Trouble w Nav Bar and Gallery Placement

I am relatively new to css but I would like to know (with css) how to move my gallery block so that it does not start behind the navigation bar but instead begins where the navigation bar ends. When I add in my announcement bar the text in the main gallery "help us break the silence" is getting cut off bec it keeps falling behind the announcement and nav bars. As you can see when I narrow the announcement bar it also leaves a gap between it and the nav bar, not sure how to fix that either!

Thanks so much!

https://kumquat-butterfly-fzgy.squarespace.com

pswd: RTW

I see you have a CSS code causes this

it is in this file: https://squareaddons.github.io/assets/plugins/gallery-slider/gallery-slider.css

So if you use SquareAddons Plugin, you can contact them to exclude this code on Homepage