/* ============================================================
   使用指南 · page-faq
   ============================================================ */

.page-faq {
  --faq-sec: clamp(56px, 8vw, 108px);
  --faq-hairline: 1px solid var(--line);
  display: block;
  background: var(--ink);
  color: var(--ivory);
}

/* ---------- 首屏 ---------- */

.page-faq .faq-hero {
  position: relative;
  padding-block: clamp(40px, 6vw, 84px) clamp(32px, 4vw, 56px);
  border-bottom: var(--faq-hairline);
  background-image:
    linear-gradient(to right, rgba(23, 65, 90, 0.34) 1px, transparent 1px),
    linear-gradient(to bottom, rgba(23, 65, 90, 0.34) 1px, transparent 1px);
  background-size: 88px 88px;
  background-position: -1px -1px;
}

.page-faq .faq-hero__title {
  margin: 14px 0 0;
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(31px, 5.4vw, 58px);
  line-height: 1.08;
  letter-spacing: -0.02em;
  max-width: 17ch;
  text-wrap: balance;
}

.page-faq .faq-hero__lede {
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  max-width: 62ch;
  font-family: var(--font-body);
  font-size: clamp(15px, 1.4vw, 17px);
  line-height: 1.85;
  color: var(--mist);
}

.page-faq .faq-hero__facts {
  list-style: none;
  margin: clamp(28px, 4vw, 46px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 2px solid var(--line);
}

.page-faq .faq-fact {
  background: var(--ink-soft);
  padding: 16px 18px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.page-faq .faq-fact__num {
  font-family: var(--font-mono);
  font-size: clamp(30px, 3.6vw, 42px);
  font-weight: 700;
  line-height: 1;
  color: var(--cyan);
  letter-spacing: -0.02em;
}

.page-faq .faq-fact__num--accent {
  color: var(--orange);
}

.page-faq .faq-fact__label {
  font-size: 13px;
  line-height: 1.5;
  color: var(--mist);
  letter-spacing: 0.02em;
}

.page-faq .faq-hero__media {
  margin: clamp(30px, 4vw, 48px) 0 0;
}

.page-faq .faq-hero__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 3 / 2;
  object-fit: cover;
  border: 2px solid var(--line);
  box-shadow: var(--shadow-hard);
}

.page-faq .faq-hero__caption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
  border-left: 2px solid var(--cyan-dim);
  padding-left: 12px;
}

/* ---------- 上手三步 ---------- */

.page-faq .faq-steps {
  padding-block: var(--faq-sec);
  border-bottom: var(--faq-hairline);
  background: var(--ink);
}

.page-faq .faq-steps__head {
  max-width: 58ch;
}

.page-faq .faq-steps__title {
  margin: 12px 0 0;
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(23px, 3.2vw, 32px);
  line-height: 1.32;
  letter-spacing: -0.01em;
}

.page-faq .faq-steps__lede {
  margin: 12px 0 0;
  font-size: 15px;
  line-height: 1.8;
  color: var(--mist);
}

.page-faq .faq-steps__list {
  list-style: none;
  margin: clamp(30px, 4vw, 52px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 3.4vw, 44px);
}

.page-faq .faq-step {
  position: relative;
  padding: 24px 22px 28px;
  background: var(--ink-soft);
  border: 2px solid var(--line);
  box-shadow: 8px 8px 0 rgba(4, 18, 28, 0.62);
}

.page-faq .faq-step::before {
  content: "";
  position: absolute;
  top: -2px;
  left: -2px;
  width: 26px;
  height: 5px;
  background: var(--cyan);
}

.page-faq .faq-step__num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  font-family: var(--font-mono);
  font-size: 20px;
  font-weight: 700;
  color: var(--ink);
  background: var(--cyan);
  clip-path: polygon(0 0, 100% 0, 100% 68%, 68% 100%, 0 100%);
}

.page-faq .faq-step__title {
  margin: 16px 0 8px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 19px;
  line-height: 1.4;
  letter-spacing: -0.01em;
}

.page-faq .faq-step__text {
  margin: 0;
  font-size: 15px;
  line-height: 1.82;
  color: var(--mist);
}

.page-faq .faq-step__link {
  color: var(--cyan);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  white-space: nowrap;
}

.page-faq .faq-step__link:hover,
.page-faq .faq-step__link:focus-visible {
  color: var(--ink);
  background: var(--cyan);
  text-decoration: none;
}

.page-faq .faq-step__arrow {
  display: none;
  color: var(--cyan-dim);
}

/* ---------- 问答主体 ---------- */

.page-faq .faq-body {
  padding-block: var(--faq-sec);
}

.page-faq .faq-body__title {
  margin: 0 0 clamp(24px, 3.2vw, 42px);
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: clamp(23px, 3.2vw, 32px);
  line-height: 1.32;
  letter-spacing: -0.01em;
  padding-left: 16px;
  border-left: 4px solid var(--orange);
}

.page-faq .faq-body__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(26px, 3.4vw, 48px);
  align-items: start;
}

/* 分组索引 */

.page-faq .faq-rail__label {
  margin: 0 0 12px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--mist);
}

.page-faq .faq-rail__list {
  list-style: none;
  margin: 0;
  padding: 0 0 4px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
  scrollbar-width: thin;
}

.page-faq .faq-rail__link {
  display: inline-flex;
  align-items: baseline;
  gap: 8px;
  padding: 9px 13px;
  border: 2px solid var(--line);
  color: var(--mist);
  font-size: 14px;
  line-height: 1.4;
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease),
    background-color var(--dur) var(--ease);
}

.page-faq .faq-rail__idx {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--cyan-dim);
}

.page-faq .faq-rail__link:hover,
.page-faq .faq-rail__link:focus-visible {
  color: var(--ivory);
  border-color: var(--cyan);
  background: rgba(53, 245, 208, 0.08);
}

.page-faq .faq-rail__link:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: 2px;
}

.page-faq .faq-rail__top {
  display: inline-block;
  margin-top: 18px;
  padding: 8px 14px;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--cyan);
  text-decoration: none;
  border: 2px solid var(--line);
  transition: border-color var(--dur) var(--ease), background-color var(--dur) var(--ease);
}

.page-faq .faq-rail__top:hover,
.page-faq .faq-rail__top:focus-visible {
  border-color: var(--cyan);
  background: rgba(53, 245, 208, 0.08);
}

/* 问答分组 */

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

.page-faq .faq-group {
  scroll-margin-top: 96px;
}

.page-faq .faq-group + .faq-group {
  margin-top: clamp(38px, 5vw, 68px);
  padding-top: clamp(26px, 3.6vw, 42px);
  border-top: var(--faq-hairline);
}

.page-faq .faq-group__head {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  margin-bottom: 16px;
}

.page-faq .faq-group__idx {
  flex: none;
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  color: var(--cyan);
  padding-top: 6px;
}

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

.page-faq .faq-group__title {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(20px, 2.5vw, 26px);
  line-height: 1.32;
  letter-spacing: -0.01em;
}

.page-faq .faq-group__lead {
  margin: 8px 0 0;
  font-size: 14px;
  line-height: 1.75;
  color: var(--mist);
  max-width: 46ch;
}

/* 问答折叠项 */

.page-faq .faq-item {
  position: relative;
  border-bottom: var(--faq-hairline);
}

.page-faq .faq-item:first-of-type {
  border-top: var(--faq-hairline);
}

.page-faq .faq-item[open]::before {
  content: "";
  position: absolute;
  left: -16px;
  top: 10px;
  bottom: 14px;
  width: 2px;
  background: linear-gradient(to bottom, var(--cyan), transparent);
}

.page-faq .faq-item__q {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: 12px;
  padding: 17px 2px;
  cursor: pointer;
  list-style: none;
  transition: background-color var(--dur) var(--ease);
}

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

.page-faq .faq-item__q:hover {
  background: rgba(23, 65, 90, 0.28);
}

.page-faq .faq-item__q:focus-visible {
  outline: 2px solid var(--cyan);
  outline-offset: -2px;
}

.page-faq .faq-item__idx {
  font-family: var(--font-mono);
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--mist);
  transition: color var(--dur) var(--ease);
}

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

.page-faq .faq-item__text {
  font-family: var(--font-body);
  font-size: clamp(15px, 1.5vw, 17px);
  font-weight: 600;
  line-height: 1.6;
  color: var(--ivory);
}

.page-faq .faq-item__mark {
  position: relative;
  flex: none;
  width: 16px;
  height: 16px;
  color: var(--cyan);
}

.page-faq .faq-item__mark::before,
.page-faq .faq-item__mark::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  height: 2px;
  background: currentColor;
  transform: translateY(-50%);
  transition: transform var(--dur) var(--ease), opacity var(--dur) var(--ease);
}

.page-faq .faq-item__mark::after {
  transform: translateY(-50%) rotate(90deg);
}

.page-faq .faq-item[open] .faq-item__mark::after {
  transform: translateY(-50%) rotate(0deg);
  opacity: 0;
}

.page-faq .faq-item__a {
  padding: 0 2px 20px 42px;
  animation: faq-open var(--dur) var(--ease) both;
}

.page-faq .faq-item__a p {
  margin: 0;
  max-width: 64ch;
  font-size: 15px;
  line-height: 1.86;
  color: var(--mist);
}

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

.page-faq .faq-item__link:hover,
.page-faq .faq-item__link:focus-visible {
  color: var(--ink);
  background: var(--cyan);
  text-decoration: none;
}

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

/* 设备对比图 */

.page-faq .faq-device__media {
  margin: clamp(24px, 3vw, 36px) 0 0;
}

.page-faq .faq-device__media img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 14 / 9;
  object-fit: cover;
  border: 2px solid var(--line);
  box-shadow: var(--shadow-hard);
}

.page-faq .faq-device__caption {
  margin-top: 12px;
  font-size: 13px;
  line-height: 1.7;
  color: var(--mist);
  border-left: 2px solid var(--cyan-dim);
  padding-left: 12px;
}

/* 人工通道 */

.page-faq .faq-help__card {
  margin-top: clamp(22px, 3vw, 34px);
  padding: clamp(20px, 2.6vw, 30px);
  background: var(--ink-soft);
  border: 2px solid var(--line);
  border-left: 4px solid var(--orange);
  box-shadow: var(--shadow-soft);
}

.page-faq .faq-help__lead {
  margin: 0;
  max-width: 60ch;
  font-size: 15px;
  line-height: 1.85;
  color: var(--ivory);
}

.page-faq .faq-help__list {
  margin: clamp(18px, 2.4vw, 26px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
}

.page-faq .faq-help__row {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 16px;
  padding: 13px 16px;
  background: var(--ink);
}

.page-faq .faq-help__key {
  flex: none;
  min-width: 84px;
  margin: 0;
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  line-height: 1.9;
  color: var(--mist);
}

.page-faq .faq-help__val {
  margin: 0;
  font-size: 15px;
  line-height: 1.7;
  color: var(--ivory);
  word-break: break-word;
}

.page-faq .faq-help__actions {
  margin-top: clamp(20px, 2.6vw, 28px);
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

/* ---------- 响应式 ---------- */

@media (min-width: 640px) {
  .page-faq .faq-hero__facts {
    grid-template-columns: repeat(3, 1fr);
  }

  .page-faq .faq-help__list {
    grid-template-columns: repeat(3, 1fr);
  }
}

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

  .page-faq .faq-step {
    padding: 26px 24px 30px;
  }

  .page-faq .faq-step__arrow {
    display: block;
    position: absolute;
    top: 50%;
    right: -30px;
    transform: translateY(-50%);
  }

  .page-faq .faq-step:last-child .faq-step__arrow {
    display: none;
  }
}

@media (min-width: 900px) {
  .page-faq .faq-body__grid {
    grid-template-columns: 208px minmax(0, 1fr);
  }

  .page-faq .faq-rail {
    position: sticky;
    top: 104px;
  }

  .page-faq .faq-rail__list {
    display: grid;
    gap: 2px;
    overflow: visible;
    padding-bottom: 0;
  }

  .page-faq .faq-rail__link {
    border: 0;
    border-left: 2px solid var(--line);
    padding: 9px 12px;
    white-space: normal;
  }

  .page-faq .faq-item[open]::before {
    left: -22px;
  }
}

@media (min-width: 1100px) {
  .page-faq .faq-body__grid {
    grid-template-columns: 232px minmax(0, 1fr);
    gap: 56px;
  }
}

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

  .page-faq .faq-rail__link,
  .page-faq .faq-rail__top,
  .page-faq .faq-item__mark::before,
  .page-faq .faq-item__mark::after,
  .page-faq .faq-item__q,
  .page-faq .faq-item__idx {
    transition: none;
  }
}