style1.css

body {
    background-color: hwb(143 20% 14%);
}

.container {
    max-width: 400px;
    margin: 200px auto;
    padding: 20px;
    background-color: #f2f2f2;
    border: 2px solid #1e5f8a;
    border-radius: 5px;
    box-shadow: 2px 10px 10px rgba(0, 0, 0, 0.2);
} 

h2 {
    margin-top: 0;
    color: #000;
    text-align: center;
    text-decoration: underline;
}

form {
    margin-bottom: 20px;
    display: flex;
    flex-direction: column;
}

label {
    font-size: large;
    font-weight: 600;
    margin-bottom: 5px;
    color: #000;
}

input[type="number"],
select {
    width: 95%;
    padding: 10px;
    border: none;
    background: #fff;
    border-radius: 5px;
    box-shadow: 0px 0px 5px rgba(0, 0, 0, 0.2);
    margin-bottom: 10px;
}

input[type="number"]:focus,
select:focus {
    outline: none;
    box-shadow: 0px 0px 5px #3498db;
}

select {
    width: 100%;
}

input[type="submit"] {
    padding: 10px;
    margin-top: 10px;
    background-color: #3498db;
    border: none;
    border-radius: 3px;
    color: #fff;
    cursor: pointer;
    transition: background-color 0.5s ease;
}

input[type="submit"]:hover {
    background-color: #2187b5;
}

#result {
    font-weight: bold;
    margin-top: 20px;
    color: #3498db;
}