body {
    background-color: #f8f9fa;
}

.card {
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.card-header {
    background-color: #f8f9fa;
    border-bottom: 2px solid #e9ecef;
}

.form-label {
    font-weight: 500;
}

.btn-primary {
    padding: 10px 30px;
}

.invalid-feedback {
    font-size: 0.875rem;
}

.preview-card {
    top: 20px;
    font-size: 0.9rem;
}

.bill-preview {
    background-color: #fff;
}

.preview-section {
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px dashed #dee2e6;
}

.preview-section:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.preview-section h6 {
    color: #495057;
    margin-bottom: 0.75rem;
    font-weight: 600;
}

@media (max-width: 768px) {
    .preview-card {
        position: relative !important;
        top: 0 !important;
        margin-bottom: 2rem;
    }
}

.opacity-50 {
    opacity: 0.5;
    pointer-events: none;
}

.opacity-50 input {
    background-color: #e9ecef;
}