Fix case-sensitive path

app/src/components/Demo/Key.tsx

@@ -0,0 +1,44 @@
+import * as React from 'react'
+import { Theme, withStyles } from '@material-ui/core'
+
+interface Props {
+  keyboardKey: string
+  classes: any
+}
+
+class Key extends React.Component<Props, {}> {
+  constructor(props: any) {
+    super(props)
+    this.state = { location: 'bottom' }
+  }
+
+  public render() {
+
+    return (
+      <div className={this.props.classes.keyStyle}>
+        <div className={this.props.classes.keyTextStyle}>{this.props.keyboardKey}</div>
+      </div>
+    )
+  }
+}
+
+const style = (theme: Theme) => ({
+  keyStyle: {
+    display: 'inline-block' as 'inline-block',
+    width: '1em',
+    height: '1em',
+    backgroundColor: '#bbb',
+    borderRadius: '10%',
+    verticalAlign: 'middle' as 'middle',
+    textAlign: 'center' as 'center',
+    textShadow: '1px 1px rgba(255,255,255,0.45)',
+    boxShadow: '0.08em 0.15em 0.01em 0px rgba(100,100,100,0.75)',
+  },
+  keyTextStyle: {
+    marginTop: '0.65em',
+    fontSize: '0.4em',
+    fontWeight: 'bold' as 'bold',
+  },
+})
+
+export default withStyles(style)(Key)