How can I change the label size of a material ui TextField?

Question

I have a TextField defined as follows:

Answer 1

Here's an example of how to modify the label font size. This example also modifies the font-size of the input on the assumption that you would want those sizes to be in sync, but you can play around with this in the sandbox to see the effects of changing one or the other.

import React from "react";
import ReactDOM from "react-dom";

import TextField from "@material-ui/core/TextField";
import { withStyles } from "@material-ui/core/styles";

const styles = {
  inputRoot: {
    fontSize: 30
  },
  labelRoot: {
    fontSize: 30,
    color: "red",
    "&$labelFocused": {
      color: "purple"
    }
  },
  labelFocused: {}
};
function App({ classes }) {
  return (
    <div className="App">
      <TextField
        id="standard-with-placeholder"
        label="First Name"
        InputProps={{ classes: { root: classes.inputRoot } }}
        InputLabelProps={{
          classes: {
            root: classes.labelRoot,
            focused: classes.labelFocused
          }
        }}
        margin="normal"
      />
    </div>
  );
}
const StyledApp = withStyles(styles)(App);
const rootElement = document.getElementById("root");
ReactDOM.render(<StyledApp />, rootElement);

Here are the relevant parts of the documentation:

• https://material-ui.com/api/text-field/
• https://material-ui.com/api/input/
• https://material-ui.com/api/input-label/
• https://material-ui.com/api/form-label/