how to change width & height in "bootstrap application wizard"

how to change width & height in "bootstrap application wizard"

im using bootstrap application wizard as my form entry, i can change the width with code

var options = { width:'900px', color:'red'};
var wizard = $("#wizard-demo").wizard(options);

but the wizard do not locate to middle of screen, any expect can help?

2nd, how to change the height of the wizard? hope it will appear in center after amend.