/* ========== 全局样式 ========== */
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --primary-light: #dbeafe;
    --bg: #f8fafc;
    --white: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --shadow: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --radius: 10px;
    --radius-sm: 6px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

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

/* ========== 顶部导航 ========== */
.header {
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text);
    font-weight: 700;
    font-size: 1.2rem;
}

.logo-icon {
    font-size: 1.6rem;
}

.nav {
    display: flex;
    gap: 8px;
}

.nav-link {
    padding: 8px 18px;
    border-radius: var(--radius-sm);
    color: var(--text-light);
    font-size: 0.95rem;
    transition: all 0.2s;
}

.nav-link:hover {
    background: var(--bg);
    color: var(--text);
}

.nav-link.active {
    background: var(--primary-light);
    color: var(--primary);
    font-weight: 600;
}

/* 移动端菜单 */
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text);
    padding: 4px 8px;
}

.mobile-menu {
    display: none;
    background: var(--white);
    border-top: 1px solid var(--border);
    padding: 12px 20px;
    flex-direction: column;
    gap: 4px;
}

.mobile-menu.active {
    display: flex;
}

.mobile-nav-link {
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    color: var(--text-light);
    font-size: 0.95rem;
}

.mobile-nav-link.active {
    background: var(--primary-light);
    color: var(--primary);
    font-weight: 600;
}

/* ========== 搜索 Hero ========== */
.hero {
    background: linear-gradient(135deg, #1e40af 0%, #3b82f6 50%, #6366f1 100%);
    color: var(--white);
    padding: 60px 0 50px;
    text-align: center;
}

.hero-title {
    font-size: 2rem;
    margin-bottom: 8px;
    font-weight: 800;
}

.hero-subtitle {
    font-size: 1.05rem;
    opacity: 0.85;
    margin-bottom: 28px;
}

.search-box {
    display: flex;
    max-width: 560px;
    margin: 0 auto;
    gap: 0;
}

.search-input {
    flex: 1;
    padding: 14px 20px;
    border: none;
    border-radius: var(--radius);
    font-size: 1rem;
    outline: none;
    background: var(--white);
    color: var(--text);
}

.search-input::placeholder {
    color: #94a3b8;
}

/* ========== 分类标签 ========== */
.categories-section {
    background: var(--white);
    border-bottom: 1px solid var(--border);
    padding: 0;
}

.categories {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    padding: 16px 0;
}

.category-tag {
    padding: 8px 20px;
    border-radius: 20px;
    border: 2px solid var(--border);
    background: var(--white);
    color: var(--text-light);
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.2s;
    user-select: none;
}

.category-tag:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.category-tag.active {
    background: var(--primary);
    color: var(--white);
    border-color: var(--primary);
}

/* ========== 文章列表 ========== */
.articles-section {
    padding: 32px 0 60px;
}

.articles-title {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 24px;
}

.article-count {
    color: var(--text-light);
    font-size: 0.9rem;
    font-weight: 400;
    margin-left: 12px;
}

/* ========== 折叠文章 (details/summary) ========== */
.faq-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.faq-item {
    background: var(--white);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    border: 1px solid transparent;
    transition: all 0.2s;
}

.faq-item:hover {
    box-shadow: var(--shadow-md);
    border-color: var(--primary-light);
}

.faq-item summary {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 18px 24px;
    cursor: pointer;
    list-style: none;
    user-select: none;
    font-size: 1rem;
}

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

.faq-item summary::before {
    content: "▶";
    font-size: 0.7rem;
    color: var(--text-light);
    transition: transform 0.2s;
    flex-shrink: 0;
}

.faq-item[open] summary::before {
    transform: rotate(90deg);
}

.faq-cat {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 12px;
    background: var(--primary-light);
    color: var(--primary);
    font-size: 0.75rem;
    font-weight: 600;
    white-space: nowrap;
    flex-shrink: 0;
}

.faq-title {
    flex: 1;
    font-weight: 600;
    color: var(--text);
    min-width: 0;
}

.faq-date {
    color: var(--text-light);
    font-size: 0.85rem;
    white-space: nowrap;
    flex-shrink: 0;
}

.faq-answer {
    padding: 0 24px 24px 24px;
    line-height: 1.8;
    font-size: 0.95rem;
    border-top: 1px solid var(--border);
    margin-top: 4px;
    padding-top: 20px;
}

.faq-answer h3 {
    margin: 20px 0 10px;
    font-size: 1.05rem;
    color: var(--text);
}

.faq-answer h3:first-child {
    margin-top: 0;
}

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

.faq-answer li {
    margin-bottom: 6px;
}

.faq-answer .step {
    background: #f0fdf4;
    border-left: 3px solid #22c55e;
    padding: 8px 14px;
    margin: 6px 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.faq-answer .warning {
    background: #fef3c7;
    border-left: 3px solid #f59e0b;
    padding: 8px 14px;
    margin: 10px 0;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

/* ========== 无结果 ========== */
.no-result {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-light);
}

.no-result p:first-child {
    font-size: 1.2rem;
    margin-bottom: 8px;
}

/* ========== 页脚 ========== */
.footer {
    background: #1e293b;
    color: #cbd5e1;
    padding: 40px 0 0;
    margin-top: auto;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    gap: 40px;
    flex-wrap: wrap;
    padding-bottom: 30px;
    border-bottom: 1px solid #334155;
}

.footer-content h3 {
    color: var(--white);
    margin-bottom: 10px;
    font-size: 1rem;
}

.footer-content p {
    font-size: 0.9rem;
    line-height: 2;
}

.footer-bottom {
    text-align: center;
    padding: 20px 0;
    font-size: 0.85rem;
    color: #64748b;
}

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .hero-title {
        font-size: 1.5rem;
    }
    .hero {
        padding: 40px 0 35px;
    }
    .nav {
        display: none;
    }
    .mobile-menu-btn {
        display: block;
    }
    .faq-item summary {
        flex-wrap: wrap;
        padding: 14px 16px;
    }
    .faq-title {
        width: 100%;
        order: 3;
    }
    .faq-date {
        font-size: 0.8rem;
    }
    .faq-answer {
        padding: 0 16px 20px 16px;
        padding-top: 16px;
    }
    .footer-content {
        flex-direction: column;
        gap: 24px;
    }
}