.psfc-calculator {
    max-width: 400px;
    padding: 20px;
    border: 2px solid #ddd;
    border-radius: 10px;
    background: #f9f9f9;
}
.psfc-calculator input {
    width: 100%;
    padding: 8px;
    margin-bottom: 10px;
}
.psfc-calculator button {
    padding: 8px 16px;
    background: #0073aa;
    color: white;
    border: none;
    cursor: pointer;
}
.psfc-calculator button:hover {
    background: #005f8d;
}
#psfc-result {
    margin-top: 15px;
    font-weight: bold;
}