.main_container {
                    left: 0px;
                    width: 99%;
                    top: 0px;
                    height: 98%;
                    border:2px solid black;
                }  
                .header {
                    left: 0px;
                    top: 0px;
                    width: 100%;
                    height:10%;
                    border:1px solid black; 
                }
                .menu {
                    float:left;
                    left:0px;
                    top:12%;
                    width: 15%;
                    height:89%;
                    border:1px solid black;
                }
                .second_menu {
                    
                    float:left;
                    border:1px solid black;
                    width:84%;
                    height:10%;
                    float:left;
                    margin-right:5px;
                    left:22%;
                    top:12%;
                }
                .main_screen {
                    float:left;
                    border:2px;
                    width:84%;
                    height:79%;
                    margin-right:5px;
                    left:19%;
                    border:1px solid black;
                }
                .mbtn {
                    border-radius:15%;
                    border-color:yellow;
                    width:150px;
                    height:50px;
                    font-size:20px;
                    color:yellow;
                    background-color:black;
                }
                .sbtn {
                    border-radius:15%;
                    border-color:yellow;
                    width:100px;
                    height:50px;
                    font-size:15px;
                    color:yellow;
                    background-color:black;
                }
                .message_text {
                    font-size:30px;
                }
                label, span {
                    font-size:20px;
                }