You want margin-inline-start

Dropping left and right for logical properties

David Bushell makes the case for a shift in habit in his post “Changing CSS for Good“: he's removing “left“ and “right“ from his vocabulary entirely, arguing that

Logical Properties and Values are the new CSS normal. Swapping left/right for inline start/end, and top/bottom for block start/end, can be as simple as that — normal inline flow, Flexbox, and Grid layouts reverse themselves automatically.

That framing is what prompted a “You want…“-style writeup, and Geoff has been documenting these properties in depth in the Almanac.

• Inline start/end stand in for left/right.
• Block start/end stand in for top/bottom.