SASS vs CSS Modules vs CSS-in-JS: How to Choose?

The team is debating the choice between SASS, CSS Modules, and CSS-in-JS for styling their API Ops platform's developer console, considering the ease of embedding components in external UIs. They ultimately decided to use CSS-in-JS due to its compatibility with embedding and theming requirements, favoring the use of libraries like styled-components and Emotion, which is integrated into Material UI (MUI). The conversation reflects considerations on maintaining a consistent theme, reducing maintenance burdens, and ensuring flexibility for future styling needs, such as implementing dark mode or allowing customer-specific theming. Despite some team members' experiences with global CSS stylesheets leading to maintenance challenges, they acknowledge that CSS-in-JS offers a more modern, efficient approach, especially for projects requiring dynamic theming capabilities.