FrontendLegacyAround since 2010
BEM
Also written as Block Element Modifier
A CSS class-naming convention (Block__Element--Modifier) meant to keep large stylesheets predictable and avoid styles accidentally colliding or overriding each other.
Think of it like
Like a strict, hierarchical filing/labeling system for a shared filing cabinet, so nobody's folder gets mixed up with someone else's just because the drawers are close together.
Junior or senior?
Junior sounds like
Names BEM as a naming convention they've heard of.
Senior sounds like
Can explain what specific collision problem it solved on a large plain-CSS codebase, or why their team moved to component-scoped styles instead.
Ask them
“What naming or scoping convention did your team use to keep CSS classes from colliding on a large project?”