So after installing the plugin, I noticed the styles on my headings (H1, H2, etc.) were looking different. I discovered the uikit.min.css file was overriding my child theme styles (and being loaded on every single page, not just the page I was using the timetable on).
I got around the issue by commenting out line 70 in the easytimetable-responsive-schedule-management-system/public/class-easy-timetable-public.php file that reads:
wp_enqueue_style( $this->plugin_name."uikit", plugin_dir_url( __FILE__ ) . 'css/uikit.min.css', array(), $this->version, 'all' );
This doesn't appear to have impacted the styles in the display of the timetable itself, interestingly, so I'm not entirely sure what the uikit.min.css styles are being used for, but wanted to bring the issue to your attention in case the UIkit CSS should be loaded differently.