:root {
    --primary-color: #4e73df;
    --primary-light: #e6f0fd;
    --secondary-color: #f8f9fc;
    --dark-color: #2e3a4d;
    --success-color: #1cc88a;
    --danger-color: #e74a3b;
}

body {
    background-color: #f8f9fa;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
}

.card {
    border: none;
    border-radius: 12px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.1);
}

.input-group-text {
    background-color: var(--primary-color);
    color: white;
}

#shorten-btn {
    min-width: 120px;
}

#result-section {
    animation: fadeIn 0.5s ease-out;
}

.stats-container {
    display: flex;
    justify-content: space-around;
    margin-top: 1.5rem;
}

.stat-item {
    text-align: center;
}

.stat-value {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
}

.stat-label {
    color: var(--dark-color);
    opacity: 0.7;
    font-size: 0.9rem;
}

#qr-code {
    display: inline-block;
    padding: 10px;
    background: white;
    border: 1px solid #dee2e6;
    border-radius: 8px;
    margin: 0 auto;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

@media (max-width: 768px) {
    .card-body {
        padding: 1.5rem !important;
    }
    
    .stats-container {
        flex-direction: column;
        gap: 1rem;
    }
    
    .input-group {
        flex-wrap: wrap;
    }
    
    .input-group > * {
        width: 100%;
        margin-bottom: 0.5rem;
    }
}