style.css

body{
    font-family: Arial, sans-serif;
    background-color: rgb(224, 222, 222);
}

h1{
    color: blue;
}

form{
    background-color: white;
    text-align: center;
    width: 300px;;
    margin: auto;
    padding: 25px;
    border-radius: 10px;
    box-shadow: 5px 5px 15px rgb(139, 138, 138);
}
#temp{
    width: 50%;
    text-align: center;
    font-size: 2em;
    border-radius: 5px;
    box-shadow: 5px 5px 15px rgb(138, 137, 137);
    margin : 20px;
}
label{
    font-size: 1.5em;
    font-weight: bold;
}
button{
    font-size: 1.5em;
    margin-top: 15px;
    color: rgb(255, 255, 255);
    background-color: black;
    border-radius: 5px;
    cursor: pointer;
}
button:hover{
    background-color: white;
    color: black;
}
#result{
    font-size: 1.5em;
    font-weight: bold;
}