Remember Chromium, similar to most browsers, have developer tools available. For Chromium press Ctrl+Shift+i to bring up the Developer Tools. Once the Developer Tools are shown, select an element to inspect the html, the css, etc. Some Developer Tools allow tweaking "on the fly" and will immediately apply the change(s). There are more abilities in the Chromium developer tools than simply showing the rendered (browser) elements. Experiment. These tools are handy for debugging, for figuring out why something isn't happening as expected.