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

Answer 1

This will work fine I think, though you might need to reset "top:200px;" according to your needs:

#main_content {
    top: 160px;
    left: 160px;
    width: 800px;
    min-height: 500px;
    height: auto;
    background-color: #2185C5;
    position: relative;
    border: 2px solid #CCCCCC;
}

#container {
    width: 100px;
    height: 20px;;
    margin: 0 auto;
    padding-top: 10px;
    position: relative;
    top: 200px;
    border: 2px solid #CCCCCC;
}