Window controls overlay (#837)

* Update main.scss

Make page header a title bar

* Update manifest.json

Allow custom titlebar

* Resize page header so it won't overlap titlebar controls

web/manifest.json

@@ -11,6 +11,7 @@
   "capture_links": "new-client",
   "start_url": "/#boot",
   "display": "standalone",
+  "display_override": ["window-controls-overlay"],
   "scope": "/",
   "theme_color": "#e1e1e1",
   "description": "Markdown as a platform"

web/styles/main.scss

@@ -70,7 +70,7 @@ body {
       flex-direction: row;
 
       .wrapper {
-        width: 100%;
+        width: env(titlebar-area-width, 100%);
         padding: 0 20px;
         display: flex;
         box-sizing: border-box;
@@ -103,6 +103,8 @@ body {
       text-align: left;
       display: block;
 
+      -webkit-app-region: drag;
+      
       .cm-scroller {
         font-family: var(--ui-font);
       }
@@ -227,4 +229,4 @@ body {
       margin: 0;
     }
   }
-}
+}