A CSS developer is responsible for designing and implementing responsive and visually appealing websites or web applications. They use CSS , the latest version of Cascading Style Sheets, to control the layout, color, font, and animations of a website. They work closely with other developers to integrate CSS with HTML and JavaScript, ensuring compatibility across different browsers and devices. They also optimize code for performance, maintainability, and scalability. Additionally, they may participate in user experience design and work with graphic designers to implement visual designs accurately. They ensure the site is accessible and provides a consistent user experience.