body {
    font-family: cursive;
    background: rgb(238, 174, 202);
    background: radial-gradient(circle,
            rgba(238, 174, 202, 1) 0%,
            rgba(148, 187, 233, 1) 100%);
    height: 100vh;
    margin: 0;
}

header {
    display: block;
    text-align: center;
    margin-bottom: 20px;
    vertical-align: middle;
}

#container {
    margin-top: 10vh;
}

#calculator {
    margin: auto;
    width: 500px;
    padding: 30px;
    border: 1px solid;
    border-radius: 5px;
    background-color: cyan;
    text-align: center;
}

input[type="number"],
button {
    width: 100%;
    padding: 20px;
    margin-bottom: 10px;
    box-sizing: border-box;
}

button {
    background-color: #007bff;
    color: #ffffff;
    border: none;
    cursor: pointer;
}

button:hover {
    background-color: #002f61;
}