.page-faq {
  --faq-rail: 276px;
  --faq-gap: clamp(30px, 5vw, 68px);
  --faq-answer: #B9BDC2;
}

/* ---------- 首屏 ---------- */

.page-faq .faq-hero {
  position: relative;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
  padding-top: clamp(44px, 8vw, 96px);
  padding-bottom: clamp(30px, 5vw, 56px);
  background:
    radial-gradient(120% 150% at 92% -10%, rgba(0, 200, 255, .12), transparent 58%),
    radial-gradient(95% 120% at 0% 100%, rgba(255, 77, 0, .16), transparent 62%),
    var(--bg);
}

.page-faq .faq-hero__label {
  margin-top: clamp(20px, 3vw, 32px);
  color: var(--muted);
}

.page-faq .faq-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(38px, 8.4vw, 84px);
  line-height: 1;
  letter-spacing: -0.035em;
  color: var(--text);
}

.page-faq .faq-hero__title em {
  font-style: normal;
  color: var(--accent);
}

.page-faq .faq-hero__lead {
  margin: clamp(18px, 3vw, 28px) 0 0;
  max-width: 62ch;
  font-size: clamp(15.5px, 1.7vw, 17px);
  line-height: 1.85;
  color: var(--muted);
}

/* ---------- 双栏骨架 ---------- */

.page-faq .faq-shell {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: var(--faq-gap);
  padding-top: clamp(34px, 6vw, 74px);
  padding-bottom: clamp(60px, 10vw, 120px);
}

.page-faq .faq-body {
  min-width: 0;
}

/* ---------- 左侧索引 ---------- */

.page-faq .faq-rail {
  border: 1px solid var(--line);
  background: var(--surface-2);
  padding: 20px 20px 22px;
}

.page-faq .faq-rail__search-label {
  display: block;
  margin-bottom: 8px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--muted);
}

.page-faq .faq-rail__input {
  box-sizing: border-box;
  width: 100%;
  padding: 11px 12px;
  background: var(--bg);
  border: 1px solid var(--line);
  clip-path: var(--cut-sm);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 14px;
}

.page-faq .faq-rail__input::placeholder {
  color: #5F646A;
}

.page-faq .faq-rail__input:focus-visible {
  border-color: var(--accent-3);
  box-shadow: 0 0 0 2px rgba(0, 255, 200, .35);
  outline: none;
}

.page-faq .faq-rail__title {
  margin: 24px 0 10px;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: .14em;
  color: var(--muted);
}

.page-faq .faq-rail__list {
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--line);
}

.page-faq .faq-rail__link {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line);
  color: var(--text);
  font-size: 14.5px;
  line-height: 1.5;
  text-decoration: none;
  transition: color .16s ease, padding-left .16s ease;
}

.page-faq .faq-rail__link:hover,
.page-faq .faq-rail__link:focus-visible {
  color: var(--accent-2);
  padding-left: 4px;
}

.page-faq .faq-rail__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 11.5px;
  letter-spacing: .06em;
  color: var(--accent);
}

.page-faq .faq-rail__note {
  margin: 18px 0 0;
  font-size: 13px;
  line-height: 1.7;
  color: var(--muted);
}

.page-faq .faq-rail__note a {
  color: var(--accent-2);
  text-decoration: none;
  border-bottom: 1px solid rgba(0, 200, 255, .4);
}

/* ---------- 分组 ---------- */

.page-faq .faq-group + .faq-group {
  margin-top: clamp(48px, 7vw, 88px);
  padding-top: clamp(6px, 1vw, 12px);
}

.page-faq .faq-group__head {
  margin-bottom: clamp(18px, 3vw, 26px);
}

.page-faq .faq-group__title {
  margin: 10px 0 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(24px, 3.4vw, 38px);
  line-height: 1.12;
  letter-spacing: -0.02em;
  color: var(--text);
}

.page-faq .faq-group__sub {
  margin: 10px 0 0;
  max-width: 58ch;
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--muted);
}

/* ---------- 图 ---------- */

.page-faq .faq-figure {
  margin: 0 0 clamp(20px, 3vw, 30px);
}

.page-faq .faq-figure .figure__frame {
  border: 1px solid var(--line);
  background: var(--surface-2);
}

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

/* ---------- 折叠问答 ---------- */

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

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

.page-faq .faq-item__q {
  position: relative;
  display: flex;
  align-items: baseline;
  gap: 12px;
  padding: 17px 40px 17px 0;
  cursor: pointer;
  list-style: none;
  color: var(--text);
  font-size: clamp(15.5px, 1.7vw, 17px);
  font-weight: 700;
  line-height: 1.55;
  transition: color .16s ease;
}

.page-faq .faq-item__q::-webkit-details-marker {
  display: none;
}

.page-faq .faq-item__q::marker {
  content: "";
}

.page-faq .faq-item__q:hover {
  color: var(--accent-2);
}

.page-faq .faq-item[open] .faq-item__q {
  color: var(--accent);
}

.page-faq .faq-item__num {
  flex: none;
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .06em;
  color: var(--muted);
}

.page-faq .faq-item[open] .faq-item__num {
  color: var(--accent-3);
}

.page-faq .faq-item__sign {
  position: absolute;
  right: 6px;
  top: 22px;
  width: 14px;
  height: 14px;
}

.page-faq .faq-item__sign::before,
.page-faq .faq-item__sign::after {
  content: "";
  position: absolute;
  background: var(--accent);
  transition: transform .2s ease, opacity .2s ease;
}

.page-faq .faq-item__sign::before {
  left: 0;
  top: 6.25px;
  width: 14px;
  height: 1.5px;
}

.page-faq .faq-item__sign::after {
  left: 6.25px;
  top: 0;
  width: 1.5px;
  height: 14px;
}

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

.page-faq .faq-item__a {
  max-width: 68ch;
  padding: 0 0 22px;
  color: var(--faq-answer);
  font-size: 15.5px;
  line-height: 1.85;
  animation: faq-open .22s ease both;
}

.page-faq .faq-item__a p {
  margin: 0 0 10px;
}

.page-faq .faq-item__a p:last-child {
  margin-bottom: 0;
}

.page-faq .faq-item__a ul {
  display: grid;
  gap: 7px;
  margin: 10px 0 0;
  padding: 0;
  list-style: none;
}

.page-faq .faq-item__a li {
  position: relative;
  padding-left: 16px;
}

.page-faq .faq-item__a li::before {
  content: "";
  position: absolute;
  left: 0;
  top: .74em;
  width: 7px;
  height: 1px;
  background: var(--accent-3);
}

@keyframes faq-open {
  from {
    opacity: 0;
    transform: translateY(-3px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* ---------- 术语卡 ---------- */

.page-faq .faq-terms {
  display: grid;
  gap: 1px;
  margin: 0 0 clamp(20px, 3vw, 30px);
  background: rgba(26, 21, 18, .22);
  border: 1px solid rgba(26, 21, 18, .22);
  clip-path: var(--cut-md);
}

.page-faq .faq-term {
  background: var(--paper);
  padding: 16px 18px;
}

.page-faq .faq-term__key {
  display: block;
  margin-bottom: 6px;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: .04em;
  color: var(--paper-ink);
}

.page-faq .faq-term__val {
  display: block;
  font-size: 14px;
  line-height: 1.7;
  color: var(--paper-muted);
}

/* ---------- 收尾条 ---------- */

.page-faq .faq-strip {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 16px 26px;
  margin-top: clamp(30px, 5vw, 52px);
  padding: clamp(20px, 3vw, 30px);
  border: 1px solid var(--line);
  background: var(--surface);
  clip-path: var(--cut-md);
}

.page-faq .faq-strip__text {
  flex: 1 1 260px;
  margin: 0;
  font-size: 15.5px;
  line-height: 1.7;
  color: var(--text);
}

.page-faq .faq-strip__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 720px) {
  .page-faq .faq-terms {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (min-width: 1000px) {
  .page-faq .faq-shell {
    grid-template-columns: var(--faq-rail) minmax(0, 1fr);
  }

  .page-faq .faq-rail {
    position: sticky;
    top: 92px;
    align-self: start;
  }
}

@media (max-width: 480px) {
  .page-faq .faq-item__q {
    padding-right: 30px;
  }

  .page-faq .faq-item__sign {
    top: 26px;
  }

  .page-faq .faq-item__a {
    font-size: 15px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-faq .faq-item__a {
    animation: none;
  }

  .page-faq .faq-item__sign::before,
  .page-faq .faq-item__sign::after,
  .page-faq .faq-rail__link {
    transition: none;
  }
}