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

:root {
    --primary: #2563eb;
    --secondary: #64748b;
    --success: #10b981;
    --danger: #ef4444;
    --warning: #f59e0b;
    --bg: #f8fafc;
    --card: #ffffff;
    --text: #1e293b;
    --border: #e2e8f0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
header {
    background: var(--card);
    border-bottom: 2px solid var(--primary);
    padding: 20px 0;
    margin-bottom: 30px;
}

header h1 {
    font-size: 2rem;
    color: var(--primary);
    margin-bottom: 10px;
}

header p {
    color: var(--secondary);
}

/* Navigation */
nav {
    background: var(--card);
    padding: 15px 0;
    margin-bottom: 30px;
    border-radius: 8px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

nav ul {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

nav a {
    display: block;
    padding: 10px 20px;
    background: var(--bg);
    color: var(--text);
    text-decoration: none;
    border-radius: 6px;
    transition: all 0.3s;
}

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

/* Grid */
.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

/* Card */
.card {
    background: var(--card);
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
    transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.card h3 {
    color: var(--primary);
    margin-bottom: 10px;
}

.card .meta {
    color: var(--secondary);
    font-size: 0.9rem;
    margin-bottom: 10px;
}

.card .excerpt {
    color: var(--text);
    margin-bottom: 15px;
}

.card a {
    display: inline-block;
    padding: 8px 16px;
    background: var(--primary);
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-size: 0.9rem;
}

.card a:hover {
    background: #1d4ed8;
}

/* Tags */
.tags {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-top: 10px;
}

.tag {
    display: inline-block;
    padding: 4px 12px;
    background: var(--bg);
    color: var(--secondary);
    border-radius: 12px;
    font-size: 0.85rem;
}

.tag.buy { background: #dcfce7; color: var(--success); }
.tag.sell { background: #fee2e2; color: var(--danger); }
.tag.sideway { background: #fef3c7; color: var(--warning); }

/* Article */
article {
    background: var(--card);
    border-radius: 8px;
    padding: 30px;
    max-width: 800px;
    margin: 0 auto;
}

article h1 {
    color: var(--primary);
    margin-bottom: 10px;
}

article .meta {
    color: var(--secondary);
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border);
}

article img {
    max-width: 100%;
    border-radius: 8px;
    margin: 20px 0;
}

article pre {
    background: var(--bg);
    padding: 15px;
    border-radius: 6px;
    overflow-x: auto;
}

article table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

article th, article td {
    padding: 10px;
    border: 1px solid var(--border);
    text-align: left;
}

article th {
    background: var(--bg);
    font-weight: 600;
}

/* Footer */
footer {
    margin-top: 50px;
    padding: 20px;
    text-align: center;
    color: var(--secondary);
    border-top: 1px solid var(--border);
}

/* Responsive */
@media (max-width: 768px) {
    nav ul {
        flex-direction: column;
    }
    
    .posts-grid {
        grid-template-columns: 1fr;
    }
}