Using CSS Variables
After years of using preprocessors such as SASS and LESS for variable support, CSS variables (Custom Properties) are finally supported sufficiently enough such that I feel comfortable in using them for new projects. According to caniuse.com, support of CSS variables currently stands at 95.13%. I understand ~4.9% of people will not be able to get a good experience using the site based on this statistic, however it is important to look at the current statistics of your/your client's site and see what technologies are actually being used.