There are various ways to modify it, one option is to incorporate media queries in your CSS code. This allows you to adjust the font size based on the screen size. Personally, I find it more effective to increase the size of the div itself. Changing the font size can be beneficial if you need a smaller title for specific devices.
To adjust the div width, simply assign a percentage value (e.g., 100%) and set the height to auto. This will automatically resize the div when making it smaller while ensuring that all text remains visible to users. If you'd like an example, feel free to visit my personal website and experiment with resizing the homepage - it may not be perfect, but it gets the job done (www.svbennekom.nl)