.page-faq {
  --faq-paper-ink: #10152F;
  --faq-paper-muted: #4A5170;
  --faq-rail-w: 132px;
  position: relative;
}

.page-faq .faq-crumb {
  margin: 0 0 26px;
}

/* ---------- 首屏 ---------- */
.page-faq .faq-hero {
  padding: clamp(18px, 4vw, 40px) 0 clamp(28px, 5vw, 52px);
  border-bottom: 1px solid var(--line-500);
}

.page-faq .faq-hero h1 {
  margin: 16px 0 20px;
  max-width: 21ch;
  font-family: var(--font-sans);
  font-size: clamp(2rem, 6.6vw, 4.2rem);
  font-weight: 250;
  line-height: 1.08;
  letter-spacing: -0.015em;
  color: var(--text-900);
}

.page-faq .faq-hero__lead {
  max-width: 68ch;
  font-size: 17px;
  line-height: 1.9;
  color: var(--text-300);
}

.page-faq .faq-hero__stats {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  margin: 26px 0 0;
  padding: 0;
  list-style: none;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.02em;
  color: var(--text-300);
}

.page-faq .faq-hero__stats b {
  font-weight: 500;
  color: var(--cyan-400);
  font-variant-numeric: tabular-nums;
}

/* ---------- 索引轴 + 内容区 ---------- */
.page-faq .faq-shell {
  display: grid;
  grid-template-columns: 1fr;
  gap: 32px;
  padding-top: clamp(32px, 5vw, 56px);
}

.page-faq .faq-rail__title {
  margin: 0 0 10px;
  font-family: var(--font-narrow);
  font-size: 11.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-300);
}

.page-faq .faq-rail__list {
  display: flex;
  gap: 6px;
  margin: 0;
  padding: 0 0 6px;
  list-style: none;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-faq .faq-rail__item {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 9px 13px;
  border: 1px solid transparent;
  border-radius: var(--radius-pill);
  font-size: 13.5px;
  white-space: nowrap;
  color: var(--text-300);
  text-decoration: none;
  transition: color 0.18s var(--ease), border-color 0.18s var(--ease), background-color 0.18s var(--ease);
}

.page-faq .faq-rail__item:hover,
.page-faq .faq-rail__item:focus-visible {
  color: var(--text-900);
  border-color: var(--line-500);
  background: var(--ink-750);
}

.page-faq .faq-rail__num {
  font-family: var(--font-mono);
  font-size: 11.5px;
  color: var(--signal-500);
  font-variant-numeric: tabular-nums;
}

.page-faq .faq-content {
  display: grid;
  gap: 64px;
  min-width: 0;
}

/* ---------- 章节头 ---------- */
.page-faq .faq-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--line-500);
}

.page-faq .faq-head__num {
  font-family: var(--font-mono);
  font-size: clamp(1.5rem, 4.2vw, 2.3rem);
  line-height: 1;
  color: var(--signal-500);
  font-variant-numeric: tabular-nums;
}

.page-faq .faq-head__title {
  margin: 0;
  font-size: clamp(1.25rem, 2.6vw, 1.85rem);
  font-weight: 400;
  line-height: 1.3;
  letter-spacing: -0.005em;
  color: var(--text-900);
}

.page-faq .faq-head__note {
  max-width: 68ch;
  margin: 16px 0 0;
  font-size: 15px;
  line-height: 1.85;
  color: var(--text-300);
}

/* ---------- 问答条目 ---------- */
.page-faq .faq-list {
  margin-top: 22px;
  border-top: 1px solid var(--line-500);
}

.page-faq .faq-item {
  border-bottom: 1px solid var(--line-500);
}

.page-faq .faq-item > summary {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr) 16px;
  gap: 10px;
  align-items: start;
  padding: 17px 0;
  cursor: pointer;
  list-style: none;
}

.page-faq .faq-item > summary::-webkit-details-marker {
  display: none;
}

.page-faq .faq-item > summary:focus-visible {
  outline: 2px solid var(--signal-500);
  outline-offset: 3px;
}

.page-faq .faq-item__num {
  padding-top: 3px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan-400);
  font-variant-numeric: tabular-nums;
}

.page-faq .faq-item__q {
  font-size: 16px;
  font-weight: 500;
  line-height: 1.7;
  color: var(--text-900);
}

.page-faq .faq-item__mark {
  position: relative;
  width: 14px;
  height: 14px;
  margin-top: 8px;
}

.page-faq .faq-item__mark::before,
.page-faq .faq-item__mark::after {
  content: "";
  position: absolute;
  background: var(--text-300);
  transition: transform 0.2s var(--ease), opacity 0.2s var(--ease);
}

.page-faq .faq-item__mark::before {
  left: 0;
  top: 6px;
  width: 14px;
  height: 1px;
}

.page-faq .faq-item__mark::after {
  left: 6px;
  top: 0;
  width: 1px;
  height: 14px;
}

.page-faq .faq-item[open] .faq-item__mark::after {
  transform: scaleY(0);
  opacity: 0;
}

.page-faq .faq-item__body {
  padding: 0 0 22px 44px;
}

.page-faq .faq-item__answer {
  max-width: 64ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--text-300);
}

.page-faq .faq-item__conclusion {
  display: block;
  margin-bottom: 4px;
  color: var(--text-900);
  font-weight: 500;
}

.page-faq .faq-item__next {
  margin: 12px 0 0;
  font-size: 13px;
  line-height: 1.8;
  color: var(--cyan-400);
}

.page-faq .faq-item__next a {
  color: var(--cyan-400);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, 0.35);
}

.page-faq .faq-item__next a:hover {
  border-bottom-color: var(--cyan-400);
}

/* ---------- 图文分栏 ---------- */
.page-faq .faq-split {
  display: grid;
  gap: 28px;
}

.page-faq .faq-figure {
  margin: 0;
}

.page-faq .faq-figure--wide {
  margin-top: 26px;
}

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

.page-faq .faq-figure .og-img__caption {
  margin-top: 10px;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: 0.02em;
  color: var(--text-300);
}

/* ---------- 对照双栏 ---------- */
.page-faq .faq-compare {
  display: grid;
  grid-template-columns: 1fr;
  margin-top: 30px;
  border: 1px solid var(--line-500);
  border-radius: var(--radius-panel);
  overflow: hidden;
  box-shadow: var(--shadow-panel);
}

.page-faq .faq-compare__col {
  padding: 22px 20px 26px;
}

.page-faq .faq-compare__col--ink {
  background: var(--ink-850);
}

.page-faq .faq-compare__col--paper {
  background: var(--paper-50);
  color: var(--faq-paper-ink);
  border-top: 1px solid var(--line-500);
}

.page-faq .faq-compare__title {
  margin: 0 0 6px;
  font-family: var(--font-mono);
  font-size: 12.5px;
  letter-spacing: 0.06em;
  color: var(--cyan-400);
}

.page-faq .faq-compare__col--paper .faq-compare__title {
  color: var(--cyan-700);
}

.page-faq .faq-compare__sub {
  margin: 0 0 16px;
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--text-300);
}

.page-faq .faq-compare__col--paper .faq-compare__sub {
  color: var(--faq-paper-muted);
}

.page-faq .faq-compare__list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.page-faq .faq-compare__row {
  display: grid;
  grid-template-columns: 34px minmax(0, 1fr);
  gap: 12px;
  padding: 11px 0;
  border-top: 1px solid var(--line-500);
}

.page-faq .faq-compare__col--paper .faq-compare__row {
  border-top-color: var(--paper-200);
}

.page-faq .faq-compare__idx {
  padding-top: 2px;
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--signal-500);
  font-variant-numeric: tabular-nums;
}

.page-faq .faq-compare__txt {
  font-size: 14.5px;
  line-height: 1.8;
  color: var(--text-300);
}

.page-faq .faq-compare__col--paper .faq-compare__txt {
  color: var(--faq-paper-muted);
}

.page-faq .faq-compare__key {
  display: block;
  margin-bottom: 2px;
  font-size: 14.5px;
  font-weight: 500;
  color: var(--text-900);
}

.page-faq .faq-compare__col--paper .faq-compare__key {
  color: var(--faq-paper-ink);
}

/* ---------- 状态说明 ---------- */
.page-faq .faq-states {
  display: grid;
  gap: 12px;
  margin-top: 26px;
}

.page-faq .faq-state {
  padding: 18px 18px 20px;
  border: 1px solid var(--line-500);
  border-radius: var(--radius-panel);
  background: var(--ink-850);
  box-shadow: var(--shadow-panel);
}

.page-faq .faq-state__desc {
  margin: 12px 0 0;
  font-size: 14px;
  line-height: 1.8;
  color: var(--text-300);
}

/* ---------- 收束 ---------- */
.page-faq .faq-cta {
  margin-top: 26px;
  padding: 26px 22px 28px;
  border: 1px solid var(--line-500);
  border-radius: var(--radius-panel);
  background: var(--ink-850);
}

.page-faq .faq-cta__text {
  max-width: 66ch;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.9;
  color: var(--text-300);
}

.page-faq .faq-cta__list {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin: 22px 0 0;
  padding: 0;
  list-style: none;
}

.page-faq .faq-cta__mail {
  margin: 20px 0 0;
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--text-300);
}

.page-faq .faq-cta__mail a {
  color: var(--cyan-400);
  text-decoration: none;
  border-bottom: 1px solid rgba(34, 211, 238, 0.35);
}

.page-faq .faq-cta__mail a:hover {
  border-bottom-color: var(--cyan-400);
}

/* ---------- 平板 ---------- */
@media (min-width: 760px) {
  .page-faq .faq-states {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* ---------- 桌面 ---------- */
@media (min-width: 1024px) {
  .page-faq .faq-shell {
    grid-template-columns: var(--faq-rail-w) minmax(0, 1fr);
    gap: 48px;
  }

  .page-faq .faq-rail {
    position: sticky;
    top: calc(var(--header-h) + 24px);
    align-self: start;
  }

  .page-faq .faq-rail__list {
    flex-direction: column;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-faq .faq-rail__item {
    border-radius: var(--radius-soft);
    white-space: normal;
  }

  .page-faq .faq-content {
    gap: 88px;
  }

  .page-faq .faq-split {
    grid-template-columns: minmax(0, 1.5fr) minmax(0, 0.72fr);
    gap: 40px;
    align-items: start;
  }

  .page-faq .faq-split .faq-list {
    margin-top: 20px;
  }

  .page-faq .faq-item > summary {
    grid-template-columns: 44px minmax(0, 1fr) 16px;
    gap: 12px;
  }

  .page-faq .faq-item__body {
    padding-left: 56px;
  }
}

@media (min-width: 900px) {
  .page-faq .faq-compare {
    grid-template-columns: 1fr 1fr;
  }

  .page-faq .faq-compare__col--paper {
    border-top: 0;
    border-left: 1px solid var(--line-500);
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-faq .faq-rail__item,
  .page-faq .faq-item__mark::before,
  .page-faq .faq-item__mark::after {
    transition-duration: 0.12s;
  }
}
</main>