v4: Update homepage, examples, and general docs styles

- Refreshes the look and feel of the homepage with fresh colors, new content, and simplified styles.
- Updates docs button styles
- Replaces bytesize icons with Bootstrap icons
- Adds themes callout to examples page

site/_includes/icons/circle-square.svg

@@ -0,0 +1,4 @@
+<svg {% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %}{% if include.class %} class="{{ include.class }}"{% endif %} focusable="false" viewBox="0 0 16 16" fill="currentColor" xmlns="http://www.w3.org/2000/svg">
+  <path d="M0 6a6 6 0 1112 0A6 6 0 010 6z"/>
+  <path d="M12.93 5h1.57a.5.5 0 01.5.5v9a.5.5 0 01-.5.5h-9a.5.5 0 01-.5-.5v-1.57a6.953 6.953 0 01-1-.22v1.79A1.5 1.5 0 005.5 16h9a1.5 1.5 0 001.5-1.5v-9A1.5 1.5 0 0014.5 4h-1.79c.097.324.17.658.22 1z"/>
+</svg>

site/_includes/icons/cloud-fill.svg

@@ -0,0 +1,3 @@
+<svg {% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %}{% if include.class %} class="{{ include.class }}"{% endif %} focusable="false" viewBox="0 0 16 16" fill="currentColor" xmlns="http://www.w3.org/2000/svg">
+  <path fill-rule="evenodd" d="M3.5 13a3.5 3.5 0 11.59-6.95 5.002 5.002 0 119.804 1.98A2.5 2.5 0 0113.5 13h-10z" clip-rule="evenodd"/>
+</svg>

site/_includes/icons/code.svg

@@ -0,0 +1,3 @@
+<svg {% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %}{% if include.class %} class="{{ include.class }}"{% endif %} focusable="false" viewBox="0 0 16 16" fill="currentColor" xmlns="http://www.w3.org/2000/svg">
+  <path fill-rule="evenodd" d="M5.854 4.146a.5.5 0 010 .708L2.707 8l3.147 3.146a.5.5 0 01-.708.708l-3.5-3.5a.5.5 0 010-.708l3.5-3.5a.5.5 0 01.708 0zm4.292 0a.5.5 0 000 .708L13.293 8l-3.147 3.146a.5.5 0 00.708.708l3.5-3.5a.5.5 0 000-.708l-3.5-3.5a.5.5 0 00-.708 0z" clip-rule="evenodd"/>
+</svg>

site/_includes/icons/download.svg

@@ -1 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg"{% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %} fill="none" stroke="currentcolor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" aria-hidden="true"{% if include.class %} class="{{ include.class }}"{% endif %} viewBox="0 0 32 32" focusable="false"><title>Download</title><path d="M9 22c-9 1-8-10 0-9C6 2 23 2 22 10c10-3 10 13 1 12m-12 4l5 4 5-4m-5-10v14"/></svg>

site/_includes/icons/droplet-fill.svg

@@ -0,0 +1,3 @@
+<svg {% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %}{% if include.class %} class="{{ include.class }}"{% endif %} focusable="false" viewBox="0 0 16 16" fill="currentColor" xmlns="http://www.w3.org/2000/svg">
+  <path fill-rule="evenodd" d="M8 16a6 6 0 006-6c0-1.655-1.122-2.904-2.432-4.362C10.254 4.176 8.75 2.503 8 0c0 0-6 5.686-6 10a6 6 0 006 6zM6.646 4.646c-.376.377-1.272 1.489-2.093 3.13l.894.448c.78-1.559 1.616-2.58 1.907-2.87l-.708-.708z" clip-rule="evenodd"/>
+</svg>

site/_includes/icons/import.svg

@@ -1 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg"{% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %} fill="none" stroke="currentcolor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" aria-hidden="true"{% if include.class %} class="{{ include.class }}"{% endif %} viewBox="0 0 32 32" focusable="false"><title>Import</title><path d="M28 22v8H4v-8M16 4v20m-8-8l8 8 8-8"/></svg>

site/_includes/icons/lightning.svg

@@ -1 +0,0 @@
-<svg xmlns="http://www.w3.org/2000/svg"{% if include.width %} width="{{ include.width }}"{% endif %}{% if include.height %} height="{{ include.height }}"{% endif %} fill="none" stroke="currentcolor" stroke-linecap="round" stroke-linejoin="round" stroke-width="2" aria-hidden="true"{% if include.class %} class="{{ include.class }}"{% endif %} viewBox="0 0 32 32" focusable="false"><title>Lightning</title><path d="M18 13l8-11L8 13l6 6-8 11 18-11z"/></svg>