Often times it is useful to be able to center the content of your design in a browser window. By default a block-level (div or container) element always takes up the full width available (stretches out to the left and right as far as it can).
However it's possible to set the width of a block-level element and prevent it from stretching out to the edges of its container.
1. Use a Div element as a first block-level element
2. Check 'Margin Auto' checkbox from the setting side panel
3. Add your width in px or in % in the Max Width textbox from the DIV setting side panel.
4. Add any elements inside that block-level element