CSS is the most powerful design tool for the web
Notes:
Designing a website for fixed desktop and mobile sizes is way too limiting, because the web is fluid. 12 years ago Photoshop was the liar, now it is Figma. All the pixel-perfect static pictures of websites that are created within those tools are not the real thing. This way, the web as a fluid medium is addressed with a static tool and a linear waterfall process. Those design tools simulate the web, but they are not the web, they hinder to touch the material of the web and underpin the separation of design and development.
We are breaking the feedback loop of the creative process. We are limiting our ability to have that creative dialog with the web and its materials, and we limit our potential for exploration and creating surprising and novel solutions. Ultimately it prevents us from making informed decisions trough out the design process, because how can you make a right decision if you are basing it on assumptions instead of insights coming from the material itself.
To properly design for a medium, one has to have a proper understanding about the medium itself. The web is evolving at an unprecedented speed, so that design tools like Figma lack the functionality of what is possible with the web.
CSS has become so capable, it is now the most powerful design tool for the web.
Therefore we have to use HTML and CSS much earlier in the design process and decide in the browser what works and what doesn´t. That means working at the intersection of design and development, which is now called design engineering.