diff --git a/src/actions/cssVariables/index.js b/src/actions/cssVariables/index.js
index 523e09e8..177a077d 100644
--- a/src/actions/cssVariables/index.js
+++ b/src/actions/cssVariables/index.js
@@ -5,16 +5,16 @@ export default (node, props) => {
   });
 
   return {
-    update(new_props) {
-      Object.entries(new_props).forEach(([key, value]) => {
+    update(newProps) {
+      Object.entries(newProps).forEach(([key, value]) => {
         node.style.setProperty(`--${key}`, value);
         delete props[key];
       });
 
-      Object.keys(props).forEach(name =>
-        node.style.removeProperty(`--${name}`),
-      );
-      props = new_props;
+      Object.keys(props).forEach((name) => {
+        node.style.removeProperty(`--${name}`);
+      });
+      props = newProps;
     },
   };
-};
\ No newline at end of file
+};
diff --git a/src/components/GraphicBlock/stories/docs/ai2svelte.md b/src/components/GraphicBlock/stories/docs/ai2svelte.md
index 13a78558..d6485156 100644
--- a/src/components/GraphicBlock/stories/docs/ai2svelte.md
+++ b/src/components/GraphicBlock/stories/docs/ai2svelte.md
@@ -14,6 +14,6 @@ You can use `GraphicBlock` with components created by [ai2svelte](https://github
   notes="Note: A shakemap represents the ground shaking produced by an earthquake."
   ariaDescription="A map showing shake intensity of the quake."
 >
-  <MyAiMap basePath={assets} />
+  <MyAiMap assetsPath={assets} />
 </GraphicBlock>
 ```
diff --git a/src/components/GraphicBlock/stories/docs/aria.md b/src/components/GraphicBlock/stories/docs/aria.md
index a8e99842..b7c2d395 100644
--- a/src/components/GraphicBlock/stories/docs/aria.md
+++ b/src/components/GraphicBlock/stories/docs/aria.md
@@ -12,7 +12,7 @@ The `ariaDescription` string will be processed as markdown, so you can add multi
   notes="Note: A shakemap represents the ground shaking produced by an earthquake."
   ariaDescription="A map showing the shake intensity produced by the earthquake."
 >
-  <MyAiMap basePath={assets} />
+  <MyAiMap assetsPath={assets} />
 </GraphicBlock>
 ```
 
diff --git a/src/components/Theme/Theme.stories.svelte b/src/components/Theme/Theme.stories.svelte
new file mode 100644
index 00000000..878d52c0
--- /dev/null
+++ b/src/components/Theme/Theme.stories.svelte
@@ -0,0 +1,100 @@
+<script>
+  import { Meta, Template, Story } from '@storybook/addon-svelte-csf';
+
+  // @ts-ignore
+  import componentDocs from './stories/docs/component.md?raw';
+
+  import Theme, { themes } from './Theme.svelte';
+
+  import {
+    withComponentDocs
+  } from '$lib/docs/utils/withParams.js';
+
+  const meta = {
+    title: 'Components/Theme',
+    component: Theme,
+    ...withComponentDocs(componentDocs),
+    argTypes: {
+      styles: {
+        options: Object.keys(themes), // An array of serializable values
+        mapping: themes, // Maps serializable option values to complex arg values
+        control: {
+          type: 'select', // Type 'select' is automatically inferred when 'options' is defined
+          labels: {
+          // 'labels' maps option values to string labels
+            main: 'Main',
+            dark: 'Dark',
+          },
+        },
+      },
+    },
+  };
+</script>
+
+<Meta {...meta} />
+
+<Template let:args>
+  <Theme {...args}>
+    <div class="themed">
+      <p>My theme</p>
+    </div>
+  </Theme>
+</Template>
+
+<Story
+  name="Default"
+  args={{
+    styles: themes.main,
+  }}
+/>
+
+<Story
+  name="Inheritance"
+  args={{
+    styles: themes.main,
+  }}
+>
+  <Theme styles={themes.main}>
+    <div class="themed">
+      <p>My theme</p>
+      <Theme styles={themes.dark}>
+        <div class="themed">
+          <p>My sub-theme</p>
+          <Theme styles={themes.main}>
+            <div class="themed">
+              <p>My sub-sub-theme</p>
+            </div>
+          </Theme>
+          <Theme styles={{ colour: { background: 'steelblue', primary: '#fff' } }}>
+            <div class="themed">
+              <p>My other sub-sub-theme</p>
+            </div>
+          </Theme>
+        </div>
+      </Theme>
+    </div>
+  </Theme>
+</Story>
+
+<style lang="scss">
+  @import "../../scss/mixins/fonts";
+  div.themed {
+    background-color: var(--theme-colour-background);
+    padding: 2rem;
+    width: 80%;
+    margin: 1rem auto;
+    display: flex;
+    justify-content: center;
+    flex-flow: column;
+    border: 1px solid var(--theme-colour-primary);
+    border-radius: 20px;
+    p {
+      @include font-display;
+      color: var(--theme-colour-primary);
+      text-align: center;
+      margin: 0;
+      display: block;
+      width: 100%;
+    }
+  }
+</style>
\ No newline at end of file
diff --git a/src/components/Theme/Theme.svelte b/src/components/Theme/Theme.svelte
new file mode 100644
index 00000000..57a0f9ab
--- /dev/null
+++ b/src/components/Theme/Theme.svelte
@@ -0,0 +1,42 @@
+<script context="module" lang="ts">
+  const main = {
+    colour: {
+      background: '#ffffff',
+      primary: '#333333',
+    },
+  };
+  const dark = {
+    colour: {
+      background: '#333333',
+      primary: '#ffffff',
+    },
+  };
+
+  export const themes = {
+    main,
+    dark,
+  };
+</script>
+
+<script lang="ts">
+  export let styles: object = main;
+  export let name: string = 'theme';
+
+  import cssVariables from '../../actions/cssVariables';
+  import flatten from './utils/flatten';
+</script>
+
+<div
+  class="theme theme-{name}"
+  style="display: contents;"
+  use:cssVariables={flatten({ [name]: styles })}
+>
+  <!-- Clients can override the theme above by attaching custom properties to this element. -->
+  <div
+    class="theme-client-override theme-{name}"
+    style="display: contents;"
+  >
+    <!-- Themed content -->
+    <slot></slot>
+  </div>
+</div>
\ No newline at end of file
diff --git a/src/components/Theme/stories/docs/component.md b/src/components/Theme/stories/docs/component.md
new file mode 100644
index 00000000..7528df87
--- /dev/null
+++ b/src/components/Theme/stories/docs/component.md
@@ -0,0 +1,3 @@
+> ⏳ Coming soon!
+
+Set a theme for your page.
diff --git a/src/components/Theme/utils/flatten.js b/src/components/Theme/utils/flatten.js
new file mode 100644
index 00000000..3385c935
--- /dev/null
+++ b/src/components/Theme/utils/flatten.js
@@ -0,0 +1,40 @@
+function isBuffer(obj) {
+  return obj &&
+    obj.constructor &&
+    (typeof obj.constructor.isBuffer === 'function') &&
+    obj.constructor.isBuffer(obj);
+}
+
+const transformKey = (key) => key.replace(/[^a-z0-9-]/gi, '');
+
+export default function flatten(target) {
+  const delimiter = '-';
+  const output = {};
+
+  function step(object, prev, currentDepth = 1) {
+    Object.keys(object).forEach(function(key) {
+      const value = object[key];
+      const isArray = Array.isArray(value);
+      const type = Object.prototype.toString.call(value);
+      const isbuffer = isBuffer(value);
+      const isObject = (
+        type === '[object Object]' ||
+        type === '[object Array]'
+      );
+
+      const newKey = prev ?
+        prev + delimiter + transformKey(key) :
+        transformKey(key);
+
+      if (!isArray && !isbuffer && isObject && Object.keys(value).length) {
+        return step(value, newKey, currentDepth + 1);
+      }
+
+      output[newKey] = value;
+    });
+  }
+
+  step(target);
+
+  return output;
+}