The Frontend Developer
The Frontend Developer is in charge of all the code running in the client's computer. This is HTML, Javascript and CSS, for a good presentation and behavior and a good user experience.
The Frontend Dev's code usually talks to the backend via REST or GraphQL calls. This way it can indirectly access database data.
Some people treat Full-stack and Frontend as similar, which in my opinion is a mistake.
Learning HTML and CSS is a lot more challenging than it used to be. Responsive web design adds more layers of complexity to design and develop websites. ― Jacob Lett
Skills
Constant changes
In the last decade there has been a cambrian explosion of frameworks and technologies in frontend. Javascript frameworks and languages that compile to Javascript, like Backbone, Angularjs, Ember, React, Vue, Svelte, Elm js, and CSS preprocessors like Less, SaSS, and React Styled components. Package management tools like the Node Package Managment (NPM) and build tools like Babel and Parcel.
The popularity of NodeJs ― which allows Javascript to run in the server ― has also increased a lot, allowing Frontend Developers to use the tools they know well for other uses.
Responsiveness
A big variety of devices used to display websites makes layout sizes more difficult to hardcode to specific sizes. The pixel density is no longer uniform and adds complexity. Instead, responsive websites adapt the design to the display size in different ways.
Accessibility
With more and more companies and government entities offering services online, special care must be given not to alienate users with disabilities. Accessibility requirements ― which are mandated for government websites, among others ― are important to guarantee the access to services to visually-impaired people.
New capabilities
Browser standards and capabilities keep progressing. Nowadays a browser can produce 3d graphics with WebGL, connect using sockets with Websockets, and access Bluetooth devices, for instance. These new features put the focus on constant learning on part of the Frontend Developer.