Add outer padding.

tt1-blocks/assets/css/style-shared.css

@@ -29,4 +29,43 @@ a:hover {
  */
 .site-header h1.wp-block-site-title a:not(:hover):not(:focus):not(:active) {
 	text-decoration: underline;
-}
+}
+
+/*
+ * Alignment styles.
+ * These rules are temporary, and should not be relied on or 
+ * modified too heavily by themes or plugins that build on 
+ * Twenty Twenty-Two. These are meant to be a precursor to 
+ * a global solution provided by the Block Editor. 
+ * 
+ * Relevant issues:
+ * https://github.com/WordPress/gutenberg/issues/35607
+ * https://github.com/WordPress/gutenberg/issues/35884
+ */
+
+.wp-site-blocks,
+body > .is-root-container,
+.edit-post-visual-editor__post-title-wrapper,
+.wp-block-group.alignfull,
+.is-root-container .wp-block[data-align="full"] > .wp-block-group {
+	padding-left: var(--wp--custom--spacing--outer);
+	padding-right: var(--wp--custom--spacing--outer);
+}
+
+.wp-site-blocks .alignfull,
+.is-root-container .wp-block[data-align="full"] {
+	margin-left: calc(-1 * var(--wp--custom--spacing--outer)) !important;
+	margin-right: calc(-1 * var(--wp--custom--spacing--outer)) !important;
+	width: unset;
+}
+
+/* Blocks inside columns don't have negative margins. */
+.wp-site-blocks .wp-block-columns .wp-block-column .alignfull,
+.is-root-container .wp-block-columns .wp-block-column .wp-block[data-align="full"],
+/* We also want to avoid stacking negative margins. */
+.wp-site-blocks .alignfull:not(.wp-block-group) .alignfull,
+.is-root-container .wp-block[data-align="full"] > *:not(.wp-block-group) .wp-block[data-align="full"] {
+	margin-left: auto !important;
+	margin-right: auto !important;
+	width: inherit;
+}

tt1-blocks/theme.json

@@ -201,7 +201,8 @@
 			"spacing": {
 				"unit": "20px",
 				"horizontal": "25px",
-				"vertical": "30px"
+				"vertical": "30px",
+				"outer": "20px"
 			},
 			"font-weight":{
 				"light": "300",