diff --git a/playground/src/common.scss b/playground/src/common.scss
index 00f474ca13073..a808b3161a8ac 100644
--- a/playground/src/common.scss
+++ b/playground/src/common.scss
@@ -21,178 +21,8 @@
 	word-wrap: normal !important;
 }
 
-// TODO: Extract these WP Global styles to a mixin
-// We can't apply these globally to html or body at the moment because of the WP sidebar/menu
 :root {
-	box-sizing: border-box;
-
-	*,
-	*::before,
-	*::after {
-		box-sizing: inherit;
-	}
-
-	select {
-		font-size: $default-font-size;
-		color: $dark-gray-500;
-	}
-
-	.input-control, // Upstream name is `.regular-text`.
-	input[type="text"],
-	input[type="search"],
-	input[type="radio"],
-	input[type="tel"],
-	input[type="time"],
-	input[type="url"],
-	input[type="week"],
-	input[type="password"],
-	input[type="checkbox"],
-	input[type="color"],
-	input[type="date"],
-	input[type="datetime"],
-	input[type="datetime-local"],
-	input[type="email"],
-	input[type="month"],
-	input[type="number"],
-	select,
-	textarea {
-		font-family: $default-font;
-		padding: 6px 8px;
-		@include input-style__neutral();
-
-		/* Fonts smaller than 16px causes mobile safari to zoom. */
-		font-size: $mobile-text-min-font-size;
-		@include break-small {
-			font-size: $default-font-size;
-		}
-
-		&:focus {
-			@include input-style__focus();
-		}
-	}
-
-	input[type="number"] {
-		padding-left: 4px;
-		padding-right: 4px;
-	}
-
-	select {
-		padding: 2px;
-
-		&:focus {
-			border-color: $blue-medium-600;
-			// Windows High Contrast mode will show this outline
-			outline: 2px solid transparent;
-			outline-offset: 0;
-		}
-	}
-
-	input[type="checkbox"],
-	input[type="radio"] {
-		border: $border-width + 1 solid $dark-gray-300;
-		margin-right: 12px;
-		transition: none;
-
-		&:focus {
-			border-color: $dark-gray-300;
-			box-shadow: 0 0 0 1px $dark-gray-300;
-		}
-
-		&:checked {
-			background: theme(toggle);
-			border-color: theme(toggle);
-		}
-
-		&:checked:focus {
-			box-shadow: 0 0 0 2px $dark-gray-500;
-		}
-	}
-
-	input[type="checkbox"] {
-		border-radius: $radius-round-rectangle / 2;
-
-		&:checked::before,
-		&[aria-checked="mixed"]::before {
-			margin: -3px -5px;
-			color: $white;
-
-			@include break-medium() {
-				margin: -4px 0 0 -5px;
-			}
-		}
-
-		&[aria-checked="mixed"] {
-			background: theme(toggle);
-			border-color: theme(toggle);
-
-			&::before {
-				// Inherited from `forms.css`.
-				// See: https://github.com/WordPress/wordpress-develop/tree/5.1.1/src/wp-admin/css/forms.css#L122-L132
-				content: "\f460";
-				float: left;
-				display: inline-block;
-				vertical-align: middle;
-				width: 16px;
-				/* stylelint-disable */
-				font: normal 30px/1 dashicons;
-				/* stylelint-enable */
-				speak: none;
-				-webkit-font-smoothing: antialiased;
-				-moz-osx-font-smoothing: grayscale;
-
-				@include break-medium() {
-					float: none;
-					font-size: 21px;
-				}
-			}
-
-			&:focus {
-				box-shadow: 0 0 0 2px $dark-gray-500;
-			}
-		}
-	}
-
-	input[type="radio"] {
-		border-radius: $radius-round;
-
-		&:checked::before {
-			margin: 3px 0 0 3px;
-			background-color: $white;
-		}
-	}
-
-	// Placeholder colors
-	input,
-	textarea {
-		// Use opacity to work in various editor styles.
-		&::-webkit-input-placeholder {
-			color: $dark-opacity-300;
-		}
-
-		&::-moz-placeholder {
-			opacity: 1; // Necessary because Firefox reduces this from 1.
-			color: $dark-opacity-300;
-		}
-
-		&:-ms-input-placeholder {
-			color: $dark-opacity-300;
-		}
-
-		.is-dark-theme & {
-			&::-webkit-input-placeholder {
-				color: $light-opacity-300;
-			}
-
-			&::-moz-placeholder {
-				opacity: 1; // Necessary because Firefox reduces this from 1.
-				color: $light-opacity-300;
-			}
-
-			&:-ms-input-placeholder {
-				color: $light-opacity-300;
-			}
-		}
-	}
+	@include reset;
 }
 
 a,