xxxxxxxxxx
/* You can't really set the width of the actual window, but
you can set the minimum width of the content, which would
create a scrollbar when the window size gets smaller than
the body */
/* Also, it's a bad idea to limit the user's ability to resize
the window, mostly because of bad UX */
body {
min-width: /* minimum width */;
min-height: /* minimum height */;
}