If you want to make ChatGPT's interface look nicer without having to write code, check out StylerGPT. This browser extension comes with 25 color themes, 100 high-resolution backgrounds, the ability to upload your own images, and 25 Google font options for better legibility. It works with ChatGPT Plus, including GPT-4 Turbo, and with Chrome and Edge browsers so it shouldn't slow down performance. StylerGPT is free to install and use, so it's a good choice if you want to customize.
Another interesting platform is Chattie. This no-code interface embeds ChatGPT in websites and lets you train chatbots with your own data sources. It's got a built-in theme editor that supports full CSS, so you can customize your chatbots' appearance. Chattie also has automated prompt generation, statistical analysis and multiple pricing plans for different needs. It's good for people who want to add a more polished and interactive element to their websites without having to write any code.