.page-faq {
  --faq-rail-w: 258px;
  --faq-num-w: 3.1rem;
  display: block;
  background: var(--ink-0);
  color: var(--white);
  overflow-x: clip;
}

.page-faq .breadcrumbs {
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 1.5rem var(--pad-x) 0;
}

.page-faq .breadcrumbs ol {
  display: flex;
  flex-wrap: wrap;
  gap: .5rem;
  margin: 0;
  padding: 0;
  list-style: none;
  font-size: 13px;
  color: var(--mist);
}

.page-faq .breadcrumbs li + li::before {
  content: "/";
  margin-right: .5rem;
  color: var(--line);
}

.page-faq .breadcrumbs a {
  color: var(--mist);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}

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

/* 首屏 */
.faq-hero {
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: clamp(1.75rem, 5vw, 3.25rem) var(--pad-x) clamp(1.5rem, 3vw, 2.5rem);
  display: grid;
  gap: clamp(1rem, 2.4vw, 1.6rem);
}

.faq-hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.9rem, 5.2vw, 3.4rem);
  line-height: 1.12;
  letter-spacing: -.015em;
  max-width: 22ch;
}

.faq-hero .lede {
  margin: 0;
  max-width: 62ch;
  color: var(--mist);
  font-size: clamp(1rem, 1.6vw, 1.08rem);
  line-height: 1.75;
}

.faq-facts {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin: 0;
  padding: 0;
  list-style: none;
  background: var(--line);
  border: var(--line-w) solid var(--line);
}

.faq-fact {
  background: var(--ink-1);
  padding: .9rem 1rem 1rem;
  display: grid;
  gap: .3rem;
  align-content: start;
}

.faq-fact .num {
  font-family: var(--font-mono);
  font-size: clamp(1.05rem, 2.4vw, 1.35rem);
  color: var(--cyan);
  letter-spacing: -.01em;
}

.faq-fact span:last-child {
  font-size: 13px;
  color: var(--mist);
  line-height: 1.5;
}

.faq-quick {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: .6rem;
}

.faq-quick a {
  display: flex;
  align-items: center;
  gap: .6rem;
  padding: .7rem .85rem;
  border: var(--line-w) solid var(--line);
  background: var(--ink-2);
  color: var(--white);
  text-decoration: none;
  font-size: .9rem;
  line-height: 1.4;
  transition: border-color .22s ease, color .22s ease, transform .22s ease;
}

.faq-quick a:hover {
  border-color: var(--cyan);
  color: var(--cyan);
  transform: translateY(-2px);
}

.faq-quick .mono {
  color: var(--cyan);
  font-size: .76rem;
}

/* 主体分栏 */
.faq-shell {
  max-width: var(--shell-max);
  margin: 0 auto;
  padding: 0 var(--pad-x) clamp(2rem, 6vw, 4rem);
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: clamp(1.5rem, 3vw, 2.5rem);
  align-items: start;
}

.faq-rail {
  border: var(--line-w) solid var(--line);
  background: var(--ink-1);
  padding: 1rem;
}

.rail-title {
  margin: 0 0 .75rem;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--mist);
}

.rail-list {
  display: flex;
  gap: .5rem;
  margin: 0;
  padding: 0 0 .3rem;
  list-style: none;
  overflow-x: auto;
}

.rail-list a {
  display: inline-flex;
  align-items: center;
  gap: .45rem;
  white-space: nowrap;
  padding: .45rem .7rem;
  border: 1px solid var(--line);
  color: var(--mist);
  text-decoration: none;
  font-size: .86rem;
  transition: color .2s ease, border-color .2s ease, background-color .2s ease;
}

.rail-list a .mono {
  color: var(--cyan);
  font-size: .72rem;
}

.rail-list a:hover {
  color: var(--white);
  border-color: var(--cyan);
}

.rail-list a[data-active] {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink-0);
}

.rail-list a[data-active] .mono {
  color: var(--ink-0);
}

.rail-note {
  margin: 1rem 0 0;
  padding-top: .85rem;
  border-top: 1px solid var(--line);
  font-size: 13px;
  line-height: 1.65;
  color: var(--mist);
}

.rail-note a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

.faq-main {
  display: grid;
  gap: clamp(1.5rem, 4vw, 2.5rem);
  min-width: 0;
}

/* 章节 */
.faq-section {
  border-top: var(--line-w) solid var(--line);
  padding-top: clamp(1.5rem, 3.5vw, 2.25rem);
  scroll-margin-top: 100px;
}

.faq-section .section-head {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: clamp(.75rem, 2vw, 1.25rem);
  align-items: start;
  margin-bottom: clamp(1rem, 2.4vw, 1.5rem);
}

.page-faq .chapter-index {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2rem, 5vw, 3.25rem);
  line-height: .9;
  letter-spacing: -.02em;
  color: var(--cyan);
}

.faq-section .section-title {
  margin: 0 0 .4rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(1.2rem, 2.6vw, 1.7rem);
  line-height: 1.28;
  letter-spacing: -.01em;
  color: var(--white);
}

.faq-section .section-sub {
  margin: 0;
  max-width: 56ch;
  color: var(--mist);
  font-size: .94rem;
  line-height: 1.7;
}

/* 图文与步骤 */
.faq-media {
  display: grid;
  gap: clamp(1rem, 2.5vw, 1.5rem);
  align-items: center;
}

.page-faq .media-frame {
  margin: 0;
  background: var(--ink-2);
}

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

.page-faq .media-caption {
  font-size: 12.5px;
  line-height: 1.5;
  color: var(--mist);
}

.step-list {
  counter-reset: faq-step;
  display: grid;
  gap: .7rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.step-list li {
  counter-increment: faq-step;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: .7rem;
  align-items: start;
  padding: .85rem .95rem;
  border: var(--line-w) solid var(--line);
  background: var(--ink-1);
  font-size: .94rem;
  line-height: 1.7;
  color: var(--white);
}

.step-list li::before {
  content: counter(faq-step, decimal-leading-zero);
  font-family: var(--font-mono);
  font-size: .76rem;
  color: var(--cyan);
  padding-top: .32rem;
}

.faq-media-note {
  border-left: 3px solid var(--cyan);
  padding: .2rem 0 .2rem 1rem;
  font-size: .94rem;
  line-height: 1.75;
  color: var(--mist);
}

.faq-media-note p {
  margin: 0 0 .6rem;
}

.faq-media-note ul {
  margin: 0;
  padding-left: 1.1rem;
  display: grid;
  gap: .35rem;
}

.faq-media-note li::marker {
  color: var(--cyan);
}

/* 手风琴 */
.faq-list {
  display: grid;
  gap: .6rem;
  margin-top: clamp(1rem, 2.4vw, 1.5rem);
}

.faq-item {
  border: var(--line-w) solid var(--line);
  background: var(--ink-1);
  box-shadow: var(--shadow-hard);
  transition: border-color .22s ease;
}

.faq-item[open] {
  border-color: var(--cyan);
}

.faq-q {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: .75rem;
  padding: .9rem 1rem;
  cursor: pointer;
  list-style: none;
  font-weight: 600;
  font-size: .97rem;
  line-height: 1.45;
  color: var(--white);
}

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

.faq-q:hover {
  color: var(--cyan);
}

.faq-num {
  display: inline-block;
  padding: .22rem .42rem;
  font-size: .72rem;
  color: var(--mist);
  background: var(--ink-2);
  border: 1px solid var(--line);
  transition: background-color .22s ease, color .22s ease, border-color .22s ease;
}

.faq-item[open] .faq-num {
  background: var(--cyan);
  border-color: var(--cyan);
  color: var(--ink-0);
}

.faq-mark {
  width: 10px;
  height: 10px;
  border-right: 2px solid var(--cyan);
  border-bottom: 2px solid var(--cyan);
  transform: rotate(45deg);
  transition: transform .24s ease;
}

.faq-item[open] .faq-mark {
  transform: rotate(-135deg);
}

.faq-a {
  margin-top: .15rem;
  padding: .9rem 1rem 1.15rem;
  border-top: 1px dashed var(--line);
  color: var(--mist);
  font-size: .94rem;
  line-height: 1.75;
}

.faq-a p {
  margin: 0;
}

.faq-a p + p {
  margin-top: .7rem;
}

.faq-item[open] .faq-a {
  animation: faq-answer-in .26s cubic-bezier(.2, .7, .3, 1) both;
}

@keyframes faq-answer-in {
  from { opacity: 0; transform: translateX(10px); }
  to { opacity: 1; transform: none; }
}

/* 指标表 */
.table-scroll {
  margin-top: clamp(1rem, 2.4vw, 1.5rem);
  overflow-x: auto;
}

.metric-table {
  width: 100%;
  min-width: 520px;
  border-collapse: collapse;
  border: var(--line-w) solid var(--line);
  font-size: .9rem;
}

.metric-table th,
.metric-table td {
  padding: .8rem .9rem;
  border-bottom: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
  line-height: 1.6;
}

.metric-table thead th {
  background: var(--ink-2);
  color: var(--cyan);
  font-size: .76rem;
  letter-spacing: .08em;
  font-weight: 600;
}

.metric-table td {
  color: var(--mist);
}

.metric-table td:first-child {
  color: var(--white);
  font-weight: 600;
  white-space: nowrap;
}

.metric-table tbody tr:last-child td {
  border-bottom: 0;
}

.metric-table .mono {
  color: var(--cyan-soft);
  font-size: .82rem;
  white-space: nowrap;
}

/* 指路条 */
.faq-next {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: .4rem .6rem;
  margin: clamp(1rem, 2.4vw, 1.4rem) 0 0;
  padding: .9rem 1rem;
  border: var(--line-w) solid var(--line);
  background: var(--ink-2);
  font-size: .92rem;
  line-height: 1.6;
  color: var(--mist);
}

.faq-next a {
  color: var(--cyan);
  text-decoration: none;
  border-bottom: 1px solid currentColor;
}

.faq-next a:hover {
  color: var(--cyan-soft);
}

/* 联系卡 */
.faq-contact {
  margin-top: clamp(1rem, 2.4vw, 1.5rem);
  padding: clamp(1.25rem, 3vw, 1.75rem);
  border: var(--line-w) solid var(--line);
  border-left: 4px solid var(--orange);
  background: var(--ink-1);
  box-shadow: var(--shadow-hard);
  display: grid;
  gap: 1.1rem;
}

.faq-contact p {
  margin: 0;
  max-width: 62ch;
  color: var(--mist);
  font-size: .95rem;
  line-height: 1.75;
}

.faq-contact-actions {
  display: flex;
  flex-wrap: wrap;
  gap: .7rem;
}

/* 响应式 */
@media (min-width: 620px) {
  .faq-facts {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .faq-a {
    padding-left: calc(1rem + var(--faq-num-w));
  }
}

@media (min-width: 860px) {
  .faq-quick {
    grid-template-columns: repeat(4, minmax(0, 1fr));
  }

  .faq-media {
    grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr);
  }
}

@media (min-width: 1000px) {
  .faq-shell {
    grid-template-columns: var(--faq-rail-w) minmax(0, 1fr);
    gap: clamp(2rem, 3.5vw, 3.25rem);
  }

  .faq-rail {
    position: sticky;
    top: 104px;
    padding: 1.25rem 1.15rem 1.35rem;
  }

  .rail-list {
    flex-direction: column;
    overflow-x: visible;
    gap: .3rem;
  }

  .rail-list a {
    width: 100%;
    white-space: normal;
    border-color: transparent;
    border-left: 2px solid var(--line);
  }

  .rail-list a:hover {
    border-left-color: var(--cyan);
  }
}

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

  .page-faq .faq-mark,
  .page-faq .faq-num,
  .page-faq .faq-quick a {
    transition: none;
  }

  .page-faq .faq-quick a:hover {
    transform: none;
  }
}