html - "background-size: cover" does not cover mobile screen

Question

I have a photo background on my site using background-size:cover. It works for the most part but leaves a weird ~30px white space on my Galaxy S3 in portrait mode.

I've attached a screenshot. The 1px teal line is to illustrate the entire screen. Seems like the background stops right after the social media uls.

I tested this by removing the ul and the background attached it self to the bottom of the tagline text.

Also, here's my CSS pertaining mobile portait view:

@media only screen and (max-width: 480px) {

.logo {
    position: relative;
    background-size:70%;
    -webkit-background-size: 70%;
    -moz-background-size: 70%;
    -o-background-size: 70%;
    margin-top: 30px;
}   

h1 {
    margin-top: -25px;
    font-size: 21px;
    line-height: 21px;
    margin-bottom: 15px;
}

h2 {
    font-size: 35px;
    line-height: 35px;
}

.footer_mobile {
    display: block;
    margin-top: 20px;
    margin-bottom: 0px;
}

li {
    display: block;
    font-size: 1.3em;
}

This used to not happen, but I guess I accidentally bugged it while trying to solve another issue.

Answer 1

After hours of trying different things, adding min-height: 100%; to the bottom of html under the { background:... } worked for me.