/* ===== 答疑中心 · page-faq ===== */

.page-faq {
  --faq-rail: 264px;
  --faq-line: rgba(30, 69, 96, 0.85);
  background: var(--ink-blue);
  color: var(--paper);
}

/* ---------- 首屏 ---------- */

.page-faq .faq-hero {
  position: relative;
  isolation: isolate;
  overflow: hidden;
  padding-block: 28px 76px;
}

.page-faq .faq-hero::before {
  content: "";
  position: absolute;
  z-index: -1;
  top: -200px;
  right: -100px;
  width: min(680px, 92vw);
  height: 680px;
  background: radial-gradient(closest-side, rgba(53, 242, 214, 0.15), rgba(53, 242, 214, 0));
  pointer-events: none;
}

.page-faq .faq-hero .crumb {
  margin-bottom: 30px;
}

.page-faq .faq-hero h1 {
  margin: 0;
  font-size: clamp(38px, 7.6vw, 96px);
  font-weight: 900;
  line-height: 1.04;
  letter-spacing: -0.02em;
  color: var(--paper);
}

.page-faq .faq-hero .lede {
  max-width: 62ch;
  margin: 26px 0 0;
  font-size: var(--step-lg);
  line-height: 1.75;
  color: var(--mist);
}

.page-faq .faq-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(168px, 1fr));
  gap: 1px;
  margin: 46px 0 0;
  padding: 0;
  list-style: none;
  background: var(--orbit);
  border: 1px solid var(--orbit);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-faq .faq-stats li {
  display: flex;
  flex-direction: column;
  gap: 7px;
  padding: 20px 22px;
  background: var(--ink-blue);
}

.page-faq .faq-stats .stat-num {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-2xl);
  line-height: 1;
  letter-spacing: -0.01em;
  color: var(--cyan);
}

.page-faq .faq-stats .stat-label {
  font-size: var(--step-sm);
  letter-spacing: 0.03em;
  color: var(--mist);
}

/* ---------- 问答主体 ---------- */

.page-faq .faq-body {
  border-top: 1px solid var(--orbit);
  padding-bottom: 96px;
}

.page-faq .faq-tools {
  position: sticky;
  top: var(--bar-h);
  z-index: 6;
  margin-bottom: 40px;
  padding: 14px 0 16px;
  background: var(--ink-blue);
  border-bottom: 1px solid var(--faq-line);
}

.page-faq .filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.page-faq .filter-chip {
  font-family: var(--font-sans);
  cursor: pointer;
}

.page-faq .is-filtered-out {
  display: none !important;
}

.page-faq .faq-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 34px;
}

/* ---------- 主题索引 ---------- */

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

.page-faq .faq-index__title {
  margin: 0 0 12px;
  font-size: var(--step-xs);
  font-weight: 500;
  letter-spacing: 0.16em;
  color: var(--mute);
}

.page-faq .topic-nav {
  display: flex;
  gap: 8px;
  margin: 0;
  padding: 0 0 10px;
  list-style: none;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-faq .topic-nav li {
  flex: 0 0 auto;
}

.page-faq .topic-nav__link {
  display: flex;
  align-items: baseline;
  gap: 9px;
  padding: 10px 14px;
  border: 1px solid var(--faq-line);
  border-radius: 999px;
  font-size: var(--step-md);
  line-height: 1.3;
  color: var(--mist);
  text-decoration: none;
  white-space: nowrap;
  transition: color 200ms var(--ease), border-color 200ms var(--ease), background-color 200ms var(--ease);
}

.page-faq .topic-nav__link:hover,
.page-faq .topic-nav__link:focus-visible {
  color: var(--paper);
  border-color: var(--cyan);
}

.page-faq .topic-nav__no {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-xs);
  letter-spacing: 0.1em;
  color: var(--mute);
}

/* ---------- 分组 ---------- */

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

.page-faq .topic {
  scroll-margin-top: calc(var(--bar-h) + 108px);
}

.page-faq .topic + .topic {
  margin-top: 64px;
  padding-top: 44px;
  border-top: 1px solid var(--faq-line);
}

.page-faq .topic__head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 6px 16px;
  margin-bottom: 24px;
}

.page-faq .topic__no {
  padding-top: 9px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-sm);
  letter-spacing: 0.12em;
  color: var(--cyan);
}

.page-faq .topic:target .topic__no {
  color: var(--amber);
}

.page-faq .topic__title {
  margin: 0;
  font-size: clamp(24px, 3.4vw, 34px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.01em;
  color: var(--paper);
}

.page-faq .topic__intro {
  margin: 10px 0 0;
  max-width: 58ch;
  font-size: var(--step-md);
  line-height: 1.75;
  color: var(--mist);
}

/* ---------- 图示 ---------- */

.page-faq .path-figure {
  margin: 0 0 24px;
  padding: 12px;
  background: var(--paper);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-faq .path-figure img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: calc(var(--r-md) - 8px);
}

.page-faq .path-figure figcaption {
  padding: 12px 6px 4px;
  font-size: var(--step-xs);
  line-height: 1.7;
  letter-spacing: 0.02em;
  color: #4b5460;
}

.page-faq .device-figure {
  margin: 0 0 24px;
  background: var(--deep-blue);
  border: 1px solid var(--faq-line);
  border-radius: var(--r-md);
  overflow: hidden;
}

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

.page-faq .device-figure figcaption {
  padding: 12px 16px 14px;
  font-size: var(--step-xs);
  line-height: 1.7;
  color: var(--mist);
}

/* ---------- 问答条目 ---------- */

.page-faq .qa-list {
  display: grid;
  gap: 10px;
}

.page-faq .qa {
  background: var(--deep-blue);
  border: 1px solid var(--faq-line);
  border-radius: var(--r-md);
  transition: border-color 200ms var(--ease), background-color 200ms var(--ease);
}

.page-faq .qa:hover {
  border-color: rgba(53, 242, 214, 0.34);
}

.page-faq .qa[open] {
  border-color: rgba(53, 242, 214, 0.55);
  background:
    linear-gradient(180deg, rgba(53, 242, 214, 0.06), rgba(53, 242, 214, 0) 46%),
    var(--deep-blue);
}

.page-faq .qa > summary {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  gap: 14px;
  align-items: start;
  padding: 18px 20px;
  list-style: none;
  cursor: pointer;
}

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

.page-faq .qa > summary:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -3px;
  border-radius: var(--r-md);
}

.page-faq .qa__no {
  padding-top: 5px;
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: var(--step-xs);
  letter-spacing: 0.1em;
  color: var(--mute);
  transition: color 200ms var(--ease);
}

.page-faq .qa[open] .qa__no {
  color: var(--cyan);
}

.page-faq .qa__text {
  font-size: var(--step-lg);
  font-weight: 600;
  line-height: 1.5;
  letter-spacing: -0.005em;
  color: var(--paper);
}

.page-faq .qa__sign {
  position: relative;
  width: 16px;
  height: 16px;
  margin-top: 6px;
}

.page-faq .qa__sign::before,
.page-faq .qa__sign::after {
  content: "";
  position: absolute;
  background: var(--cyan);
  border-radius: 2px;
  transition: transform 220ms var(--ease), opacity 220ms var(--ease);
}

.page-faq .qa__sign::before {
  left: 0;
  right: 0;
  top: 7px;
  height: 2px;
}

.page-faq .qa__sign::after {
  top: 0;
  bottom: 0;
  left: 7px;
  width: 2px;
}

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

.page-faq .qa__a {
  padding: 14px 20px 20px;
  border-top: 1px solid rgba(30, 69, 96, 0.6);
  font-size: var(--step-md);
  line-height: 1.8;
  color: var(--mist);
}

.page-faq .qa__a p {
  margin: 0;
  max-width: 66ch;
}

.page-faq .qa__a p + p {
  margin-top: 10px;
}

.page-faq .qa__a ul {
  margin: 0;
  padding-left: 18px;
  max-width: 66ch;
}

.page-faq .qa__a li + li {
  margin-top: 8px;
}

.page-faq .qa__a a {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
}

.page-faq .qa__a a:hover {
  color: var(--amber);
}

.page-faq .k {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--paper);
}

@keyframes faq-answer-in {
  from {
    opacity: 0;
    transform: translateY(-6px);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

.page-faq .qa[open] .qa__a {
  animation: faq-answer-in 220ms var(--ease);
}

/* ---------- 收尾 ---------- */

.page-faq .faq-tail {
  padding-block: 76px;
  background: var(--paper);
  color: var(--ink);
}

.page-faq .faq-tail h2 {
  margin: 0 0 12px;
  font-size: clamp(26px, 3.6vw, 42px);
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.015em;
  color: var(--ink);
}

.page-faq .tail-lede {
  margin: 0 0 34px;
  max-width: 58ch;
  font-size: var(--step-lg);
  line-height: 1.7;
  color: #4b5460;
}

.page-faq .tail-links {
  display: grid;
  gap: 1px;
  background: rgba(11, 14, 19, 0.14);
  border: 1px solid rgba(11, 14, 19, 0.14);
  border-radius: var(--r-md);
  overflow: hidden;
}

.page-faq .tail-link {
  display: block;
  padding: 24px 22px 26px;
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  transition: background-color 200ms var(--ease);
}

.page-faq .tail-link:hover {
  background: #ffffff;
}

.page-faq .tail-link:focus-visible {
  outline: 2px solid var(--ink-blue);
  outline-offset: -4px;
}

.page-faq .tail-link__title {
  display: block;
  font-size: var(--step-lg);
  font-weight: 700;
  color: var(--ink);
}

.page-faq .tail-link__desc {
  display: block;
  margin-top: 9px;
  font-size: var(--step-sm);
  line-height: 1.7;
  color: #4b5460;
}

.page-faq .tail-link__arrow {
  display: block;
  margin-top: 16px;
  font-family: var(--font-mono);
  font-size: var(--step-xs);
  letter-spacing: 0.12em;
  color: var(--cyan-ink);
}

/* ---------- 响应式 ---------- */

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

@media (min-width: 980px) {
  .page-faq .faq-layout {
    grid-template-columns: var(--faq-rail) minmax(0, 1fr);
    gap: 64px;
    align-items: start;
  }

  .page-faq .faq-index {
    position: sticky;
    top: calc(var(--bar-h) + 96px);
    align-self: start;
  }

  .page-faq .topic-nav {
    display: block;
    padding: 0;
    overflow: visible;
    border-left: 1px solid var(--faq-line);
  }

  .page-faq .topic-nav__link {
    margin-left: -1px;
    padding: 10px 0 10px 16px;
    border: 0;
    border-left: 2px solid transparent;
    border-radius: 0;
    white-space: normal;
  }

  .page-faq .topic-nav__link:hover,
  .page-faq .topic-nav__link:focus-visible {
    color: var(--paper);
    border-left-color: var(--cyan);
    background: linear-gradient(90deg, rgba(53, 242, 214, 0.09), rgba(53, 242, 214, 0) 72%);
  }
}

@media (min-width: 1080px) {
  .page-faq .tail-links {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }
}

@media (max-width: 560px) {
  .page-faq .faq-hero {
    padding-block: 22px 58px;
  }

  .page-faq .faq-stats li {
    padding: 16px 18px;
  }

  .page-faq .topic + .topic {
    margin-top: 48px;
    padding-top: 34px;
  }

  .page-faq .qa > summary {
    gap: 10px;
    padding: 15px 15px;
  }

  .page-faq .qa__text {
    font-size: var(--step-md);
  }

  .page-faq .qa__a {
    padding: 12px 15px 16px;
  }

  .page-faq .faq-tail {
    padding-block: 56px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-faq .qa[open] .qa__a {
    animation: none;
  }

  .page-faq .qa__sign::before,
  .page-faq .qa__sign::after,
  .page-faq .qa,
  .page-faq .tail-link,
  .page-faq .topic-nav__link {
    transition: none;
  }
}