How can I center a div within another div? [duplicate]

Answer 1

Try to get the position:relative; in your #container. Add an exact width to #container:

#main_content {
    top: 160px;
    left: 160px;
    width: 800px;
    min-height: 500px;
    height: auto;
    background-color: #2185C5;
    position: relative;
}

#container {
    width: 600px;
    height: auto;
    margin: auto;
    padding: 10px;
}

Working demo