In the following code snippet, we show a Grid element declared with a background color set to #E6E6E6 (a very light grey). If you hard-code the color in this way, you also override the background color across all themes. For example, if the user selects the Aquatic contrast theme, instead of white text on a near black background, the text color in this app changes to white while the background remains light grey. The very low contrast between text and background could make this app very difficult to use.