S1

From SupportWiki

Style System 1, or S1, was LiveJournal's original style system. It relies primarily on overrides and the use of CSS, though users with Paid accounts can also create custom styles. Though it is no longer being updated with new features and lacks much of the flexibility of S2, many users still use this system because it is possible to achieve extensive customizations with overrides on a Basic account. These customizations often require both a Paid account and some programming knowledge to achieve in S2, and so S1 still enjoys widespread use over much of LiveJournal's userbase.