function receivedText(e) {
        const lines = JSON.parse(e.target.result);
        customTheme = CreateAbstraction(lines);
        themeOptions['Custom Theme'] = lines;
        // preview theme
        updateThemeForStyle('Custom Theme');
        updateBG();
        // update colors in dialog box
        $('#CustomColorThemesDialog').empty();
        $('#CustomColorThemesDialog').append(getCustomThemeCard());
        setColorEvent();
    }
Read JSON file and
set Custom theme to the Content of the JSON file