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

:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --danger-color: #ef4444;
    --dark-bg: #1f2937;
    --light-bg: #f9fafb;
    --card-bg: #ffffff;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --border-color: #e5e7eb;
    --shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.1), 0 1px 2px 0 rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Header */
header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 40px 0;
    box-shadow: var(--shadow-lg);
}

.header-content {
    text-align: center;
    margin-bottom: 30px;
}

.header-content h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 10px;
}

.tagline {
    font-size: 1.1rem;
    opacity: 0.95;
}

/* Search */
.search-container {
    max-width: 700px;
    margin: 30px auto;
    position: relative;
}

#searchInput {
    width: 100%;
    padding: 15px 45px 15px 20px;
    font-size: 1rem;
    border: none;
    border-radius: 8px;
    box-shadow: var(--shadow-lg);
    outline: none;
}

#searchInput:focus {
    box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.3);
}

.clear-btn {
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-secondary);
    cursor: pointer;
    padding: 5px 10px;
    display: none;
}

.clear-btn:hover {
    color: var(--text-primary);
}

/* Filters */
.filter-container {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    justify-content: center;
    margin-top: 20px;
}

.filter-group {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.1);
    padding: 8px 15px;
    border-radius: 6px;
}

.filter-group label {
    font-weight: 500;
    font-size: 0.9rem;
}

.filter-group select {
    padding: 6px 12px;
    border: none;
    border-radius: 4px;
    background: white;
    color: var(--text-primary);
    font-size: 0.9rem;
    cursor: pointer;
    outline: none;
}

.reset-btn {
    padding: 8px 20px;
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
    border-radius: 6px;
    cursor: pointer;
    font-weight: 500;
    transition: all 0.2s;
}

.reset-btn:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Main Content */
main {
    padding: 40px 20px;
}

.stats-bar {
    background: var(--card-bg);
    padding: 15px 20px;
    border-radius: 8px;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.stats-bar span {
    font-weight: 500;
    color: var(--text-secondary);
}

/* Resources Grid */
.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 25px;
}

.resource-card {
    background: var(--card-bg);
    border-radius: 10px;
    padding: 25px;
    box-shadow: var(--shadow);
    transition: transform 0.2s, box-shadow 0.2s;
    border-left: 4px solid var(--primary-color);
    display: flex;
    flex-direction: column;
}

.resource-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.resource-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 12px;
    gap: 10px;
}

.resource-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin: 0;
    flex: 1;
}

.category-badge {
    display: inline-block;
    padding: 4px 10px;
    background: var(--primary-color);
    color: white;
    border-radius: 4px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    white-space: nowrap;
}

.resource-description {
    color: var(--text-secondary);
    margin-bottom: 15px;
    flex: 1;
    line-height: 1.5;
}

.resource-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 15px;
}

.meta-badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 10px;
    background: var(--light-bg);
    border-radius: 4px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    gap: 5px;
}

.level-beginner { background: #dbeafe; color: #1e40af; }
.level-intermediate { background: #fef3c7; color: #92400e; }
.level-advanced { background: #fee2e2; color: #991b1b; }

.resource-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 15px;
}

.tag {
    padding: 3px 8px;
    background: #f3f4f6;
    border-radius: 3px;
    font-size: 0.75rem;
    color: var(--text-secondary);
}

.resource-link {
    display: inline-block;
    padding: 10px 20px;
    background: var(--primary-color);
    color: white;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 500;
    text-align: center;
    transition: background 0.2s;
    margin-top: auto;
}

.resource-link:hover {
    background: var(--secondary-color);
}

/* No Results */
.no-results {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.no-results h2 {
    color: var(--text-primary);
    margin-bottom: 10px;
}

/* Footer */
footer {
    background: var(--dark-bg);
    color: white;
    text-align: center;
    padding: 30px 20px;
    margin-top: 60px;
}

footer p {
    margin: 8px 0;
}

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

footer a:hover {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header-content h1 {
        font-size: 1.8rem;
    }

    .tagline {
        font-size: 1rem;
    }

    .filter-container {
        flex-direction: column;
        align-items: stretch;
    }

    .filter-group {
        flex-direction: column;
        align-items: flex-start;
    }

    .filter-group select {
        width: 100%;
    }

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

    .stats-bar {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    header {
        padding: 30px 0;
    }

    .resource-card {
        padding: 20px;
    }
}