Do you like translucent/transparent theme? If so this guide is for you. Note: It have only been tested with elementary OS default elementary theme. Open the terminal and copy/paste;
io.elementary.code '~/.config/gtk-3.0/gtk.css'
Add the following to the file;
.panel {
background-color: rgba(255,255,255,0.5);
transition: all 1s ease-in-out;
}
.panel.maximized {
background-color: rgba(255,255,255,0.5);
}
@define-color base_color #ffffff;
@define-color bg_color alpha (shade (@base_color, 0.96), 0.6);
@define-color bg_highlight_color shade (@bg_color, 1.4);
@define-color border_color alpha (#000, 0.25);
@define-color fg_color #969f9d;
You can adjust the transparency of the Wingpanel by change the 0.5 to 0.0 (transpancy) – 1.0 (Solid)
The Slingshots transparency you can adjust 0.6 likewise.
Logout and login to take affect.
Enjoy ^_^
Tested on: elementary OS 5.1.4
Tips and Guides for elementary OS 
Hi, very interesting but it does not work with elementary OS 5.1.7 Hera … the gtk.css folder does not exist in the path you indicate, can you give me some solution about it, congratulations for the site, I like it so much.
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Hi. If it doesn’t exist, you can create it and then fill out the .css.
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