:root {
    --primary: #2563eb;
    --primary-light: #eff6ff;
    --text: #1e293b;
    --text-secondary: #64748b;
    --border: #e2e8f0;
    --bg: #f8fafc;
    --white: #ffffff;
    --radius: 12px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
}

.hero {
    background: linear-gradient(135deg, #1e40af 0%, #3b82f6 100%);
    color: white;
    padding: 64px 24px;
    text-align: center;
}

    .hero h1 {
        font-size: 2rem;
        font-weight: 700;
        margin-bottom: 12px;
    }

    .hero p {
        font-size: 1.1rem;
        opacity: 0.9;
        max-width: 600px;
        margin: 0 auto;
    }

.category-nav {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    padding: 16px 24px;
    position: sticky;
    top: 0;
    z-index: 100;
    overflow-x: auto;
    white-space: nowrap;
}

    .category-nav a {
        display: inline-block;
        padding: 8px 20px;
        margin-right: 8px;
        border-radius: 999px;
        font-size: 0.9rem;
        color: var(--text-secondary);
        text-decoration: none;
        background: var(--bg);
        transition: all 0.2s;
    }

        .category-nav a:hover,
        .category-nav a.active {
            background: var(--primary);
            color: white;
        }

.container {
    max-width: 860px;
    margin: 0 auto;
    padding: 40px 24px 80px;
}

.category-title {
    font-size: 1.3rem;
    font-weight: 700;
    margin: 48px 0 20px;
    padding-left: 14px;
    border-left: 4px solid var(--primary);
    color: var(--text);
    scroll-margin-top: 80px;
}

    .category-title:first-of-type {
        margin-top: 0;
    }

.faq-item {
    background: var(--white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    margin-bottom: 12px;
    overflow: hidden;
    transition: box-shadow 0.2s;
}

    .faq-item:hover {
        box-shadow: 0 2px 12px rgba(0,0,0,0.06);
    }

.faq-question {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 20px 24px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1rem;
    color: var(--text);
    user-select: none;
}

    .faq-question::before {
        content: "Q";
        flex-shrink: 0;
        width: 28px;
        height: 28px;
        border-radius: 50%;
        background: var(--primary-light);
        color: var(--primary);
        display: flex;
        align-items: center;
        justify-content: center;
        font-size: 0.8rem;
        font-weight: 700;
    }

    .faq-question .arrow {
        margin-left: auto;
        transition: transform 0.3s;
        color: var(--text-secondary);
        font-size: 0.8rem;
    }

.faq-item.open .faq-question .arrow {
    transform: rotate(180deg);
}

.faq-answer {
    display: none;
    padding: 0 24px 20px 64px;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.8;
}

.faq-item.open .faq-answer {
    display: block;
}

.faq-answer ul, .faq-answer ol {
    padding-left: 20px;
    margin: 8px 0;
}

.faq-answer li {
    margin-bottom: 4px;
}

.faq-answer strong {
    color: var(--text);
}

.faq-answer table {
    width: 100%;
    border-collapse: collapse;
    margin: 12px 0;
    font-size: 0.9rem;
}

    .faq-answer table th,
    .faq-answer table td {
        padding: 10px 14px;
        border: 1px solid var(--border);
        text-align: left;
    }

    .faq-answer table th {
        background: var(--primary-light);
        color: var(--primary);
        font-weight: 600;
    }

.footer {
    text-align: center;
    padding: 32px 24px;
    color: var(--text-secondary);
    font-size: 0.85rem;
    border-top: 1px solid var(--border);
}

    .footer a {
        color: var(--primary);
        text-decoration: none;
    }

@media (max-width: 640px) {
    .hero h1 {
        font-size: 1.5rem;
    }

    .hero {
        padding: 40px 16px;
    }

    .container {
        padding: 24px 16px 60px;
    }

    .faq-question {
        padding: 16px 18px;
        font-size: 0.95rem;
    }

    .faq-answer {
        padding: 0 18px 16px 54px;
    }
}