wider_gutenberg_sidebar.php

// *******************************
// Make Gutenberg Sidebar Wider / Fluid
// -------------------------------
function wider_gutenberg_settings_sidebar() { ?>
	<style>
		@media (min-width: 1080px) {
			#wpwrap .edit-post-layout.is-sidebar-opened .components-notice-list {
				right: 26vw !important;
			}
			#wpwrap .edit-post-layout.is-sidebar-opened .edit-post-plugin-sidebar__sidebar-layout,
			#wpwrap .edit-post-layout.is-sidebar-opened .edit-post-sidebar {
				width: 26vw !important;
			}
			#wpwrap .edit-post-layout.is-sidebar-opened .edit-post-layout__content {
				margin-right: 26vw !important;
			}
		}
	</style>
<?php
}
add_action('admin_head','wider_gutenberg_settings_sidebar');