Fix html label

Author: remcoder

demo/index.html

@@ -237,8 +237,8 @@ <h1 class="text-center m-3 mb-5">GCode Preview
                   <input type="checkbox" v-model="drawBoundingBox" />
                 </div>
                 <div class="controls">
-                  <label for="background-color">Background color</label>
-                  <input type="color" v-model="settings.boundingBoxColor" />
+                  <label for="bbx-color">Bounding box color</label>
+                  <input id="bbx-color" type="color" v-model="settings.boundingBoxColor" />
                 </div>
               </section>
             </div>