How do you translate Figma Smart Animate into CSS or JS?

WHAT THIS TESTS: This question probes whether you can decompose a design tool's abstraction into concrete implementation details. Interviewers want to see that you understand animation performance at the browser level, that you respect the precision of design specs, and that you know when CSS alone is sufficient versus when JavaScript measurement and orchestration are required. It is fundamentally about cross-functional fluency: speaking both designer and browser.

A GOOD ANSWER COVERS: A strong response walks through four steps in order. First, translate Figma easing curves into exact mathematical equivalents, such as cubic-bezier values for CSS or matching spring physics in Framer Motion or GSAP. Second, convert durations precisely, noting that 300ms in Figma is 300ms in code, not an eyeballed approximation. Third, decompose Smart Animate into animatable properties, preferring transform and opacity because they composite on the GPU, while treating width, height, top, or left changes as layout shifts that may need FLIP or a measurement pass. Fourth, identify state management boundaries, deciding whether a hover or toggle lives in CSS transitions or requires a JS animation library because of chained timelines, gesture interruption, or dynamic layout.

COMMON WRONG ANSWERS: Red flags include treating Smart Animate as a magic black box that cannot be inspected, guessing easing values like ease-in-out instead of reading the exact curve, or animating layout properties like margin or width directly without considering reflow cost. Another danger sign is insisting on a single tool for everything, such as pure CSS for a complex multi-step sequence that clearly needs orchestration, or conversely pulling in a heavy JS library for a simple opacity fade.

LIKELY FOLLOW-UPS: Expect the interviewer to push on performance budgets, asking how you keep animations at 60fps on low-end devices. They may ask how you handle interrupted animations, how you version control design tokens for motion, or how you validate that the implemented animation matches the Figma spec, perhaps using screen recording and pixel diffing. A senior candidate might also be asked to compare spring-based physics in design tools versus CSS cubic-bezier limitations.

ONE CONCRETE EXAMPLE: Imagine a card that Smart Animates from a list to a detail view. In Figma, the card scales and translates with an ease-out curve of 200ms. In code, you would use transform scale and translate3d with a cubic-bezier of 0, 0, 0.2, 1 for 200ms. If the card also changes width and height, you cannot animate those smoothly with CSS alone without causing layout thrash, so you would either capture the initial bounding rect, apply a FLIP inversion with requestAnimationFrame, or use a library like GSAP Flip that automates the measurement and interpolation.