Define custom theme

Custom_Theme.txt

    // define theme
    const theme = createTheme({
        palette: {
            primary: {
                light: '#63b8ff',
                main: '#0989e3',
                dark: '#005db0',
                contrastText: '#000',
            },
            secondary: {
                main: '#4db6ac',
                light: '#82e9de',
                dark: '#00867d',
                contrastText: '#000',
            },
        },
    });