templates: Add Conservancy Supporter appeal to sidebar.

pinaxcon/templates/_default_sidebar.html

@@ -4,6 +4,13 @@
 
 {% sponsor_levels as levels %}
 
+<p>Conservancy makes CopyleftConf happen. Please consider becoming a
+Supporter of our work year-round!</p>
+
+<div class="conservancy-support-button">
+  <div><a href="https://sfconservancy.org/supporter/">Support<br>now!</a></div>
+</div>
+
 <h3>Sponsors</h3>
 
 <div class="sponsor-list">

static/scss/custom.scss

@@ -652,3 +652,32 @@ table.calendar, table.calendar td:empty {
 table.calendar th, table.calendar td {
   background-color: #fff;
 }
+
+.conservancy-support-button {
+    background-color: #F0FFB8;
+    border-color: #577632;
+    border-radius: 50%;
+    border-style: outset;
+    border-width: .3em;
+    color: #577632;
+    display: inline-block;
+    font-size: xx-large;
+    font-weight: bold;
+    max-width: 95%;
+    text-align: center;
+    vertical-align: middle;
+    width: 6em;
+    margin-left: 50%;
+    transform: translateX(-50%);
+
+    a {
+        color: inherit;
+        text-decoration: none !important;
+    }
+
+    div {
+        height: 0;
+        padding-bottom: 75%;
+        padding-top: 25%;
+    }
+}