Add styling

src/App.vue

@@ -40,8 +40,42 @@ export default {
 </script>
 
 <style lang="stylus">
+@import "theme.styl"
+
+html, body, #app {
+	font-family: $fonts
+	font-style: normal
+	overflow: hidden
+	padding: 0
+	margin: 0
+}
+
 #app {
+	background-color: $main-background-colour
 	height: 100vh
 	width: 100vw
 }
-</style>
+
+.input {
+	background-color: $input-background
+	border-radius: $input-border-radius
+	border-color: $input-border-colour
+	border-width: $input-border-width
+	border-style: solid
+	text-align: center
+	padding: 10px 15px
+	color: $input-text
+	outline: none
+}
+
+input[type="text"] {
+	@extend .input
+}
+
+button {
+	@extend .input
+	font-family: $fonts
+	letter-spacing: $input-letter-spacing
+	font-size: 17px
+}
+</style>