Robert, this should do it for you:
body.post-type-archive-tribe_events.events-list .tribe-events-list .type-tribe_events h2 {
font-size: 1.2em;
}
body.post-type-archive-tribe_events.events-list .tribe-events-list .type-tribe_events {
padding-top: 1em;
padding-bottom: 1em;
}
You can add custom CSS code via your child theme’s style.css file or via a plugin like Simple Custom CSS or, my favorite, Jetpack. Jetpack supports regular CSS and the LESS and Sass pre-processors.
If you’re not a CSS expert, Jetpack’s Custom Design reference may prove helpful.
Please let me know how it goes for you.