Advanced styling in material-ui
问题 I start to study material-ui and create a simple app in the SandBox: https://codesandbox.io/s/eager-ride-cmkrc The style of jss is unusual for me, but if you help me with these two simple exercises, then I will understand everything. First: I want union common properties of ButtonLeft and ButtonRight into new class and extend it: (https://github.com/cssinjs/jss-extend#use-rule-name-from-the-current-styles-object) ButtonControll: { display: "none", position: "absolute", fontSize: "24px" },