/* ===== 使用指南页 · page-faq ===== */

.page-faq {
  --faq-toc-w: 15.5rem;
  --faq-rule: rgba(30, 58, 92, 0.62);
  --faq-rule-soft: rgba(30, 58, 92, 0.34);
  display: block;
  background: var(--yb-void);
  color: var(--yb-body-text);
}

/* ---------- 首屏 ---------- */

.page-faq .faq-hero {
  position: relative;
  padding: clamp(1.5rem, 4vw, 2.5rem) 0 clamp(2.25rem, 5vw, 3.5rem);
  background:
    linear-gradient(180deg, rgba(18, 33, 58, 0.6) 0%, rgba(5, 9, 15, 0) 82%),
    var(--yb-void);
  border-bottom: 1px solid var(--yb-line);
  overflow: hidden;
}

.page-faq .faq-hero::before {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    repeating-linear-gradient(0deg, var(--faq-rule-soft) 0 1px, transparent 1px 96px),
    repeating-linear-gradient(90deg, var(--faq-rule-soft) 0 1px, transparent 1px 96px);
  -webkit-mask-image: linear-gradient(180deg, #000 0%, transparent 90%);
  mask-image: linear-gradient(180deg, #000 0%, transparent 90%);
}

.page-faq .faq-hero .yb-wrap {
  position: relative;
  z-index: 1;
}

.page-faq .faq-hero__grid {
  margin-top: clamp(1.5rem, 4vw, 2.75rem);
  display: grid;
  gap: clamp(1.75rem, 4vw, 2.5rem);
}

.page-faq .faq-hero__title {
  margin: 0.65rem 0 0;
  max-width: 17em;
  color: var(--yb-ink);
}

.page-faq .faq-hero__lede {
  margin-top: 1rem;
  max-width: 36em;
  color: var(--yb-body-text);
}

.page-faq .faq-hero__aside {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  border: 1px solid var(--yb-line);
  background: rgba(11, 20, 32, 0.72);
}

.page-faq .faq-hero__metric {
  padding: clamp(0.85rem, 2.2vw, 1.3rem);
  border-right: 1px solid var(--yb-line);
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0.15rem 0.3rem;
}

.page-faq .faq-hero__metric:last-child {
  border-right: 0;
}

.page-faq .faq-hero__metric-num {
  font-size: clamp(1.55rem, 5vw, 2.4rem);
  line-height: 1;
  color: var(--yb-signal);
  letter-spacing: -0.02em;
}

.page-faq .faq-hero__metric-unit {
  font-family: var(--yb-font-mono);
  font-size: 0.78rem;
  color: var(--yb-signal-dim);
}

.page-faq .faq-hero__metric-label {
  flex: 0 0 100%;
  margin-top: 0.3rem;
  font-size: 0.72rem;
  line-height: 1.45;
  color: var(--yb-muted);
}

@media (min-width: 960px) {
  .page-faq .faq-hero__grid {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: end;
  }
}

/* ---------- 主体骨架 ---------- */

.page-faq .faq-body {
  padding: clamp(2rem, 5vw, 3.25rem) 0 clamp(3rem, 7vw, 5rem);
}

.page-faq .faq-body__inner {
  display: grid;
  gap: clamp(1.75rem, 4vw, 3rem);
}

@media (min-width: 1000px) {
  .page-faq .faq-body__inner {
    grid-template-columns: var(--faq-toc-w) minmax(0, 1fr);
    align-items: start;
    gap: clamp(2.5rem, 5vw, 4.5rem);
  }
}

/* ---------- 环节目录 ---------- */

.page-faq .faq-toc {
  border-top: 1px solid var(--yb-line);
  padding-top: 0.85rem;
}

.page-faq .faq-toc__head {
  margin: 0 0 0.75rem;
  font-family: var(--yb-font-serif);
  font-size: 0.76rem;
  letter-spacing: 0.18em;
  color: var(--yb-muted);
}

.page-faq .faq-toc__list {
  list-style: none;
  margin: 0;
  padding: 0 0 0.4rem;
  display: flex;
  gap: 0.5rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: thin;
}

.page-faq .faq-toc__list::-webkit-scrollbar {
  height: 4px;
}

.page-faq .faq-toc__list::-webkit-scrollbar-thumb {
  background: var(--yb-line-strong);
}

.page-faq .faq-toc__link {
  flex: 0 0 auto;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  min-height: var(--yb-tap);
  padding: 0 0.85rem;
  border: 1px solid var(--yb-line);
  color: var(--yb-body-text);
  text-decoration: none;
  white-space: nowrap;
  font-size: 0.85rem;
  transition: border-color 160ms ease, color 160ms ease, background 160ms ease;
}

.page-faq .faq-toc__link:hover,
.page-faq .faq-toc__link:focus-visible {
  border-color: var(--yb-signal-dim);
  color: var(--yb-ink);
}

.page-faq .faq-toc__num {
  font-size: 0.74rem;
  letter-spacing: 0.08em;
  color: var(--yb-signal-dim);
}

@media (min-width: 1000px) {
  .page-faq .faq-toc {
    position: sticky;
    top: 7.5rem;
    max-height: calc(100vh - 9.5rem);
    overflow: auto;
  }

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

  .page-faq .faq-toc__link {
    width: 100%;
    min-height: 0;
    padding: 0.7rem 0.5rem 0.7rem 0.85rem;
    border: 0;
    border-bottom: 1px solid var(--faq-rule-soft);
    border-left: 2px solid transparent;
    white-space: normal;
    align-items: baseline;
  }

  .page-faq .faq-toc__link:hover,
  .page-faq .faq-toc__link:focus-visible {
    background: rgba(18, 33, 58, 0.55);
  }

  .page-faq .faq-toc__link[aria-current="true"] {
    border-left-color: var(--yb-signal);
    background: linear-gradient(90deg, var(--yb-signal-a12), transparent 72%);
    color: var(--yb-ink);
  }
}

/* ---------- 章节 ---------- */

.page-faq .faq-chapters {
  display: grid;
  gap: clamp(2.5rem, 6vw, 4.5rem);
}

.page-faq .faq-chapter {
  scroll-margin-top: 6.5rem;
}

.page-faq .faq-chapter__head {
  display: grid;
  gap: 0.55rem;
  padding-bottom: 1.2rem;
  border-bottom: 1px solid var(--yb-line);
}

.page-faq .faq-chapter__bar {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.page-faq .faq-chapter__num {
  font-size: 0.9rem;
  letter-spacing: 0.16em;
  color: var(--yb-signal);
}

.page-faq .faq-chapter__rule {
  flex: 1 1 auto;
  height: 1px;
  background: linear-gradient(90deg, var(--yb-signal-a35), transparent 85%);
}

.page-faq .faq-chapter__title {
  margin: 0;
  color: var(--yb-ink);
}

.page-faq .faq-chapter__intro {
  margin: 0;
  max-width: 40em;
  color: var(--yb-muted);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ---------- 三步上手 ---------- */

.page-faq .faq-steps {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  gap: 1px;
  background: var(--yb-line);
  border: 1px solid var(--yb-line);
}

.page-faq .faq-step {
  position: relative;
  background: var(--yb-panel);
  padding: clamp(1.1rem, 3vw, 1.6rem);
  display: grid;
  gap: 0.55rem;
  align-content: start;
}

.page-faq .faq-step::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--yb-signal);
  opacity: 0.85;
}

.page-faq .faq-step__idx {
  font-size: 0.82rem;
  letter-spacing: 0.16em;
  color: var(--yb-signal-dim);
}

.page-faq .faq-step__title {
  margin: 0;
  color: var(--yb-ink);
  font-size: 1.02rem;
  line-height: 1.5;
}

.page-faq .faq-step p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.72;
  color: var(--yb-body-text);
}

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

/* ---------- 排查步骤 ---------- */

.page-faq .faq-trace {
  list-style: none;
  margin: 1.75rem 0 0;
  padding: 0;
  display: grid;
  gap: 1.35rem;
  counter-reset: faqtrace;
}

.page-faq .faq-trace__item {
  position: relative;
  padding-left: 2.4rem;
}

.page-faq .faq-trace__item::before {
  counter-increment: faqtrace;
  content: counter(faqtrace, decimal-leading-zero);
  position: absolute;
  left: 0;
  top: 0.05rem;
  font-family: var(--yb-font-mono);
  font-size: 0.76rem;
  line-height: 1.2;
  letter-spacing: 0.06em;
  color: var(--yb-signal);
  border: 1px solid var(--yb-signal-a35);
  padding: 0.16rem 0.34rem;
  background: rgba(18, 33, 58, 0.7);
}

.page-faq .faq-trace__item:not(:last-child)::after {
  content: "";
  position: absolute;
  left: 1.12rem;
  top: 2rem;
  bottom: -1.3rem;
  width: 1px;
  background: var(--yb-line);
}

.page-faq .faq-trace__title {
  margin: 0 0 0.45rem;
  color: var(--yb-ink);
  font-size: 1.02rem;
  line-height: 1.5;
}

.page-faq .faq-trace__item p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.72;
  color: var(--yb-body-text);
}

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

  .page-faq .faq-trace__item {
    padding: 1.45rem 1.5rem 1.5rem 0;
    border-top: 1px solid var(--yb-line);
  }

  .page-faq .faq-trace__item:not(:first-child) {
    padding-left: 1.5rem;
  }

  .page-faq .faq-trace__item:not(:last-child) {
    border-right: 1px solid var(--yb-line);
  }

  .page-faq .faq-trace__item::before {
    position: static;
    display: inline-block;
    margin-bottom: 0.8rem;
  }

  .page-faq .faq-trace__item:not(:last-child)::after {
    display: none;
  }
}

/* ---------- 图文块 ---------- */

.page-faq .faq-figure {
  margin: 1.75rem 0 0;
}

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

/* ---------- 问答条目 ---------- */

.page-faq .faq-qa {
  margin-top: 1.5rem;
  border-top: 1px solid var(--yb-line);
}

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

.page-faq .faq-item__q {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 1.05rem 0.2rem 1.05rem 0;
  min-height: var(--yb-tap);
  cursor: pointer;
  list-style: none;
  color: var(--yb-ink);
  font-weight: 700;
  font-size: 0.98rem;
  line-height: 1.6;
  transition: color 160ms ease;
}

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

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

.page-faq .faq-item__q:hover,
.page-faq .faq-item__q:focus-visible {
  color: var(--yb-signal);
}

.page-faq .faq-item__mark {
  flex: 0 0 auto;
  width: 2px;
  align-self: stretch;
  min-height: 1.2rem;
  margin-top: 0.15rem;
  background: var(--yb-line-strong);
  transition: background 160ms ease;
}

.page-faq .faq-item[open] .faq-item__mark {
  background: var(--yb-signal);
}

.page-faq .faq-item__text {
  flex: 1 1 auto;
}

.page-faq .faq-item__q::after {
  content: "+";
  flex: 0 0 auto;
  margin-left: 0.5rem;
  font-family: var(--yb-font-mono);
  font-size: 1.05rem;
  line-height: 1.2;
  color: var(--yb-signal-dim);
}

.page-faq .faq-item[open] .faq-item__q::after {
  content: "−";
  color: var(--yb-signal);
}

.page-faq .faq-item__a {
  padding: 0 0 1.2rem 0.9rem;
}

.page-faq .faq-item__a p {
  margin: 0 0 0.65rem;
  max-width: 42em;
  font-size: 0.93rem;
  line-height: 1.76;
  color: var(--yb-body-text);
}

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

/* ---------- 联系与反馈 ---------- */

.page-faq .faq-contact {
  margin-top: 1.75rem;
  display: grid;
  gap: 1.75rem;
}

.page-faq .faq-contact__list {
  margin: 0;
  display: grid;
  gap: 1px;
  background: var(--yb-line);
  border: 1px solid var(--yb-line);
}

.page-faq .faq-contact__row {
  background: var(--yb-panel);
  padding: clamp(1rem, 2.5vw, 1.35rem);
  display: grid;
  gap: 0.4rem;
}

.page-faq .faq-contact__key {
  font-family: var(--yb-font-serif);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  color: var(--yb-muted);
}

.page-faq .faq-contact__val {
  margin: 0;
  display: grid;
  gap: 0.3rem;
}

.page-faq .faq-contact__link {
  color: var(--yb-signal);
  font-family: var(--yb-font-mono);
  font-size: clamp(1rem, 3.4vw, 1.25rem);
  letter-spacing: 0.01em;
  text-decoration: none;
  border-bottom: 1px solid var(--yb-signal-a35);
  padding-bottom: 0.15rem;
  width: fit-content;
  word-break: break-all;
}

.page-faq .faq-contact__link:hover,
.page-faq .faq-contact__link:focus-visible {
  border-bottom-color: var(--yb-signal);
}

.page-faq .faq-contact__num {
  font-size: clamp(1rem, 3.4vw, 1.2rem);
  color: var(--yb-ink);
}

.page-faq .faq-contact__hint {
  font-size: 0.84rem;
  line-height: 1.6;
  color: var(--yb-muted);
}

.page-faq .faq-contact__side {
  border: 1px solid var(--yb-line);
  border-left: 3px solid var(--yb-action);
  background: rgba(18, 33, 58, 0.55);
  padding: clamp(1.1rem, 3vw, 1.5rem);
}

.page-faq .faq-contact__side-title {
  margin: 0 0 0.85rem;
  font-family: var(--yb-font-serif);
  font-size: 0.82rem;
  letter-spacing: 0.14em;
  color: var(--yb-amber);
}

.page-faq .faq-contact__side-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.68rem;
}

.page-faq .faq-contact__side-list li {
  position: relative;
  padding-left: 1rem;
  font-size: 0.9rem;
  line-height: 1.68;
  color: var(--yb-body-text);
}

.page-faq .faq-contact__side-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.68em;
  width: 5px;
  height: 5px;
  background: var(--yb-action);
}

.page-faq .faq-contact__side-note {
  margin: 1.1rem 0 0;
  padding-top: 0.9rem;
  border-top: 1px solid var(--yb-line-soft);
  font-size: 0.83rem;
  line-height: 1.65;
  color: var(--yb-muted);
}

@media (min-width: 860px) {
  .page-faq .faq-contact {
    grid-template-columns: minmax(0, 7fr) minmax(0, 5fr);
    align-items: start;
    gap: 2rem;
  }
}

/* ---------- 返回顶部 ---------- */

.page-faq .yb-totop {
  position: fixed;
  right: clamp(0.75rem, 3vw, 1.75rem);
  bottom: clamp(0.9rem, 3vw, 1.75rem);
  z-index: 40;
  min-height: var(--yb-tap);
  min-width: var(--yb-tap);
  padding: 0 1rem;
  border: 1px solid var(--yb-signal-a35);
  background: var(--yb-void-a92);
  color: var(--yb-signal);
  font-family: var(--yb-font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  cursor: pointer;
}

.page-faq .yb-totop:hover,
.page-faq .yb-totop:focus-visible {
  border-color: var(--yb-signal);
  background: var(--yb-elevated);
}

/* ---------- 窄屏收敛 ---------- */

@media (max-width: 420px) {
  .page-faq .faq-hero__aside {
    grid-template-columns: minmax(0, 1fr);
  }

  .page-faq .faq-hero__metric {
    border-right: 0;
    border-bottom: 1px solid var(--yb-line);
    display: flex;
    align-items: baseline;
    gap: 0.35rem;
  }

  .page-faq .faq-hero__metric:last-child {
    border-bottom: 0;
  }

  .page-faq .faq-hero__metric-label {
    flex: 1 1 auto;
    margin-top: 0;
    text-align: right;
  }
}

@media (prefers-reduced-motion: reduce) {
  .page-faq .faq-toc__link,
  .page-faq .faq-item__mark,
  .page-faq .faq-item__q {
    transition: none;
  }
}