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

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --text-color: #333;
    --light-gray: #f8f9fa;
    --border-color: #e0e0e0;
    --white: #ffffff;
}

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

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

header {
    background-color: var(--white);
    border-bottom: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-bottom: 3rem;
}

header h1 {
    color: var(--primary-color);
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

header h1 a {
    color: var(--primary-color);
    text-decoration: none;
}

header h1 a:hover {
    color: var(--secondary-color);
}

.tagline {
    color: #666;
    font-size: 1.1rem;
}

.search-section {
    margin-bottom: 2rem;
}

.search-box {
    width: 100%;
    max-width: 600px;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 2px solid var(--border-color);
    border-radius: 8px;
    outline: none;
    transition: border-color 0.3s;
}

.search-box:focus {
    border-color: var(--secondary-color);
}

.filter-section {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 2rem;
}

.filter-btn {
    padding: 0.5rem 1.25rem;
    background-color: var(--white);
    border: 2px solid var(--border-color);
    border-radius: 20px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: all 0.3s;
}

.filter-btn:hover {
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}

.filter-btn.active {
    background-color: var(--secondary-color);
    color: var(--white);
    border-color: var(--secondary-color);
}

.posts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.post-card {
    background-color: var(--white);
    border-radius: 8px;
    padding: 1.75rem;
    border: 1px solid var(--border-color);
    transition: transform 0.3s, box-shadow 0.3s;
    cursor: pointer;
}

.post-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.post-card .category {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    background-color: var(--light-gray);
    color: var(--secondary-color);
    border-radius: 4px;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 1rem;
    text-transform: uppercase;
}

.post-card h3 {
    color: var(--primary-color);
    font-size: 1.5rem;
    margin-bottom: 0.75rem;
    line-height: 1.3;
}

.post-card .excerpt {
    color: #666;
    margin-bottom: 1rem;
    line-height: 1.6;
}

.post-card .meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #999;
    font-size: 0.9rem;
}

.post-card .read-more {
    color: var(--secondary-color);
    font-weight: 500;
    text-decoration: none;
}

.no-results {
    text-align: center;
    padding: 3rem;
    color: #999;
    font-size: 1.1rem;
}

.post-content {
    background-color: var(--white);
    border-radius: 8px;
    padding: 3rem;
    margin-bottom: 3rem;
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.post-header {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.post-category {
    display: inline-block;
    padding: 0.35rem 1rem;
    background-color: var(--light-gray);
    color: var(--secondary-color);
    border-radius: 4px;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 1rem;
    text-transform: uppercase;
}

.post-title {
    color: var(--primary-color);
    font-size: 2.5rem;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.post-meta {
    color: #999;
    font-size: 0.95rem;
}

.post-meta span {
    margin-right: 1.5rem;
}

.post-body {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--text-color);
}

.post-body h3 {
    color: var(--primary-color);
    margin-top: 2rem;
    margin-bottom: 1rem;
    font-size: 1.75rem;
}

.post-body p {
    margin-bottom: 1.5rem;
}

.post-body ul, .post-body ol {
    margin-bottom: 1.5rem;
    padding-left: 2rem;
}

.post-body li {
    margin-bottom: 0.5rem;
}

.post-footer {
    margin-top: 3rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

.back-link {
    color: var(--secondary-color);
    text-decoration: none;
    font-weight: 500;
    font-size: 1.05rem;
}

.back-link:hover {
    text-decoration: underline;
}

footer {
    background-color: var(--white);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    margin-top: 4rem;
    text-align: center;
    color: #666;
}

@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }

    .posts-grid {
        grid-template-columns: 1fr;
    }

    .post-content {
        padding: 1.5rem;
    }

    .post-title {
        font-size: 2rem;
    }
}