:root {
    --primary: #3498db;
    --success: #2ecc71;
    --warning: #f39c12;
    --danger: #e74c3c;
    --info: #9b59b6;
    --secondary: #95a5a6;
    --light: #ecf0f1;
    --dark: #34495e;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #f5f7fa;
    color: #333;
    line-height: 1.4;
    padding: 15px;
}

.container {
    max-width: 960px;
    margin: 0 auto;
}

header {
    text-align: center;
    margin-bottom: 20px;
    padding: 15px 0;
}

h1 {
    color: var(--dark);
    font-size: 1.8rem;
    margin-bottom: 5px;
}

.subtitle {
    color: var(--secondary);
    font-size: 0.9rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.stat-card {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    padding: 10px 18px;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.stat-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
}

.stat-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 3px;
}

.stat-title {
    font-size: 0.9rem;
    color: var(--secondary);
    font-weight: 500;
}

.stat-value {
    font-size: 1.8rem;
    font-weight: 700;
    margin: 2px 0;
}

.last-updated {
    text-align: right;
    color: var(--secondary);
    font-size: 0.8rem;
    margin-top: 20px;
    padding: 8px;
}

/* Card colors */
.card-total {
    border-top: 3px solid var(--primary);
}

.card-monthly {
    border-top: 3px solid var(--success);
}

.card-weekly {
    border-top: 3px solid var(--warning);
}

.card-today {
    border-top: 3px solid var(--danger);
}

.card-yesterday {
    border-top: 3px solid var(--info);
}

.card-recharge {
    border-top: 3px solid var(--dark);
}

/* Responsive adjustments */
@media (max-width: 768px) {
    h1 {
        font-size: 1.5rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
        gap: 12px;
    }
    
    .stat-value {
        font-size: 1.5rem;
    }
    
    .stat-card {
        padding: 10px 15px;
    }
}