:root {
    --textcolor: white;
    --backcolor: darkblue;
    --backcolor2: lightblue;
}
        * {
            font-family: sans-serif;
            font-size: 2.3vw;
            box-sizing: border-box;
        }
        
        @media only screen and (max-width: 1000px) {
            * {
                font-size: 4vw;
            }
        }
        
        a {
            text-decoration: none;
        }
        
        th, td {
            padding: 0.5em 0.7em;
            white-space: nowrap;
        }
        th {
            margin: 0;
            background-color: var(--backcolor);
            color: var(--textcolor);
            
        }

        .already { 
            color: red;
        }
        
        table {
            border-collapse: collapse;
            width: 100%;
            margin: 0;
            padding: 0;
            border: 3px solid var(--backcolor);
        }
        .container {
            margin: 0;
            padding: 0;
        }
        .center { 
            margin: auto;
            padding: 0;
        }
        .column { 
            float: left;
            padding: 0px;
            margin: 0;
            padding: 0;
        }
        .middle { 
            margin: auto;
            padding: 0;
            margin: 0;
        }
        .left , .right {
            padding: 0;
            margin: 0;
        }
        .container:after {
            content: "";
            display: table;
            clear: both;
        }
         body {
            padding-top: 40px;
            padding-bottom: 40px;
         }
         
         .form-signin {
            max-width: 100%;
            padding: 15px;
            margin: 0 auto;
         }
         
         .form-signin .form-signin-heading,
         .form-signin .checkbox {
            margin-bottom: 10px;
         }
         
         .form-signin .checkbox {
            font-weight: normal;
         }
         
         .form-signin .form-control {
            position: relative;
            height: auto;
            -webkit-box-sizing: border-box;
            -moz-box-sizing: border-box;
            box-sizing: border-box;
            border-radius: 5px;
            padding: 10px;
         }
         
         .form-signin .form-control:focus {
            z-index: 2;
         }
         
         .form-signin input[type="email"] {
            margin-bottom: -1px;
            border-color:#017572;
         }
         
         .form-signin input[type="password"] {
            margin-bottom: 10px;
            border-color:#017572;
         }
         
         h2{
            text-align: center;
            color: #017572;
         }
         
         table tr:nth-child(odd) {
            background-color: #DCDCDC;
         }
         
form {
}