What are the different ways in which we can include CSS in our HTML file?

0-2 years experience

1. 1You need to make a single paragraph text red on a static page. How would you add the CSS directly in the HTML?
2. 2If you want all headings on the page to share the same font, which inclusion method would you pick and why?
3. 3Show me the HTML tag you would use to link an external stylesheet called styles.css.

2-5 years experience

1. 1Your teammate added a <link> to a stylesheet but the styles aren't applying. Walk me through how you'd debug the issue.
2. 2We have a component that sometimes needs dynamic colors based on user input. Which CSS inclusion technique would you use and what trade‑offs does it have?
3. 3Explain why using inline styles for layout caused the page to load slower than expected.

5-8 years experience

1. 1Our web app has critical above‑the‑fold CSS that must load fast, but also large shared styles. How would you structure the inclusion methods to optimise load time and caching?
2. 2Design a theming approach for a large SPA that allows per‑brand customisation while keeping CSS maintainable. Which inclusion strategies would you combine?
3. 3What security considerations (e.g., CSP) arise when using @import versus <link> in a multi‑tenant environment?

8+ years experience

1. 1We are migrating a legacy monolithic CSS codebase to a component‑scoped CSS‑in‑JS solution across several teams. How would you plan the transition while preserving existing styling and minimizing disruption?
2. 2Describe a company‑wide policy for CSS inclusion that balances performance, developer experience, and long‑term maintainability. How would you enforce it across CI/CD pipelines?
3. 3In a micro‑frontend architecture, how do you prevent style leakage and conflicts when each team may choose different inclusion methods?