.welcome{max-width:400px;margin-top:100px}.welcome h2{font-size:3em}.welcome button{margin:30px auto}.chat h2{font-size:2.6em;margin-bottom:40px}.chat span{font-size:1.4em}.chat .time{display:block;font-size:1.1em}.messages{max-height:300px;overflow:auto}.messages::-webkit-scrollbar{width:2px}.messages::-webkit-scrollbar-track{background:#ddd}.messages::-webkit-scrollbar-thumb{background:#aaa}