How to remove the style from my submit button?

Ho to remove button styles through CSS.. no border, no outlines, no shade and no glare.. just one plain color.

You could inject this CSS code to your form in order to remove all the style and leave just a flat background color: 

.form-submit-button {

    background: gray;

    box-shadow: 0px 0px 0px transparent;

    border: 0px solid transparent;

    text-shadow: 0px 0px 0px transparent;

}

.form-submit-button:hover {

    background: gray;

    box-shadow: 0px 0px 0px transparent;

    border: 0px solid transparent;

    text-shadow: 0px 0px 0px transparent;

}

Feel free to change the background color to the one you need your button to have. 

Hope this helps.