Add minor style changes on homepage.

static/homepage.html

@@ -5,12 +5,16 @@
         <title>Código para llevar</title>
         <meta name="viewport" content="width=device-width, initial-scale=1">
         <style>
-         body {
+          body {
+             font-family: sans-serif;
              margin: 0 auto;
              width: fit-content;
              max-width: 100ex;
              padding: 0 1ex;
-         }
+          }
+          .header h1 {
+             text-align: center;
+          }
          .links section {
              margin-top: 1em;
              display: inline-block;