body {
    font-family: Arial, sans-serif;
    margin: 50px;
    background-color: aqua;

}
.container {
    max-width: 400px;
    margin: 0 auto;
}
input, button {
    width: 100%;
    padding: 10px;
    margin: 10px 0;
    box-sizing: border-box;

}
button{
    cursor: pointer;
}
.result {
    margin-top: 20px;
    font-size: 1.2em;
}