Exposed filters "grabbed" by CSS

Hi,

I have a view of images set by CSS to make a "Masonry".

Works great, except for the fact that my exposed filters are now part of the view (in the first column) instead of beign on "top" of it.

In "Advanced" I have set the "CSS Class" to : "Brique"
For the "Format" settings of "Unformated list", I have set the "Row class" to "brique-item".

Cant see why the exposed filters are now part of the view. Could it be a "side effect" of Colorbox?

Thanks.

My CSS (if this can be usefull):

.brique {
    margin: 1.5em 0;
    padding: 0;
    -moz-column-gap: 10px;
    -webkit-column-gap: 10px;
    column-gap: 3em;
    font-size: .85em;
}

.brique-item {
    display: inline-block;
    background: #fff;
    border: 1px solid lightgrey;
    padding: 15px;
    margin: 0 0 1.5em;
    text-align: center;
    width: 100%;
    box-sizing: border-box;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-shadow: 2px 2px 4px 0 #ccc;
    
}