Add online usage disclaimer (#5)

Resolves #4

website/index.html

@@ -35,6 +35,7 @@
         <p>Doge seeds are <strong>cryptographically secure</strong> mnemonic seed phrases with added dankness. The first four words will be a randomly generated Doge-like sentence.</p>
         <p>The seed phrases are <strong>fully valid checksummed BIP39 seeds</strong>. They can be used with any cryptocurrency and can be imported into any BIP39 compliant wallet.</p>
         <p>You can test them here: <a rel="noopener noreferrer" target="_blank" href="https://iancoleman.io/bip39/">iancoleman.io/bip39</a></p>
+        <p>If you're using this for anything important, you should download this page with <code>File > Save Page As...</code> and run it on an offline machine.</p>
 
         <h3>Very entropy, such secure.</h3>
         <p>The mnemonic is seeded by a cryptographically secure random number generator. However there is a slight reduction in entropy due to the introduction of the doge-isms. A doge seed has about 19.415 fewer bits of entropy than a standard BIP39 seed of equivalent length.</p>

website/style.css

@@ -151,6 +151,13 @@ a:hover {
   padding: 1em 0;
 }
 
+code {
+  font-size: 0.8em;
+  background: #d8d8d8;
+  padding: 0.2em 0.4em;
+  border-radius: 2px;
+}
+
 table.entropy-table {
   border-spacing: 0;
   border-collapse: collapse;