#iifh-container {
    max-width: 600px;
    margin: 20px auto;
    padding: 20px;
    background: #fafafa;
    border: 1px solid #ddd;
    border-radius: 8px;
}
.iifh-selects {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}
.iifh-selects select {
    flex: 1 1 45%;
    padding: 10px;
}
#calculate {
    width: 100%;
    margin-top: 15px;
    padding: 10px;
    background: #3498db;
    color: white;
    border: none;
    border-radius: 5px;
}
#calculate:hover {
    background: #2980b9;
}
#result {
    margin-top: 15px;
    font-weight: bold;
}