@media only screen and (max-width: 750px) {
    #form {
        width: 600px;
    }
    #form div p {
        font-size: 18px;
    }
    
    #form div input {
        font-size: 14px;
        letter-spacing: 3px;
    }
}

@media only screen and (max-width: 650px) {
    #form {
        width: 580px;
    }
}

@media only screen and (max-width: 550px) {
    #form {
        width: 480px;
    }
    #form div p {
        font-size: 16px;
    }
    
    #form div input {
        font-size: 13px;
        letter-spacing: 2px;
    }
}

@media only screen and (max-width: 450px) {
    #form {
        width: 380px;
    }
    .heading-1 {
        font-size: 24px;
    }
}

@media only screen and (max-width: 400px) {
    #form {
        width: 320px;
    }
    .heading-1 {
        font-size: 22px;
    }
    #form div p {
        font-size: 15px;
    }
    
    #form div input {
        font-size: 11px;
        letter-spacing: 1px;
    }
}

@media only screen and (max-width: 350px) {
    #form {
        width: 250px;
    }
}