;
}

.page-about .cov-table tbody td,
.page-about .cov-table tbody th {
  padding: 13px 16px;
  border-bottom: 1px solid var(--line);
  text-align: left;
  font-weight: 500;
  color: var(--ink);
}

.page-about .cov-table tbody tr:last-child td,
.page-about .cov-table tbody tr:last-child th {
  border-bottom: 0;
}

.page-about .cov-table tbody tr:nth-child(even) {
  background: rgba(228, 232, 239, 0.45);
}

.page-about .cov-table tbody tr:hover {
  background: rgba(28, 78, 216, 0.06);
}

.page-about .cov-table tbody td.mono {
  color: var(--ink-2);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
}

.page-about .cov-table tbody th[scope="row"] {
  font-weight: 700;
}

.page-about .cov-note {
  margin-top: 18px;
  font-size: 0.88rem;
  color: var(--ink-2);
  max-width: 70ch;
}

/* ---------- 07 边界与联络 ---------- */

.page-about .about-edge {
  background: var(--deep);
  color: var(--white);
}

.page-about .about-edge h2 {
  color: var(--white);
}

.page-about .about-edge .eyebrow {
  color: var(--circuit);
}

.page-about .edge-grid {
  display: grid;
  gap: 30px;
}

.page-about .edge-body p {
  color: rgba(255, 255, 255, 0.76);
  max-width: 60ch;
}

.page-about .edge-contact {
  margin: 26px 0 0;
  display: grid;
  gap: 2px;
  border-top: 1px solid rgba(127, 163, 255, 0.28);
}

.page-about .edge-contact__row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 4px;
  padding: 13px 0;
  border-bottom: 1px solid rgba(127, 163, 255, 0.18);
}

.page-about .edge-contact dt {
  font-size: 0.74rem;
  letter-spacing: 0.16em;
  color: var(--circuit);
}

.page-about .edge-contact dd {
  margin: 0;
  font-size: 0.92rem;
  color: var(--white);
  word-break: break-word;
}

.page-about .edge-links {
  margin-top: 22px;
  font-size: 0.88rem;
}

.page-about .edge-links a {
  color: var(--orange);
  border-bottom-color: rgba(255, 122, 47, 0.6);
}

.page-about .edge-links a:hover {
  color: var(--white);
}

.page-about .edge-aside {
  display: grid;
  gap: 14px;
  align-content: start;
}

.page-about .edge-fold {
  background: rgba(127, 163, 255, 0.1);
  border: 1px solid rgba(127, 163, 255, 0.34);
  border-radius: var(--radius-sm);
  padding: 4px 16px;
}

.page-about .edge-fold summary {
  cursor: pointer;
  padding: 12px 0;
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--white);
  list-style: none;
}

.page-about .edge-fold summary::-webkit-details-marker { display: none; }

.page-about .edge-fold summary::after {
  content: "＋";
  float: right;
  color: var(--circuit);
  font-weight: 400;
}

.page-about .edge-fold[open] summary::after {
  content: "－";
}

.page-about .edge-fold p {
  margin: 0 0 14px;
  font-size: 0.86rem;
  color: rgba(255, 255, 255, 0.74);
  line-height: 1.8;
}

/* ---------- 焦点可见性 ---------- */

.page-about a:focus-visible,
.page-about summary:focus-visible,
.page-about .btn:focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 2px;
  border-radius: 6px;
}

/* ============================================================
   媒体查询：平板及以上
   ============================================================ */

@media (min-width: 720px) {
  .page-about .container {
    padding: 0 32px;
  }

  .page-about .about-hero {
    padding: 32px 0 76px;
  }

  .page-about .about-origin,
  .page-about .about-stages,
  .page-about .about-method,
  .page-about .about-quality,
  .page-about .about-people,
  .page-about .about-coverage,
  .page-about .about-edge {
    padding: 88px 0;
  }

  .page-about .origin-grid {
    grid-template-columns: minmax(0, 1.55fr) minmax(0, 1fr);
    gap: 48px;
    align-items: start;
  }

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

  .page-about .method-steps li {
    grid-template-columns: 60px 1fr;
    gap: 20px;
  }

  .page-about .quality-timeline {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
  }

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

  .page-about .edge-contact__row {
    grid-template-columns: 130px 1fr;
    align-items: baseline;
    gap: 16px;
  }
}

/* ============================================================
   媒体查询：桌面及以上
   ============================================================ */

@media (min-width: 960px) {
  .page-about .about-hero__layout {
    grid-template-columns: minmax(0, 1.75fr) minmax(280px, 1fr);
    gap: 56px;
    align-items: end;
  }

  .page-about .about-hero h1 {
    max-width: 15ch;
  }

  .page-about .about-hero__lede {
    font-size: 1.08rem;
  }

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

  /* 横向阶段时间带 */
  .page-about .stage-track {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0;
    padding-top: 58px;
    position: relative;
  }

  .page-about .stage-track::before {
    content: "";
    position: absolute;
    top: 7px;
    left: 12.5%;
    right: 12.5%;
    height: 2px;
    background: linear-gradient(90deg, var(--circuit), var(--blue) 60%, var(--orange));
    opacity: 0.6;
  }

  .page-about .stage-node {
    padding: 0 22px;
    border-left: 2px solid var(--line);
  }

  .page-about .stage-node:first-child {
    border-left: 0;
  }

  .page-about .stage-node::before {
    left: 50%;
    top: -58px;
    margin-left: -8px;
    width: 16px;
    height: 16px;
    border: 3px solid var(--white);
    background: var(--blue);
    box-shadow: 0 0 0 2px var(--circuit);
  }

  .page-about .stage-node--now::before {
    background: var(--orange);
    border-color: var(--white);
    box-shadow: 0 0 0 2px var(--orange);
  }

  .page-about .method-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .method-media {
    position: sticky;
    top: 96px;
  }

  .page-about .quality-grid {
    grid-template-columns: minmax(0, 1fr) minmax(0, 1.15fr);
    gap: 56px;
    align-items: start;
  }

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

  .page-about .people-grid {
    grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .people-stats {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 14px;
  }

  /* 数据卡向右越出半列，制造方向感 */
  .page-about .about-people .people-grid {
    grid-template-columns: minmax(0, 1.05fr) minmax(0, 0.95fr);
  }

  .page-about .people-media {
    transform: translateX(24px);
  }

  .page-about .edge-grid {
    grid-template-columns: minmax(0, 1.4fr) minmax(0, 1fr);
    gap: 56px;
    align-items: start;
  }

  .page-about .edge-contact {
    max-width: 640px;
  }
}

@media (min-width: 1200px) {
  .page-about .about-hero__layout {
    gap: 80px;
  }

  .page-about .stage-node {
    padding: 0 26px;
  }
}

/* ---------- 减少动效 ---------- */

@media (prefers-reduced-motion: reduce) {
  .page-about .btn,
  .page-about .toc a {
    transition: none;
  }

  .page-about .btn:hover {
    transform: none;
  }

  .page-about .people-media {
    transform: none;
  }
}