You have selected the S2 style system, which is not controlled by overrides. Please see http://www.livejournal.com/support/faqbrowse.bml?faqid=173 for information on each style system and which users it is most appropriate for.
http://www.livejournal.com/support/faqbrowse.bml?faqid=168 contains information on switching your journal between the S1 and S2 style systems.
* Moved to S1 from Paid Accounts: {128} "How do I make a custom style?" & renamed to "How do I make a custom S1 style?" Replaced "style" with "S1 style" in text of FAQ. Rewrote second paragraph:
Old text: "If you are a free user and are interested in modifying the look of your journal, please see: "What are overrides? How do they work?" (http://www.livejournal.com/support/faqbrowse.bml?faqid=124)"
New text: "If you are a free user, you can use S1 overrides to customize your journal, or S2's customization wizard. Information on the difference between S1 and S2 can be found at http://www.livejournal.com/support/faqbrowse.bml?faqid=173. Information on S1 overrides can be found at http://www.livejournal.com/support/faqbrowse.bml?faqid=124. Information on S2's customization wizard can be found at http://www.livejournal.com/support/faqbrowse.bml?faqid=170."
* Moved to Customization from Paid Accounts: {14} "Why can't I use JavaScript or Flash in my styles?" & renamed to "Why can't I use JavaScript or Flash in my customization or entries?" Text of FAQ changed to include "entries" along with styles.
* Re-ordered S1 category to the following (final, unless anyone has better suggestions):
[edit] (20) {124} What are overrides? How do they work?
[edit] (30) {12} How do I change the font in my journal?
[edit] (40) {13} How do I change the number of journal entries per page?
[edit] (50) {96} How do I change what my comments links say?
[edit] (60) {97} How do I add a background image?
[edit] (70) {138} In what other ways can I customize my journal?
[edit] (80) {140} My overrides won't work. What's wrong?
[edit] (90) {141} I tried to customize my journal using overrides and now it won't display. Why?
[edit] (95) {174} Why has my overrides box disappeared?
[edit] (99) {128} How do I make a custom S1 style?