Hide native tab bar + TST header

TST - userChrome.css

/* Source file https://github.com/MrOtherGuy/firefox-csshacks/tree/master/chrome/hide_tabs_toolbar.css made available under Mozilla Public License v. 2.0
See the above repository for updates as well as full license text. */

/* Hides tabs toolbar */
/* For OSX use hide_tabs_toolbar_osx.css instead */

/* Note, if you have either native titlebar or menubar enabled, then you don't really need this style.
 * In those cases you can just use: #TabsToolbar{ visibility: collapse !important }
 */

/* IMPORTANT */
/*
Get window_control_placeholder_support.css
Window controls will be all wrong without it
*/

:root[tabsintitlebar] {
	--uc-toolbar-height: 40px;
}

:root[tabsintitlebar][uidensity="compact"] {
	--uc-toolbar-height: 32px
}

#titlebar {
	will-change: unset !important;
	transition: none !important;
	opacity: 1 !important;
}

#TabsToolbar {
	visibility: collapse !important
}

:root[sizemode="fullscreen"] #TabsToolbar> :is(#window-controls, .titlebar-buttonbox-container) {
	visibility: visible !important;
	z-index: 2;
}

:root:not([inFullscreen]) #nav-bar {
	margin-top: calc(0px - var(--uc-toolbar-height, 0px));
}

:root[tabsintitlebar] #toolbar-menubar[autohide="true"] {
	min-height: unset !important;
	height: var(--uc-toolbar-height, 0px) !important;
	position: relative;
}

#toolbar-menubar[autohide="false"] {
	margin-bottom: var(--uc-toolbar-height, 0px)
}

:root[tabsintitlebar] #toolbar-menubar[autohide="true"] #main-menubar {
	flex-grow: 1;
	align-items: stretch;
	background-attachment: scroll, fixed, fixed;
	background-position: 0 0, var(--lwt-background-alignment), right top;
	background-repeat: repeat-x, var(--lwt-background-tiling), no-repeat;
	background-size: auto 100%, var(--lwt-background-size, auto auto), auto auto;
	padding-right: 20px;
}

:root[tabsintitlebar] #toolbar-menubar[autohide="true"]:not([inactive]) #main-menubar {
	background-color: var(--lwt-accent-color);
	background-image: linear-gradient(var(--toolbar-bgcolor, --toolbar-non-lwt-bgcolor), var(--toolbar-bgcolor, --toolbar-non-lwt-bgcolor)), var(--lwt-additional-images, none), var(--lwt-header-image, none);
	mask-image: linear-gradient(to left, transparent, black 20px);
}

#toolbar-menubar:not([inactive]) {
	z-index: 2
}

#toolbar-menubar[autohide="true"][inactive]>#menubar-items {
	opacity: 0;
	pointer-events: none;
	margin-left: var(--uc-window-drag-space-pre, 0px)
}

.treestyletab-tabbar-toolbar {
	opacity: 1.0 !important;
}

.tabbrowser-tabs[treestyletab-mode="vertical"] {
	opacity: 1.0 !important;
}

.tabbrowser-tabs[treestyletab-mode="vertical"] .tabbrowser-tab {
	opacity: 1.0 !important;
	text-shadow: 0px 0px 0px white !important;
	margin-top: -2px !important;
	margin-bottom: -2px !important;
}

#sidebar-box[sidebarcommand="treestyletab_piro_sakura_ne_jp-sidebar-action"] #sidebar-header {
	display: none;
}