Changing layout in sugarcube 2

I am trying to setup the layout for multiple panes using multiple divs. my simple test code i cant seem to get working each box is about 1/5th lower than the previous, so they don't line up at all. I am also wondering if flexbox does not work with sugarcube, I am not sure if I did something wrong but when I tried using it, I got a full page of garbage text.

css code

.floatbox{
margin: 1%;
float:left;
width:15%;
height:400px;
background-color: green;
}

code in the passage

<div class="floatbox">text</div>

<div class="floatbox">text</div>

<div class="floatbox">text</div>

Thanks