style.css

* {
    margin: 0;
    padding: 0;
}
body {
    background-color: #272640;
    color: #179092;
    font-family:'Courier New', Courier, monospace;
}

main {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    position:absolute;
    background: #302f4d;
    padding:20px;
    border: 1px solid #45335c;
    width:300px;
    text-align:center;

}

h1 {
    text-align:center;
    font-size: 16px;
    color:#5dc7c9;
    font-weight: normal;
    margin-bottom: 10px;
}

#calcular {
    border: none;
    padding:5px;
    cursor: pointer;
    background-color: #292844;
    color: white;
    margin-top:10px;
    border: 1px solid #45335c;
    font-size:16px;
}

input {
    background-color: #292844;
    color: white;
    padding:5px;
    border: 1px solid #45335c;
}

.result {
    background-color: #292844;
    color: white;
    margin-top:10px;
    border: 1px solid #45335c;
    padding:20px;
}

footer {
    color: #065a60;
    margin-top:20px;
    font-size:12px;
}