body {
    font-family: Helvetica, sans-serif;

    opacity: 0;
    -moz-transition: opacity 1.5s;
    -webkit-transition: opacity 1.5s;
    -o-transition: opacity 1.5s;
    transition: opacity 1.5s;
    margin: 0px;
}

/* Style the tab */
.tab {
    overflow: hidden;
    border: 1px solid #ccc;
    background-color: #f1f1f1;
}

/* Style the buttons that are used to open the tab content */
.tab button {
    background-color: inherit;
    float: left;
    border: none;
    outline: none;
    cursor: pointer;
    padding: 14px 16px;
    width: 33.3%;
    transition: 0.3s;
}

/* Change background color of buttons on hover */
.tab button:hover {
    background-color: #ddd;
}

/* Create an active/current tablink class */
.tab button.active {
    background-color: #ccc;
}

.sticky {
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 5;
}

/* Style the tab content */
.hidden {
    display: none;
}

div.active {
    display: block;
    -webkit-animation: fadeIn 0.5s ease-out;
    -moz-animation: fadeIn 0.5s ease-out;
    -o-animation: fadeIn 0.5s ease-out;
    animation: fadeIn 0.5s ease-out;
}

@-webkit-keyframes fadeIn{
    0% {
        display: none;
        opacity: 0;
    }
    1% {
        display: block;
        opacity: 0;
    }
    100% {
        display: block;
        opacity: 1;
    }
}

@-moz-keyframes fadeIn {
    0% {
        display: none;
        opacity: 0;
    }
    1% {
        display: block;
        opacity: 0;
    }
    100% {
        display: block;
        opacity: 1;
    }
}

@-o-keyframes fadeIn {
    0% {
        display: none;
        opacity: 0;
    }
    1% {
        display: block;
        opacity: 0;
    }
    100% {
        display: block;
        opacity: 1;
    }
}

@keyframes fadeIn {
    0% {
        display: none;
        opacity: 0;
    }
    1% {
        display: block;
        opacity: 0;
    }
    100% {
        display: block;
        opacity: 1;
    }
}