.stats-container {
    max-width: 1000px;
    margin: 2rem auto;
}

.stats-header {
    text-align: center;
    margin-bottom: 3rem;
}

.stats-header h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.stats-overview {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: #111111;
    border: 1px solid #333333;
    padding: 2rem;
    text-align: center;
    transition: border-color 0.3s ease;
}

.stat-card:hover {
    border-color: #ffffff;
}

.stat-card h3 {
    font-size: 2.5rem;
    font-weight: 700;
    color: #ffffff;
    margin-bottom: 0.5rem;
}

.stat-card p {
    color: #cccccc;
    font-size: 0.9rem;
    margin: 0;
}

.chart-section {
    background: #111111;
    border: 1px solid #333333;
    padding: 2rem;
    margin-bottom: 2rem;
}

.chart-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: #ffffff;
}

.chart-container {
    position: relative;
    height: 300px;
    margin-bottom: 1rem;
}

.recent-tests {
    background: #111111;
    border: 1px solid #333333;
    padding: 2rem;
}

.recent-tests h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: #ffffff;
}

.test-table {
    width: 100%;
    border-collapse: collapse;
}

.test-table th,
.test-table td {
    padding: 1rem;
    text-align: left;
    border-bottom: 1px solid #333333;
}

.test-table th {
    color: #ffffff;
    font-weight: 600;
    border-bottom: 2px solid #ffffff;
}

.test-table td {
    color: #cccccc;
}

.test-table tr:hover {
    background: rgba(255, 255, 255, 0.05);
}

.difficulty-badge {
    display: inline-block;
    padding: 0.25rem 0.5rem;
    font-size: 0.7rem;
    border: 1px solid #333333;
    color: #cccccc;
}

.difficulty-easy {
    border-color: #4CAF50;
    color: #4CAF50;
}

.difficulty-medium {
    border-color: #FF9800;
    color: #FF9800;
}

.difficulty-hard {
    border-color: #F44336;
    color: #F44336;
}

.achievements-section {
    background: #111111;
    border: 1px solid #333333;
    padding: 2rem;
    margin-bottom: 2rem;
}

.achievements-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: #ffffff;
}

.achievements-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 1rem;
}

.achievement-card {
    background: #000000;
    border: 1px solid #333333;
    padding: 1.5rem;
    text-align: center;
    transition: all 0.3s ease;
}

.achievement-card.unlocked {
    border-color: #ffffff;
    background: rgba(255, 255, 255, 0.05);
    transform: scale(1.02);
}

.achievement-card.locked {
    opacity: 0.5;
}

.achievement-card:hover {
    transform: translateY(-2px);
}

.achievement-icon {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.achievement-name {
    font-weight: 600;
    margin-bottom: 0.5rem;
    color: #ffffff;
}

.achievement-desc {
    font-size: 0.8rem;
    color: #cccccc;
}

.no-data {
    text-align: center;
    color: #cccccc;
    padding: 3rem;
    font-style: italic;
}

.export-btn {
    margin-top: 1rem;
    padding: 0.5rem 1rem;
    background: transparent;
    color: #ffffff;
    border: 1px solid #333333;
    cursor: pointer;
    font-family: 'JetBrains Mono', monospace;
    transition: all 0.3s ease;
}

.export-btn:hover {
    border-color: #ffffff;
    background: #ffffff;
    color: #000000;
}

.chart-loading {
    display: flex;
    justify-content: center;
    align-items: center;
    height: 300px;
    color: #cccccc;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #333333;
    border-top: 4px solid #ffffff;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

@media (max-width: 768px) {
    .stats-overview {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }

    .test-table {
        font-size: 0.8rem;
    }

    .test-table th,
    .test-table td {
        padding: 0.5rem;
    }

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

    .chart-container {
        height: 250px;
    }
}