* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  html, body {
    height: 100%;
    font-family: Arial, sans-serif;
    background-color: #f5f5f5;
  }
  
  #chat-container {
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    height: calc(100% - 60px);
    max-width: 800px;
    margin: 20px auto;
    padding: 20px;
    border: 1px solid #ccc;
    border-radius: 8px;
    background-color: #fff;
  }
  
  #messages {
    flex-grow: 1;
    overflow: auto;
    margin-bottom: 20px;
  }
  
  .message {
    margin-bottom: 10px;
  }
  
  input {
    font-size: 16px;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 4px;
  }
  
  input[type="text"] {
    width: 100%;
  }
  
  #username-container,
  #message-container {
    display: flex;
    margin-bottom: 10px;
  }
  
  #message-container {
    margin-bottom: 0;
  }
  
  #send {
    font-size: 16px;
    background-color: #4a90e2;
    color: white;
    padding: 10px 15px;
    margin-left: 10px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    outline: none;
  }
  
  #send:hover {
    background-color: #3d7ac9;
  }
  
  #new-chat {
    display: block;
    font-size: 16px;
    background-color: #4a90e2;
    color: white;
    padding: 10px 15px;
    margin: 20px auto;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    outline: none;
    max-width: 200px;
  }
  
  #new-chat:hover {
    background-color: #3d7ac9;
  }