Color wheel: https://developer.mozilla.org/en-US/docs/Web/CSS/gradient/conic-gradient
Flexbox: https://codepen.io/team/css-tricks/pen/EKEYob
Examples of CSS gradients: https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Images/Using_CSS_gradients
Browsers that support accent-color currently apply it to the following HTML elements:
<input type="checkbox">
<input type="radio">
<input type="range">
<progress>
(https://developer.mozilla.org/en-US/docs/Web/CSS/accent-color)
Color schemes for accent-color demo:
https://accent-color.glitch.me/