If you are actively developing and testing a site on an Android device, you can control the mobile browser's cache behavior from your laptop or desktop.
Enable USB Debugging on your Android phone.
Connect your phone to your computer via a USB cable.
On your desktop Chrome browser, navigate to chrome://inspect/#devices.
Find your mobile tab under the device list and click Inspect.
In the DevTools panel that pops up, go to the Network tab and check the Disable cache checkbox.
As long as this window stays open, reloading the page on your phone will completely bypass the mobile CSS cache.