table tr.active{
    background: green;
    color: yellow;
}

ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: #333;
    width:100%;
}

li {
    float: left;
}

li a {
    display: block;
    color: white;
    text-align: center;
    padding: 10px 12px;
    text-decoration: none;
}

li a:hover:not(.active) {
    background-color: #111;
}

.active {
    background-color: #4CAF50;
}

#content {
  margin: 0 auto;
  border: 1px solid red;
  width:99%;
  position:absolute;
  bottom:0px;
  top:47px;
  overflow:auto;
  background-color: #00ace6;
}

.btn-link {
    border: none;
    outline: none;
    background: none;
    cursor: pointer;
    color: #0000EE;
    padding: 0;
    text-decoration: underline;
    font-family: inherit;
    font-size: inherit;
}