diff --git a/resources/mixins.less b/resources/mixins.less
new file mode 100644
index 0000000..bb57dc0
--- /dev/null
+++ b/resources/mixins.less
@@ -0,0 +1,148 @@
+// Miscellaneous assembly
+// Remember to use this for similar things that need to be consistent, not
+// for things that are basically the same thing repeated, which should use
+// a shared class instead.
+
+// To hide objects, but keep them accessible for screen-readers
+.hidden() {
+	position: absolute;
+	top: -9999px;
+	left: 0;
+}
+
+// Icons - hides labels, but keep them accessible for screen-readers
+.icon() {
+	text-indent: -99999px;
+	border: 0;
+	background-color: transparent;
+	background-repeat: no-repeat;
+}
+
+.box() {
+	background: @base90;
+	border: solid @base80;
+	border-width: 1px 1px @border;
+	padding: 1.25em 1.75em;
+	box-shadow: 0 1px 2px 1px rgba( 0, 0, 0, 0.02 );
+}
+
+.unbox() {
+	background: transparent;
+	border: 0;
+	padding: 0;
+	box-shadow: none;
+}
+
+// Icons for the page actions menus
+.ca-icon() {
+	.icon;
+	display: inline-block;
+	width: 20px;
+	height: 20px;
+	box-sizing: border-box;
+	margin-bottom: -0.5em;
+}
+
+// Navigation column blocks
+
+.nav-block() {
+	.box();
+	padding: 1.5em 1.5em 0;
+	margin: 1em 0;
+	line-height: 1.125;
+	word-wrap: break-word;
+	font-size: 0.95em;
+
+	ul,
+	li {
+		list-style: none;
+		margin: 0;
+		padding: 0;
+	}
+
+	h3 {
+		font-weight: normal;
+		font-size: 1em;
+		margin: 0.25em 0 0.75em 0;
+		padding-bottom: 0.15em;
+		border-bottom: solid 2px @base70;
+	}
+
+	ul {
+		margin-bottom: 2em;
+	}
+
+	li {
+		padding: 0.25em 0;
+	}
+}
+
+.column-right() {
+	padding-left: 1em;
+	box-sizing: border-box;
+
+	.sidebar-chunk {
+		.nav-block();
+	}
+}
+
+.column-left() {
+	padding-right: 1em;
+	box-sizing: border-box;
+
+	.sidebar-chunk {
+		.nav-block();
+	}
+}
+
+// Dropdowns
+.dropdown-header() {
+	cursor: pointer;
+	margin-bottom: -1em;
+	padding-bottom: 1em;
+
+	&:after {
+		display: inline-block;
+		content: '';
+		width: 22px;
+		height: 12px;
+		.background-image-svg( 'images/arrow-down-grey.svg', 'images/arrow-down-grey.png' );
+		background-position: center center;
+		background-repeat: no-repeat;
+	}
+}
+
+.dropdown-menu( @direction: right ) {
+	.nav-block();
+	background: @background;
+	box-shadow: 0 2px 3px 1px rgba( 0, 0, 0, 0.05 );
+	position: absolute;
+	padding: 20px 2em 0;
+	margin: 0;
+	min-width: 9.153em;
+	top: 2.95em;
+	@{direction}: -1em;
+	overflow: visible;
+	z-index: 3;
+}
+
+// Categories on bottom of page
+
+.categories-bottom() {
+	#catlinks-sidebar {
+		display: none;
+	}
+
+	#catlinks {
+		margin: 0 @content-padding;
+		padding: 1.5em 0 0.5em;
+
+		li {
+			border-left: 0;
+		}
+
+		div {
+			margin: 0 0 0.35em;
+		}
+	}
+}
diff --git a/resources/themes/wikimedia.less b/resources/themes/wikimedia.less
new file mode 100644
index 0000000..b60c8fb
--- /dev/null
+++ b/resources/themes/wikimedia.less
@@ -0,0 +1,39 @@
+// Colours; see https://design.wikimedia.org/style-guide/visual-style_colors.html
+
+@base100: #fff;
+@base90: #f8f9fa;
+@base80: #eaecf0;
+@base70: #c8ccd1;
+@base30: #72777d;
+@base20: #54595d;
+@base0: #000;
+
+@red: #d33;
+@red-bright: #fee7e6;
+@red-dark: #b32424;
+
+@green: #00af89;
+@green-bright: #d5fdf4;
+@green-dark: #14866d;
+
+@blue: #36c;
+@blue-bright: #eaf3ff;
+@blue-dark: #2a4b8d;
+
+@background: @base100;
+@text: @base0;
+
+@link: @blue;
+@link-visited: @blue-dark;
+
+@link-red: @red;
+@link-red-visited: @red-dark;
+
+// Flair
+
+// Fonts are chosen for consistent metrics, not necessarily overall prettiness.
+@fonts: 'Segoe UI', 'Segoe UI Emoji', 'Segoe UI Symbol', 'Lato', 'Liberation Sans', 'Noto Sans', 'Helvetica Neue', 'Helvetica', sans-serif;
+@fonts-secondary: 'Linux Libertine', 'Times New Roman', 'Liberation Serif', 'Nimbus Roman', 'Noto Serif', 'Times', serif;
+
+@border: 0.2em;
+@radius: 0.2em;
diff --git a/resources/variables.less b/resources/variables.less
index a814956..bb1332e 100644
--- a/resources/variables.less
+++ b/resources/variables.less
@@ -1,45 +1,9 @@
 @import 'mediawiki.mixins';
+@import 'themes/wikimedia.less'; // default theme
+// .import-themes(); // might be how we apply any selected theme(s); not implemented
 
-// Colours; see https://design.wikimedia.org/style-guide/visual-style_colors.html
-
-@base100: #fff;
-@base90: #f8f9fa;
-@base80: #eaecf0;
-@base70: #c8ccd1;
-@base30: #72777d;
-@base20: #54595d;
-@base0: #000;
-
-@red: #d33;
-@red-bright: #fee7e6;
-@red-dark: #b32424;
-
-@green: #00af89;
-@green-bright: #d5fdf4;
-@green-dark: #14866d;
-
-@blue: #36c;
-@blue-bright: #eaf3ff;
-@blue-dark: #2a4b8d;
-
-@background: @base100;
-@text: @base0;
-
-@link: @blue;
-@link-visited: @blue-dark;
-
-@link-red: @red;
-@link-red-visited: @red-dark;
-
-// Flair
-
-// Fonts are chosen for consistent metrics, not necessarily overall prettiness.
-@fonts: 'Segoe UI', 'Segoe UI Emoji', 'Segoe UI Symbol', 'Lato', 'Liberation Sans', 'Noto Sans', 'Helvetica Neue', 'Helvetica', sans-serif;
-@fonts-secondary: 'Linux Libertine', 'Times New Roman', 'Liberation Serif', 'Nimbus Roman', 'Noto Serif', 'Times', serif;
-
-@border: 0.2em;
-@radius: 0.2em;
-
+// Should really be part of the theme, but currently too much alignment/positioning
+// breaks if this is changed.
 @font-size: 0.95em;
 
 // Widths
@@ -65,148 +29,5 @@
 @fixed-header-height: 3.125em;
 @color-height: 0.35em;
 
-// Miscellaneous functions
-
-// To hide objects, but keep them accessible for screen-readers
-.hidden() {
-	position: absolute;
-	top: -9999px;
-	left: 0;
-}
-
-// Icons - hides labels, but keep them accessible for screen-readers
-.icon() {
-	text-indent: -99999px;
-	border: 0;
-	background-color: transparent;
-	background-repeat: no-repeat;
-}
-
-.box() {
-	background: @base90;
-	border: solid @base80;
-	border-width: 1px 1px @border;
-	padding: 1.25em 1.75em;
-	box-shadow: 0 1px 2px 1px rgba( 0, 0, 0, 0.02 );
-}
-
-.unbox() {
-	background: transparent;
-	border: 0;
-	padding: 0;
-	box-shadow: none;
-}
-
-// Icons for the page actions menus
-.ca-icon() {
-	.icon;
-	display: inline-block;
-	width: 20px;
-	height: 20px;
-	box-sizing: border-box;
-	margin-bottom: -0.5em;
-}
-
-// Navigation column blocks
-
-.nav-block() {
-	.box();
-	padding: 1.5em 1.5em 0;
-	margin: 1em 0;
-	line-height: 1.125;
-	word-wrap: break-word;
-	font-size: 0.95em;
-
-	ul,
-	li {
-		list-style: none;
-		margin: 0;
-		padding: 0;
-	}
-
-	h3 {
-		font-weight: normal;
-		font-size: 1em;
-		margin: 0.25em 0 0.75em 0;
-		padding-bottom: 0.15em;
-		border-bottom: solid 2px @base70;
-	}
-
-	ul {
-		margin-bottom: 2em;
-	}
-
-	li {
-		padding: 0.25em 0;
-	}
-}
-
-.column-right() {
-	padding-left: 1em;
-	box-sizing: border-box;
-
-	.sidebar-chunk {
-		.nav-block();
-	}
-}
-
-.column-left() {
-	padding-right: 1em;
-	box-sizing: border-box;
-
-	.sidebar-chunk {
-		.nav-block();
-	}
-}
-
-// Dropdowns
-.dropdown-header() {
-	cursor: pointer;
-	margin-bottom: -1em;
-	padding-bottom: 1em;
-
-	&:after {
-		display: inline-block;
-		content: '';
-		width: 22px;
-		height: 12px;
-		.background-image-svg( 'images/arrow-down-grey.svg', 'images/arrow-down-grey.png' );
-		background-position: center center;
-		background-repeat: no-repeat;
-	}
-}
-
-.dropdown-menu( @direction: right ) {
-	.nav-block();
-	background: @background;
-	box-shadow: 0 2px 3px 1px rgba( 0, 0, 0, 0.05 );
-	position: absolute;
-	padding: 20px 2em 0;
-	margin: 0;
-	min-width: 9.153em;
-	top: 2.95em;
-	@{direction}: -1em;
-	overflow: visible;
-	z-index: 3;
-}
-
-// Categories on bottom of page
-
-.categories-bottom() {
-	#catlinks-sidebar {
-		display: none;
-	}
-
-	#catlinks {
-		margin: 0 @content-padding;
-		padding: 1.5em 0 0.5em;
-
-		li {
-			border-left: 0;
-		}
-
-		div {
-			margin: 0 0 0.35em;
-		}
-	}
-}
+// Timeless functions
+@import 'mixins.less';