Color Scheme
Changing the color scheme might be the most important change you will make. The website should represent the company and/or product, thus color scheme should be the same. Docusaurus comes with 'Dark Mode' out of the box, so a color scheme should be created for both Dark and Light mode.
See Manual migration | Docusaurus for more information and help on color scheme.
We will be modifying the /src/css/custom.css file to create a color scheme using the 4d Method logo colors:

The blue color #96D9FF will be used as the base color for dark mode.
The purple color #9337C5 will be used as a base color for light mode.
Putting these color codes in the Tool we get the following code:
:root {
--ifm-color-primary: #2e8555;
--ifm-color-primary-dark: #29784c;
--ifm-color-primary-darker: #277148;
--ifm-color-primary-darkest: #205d3b;
--ifm-color-primary-light: #33925d;
--ifm-color-primary-lighter: #359962;
--ifm-color-primary-lightest: #3cad6e;
--ifm-code-font-size: 95%;
--docusaurus-highlighted-code-line-bg: rgba(0, 0, 0, 0.1);
}
[data-theme='dark'] {
--ifm-color-primary: #25c2a0;
--ifm-color-primary-dark: #21af90;
--ifm-color-primary-darker: #1fa588;
--ifm-color-primary-darkest: #1a8870;
--ifm-color-primary-light: #29d5b0;
--ifm-color-primary-lighter: #32d8b4;
--ifm-color-primary-lightest: #4fddbf;
--docusaurus-highlighted-code-line-bg: rgba(0, 0, 0, 0.3);
}
You are free to use your own colors. You can even overwrite elements using standard .css.