Aligning two divs side-by-side [duplicate]

Answer 1

I don't understand why Nick is using margin-left: 200px; instead off floating the other div to the left or right, I've just tweaked his markup, you can use float for both elements instead of using margin-left.

Demo

#main {
    margin: auto;
    width: 400px;
}

#sidebar    {
    width: 100px;
    min-height: 400px;
    background: red;
    float: left;
}

#page-wrap  {
    width: 300px;
    background: #0f0;
    min-height: 400px;
    float: left;
}

.clear:after {
    clear: both;
    display: table;
    content: "";
}

Also, I've used .clear:after which am calling on the parent element, just to self clear the parent.