Add checkbox images for remarkup

Summary: Minor, adds some weightier checkbox styles for use in Remarkup.

Test Plan:
Test a task, Phriction, various remarkup list styles.

{F4990161}

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: cspeckmim, Korvin

Differential Revision: https://secure.phabricator.com/D18080

resources/celerity/map.php

@@ -9,7 +9,7 @@ return array(
   'names' => array(
     'conpherence.pkg.css' => 'ff161f2d',
     'conpherence.pkg.js' => 'b5b51108',
-    'core.pkg.css' => '1a935531',
+    'core.pkg.css' => '176b5104',
     'core.pkg.js' => '1475bd91',
     'darkconsole.pkg.js' => '1f9a31bc',
     'differential.pkg.css' => '1ccbf3a9',
@@ -115,7 +115,7 @@ return array(
     'rsrc/css/application/tokens/tokens.css' => '3d0f239e',
     'rsrc/css/application/uiexample/example.css' => '528b19de',
     'rsrc/css/core/core.css' => '23beb330',
-    'rsrc/css/core/remarkup.css' => 'd1a5e11e',
+    'rsrc/css/core/remarkup.css' => '509fb36e',
     'rsrc/css/core/syntax.css' => 'cae95e89',
     'rsrc/css/core/z-index.css' => '9d8f7c4b',
     'rsrc/css/diviner/diviner-shared.css' => '896f1d43',
@@ -298,6 +298,8 @@ return array(
     'rsrc/image/checker_dark.png' => 'd8e65881',
     'rsrc/image/checker_light.png' => 'a0155918',
     'rsrc/image/checker_lighter.png' => 'd5da91b6',
+    'rsrc/image/controls/checkbox-checked.png' => 'ad6441ea',
+    'rsrc/image/controls/checkbox-unchecked.png' => '8eb1f0ae',
     'rsrc/image/d5d8e1.png' => '0c2a1497',
     'rsrc/image/darkload.gif' => '1ffd3ec6',
     'rsrc/image/divot.png' => '94dded62',
@@ -793,7 +795,7 @@ return array(
     'phabricator-object-selector-css' => '85ee8ce6',
     'phabricator-phtize' => 'd254d646',
     'phabricator-prefab' => 'c5af80a2',
-    'phabricator-remarkup-css' => 'd1a5e11e',
+    'phabricator-remarkup-css' => '509fb36e',
     'phabricator-search-results-css' => '8f8e08ed',
     'phabricator-shaped-request' => '7cbe244b',
     'phabricator-slowvote-css' => 'a94b7230',

webroot/rsrc/css/core/remarkup.css

@@ -122,17 +122,38 @@
 .phabricator-remarkup .remarkup-list-with-checkmarks .remarkup-checked-item,
 .phabricator-remarkup .remarkup-list-with-checkmarks .remarkup-unchecked-item {
   list-style: none;
-  margin-left: -18px;
+  margin-left: -20px;
+  position: relative;
+  padding-left: 22px;
 }
 
 .phabricator-remarkup .remarkup-list-with-checkmarks input {
-  margin-right: 4px;
-  opacity: 1;
+  display: none;
+}
+
+.phabricator-remarkup .remarkup-list-with-checkmarks
+  .remarkup-list-item::before {
+    height: 16px;
+    width: 16px;
+    background-size: 16px;
+    display: inline-block;
+    content: '';
+    position: absolute;
+    top: 3px;
+    left: 0;
+}
+
+.remarkup-list-with-checkmarks .remarkup-checked-item::before {
+  background-image: url(rsrc/image/controls/checkbox-checked.png);
+}
+
+.remarkup-list-with-checkmarks .remarkup-unchecked-item::before {
+  background-image: url(rsrc/image/controls/checkbox-unchecked.png);
 }
 
 .phabricator-remarkup .remarkup-list-with-checkmarks .remarkup-checked-item {
-  text-decoration: line-through;
   color: {$lightgreytext};
+  text-decoration: line-through;
 }
 
 .phabricator-remarkup ul.remarkup-list ol.remarkup-list,