.fence-calculator {
    padding: 20px;
    background: #ffffff;
    border-radius: 10px;
    max-width: 350px;
}
.fence-calculator input,
.fence-calculator select {
    width: 100%;
    margin-bottom: 10px;
}
button {
    width: 100%;
    padding: 10px;
    cursor: pointer;
}