dark mode (#4)

Author: StevenClontz

index.html

@@ -8,7 +8,10 @@
 <title>code4math</title>
 <meta name="description" content="Consortium of Digital Ecosystems for Mathematics" />
 <link rel="stylesheet" href="./simple.min.css">
-<style>:root {--accent-bg: #f7fff5; --accent: #47a10d}</style>
+<style>
+  :root {--accent-bg: #f7fff5; --accent: #47a10d}
+  @media (prefers-color-scheme: dark) { :root {--accent-bg: #212a22; --accent: #00b928} }
+</style>
 
 <link rel="icon" href="/favicon.png" />
 <link rel="apple-touch-icon" href="/favicon.png">