/* ===== 全局样式 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary: #64748b;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --bg: #f8fafc;
    --card-bg: #ffffff;
    --text: #1e293b;
    --text-light: #64748b;
    --border: #e2e8f0;
    --code-bg: #1e293b;
    --code-text: #e2e8f0;
    --shadow: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 25px rgba(0,0,0,0.1);
    --radius: 12px;
}

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

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

/* ===== 导航栏 ===== */
.navbar {
    background: var(--card-bg);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow);
}
.navbar-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}
.logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--text);
    display: flex;
    align-items: center;
    gap: 8px;
}
.logo-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, var(--primary), #8b5cf6);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 18px;
}
.nav-links { display: flex; gap: 24px; list-style: none; }
.nav-links a {
    color: var(--text-light);
    font-size: 15px;
    font-weight: 500;
    transition: color 0.2s;
}
.nav-links a:hover, .nav-links a.active {
    color: var(--primary);
    text-decoration: none;
}

/* ===== Hero区域 ===== */
.hero {
    background: linear-gradient(135deg, #1e3a8a 0%, #7c3aed 100%);
    color: white;
    padding: 60px 20px;
    text-align: center;
}
.hero h1 {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 16px;
}
.hero p {
    font-size: 18px;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto 24px;
}
.hero-badges {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}
.hero-badge {
    background: rgba(255,255,255,0.15);
    backdrop-filter: blur(10px);
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 14px;
}

/* ===== 容器 ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 20px;
}
.container-narrow {
    max-width: 800px;
    margin: 0 auto;
    padding: 40px 20px;
}

/* ===== 区块标题 ===== */
.section-title {
    font-size: 24px;
    font-weight: 700;
    margin-bottom: 8px;
}
.section-subtitle {
    color: var(--text-light);
    margin-bottom: 24px;
}

/* ===== 卡片网格 ===== */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}
.card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 24px;
    box-shadow: var(--shadow);
    transition: all 0.3s;
    border: 1px solid var(--border);
}
.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}
.card-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 16px;
}
.card-icon.blue { background: #dbeafe; color: #2563eb; }
.card-icon.green { background: #d1fae5; color: #059669; }
.card-icon.orange { background: #fed7aa; color: #ea580c; }
.card-icon.purple { background: #ede9fe; color: #7c3aed; }
.card-icon.red { background: #fee2e2; color: #dc2626; }
.card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
}
.card p {
    color: var(--text-light);
    font-size: 14px;
    margin-bottom: 16px;
}
.card-meta {
    display: flex;
    gap: 12px;
    font-size: 12px;
    color: var(--text-light);
}
.card-meta span {
    display: flex;
    align-items: center;
    gap: 4px;
}

/* ===== 教程页面 ===== */
.tutorial-header {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 32px;
    margin-bottom: 24px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.tutorial-header h1 {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 12px;
}
.tutorial-meta {
    display: flex;
    gap: 20px;
    color: var(--text-light);
    font-size: 14px;
    flex-wrap: wrap;
}
.tutorial-meta span {
    display: flex;
    align-items: center;
    gap: 6px;
}
.difficulty {
    padding: 2px 10px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 600;
}
.difficulty.easy { background: #d1fae5; color: #059669; }
.difficulty.medium { background: #fef3c7; color: #d97706; }
.difficulty.hard { background: #fee2e2; color: #dc2626; }

.tutorial-content {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 32px;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.tutorial-content h2 {
    font-size: 22px;
    font-weight: 700;
    margin: 32px 0 16px;
    padding-bottom: 8px;
    border-bottom: 2px solid var(--border);
}
.tutorial-content h2:first-child { margin-top: 0; }
.tutorial-content h3 {
    font-size: 18px;
    font-weight: 600;
    margin: 24px 0 12px;
}
.tutorial-content p {
    margin-bottom: 16px;
    color: #334155;
}
.tutorial-content ul, .tutorial-content ol {
    margin: 12px 0 16px 24px;
}
.tutorial-content li {
    margin-bottom: 8px;
    color: #334155;
}

/* 代码块 */
.code-block {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 16px 20px;
    border-radius: 8px;
    overflow-x: auto;
    margin: 16px 0;
    font-family: 'Consolas', 'Monaco', monospace;
    font-size: 14px;
    line-height: 1.6;
}
.code-block .comment { color: #64748b; }
.code-block .keyword { color: #c084fc; }
.code-block .string { color: #86efac; }

/* 提示框 */
.alert {
    padding: 16px 20px;
    border-radius: 8px;
    margin: 16px 0;
    border-left: 4px solid;
}
.alert-info {
    background: #eff6ff;
    border-color: #3b82f6;
    color: #1e40af;
}
.alert-warning {
    background: #fffbeb;
    border-color: #f59e0b;
    color: #92400e;
}
.alert-danger {
    background: #fef2f2;
    border-color: #ef4444;
    color: #991b1b;
}
.alert-success {
    background: #f0fdf4;
    border-color: #22c55e;
    color: #166534;
}
.alert strong { display: block; margin-bottom: 4px; }

/* 步骤 */
.step {
    display: flex;
    gap: 16px;
    margin: 24px 0;
}
.step-number {
    flex-shrink: 0;
    width: 36px;
    height: 36px;
    background: var(--primary);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 16px;
}
.step-content { flex: 1; }
.step-content h4 {
    font-size: 17px;
    font-weight: 600;
    margin-bottom: 8px;
}

/* 表格 */
.table-wrap {
    overflow-x: auto;
    margin: 16px 0;
}
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 14px;
}
th, td {
    padding: 12px 16px;
    text-align: left;
    border-bottom: 1px solid var(--border);
}
th {
    background: #f1f5f9;
    font-weight: 600;
    color: var(--text);
}
tr:hover { background: #f8fafc; }

/* ===== 对比表格 ===== */
.compare-table {
    background: var(--card-bg);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.compare-table table { margin: 0; }
.compare-table .recommended {
    background: #f0fdf4;
}
.compare-table .recommended td:first-child {
    font-weight: 700;
    color: #166534;
}

/* ===== 底部 ===== */
.footer {
    background: #1e293b;
    color: #94a3b8;
    padding: 40px 20px;
    margin-top: 60px;
}
.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 40px;
}
.footer h4 {
    color: white;
    font-size: 16px;
    margin-bottom: 16px;
}
.footer ul { list-style: none; }
.footer li { margin-bottom: 8px; }
.footer a { color: #94a3b8; font-size: 14px; }
.footer a:hover { color: white; }
.footer-bottom {
    max-width: 1200px;
    margin: 32px auto 0;
    padding-top: 24px;
    border-top: 1px solid #334155;
    text-align: center;
    font-size: 13px;
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .hero h1 { font-size: 28px; }
    .hero p { font-size: 16px; }
    .card-grid { grid-template-columns: 1fr; }
    .footer-inner { grid-template-columns: 1fr; gap: 24px; }
    .tutorial-content { padding: 20px; }
    .tutorial-header { padding: 20px; }
}