Twenty Sixteen: Fix issues with theme's Gutenberg support.

A handful of issues were missed in Twenty Sixteen's Gutenberg support, added in #45044. This commit includes the following fixes:

* Center text and bullets in list-based widget blocks, when block itself is centered.
* Correct styles for the editor placeholder text, so it's not inheriting a darker gray from the theme's CSS. 
* Include non "image" variations of the Cover block classes `.wp-block-cover` and `.wp-block-cover-text` in the styles.
* Reset Cover blocks as `display: flex` when they are centered, to maintain their original appearance.
* Add spacing underneath the Media & Text block, but make sure the final paragraph in the block doesn't add too much space.
* Simplify selectors used to set editor width to just `.wp-block`.
* Prevent margin from theme's editor-style.css from interfering with editor alignment. 
 
Props pento, davidakennedy.
Fixes #45245.


Built from https://develop.svn.wordpress.org/branches/5.0@43875


git-svn-id: http://core.svn.wordpress.org/branches/5.0@43704 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-content/themes/twentysixteen/css/blocks.css

@@ -76,6 +76,13 @@ p.has-drop-cap:not(:focus)::first-letter {
 	width: 100%;
 }
 
+/* Cover */
+
+.wp-block-cover-image.aligncenter,
+.wp-block-cover.aligncenter {
+	display: flex;
+}
+
 /* File */
 
 .wp-block-file .wp-block-file__button {
@@ -240,10 +247,29 @@ hr.wp-block-separator {
 	max-width: 100%;
 }
 
+/* Media & Text */
+
+.wp-block-media-text {
+	margin-bottom: 1.75em;
+}
+
+.wp-block-media-text *:last-child {
+	margin-bottom: 0;
+}
+
 /*--------------------------------------------------------------
 5.0 Blocks - Widget Blocks
 --------------------------------------------------------------*/
 
+/* Archives, Categories & Latest Posts */
+
+.wp-block-archives.aligncenter,
+.wp-block-categories.aligncenter,
+.wp-block-latest-posts.aligncenter {
+	list-style-position: inside;
+	text-align: center;
+}
+
 /* Latest Comments */
 
 .wp-block-latest-comments__comment-meta a {

wp-content/themes/twentysixteen/css/editor-blocks.css

@@ -20,7 +20,6 @@ Description: Used to style Gutenberg Blocks in the editor.
 
 .edit-post-visual-editor .editor-block-list__block,
 .editor-default-block-appender input[type="text"].editor-default-block-appender__content {
-	color: #1a1a1a;
 	font-family: Merriweather, Georgia, serif;
 	font-size: 16px;
 	font-size: 1rem;
@@ -173,10 +172,12 @@ Description: Used to style Gutenberg Blocks in the editor.
 
 /* Main column width */
 
-body.gutenberg-editor-page .edit-post-visual-editor .editor-post-title__block,
-body.gutenberg-editor-page .edit-post-visual-editor .editor-default-block-appender,
-body.gutenberg-editor-page .edit-post-visual-editor .editor-block-list__block {
-	max-width: 630px; /* 600px + 30px for padding; should be 840px for pages */
+.editor-styles-wrapper {
+	max-width: 100% !important; /* Override where editor-style.css is affecting this */
+}
+
+.wp-block {
+	max-width: 630px; /* 600px + 30px to account for padding. */
 }
 
 /* Link styles */
@@ -535,6 +536,7 @@ body.gutenberg-editor-page .edit-post-visual-editor .editor-block-list__block {
 --------------------------------------------------------------*/
 
 /* Buttons */
+
 .wp-block-button .wp-block-button__link {
 	background: #1a1a1a;
 	border: 0;
@@ -548,10 +550,24 @@ body.gutenberg-editor-page .edit-post-visual-editor .editor-block-list__block {
 	text-transform: uppercase;
 }
 
+/* Media & Text */
+
+.wp-block-media-text *:last-child {
+	margin-bottom: 0;
+}
+
 /*--------------------------------------------------------------
 6.0 Blocks - Widgets
 --------------------------------------------------------------*/
 
+/* Archives, Categories & Latest Posts */
+
+[data-align="center"] .wp-block-archives ul,
+[data-align="center"] .wp-block-categories ul,
+[data-align="center"] .wp-block-latest-posts ul {
+	list-style-position: inside;
+}
+
 /* Latest Comments */
 
 .editor-block-list__block .wp-block-latest-comments__comment-meta a {

wp-includes/version.php

@@ -4,7 +4,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.0-beta3-43874';
+$wp_version = '5.0-beta3-43875';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.