done2

public/style.css

-body {
-  font-family: sans-serif;
-  margin: auto;
-  max-width: 1280px;
-}
-
-.navbar {
-  background-color: #313236;
-  border-radius: 2px;
-  max-width: 800px;
-}
-
-.navbar a {
-  color: #aaa;
-  display: inline-block;
-  font-size: 15px;
-  padding: 10px;
-  text-decoration: none;
-}
-
-.navbar a:hover {
-  color: #ffffff;
-}
-

src/App.js

@@ -20,7 +20,7 @@ const TimeButton = (props) => {
 
   return (
     <>
-      <button onClick={displayTime} tz={props.tz}>
+      <button onClick={displayTime}>
         {props.cityName}
       </button>
       <div>{time}</div>