userChrome: fix convergence usage case

Only apply rules from userChrome.css if the screen width is 700px or
less.

src/userChrome/appMenu.css

@@ -1,6 +1,7 @@
 /* Copyright 2020 Oliver Smith
    SPDX-License-Identifier: GPL-3.0-or-later */
 
+@media (max-width: 700px) {
 	.subviewbutton,
 	.toolbaritem-combined-buttons {
 	  font-size: 8pt;
@@ -22,7 +23,8 @@ toolbarseparator {
 	  display: none;
 	}
 
-/* Zoom/edit: move controls to the left (so they are visible), hide label (it's obvious what they do) and spacer */
+	/* Zoom/edit: move controls to the left (so they are visible), hide
+	 * label (it's obvious what they do) and spacer */
 	#appMenu-zoom-controls spacer,
 	#appMenu-zoom-controls label,
 	#appMenu-edit-controls spacer,
@@ -38,8 +40,9 @@ toolbarseparator {
 	  padding-left: 15px;
 	}
 
-/* Zoom: hide fullscreen button (not possible to exit fullscreen without keyboard) */
+	/* Zoom: hide fullscreen button (not possible to exit fullscreen
+	 * without keyboard) */
 	#appMenu-fullscreen-button {
 	  display: none;
 	}
-
+}

src/userChrome/findbar.css

@@ -1,6 +1,7 @@
 /* Copyright 2020 Oliver Smith
    SPDX-License-Identifier: GPL-3.0-or-later */
 
+@media (max-width: 700px) {
 	/* Findbar */
 	[anonid="findbar-textbox-wrapper"] {
 	  min-width: 160px;
@@ -23,3 +24,4 @@
 	{
 	  display: none;
 	}
+}

src/userChrome/popups.css

@@ -1,6 +1,7 @@
 /* Copyright 2020 Oliver Smith
    SPDX-License-Identifier: GPL-3.0-or-later */
 
+@media (max-width: 700px) {
 	/* Popup notifications (install add-on etc.): set max-width, remove icon and
 	 * make font smaller so it fits the box */
 	.popup-notification-body-container {
@@ -29,3 +30,4 @@
 	#protections-popup-mainView {
 	  font-size: 4pt;
 	}
+}

src/userChrome/urlbar.css

@@ -6,13 +6,15 @@
   min-width: 150px !important;
 }
 
+@media (max-width: 700px) {
 	/* Remove various buttons left and right of the URL bar:
 	   - forward-button: also reachable via longpress of back button
 	   - home-button: not important enough
 	   - customizableui-special-spring: empty space
 	   - library-button: also reachable via PanelUI-menu-button
 	   - sidebar-button: not useful on mobile (we try to gain horizontal space)
-   - fxa-toolbar-menu-button: firefox cloud stuff, also reachable via #PanelUI-menu-button
+	   - fxa-toolbar-menu-button: firefox cloud stuff, also reachable via
+	     #PanelUI-menu-button
 	*/
 	/* #back-button */
 	#forward-button,
@@ -41,3 +43,4 @@
 	#urlbar[focused] #pageActionButton {
 	  display: none;
 	}
+}