fix styling bugs

Author: trentfridey

src/App.css

@@ -1,5 +1,5 @@
 #root {
-    height: 100vh;
+    height: 100%;
     display: flex;
     flex-direction: column;
     background-color: var(--darkgrey);

src/Help.css

@@ -8,6 +8,9 @@
     width: 100px;
     height: 35px;
     cursor: pointer;
+    background: black;
+    color: var(--white);
+    font-family: monospace;
 }
 
 .button-group > button + button {