add styling for banner

Author: raclim

client/styles/components/_banner.scss

@@ -0,0 +1,30 @@
+.banner {
+  width: 100%;
+  min-height: 2.2rem;
+  text-align: center;
+  padding: 1rem;
+  background-color: #DFED33; // yellow from p5.js website
+  border-bottom: 1px solid #000;
+
+  a {
+    color: #000;
+  }
+
+  a:hover {
+    text-decoration: underline;
+  }
+
+  @media (max-width: 770px) {
+    min-height: 3.3rem;
+  }
+}
+
+.banner-close-button {
+  display: flex;
+  flex-direction: column;
+  align-items: center; 
+  justify-content: center;
+  height: 20px;
+  width:20px;
+  float: right;
+}

client/styles/main.scss

@@ -55,6 +55,7 @@
 @import 'components/skip-link';
 @import 'components/stars';
 @import 'components/admonition';
+@import 'components/banner';
 
 @import 'layout/dashboard';
 @import 'layout/ide';