/* ==================== 全局变量（与首页统一） ==================== */
:root {
    --bg-deep: #050b14;
    --bg-card: rgba(15, 23, 42, 0.7);
    --bg-card-hover: rgba(30, 41, 59, 0.85);
    --border-soft: #334155;
    --border-glow: rgba(56, 189, 248, 0.25);
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent-blue: #38bdf8;
    --accent-purple: #a855f7;
    --gradient-hero: linear-gradient(135deg, #38bdf8, #a855f7);
    --radius-xl: 28px;
    --radius-2xl: 48px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg-deep);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 32px;
}

a { text-decoration: none; color: inherit; transition: color 0.2s; }

/* ==================== 导航栏（统一首页） ==================== */
header {
    background: rgba(5, 11, 20, 0.92);
    backdrop-filter: blur(14px);
    -webkit-backdrop-filter: blur(14px);
    border-bottom: 1px solid var(--border-glow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.nav-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    padding: 16px 0;
}

.brand { display: flex; flex-direction: column; }

.brand-name {
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--gradient-hero);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    letter-spacing: -0.5px;
    line-height: 1.2;
}

.brand-accent {
    color: var(--accent-blue);
    -webkit-text-fill-color: var(--accent-blue);
}

.brand-tagline {
    font-size: 0.7rem;
    color: var(--text-secondary);
    letter-spacing: 0.3px;
    margin-top: 2px;
}

.nav-menu {
    display: flex;
    gap: 2rem;
    align-items: center;
    flex-wrap: wrap;
}

.nav-link {
    font-size: 0.95rem;
    font-weight: 500;
    color: #cbd5e1;
    position: relative;
    padding: 4px 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-blue);
    transition: width 0.25s;
    box-shadow: 0 0 20px rgba(56,189,248,0.3);
}

.nav-link:hover,
.nav-link.active { color: var(--accent-blue); }

.nav-link:hover::after,
.nav-link.active::after { width: 100%; }

.menu-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-between;
    width: 28px;
    height: 20px;
    background: transparent;
    border: none;
    cursor: pointer;
}

.menu-toggle span {
    width: 100%;
    height: 2px;
    background: #cbd5e1;
    border-radius: 2px;
    transition: all 0.3s;
}

.menu-toggle--active span:nth-child(1) { transform: translateY(9px) rotate(45deg); }
.menu-toggle--active span:nth-child(2) { opacity: 0; }
.menu-toggle--active span:nth-child(3) { transform: translateY(-9px) rotate(-45deg); }

/* ==================== Hero ==================== */
.hero-faq {
    text-align: center;
    padding: 50px 0 24px;
}

.hero-faq h1 {
    font-size: 2.8rem;
    font-weight: 800;
    background: linear-gradient(to right, #f0f9ff, #a5f3fc);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    margin-bottom: 12px;
}

.hero-faq p {
    font-size: 1.1rem;
    color: var(--text-secondary);
}

/* ==================== 统计圆点 ==================== */
.stats-row {
    display: flex;
    justify-content: center;
    gap: 40px;
    margin: 32px 0 40px;
    flex-wrap: wrap;
}

.stat-circle {
    width: 120px;
    height: 120px;
    border-radius: 50%;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(6px);
    border: 1px solid var(--border-soft);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    transition: border-color 0.3s;
}

.stat-circle:hover {
    border-color: var(--accent-blue);
}

.stat-number {
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--gradient-hero);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-top: 4px;
}

/* ==================== 分类筛选按钮 ==================== */
.category-grid {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 14px;
    margin-bottom: 36px;
}

.category-pill {
    background: rgba(15, 23, 42, 0.65);
    backdrop-filter: blur(4px);
    border: 1px solid var(--border-soft);
    border-radius: 60px;
    padding: 10px 22px;
    font-weight: 600;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all 0.25s;
    font-size: 0.9rem;
}

.category-pill:hover {
    border-color: var(--accent-blue);
    color: white;
}

.category-pill.active {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
    color: #0f172a;
    box-shadow: 0 0 16px rgba(56,189,248,0.4);
}

/* ==================== FAQ 网格与手风琴 ==================== */
.faq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 20px;
    margin-bottom: 50px;
}

.empty-state {
    grid-column: 1/-1;
    text-align: center;
    padding: 60px;
    background: rgba(15,23,42,0.5);
    border-radius: 32px;
    color: var(--text-secondary);
}

.faq-card {
    background: var(--bg-card);
    backdrop-filter: blur(6px);
    border: 1px solid var(--border-soft);
    border-radius: 20px;
    overflow: hidden;
    transition: border-color 0.3s;
}

.faq-card:hover {
    border-color: var(--accent-blue);
}

.faq-question {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 18px 22px;
    font-weight: 600;
    color: #f1f5f9;
    cursor: pointer;
    user-select: none;
    gap: 12px;
}

.faq-question .icon {
    font-size: 0.8rem;
    transition: transform 0.3s;
    color: var(--accent-blue);
}

.faq-card.open .faq-question .icon {
    transform: rotate(180deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease;
    background: rgba(5,11,20,0.5);
    padding: 0 22px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

.faq-card.open .faq-answer {
    max-height: 600px;
    padding: 0 22px 18px;
}

.tip-inline {
    background: rgba(56,189,248,0.1);
    border-left: 3px solid var(--accent-blue);
    padding: 10px 14px;
    margin: 12px 0 0;
    border-radius: 0 8px 8px 0;
    font-size: 0.85rem;
    color: #bae6fd;
}

.code-snip {
    background: #0b1120;
    border: 1px solid var(--border-soft);
    border-radius: 10px;
    padding: 10px 14px;
    font-family: 'Fira Code', monospace;
    font-size: 0.8rem;
    margin: 10px 0 0;
    white-space: pre-wrap;
    color: #a5f3fc;
}

/* ==================== 联系引导块 ==================== */
.contact-block {
    text-align: center;
    background: linear-gradient(145deg, #0f172a, #020617);
    border-radius: var(--radius-xl);
    padding: 48px 24px;
    margin-bottom: 50px;
    border: 1px solid var(--border-soft);
}

.contact-block h3 {
    font-size: 1.8rem;
    color: white;
    margin-bottom: 16px;
}

.contact-block p {
    color: var(--text-secondary);
    margin-bottom: 28px;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.contact-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
}

.btn-glow {
    background: var(--gradient-hero);
    border: none;
    padding: 12px 32px;
    border-radius: 40px;
    font-weight: 700;
    color: white;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.3s;
    display: inline-block;
    text-align: center;
    font-size: 1rem;
    box-shadow: 0 6px 18px rgba(56,189,248,0.3);
}

.btn-glow:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 28px rgba(56,189,248,0.45);
}

.btn-ghost {
    background: transparent;
    border: 1px solid var(--accent-blue);
    padding: 12px 32px;
    border-radius: 40px;
    font-weight: 600;
    color: var(--accent-blue);
    display: inline-flex;
    align-items: center;
    gap: 6px;
    transition: background 0.2s, color 0.2s;
}

.btn-ghost:hover {
    background: var(--accent-blue);
    color: #0f172a;
}

/* ==================== CTA 号召区域（统一风格） ==================== */
.cta-banner {
    position: relative;
    background: linear-gradient(135deg, #0b1622 0%, #1a1040 100%);
    border-radius: var(--radius-2xl);
    margin: 40px 0 60px;
    overflow: hidden;
    padding: 60px 0;
}

.cta-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 28px;
    position: relative;
    z-index: 2;
}

.cta-text h2 {
    font-size: 2rem;
    color: white;
    margin-bottom: 12px;
}

.cta-text p {
    color: #cbd5e1;
    max-width: 500px;
}

.cta-buttons {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
}

.btn-glow-lg { padding: 14px 36px; font-size: 1.1rem; }

.btn-ghost-light {
    background: transparent;
    border: 1px solid rgba(255,255,255,0.25);
    color: white;
    padding: 10px 28px;
    border-radius: 40px;
    font-weight: 600;
    transition: background 0.2s;
    display: inline-block;
    text-align: center;
}

.btn-ghost-light:hover { background: rgba(255,255,255,0.1); }

.cta-decoration {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.cta-dot {
    position: absolute;
    border-radius: 50%;
    background: var(--accent-blue);
    opacity: 0.15;
    filter: blur(30px);
}
.cta-dot-1 { width:200px; height:200px; top:-50px; right:-40px; }
.cta-dot-2 { width:150px; height:150px; bottom:-30px; left:10%; background:var(--accent-purple); }
.cta-dot-3 { width:100px; height:100px; top:40%; left:55%; }

/* ==================== 页脚（统一） ==================== */
footer {
    background: #020617;
    border-top: 1px solid #1e293b;
    padding: 56px 0 28px;
    margin-top: 40px;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 40px;
}

.footer-col h4 {
    color: #f1f5f9;
    margin-bottom: 18px;
    font-size: 1rem;
    font-weight: 700;
}

.footer-col p {
    color: var(--text-secondary);
    font-size: 0.85rem;
    line-height: 1.6;
}

.footer-col a {
    display: block;
    color: #94a3b8;
    font-size: 0.9rem;
    margin-bottom: 8px;
    transition: color 0.2s;
}

.footer-col a:hover { color: var(--accent-blue); }

.footer-brand {
    font-size: 1.4rem;
    font-weight: 800;
    background: var(--gradient-hero);
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    margin-bottom: 8px;
}

.footer-bottom {
    text-align: center;
    padding-top: 40px;
    color: #475569;
    font-size: 0.8rem;
    border-top: 1px solid #1e293b;
    margin-top: 36px;
}

/* ==================== 响应式 ==================== */
@media (max-width: 768px) {
    .container { padding: 0 20px; }

    .nav-menu {
        display: none;
        flex-direction: column;
        width: 100%;
        background: rgba(5,11,20,0.98);
        backdrop-filter: blur(20px);
        margin-top: 16px;
        padding: 16px 0;
        gap: 12px;
        border-radius: 16px;
    }
    .nav-menu--open { display: flex; }
    .menu-toggle { display: flex; }

    .hero-faq h1 { font-size: 2.2rem; }
    .stats-row { gap: 20px; }
    .stat-circle { width: 100px; height: 100px; }
    .faq-grid { grid-template-columns: 1fr; }
    .cta-content { flex-direction: column; text-align: center; }
    .cta-buttons { justify-content: center; }
}