The size modes scale rem line heights to fractions (1.25rem = 22.857px in Large), and pixel rounding moved text up to 1.2px off center. Type scale line heights and the header's 3rem now round to whole px (no change in Normal). Segmented buttons, Reset to default and the project select drop core's vertical padding, which made the line overflow and sink. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>