Question

I have a parent div #modal_share that contains a floating div modal_big_hline and a unfloated div modal_big_button_container (with clear: both).

modal_big_button_container‘s CSS is created to allow it to be the width of the parent div minus 25px on its left and right sides.

Problem: Changing the margin-top of modal_big_button_container does not cause it to shift up/down, instead it remains in the same position, although its margin can be seen to be changing using Chrome’s developer tools.

Why is this happening, and how can I solve this? Thanks!

CSS

#modal_share {
    width: 565px;
    height: 400px;
    position: relative;
    background: whiteSmoke;
    padding-top: 10px;      
    -webkit-border-radius: 10px;
    -moz-border-radius: 10px;
    border-radius: 10px;
    -webkit-box-shadow: 0px 3px 16px #222;
    -moz-box-shadow: 0px 3px 16px #222;
    box-shadow: 0px 3px 16px #222;
    display: none;  
}

.modal_big_hline {
    width: 100%;
    height: 1px;
    margin-top: 25px;
    border-top: 1px solid #CCC;
    float: left;
}

#modal_big_button_container {
    height: 14px;
    width: auto;
    margin: 10px 25px 0px 25px;
    clear: both;
}

HTML Structure

<div id="#modal_share">
    <div class="modal_big_hline"></div>
    <div id="modal_big_button_container"></div>
</div>

JSFiddle: http://jsfiddle.net/5LG2w/

Answer 1

try

modal_big_button_container{
    position: relative;
      top: 20px;
}

here is the fiddle – http://jsfiddle.net/5LG2w/2/.

or you can take the float out of .modal_big_hline. then your margin-top will work – http://jsfiddle.net/5LG2w/3/.

#modal_big_button_container {
    height: 14px;
    width: auto;
    margin: 10px 25px 0px 25px;
    clear: both;
    background: red;
}