body {
    background-color: #f5f5f5;
}

.navbar {
    box-shadow: 0 2px 4px rgba(0,0,0,.1);
}

.card {
    border: none;
    box-shadow: 0 2px 4px rgba(0,0,0,.1);
    margin-bottom: 20px;
}

.card-header {
    background-color: #f8f9fa;
    border-bottom: 1px solid #dee2e6;
}

#qrcode-container {
    min-height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px dashed #dee2e6;
    border-radius: 8px;
}

.nav-tabs .nav-link {
    color: #495057;
}

.nav-tabs .nav-link.active {
    font-weight: 500;
}

.table th {
    border-top: none;
    font-weight: 500;
}

.text-muted {
    font-size: 0.875rem;
}

#delay-value {
    font-weight: bold;
}