Fixes for Firefox, part I

src/options.css

 	min-height: 100vh;
 	padding: 10px 20px;
 	font-size: 1rem;
+	font-family: sans-serif;
 }
 body.noscroll {
 	overflow: hidden;

src/platform/chrome/background.js

 	*/
 chrome.runtime.onMessage.addListener((request, sender, sendResponse) => {
 	let icons = request.killingStickies ? {
-			"16":	"images/ASK_on_16.png",
-			"32":	"images/ASK_on_32.png",
-			"48":	"images/ASK_on_48.png",
-			"128":	"images/ASK_on_128.png"
+			"19": 	"images/ASK_on_19.png",
+			"38": 	"images/ASK_on_38.png",
 	} : {
-			"16":	"images/ASK_off_16.png",
-			"32":	"images/ASK_off_32.png",
-			"48":	"images/ASK_off_48.png",
-			"128":	"images/ASK_off_128.png"
+			"19": 	"images/ASK_off_19.png",
+			"38": 	"images/ASK_off_38.png",
 	};
 	chrome.pageAction.setIcon({
 		path: icons,

src/platform/firefox/background.js

-/*	Enables the page action (i.e., the browser toolbar icon).
-	*/
-chrome.runtime.onInstalled.addListener(() => {
-	chrome.declarativeContent.onPageChanged.removeRules(undefined, () => {
-		chrome.declarativeContent.onPageChanged.addRules([{
-			conditions: [ new chrome.declarativeContent.PageStateMatcher({
-				pageUrl: { schemes: [ 'http', 'https' ] },
-			})
-			], actions: [ new chrome.declarativeContent.ShowPageAction() ]
-		}]);
-	});
-});
-
 /*	Toggle the toolbar icon based on whether stickies are, or are not, set to
 	be killed on the current tab.
 

src/platform/firefox/manifest.json

 	"homepage_url":					"https://git.sr.ht/~achmizs/AlwaysKillSticky.git",
 	"permissions":					[ "activeTab", "storage" ],
 	"background":					{
-		"scripts":						["background.js"]
+		"scripts":						[ "background.js" ]
 	},
 	"content_scripts":				[	{
 			"matches":						[ "http://*/*", "https://*/*" ],
 			"js":							[ "functions.js", "contentScript.js" ]
 		}
 	],
-	"page_action":					{
+	"browser_action":					{
 		"default_popup":				"popup.html",
 		"default_title":				"AlwaysKillSticky - Click the icon to control sticky-killing on this site!",
 		"default_icon":					{
-			"48": 							"images/ASK_on_48.png",
-			"96": 							"images/ASK_on_96.png",
+			"19": 							"images/ASK_on_19.png",
+			"38": 							"images/ASK_on_38.png"
 		}
 	},
 	"icons":						{
 		"48": 							"images/ASK_on_48.png",
-		"96": 							"images/ASK_on_96.png",
+		"96": 							"images/ASK_on_96.png"
 	},
 	"options_ui":					{
 		"page":							"options.html",