Add dark theme icon

icons/icon-light.svg

@@ -0,0 +1,60 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg
+   xmlns:dc="http://purl.org/dc/elements/1.1/"
+   xmlns:cc="http://creativecommons.org/ns#"
+   xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
+   xmlns:svg="http://www.w3.org/2000/svg"
+   xmlns="http://www.w3.org/2000/svg"
+   xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd"
+   xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape"
+   inkscape:version="1.0 (4035a4fb49, 2020-05-01)"
+   height="55"
+   width="55"
+   sodipodi:docname="icon-light.svg"
+   xml:space="preserve"
+   viewBox="0 0 55 55"
+   y="0px"
+   x="0px"
+   id="Layer_1"
+   version="1.1"><metadata
+   id="metadata19"><rdf:RDF><cc:Work
+       rdf:about=""><dc:format>image/svg+xml</dc:format><dc:type
+         rdf:resource="http://purl.org/dc/dcmitype/StillImage" /><dc:title></dc:title></cc:Work></rdf:RDF></metadata><defs
+   id="defs17" /><sodipodi:namedview
+   inkscape:document-rotation="0"
+   inkscape:current-layer="Layer_1"
+   inkscape:window-maximized="1"
+   inkscape:window-y="0"
+   inkscape:window-x="0"
+   inkscape:cy="24.755448"
+   inkscape:cx="38.702179"
+   inkscape:zoom="8.6041667"
+   showgrid="false"
+   id="namedview15"
+   inkscape:window-height="1016"
+   inkscape:window-width="1920"
+   inkscape:pageshadow="2"
+   inkscape:pageopacity="0"
+   guidetolerance="10"
+   gridtolerance="10"
+   objecttolerance="10"
+   borderopacity="1"
+   bordercolor="#666666"
+   pagecolor="#ffffff" />
+<style
+   id="style10"
+   type="text/css">
+	.st0{fill:#333333;}
+</style>
+<g
+   style="fill:#acacac;fill-opacity:1"
+   transform="translate(-20.455206,-19.566586)"
+   id="XMLID_2_">
+	<path
+   style="fill:#acacac;fill-opacity:1"
+   inkscape:connector-curvature="0"
+   d="m 75.5,44.1 c 0,3.6 -1.2,6.8 -3.7,9.9 -2.5,3 -5.8,5.4 -10,7.2 -4.2,1.7 -8.8,2.6 -13.8,2.6 -1.4,0 -2.9,-0.1 -4.5,-0.2 -4.1,3.6 -8.8,6.1 -14.1,7.4 -1,0.3 -2.2,0.5 -3.5,0.7 -0.3,0 -0.7,-0.1 -0.9,-0.3 -0.2,-0.2 -0.5,-0.5 -0.5,-0.9 v 0 c -0.1,-0.1 -0.1,-0.2 0,-0.4 0.1,-0.2 0.1,-0.3 0.1,-0.3 0,0 0,-0.1 0.1,-0.3 l 0.2,-0.3 0.2,-0.3 0.2,-0.3 c 0.1,-0.2 0.5,-0.5 1,-1.1 0.5,-0.5 0.8,-0.9 1.1,-1.2 0.3,-0.3 0.5,-0.6 1,-1.2 0.4,-0.6 0.8,-1.1 1,-1.6 0.2,-0.5 0.5,-1.1 0.8,-1.8 C 30.5,61 30.8,60.2 31,59.4 27.8,57.6 25.3,55.3 23.4,52.6 21.5,49.9 20.6,47 20.6,44 c 0,-2.7 0.7,-5.2 2.2,-7.6 1.5,-2.4 3.4,-4.5 5.9,-6.3 2.5,-1.8 5.4,-3.2 8.8,-4.2 3.4,-1 7,-1.5 10.7,-1.5 5,0 9.6,0.9 13.8,2.6 4.2,1.7 7.6,4.1 10,7.2 2.3,3 3.5,6.3 3.5,9.9 z"
+   class="st0"
+   id="XMLID_4_" />
+</g>
+</svg>

manifest.json

@@ -2,15 +2,20 @@
     "description": "Button to like and reply",
     "manifest_version": 2,
     "name": "Indie Reply Button",
-    "version": "2.0",
+    "version": "3.0",
     "icons": {
         "48": "icons/icon.svg"
     },
     "browser_action": {
-        "default_icon": "icons/icon.svg",
         "default_title": "IndieButton",
         "default_popup": "popup.html",
-        "browser_style": false
+        "browser_style": false,
+        "default_icon": "icons/icon.svg",
+        "theme_icons": [{
+            "light": "icons/icon-light.svg",
+            "dark": "icons/icon.svg",
+            "size": 32
+        }]
     },
     "permissions": [
         "tabs"

popup.html

@@ -4,7 +4,6 @@
     <meta charset="utf-8">
     <title>Indie Buttons</title>
     <style>
-      body { line-height: 0; vertical-align: middle; }
       img { width: 20px; height: 20px; }
     </style>
   </head>