How To Remove Div Background Color

I have set the background of my site to an image by doing this:

html {
    font-family: adamina;
    background: url("../images/beach2.jpg") no-repeat center center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

Then I created a div and as soon as I give the div a border it has this white background that I don't want to see. I tried setting background color to transparent but it's still there. Is there anyway I can remove this white background from the div?