FrontendHaltCSS·Intermediate·Conceptual·1 min read
What established box-sizing before border-box became the common default reset?
Short interview answer
content-box was the original CSS default, inherited from the specification's early design, and remains the default today unless explicitly overridden — border-box only became a common reset choice once its predictability advantages were widely recognized.
Key takeaway
Explain the underlying mental model clearly, then support it with a concrete example and its trade-offs.