.letter {
            display: inline-block;
            padding: 5px;
            border: 1px solid #ddd;
            border-radius: 15px;
            margin-left: 10px;
            cursor: pointer;
            font-size: 1.5em;
        }
        
        .letter2 {
            display: inline-block;
            padding: 5px;
            margin-left: 10px;
            font-size: 3em;
        }
        
        .done {
            cursor: default;
            color: #ddd;
            border: 1px solid white;
        }
        
        #kopcence {
            background-color: #297FBA;
            width: 200px;
            text-align: center;
            padding: 20px;
            font-size: 2em;
            color: white;
        }
        
        .message {
            font-size: 2.5em;
            margin-top: 20px;
            font-family: cursive;
        }

/*
.navbar{
    background-color: #2C3D50;
 }

 .nav li {
  font-weight: bold;
  color: #ffffff;
 }
 */