How to change an Ordered list sub-list's indent

Take a list of 6 items. Make it a numbered list (ordered). Select items 3 and 4 and indent. Lines 3 and 4 become a sublist designated with an i and ii. The following lines become labeled 3 and 4. So far good. Now indent the sublist once again. When viewing this page in Chrome it becomes a list 1,2,3,i,ii,1,2. And the second set of 1 and 2 are also indented at the same level as the sublist. Looking at the page in firefox shows the list as if it was not indented twice. But inspecting the HTML shows that the last two list items are not on a ol tag. That list items with no ordered list tag. So what is the proper way to indent a sublist beyond the 14 pixels that it does by default? Is there a way to set this to 25pixels?