I'm trying to understand how to center elements within a div. I have this basic code I am working with and am trying to get the 'This is a button' element to be in the center
<body>
<div style="width:960px;background-color:#d7d7d7;">
<div style="
width:400px;
padding:10px;
height:auto;
background-color:#006699;
display:inline-block;
">
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</div>
<div style="
width:100px;
padding:10px;
height:auto;
background-color:#b1b1b1;
float:right;
display:inline-block;
margin:auto!important;
vertical-align:middle;
">
<p>This is a button</p>
</div>
</div>
</body>
It's essentially 1 div, divided into 2 with text on the left hand side and a 'This is a button' label to be in the center of the right side, but I can;t figure out how to get it to center, I've tried all sorts of methods.
All help/advice is appreciated.