At this level, individuals have a basic understanding of CSS3. They can write simple stylesheets using correct syntax and selectors, apply color codes, understand the box model, and manipulate text properties. However, their knowledge is mostly theoretical and they may need guidance to apply it in practice.

Novices can independently write CSS3 code for simple web pages. They know how to use classes and IDs, understand basic layout properties like display and position, and can apply pseudo-classes and pseudo-elements. They also have a basic understanding of transitions and animations.

Intermediate users are comfortable with CSS3 and can create responsive designs using media queries. They can use advanced selectors, understand flexbox layout, and create complex animations and transitions. They also know how to apply gradient backgrounds.

Advanced users have a deep understanding of CSS3. They can use grid layouts, variables, and calculations, understand transform properties, and can apply custom fonts using @font-face. They also have a good grasp of advanced pseudo-classes and pseudo-elements.

Experts have mastered CSS3 and can optimize performance, write maintainable and scalable CSS, and understand CSS preprocessors like Sass and Less. They are familiar with CSS architecture methodologies like BEM and SMACSS, and can use CSS in JS libraries like Styled Components and Emotion.