* {box-sizing: border-box}

/* Set height of body and the document to 100% */
body, html {
    height: 100%;
    margin: 0;
    font-family: Arial;
}

/* Style tab links */
.tablink {
    background-color: gray;
    color: white;
    float: left;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 14px 16px;
    font-size: 17px;
    width: 25%;
}

.tablink:hover {
    background-color: #777;
}

/* Style the tab content (and add height:100% for full page content) */
.tabcontent {
    display: none;
    padding: 100px 20px;
    height: 100%;
    border-style: solid;
    border-color: gray;
    border-width: 2px;
}