:root {
    --faq-ink: #1d1d1f;
    --faq-muted: #6e6e73;
    --faq-blue: #1677ff;
    --faq-line: rgba(29, 29, 31, 0.12);
    --faq-surface: #f5f5f7;
    --faq-font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text", "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
}

.faq-page {
    color: var(--faq-ink);
    background: #fff;
    font-family: var(--faq-font);
}

.faq-page .page-wrapper { overflow: clip; }

.faq-container {
    width: min(100% - 48px, 1240px);
    margin: 0 auto;
}

.faq-main { padding-top: 68px; }

.faq-hero {
    padding: clamp(78px, 12vw, 154px) 0 clamp(54px, 8vw, 96px);
    background: radial-gradient(circle at 88% 18%, rgba(22, 119, 255, 0.13), transparent 28%), #fff;
    border-bottom: 1px solid var(--faq-line);
}

.faq-eyebrow {
    margin: 0 0 18px;
    color: #4c77a4;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: .18em;
}

.faq-hero h1 {
    max-width: 820px;
    margin: 0;
    color: var(--faq-ink);
    font-size: clamp(48px, 7vw, 88px);
    font-weight: 700;
    letter-spacing: -.07em;
    line-height: .98;
}

.faq-intro {
    max-width: 590px;
    margin: 28px 0 0;
    color: var(--faq-muted);
    font-size: clamp(17px, 2vw, 21px);
    letter-spacing: -.025em;
    line-height: 1.65;
}

.faq-section { padding: clamp(52px, 8vw, 112px) 0 clamp(76px, 11vw, 150px); }

.faq-layout {
    display: grid;
    grid-template-columns: minmax(255px, 320px) minmax(0, 1fr);
    gap: clamp(42px, 8vw, 120px);
    align-items: start;
}

.faq-sidebar {
    position: sticky;
    top: 104px;
    max-height: calc(100vh - 128px);
    overflow-y: auto;
    overscroll-behavior: contain;
    padding-right: 10px;
    scrollbar-color: rgba(29, 29, 31, .22) transparent;
    scrollbar-width: thin;
}

.faq-sidebar-label {
    margin: 0 0 18px;
    color: var(--faq-muted);
    font-size: 13px;
    font-weight: 600;
    letter-spacing: -.015em;
}

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

.faq-question {
    display: grid;
    grid-template-columns: 28px minmax(0, 1fr);
    gap: 12px;
    width: 100%;
    padding: 17px 4px;
    color: var(--faq-muted);
    background: transparent;
    border: 0;
    border-bottom: 1px solid var(--faq-line);
    cursor: pointer;
    font: inherit;
    font-size: 15px;
    font-weight: 550;
    letter-spacing: -.025em;
    line-height: 1.45;
    text-align: left;
    transition: color 180ms ease, padding-left 180ms ease;
}

.faq-question > span:first-child {
    color: #98a2ad;
    font-size: 12px;
    font-weight: 700;
    letter-spacing: .08em;
    line-height: 1.8;
}

.faq-question:hover,
.faq-question:focus-visible,
.faq-question.is-active { color: var(--faq-ink); }

.faq-question.is-active { padding-left: 10px; }
.faq-question.is-active > span:first-child { color: var(--faq-blue); }

.faq-question:focus-visible {
    outline: 2px solid var(--faq-blue);
    outline-offset: -2px;
}

.faq-answers { min-width: 0; }

.faq-answer {
    animation: faq-answer-in 260ms ease both;
}

.faq-answer[hidden] { display: none; }

.faq-answer-index {
    display: block;
    margin-bottom: 24px;
    color: var(--faq-blue);
    font-size: 13px;
    font-weight: 750;
    letter-spacing: .12em;
}

.faq-answer h2 {
    max-width: 790px;
    margin: 0;
    color: var(--faq-ink);
    font-size: clamp(29px, 4vw, 47px);
    font-weight: 680;
    letter-spacing: -.055em;
    line-height: 1.14;
}

.faq-prose,
.faq-answer-lead {
    max-width: 780px;
    margin-top: clamp(28px, 4vw, 46px);
}

.faq-prose p,
.faq-answer-lead {
    margin: 0 0 22px;
    color: #525259;
    font-size: clamp(16px, 1.7vw, 18px);
    letter-spacing: -.02em;
    line-height: 1.85;
}

.faq-prose h3 {
    max-width: 780px;
    margin: 46px 0 18px;
    color: var(--faq-ink);
    font-size: clamp(22px, 2.5vw, 30px);
    font-weight: 680;
    letter-spacing: -.04em;
    line-height: 1.28;
}

.faq-topic {
    max-width: 780px;
    margin: 0 0 28px;
    padding: 24px 26px;
    background: var(--faq-surface);
    border: 1px solid rgba(29, 29, 31, 0.06);
    border-radius: 18px;
}

.faq-topic h4 {
    margin: 0 0 10px;
    color: var(--faq-ink);
    font-size: clamp(17px, 2vw, 20px);
    font-weight: 680;
    letter-spacing: -.025em;
    line-height: 1.4;
}

.faq-topic p {
    margin-bottom: 0;
    font-size: 15px;
    line-height: 1.75;
}

.faq-step-list,
.faq-bullet-list {
    max-width: 780px;
    margin: 24px 0 34px;
    padding: 0;
    list-style: none;
}

.faq-step-list {
    counter-reset: faq-step;
}

.faq-step-list li,
.faq-bullet-list li {
    position: relative;
    margin: 0;
    padding: 20px 0 20px 50px;
    color: #525259;
    border-top: 1px solid var(--faq-line);
    font-size: clamp(15px, 1.6vw, 17px);
    letter-spacing: -.018em;
    line-height: 1.75;
}

.faq-step-list li:last-child,
.faq-bullet-list li:last-child {
    border-bottom: 1px solid var(--faq-line);
}

.faq-step-list li {
    counter-increment: faq-step;
}

.faq-step-list li::before,
.faq-bullet-list li::before {
    position: absolute;
    left: 4px;
    top: 22px;
    display: grid;
    width: 28px;
    height: 28px;
    place-items: center;
    color: var(--faq-blue);
    font-size: 12px;
    font-weight: 750;
}

.faq-step-list li::before {
    content: counter(faq-step, decimal-leading-zero);
}

.faq-bullet-list li::before {
    content: "•";
    font-size: 22px;
    line-height: 1;
}

.faq-step-list strong {
    display: block;
    margin-bottom: 6px;
    color: var(--faq-ink);
    font-size: 17px;
    font-weight: 680;
}

.faq-step-list span {
    display: block;
}

.faq-metric-list {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 14px;
    margin-top: 34px;
}

.faq-metric {
    min-height: 220px;
    padding: 28px;
    background: var(--faq-surface);
    border: 1px solid rgba(29, 29, 31, 0.06);
    border-radius: 22px;
}

.faq-metric h3 {
    margin: 0 0 13px;
    color: var(--faq-ink);
    font-size: 20px;
    font-weight: 680;
    letter-spacing: -.04em;
}

.faq-metric p {
    margin: 0;
    color: var(--faq-muted);
    font-size: 14px;
    letter-spacing: -.015em;
    line-height: 1.75;
}

.faq-figure-grid,
.faq-evidence-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
    margin-top: 34px;
}

.faq-figure {
    margin: 0;
    padding: 16px;
    overflow: hidden;
    background: #fff;
    border: 1px solid var(--faq-line);
    border-radius: 20px;
}

.faq-figure img {
    display: block;
    width: 100%;
    height: auto;
    background: #fff;
    border-radius: 11px;
    object-fit: contain;
}

.faq-figure figcaption {
    margin-top: 13px;
    color: var(--faq-muted);
    font-size: 13px;
    letter-spacing: -.01em;
    line-height: 1.45;
}

.faq-evidence-grid .faq-figure:first-child img {
    aspect-ratio: 1.51;
}

.faq-evidence-grid .faq-figure:last-child img {
    aspect-ratio: 1.92;
}

.faq-figure-wide {
    max-width: 880px;
    margin-top: 34px;
}

.faq-back-to-top {
    position: fixed;
    right: 24px;
    bottom: 24px;
    z-index: 10;
    display: grid;
    width: 42px;
    height: 42px;
    place-items: center;
    color: #fff;
    background: rgba(29, 29, 31, .9);
    border: 0;
    border-radius: 50%;
    cursor: pointer;
    opacity: 0;
    pointer-events: none;
    transition: opacity 180ms ease, transform 180ms ease;
}

.faq-back-to-top.is-visible { opacity: 1; pointer-events: auto; }
.faq-back-to-top:hover { transform: translateY(-3px); }

@keyframes faq-answer-in {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 767px) {
    .faq-container { width: min(100% - 36px, 1240px); }
    .faq-hero { padding-top: 80px; }
    .faq-layout { display: block; }
    .faq-sidebar {
        position: static;
        max-height: none;
        margin-bottom: 44px;
        overflow: visible;
        padding-right: 0;
    }
    .faq-question-list {
        display: flex;
        gap: 8px;
        overflow-x: auto;
        padding-bottom: 8px;
        border-top: 0;
        scrollbar-width: none;
    }
    .faq-question-list::-webkit-scrollbar { display: none; }
    .faq-question {
        display: block;
        flex: 0 0 min(82vw, 288px);
        min-height: 92px;
        padding: 17px;
        background: var(--faq-surface);
        border: 1px solid transparent;
        border-radius: 16px;
    }
    .faq-question > span:first-child { display: block; margin-bottom: 5px; }
    .faq-question.is-active { padding-left: 17px; border-color: rgba(22, 119, 255, .38); background: #f8fbff; }
    .faq-prose h3 { margin-top: 38px; }
    .faq-topic { padding: 20px; border-radius: 16px; }
    .faq-step-list li,
    .faq-bullet-list li { padding-left: 44px; }
    .faq-metric-list { grid-template-columns: 1fr; }
    .faq-metric { min-height: auto; padding: 24px; }
    .faq-figure-grid,
    .faq-evidence-grid { grid-template-columns: 1fr; }
    .faq-back-to-top { right: 16px; bottom: 16px; }
}

@media (prefers-reduced-motion: reduce) {
    .faq-answer { animation: none; }
    .faq-question, .faq-back-to-top { transition: none; }
}