html {
    width: 100%;
    height: 100%;
    margin:0;
    padding:0;
}

body {
    /*display: table-cell;*/
    text-align: center;
    height: 100%;
    width: 100%;
    margin:0;
    padding:0;
    overflow:hidden;
}
/* Version one: Moving the background
#background1 {
    background: url(../pictures/background.jpg);
    left: 0;
}
#background2 {
    background: url(../pictures/background-nature.jpg);
    left: -100vw;
}
#background1, #background2 {
    background-size: cover;
    background-position: center;
    width: 100vw;
    height: 100vh;
    position: absolute;
    transition: transform 1s ease-in-out;
    z-index:-1;
}
*/
#background1 {
    background: url(../pictures/background-nature.jpg);
    opacity: 1;
    z-index:-1;
    transition: opacity 1.5s;
}
#background2 {
    background: url(../pictures/background.jpg);
    z-index:-2;
}
#background1, #background2 {
    background-size: cover;
    background-position: center;
    width: 100vw;
    height: 100vh;
    position: absolute;
    left:0;
    top:0;
}


header {
    position: absolute;
    top:0;
    width: 100%;
    text-align: center;
    font-family: 'Arial';
    font-weight: bold;
    font-size: 5vmin;
    text-align: left;
    margin: 0 0 1vmin 0;
    height: 7vmin;
    background-color: rgba(0,0,0,0.7);
    color: white;
    /* background-color: rgba(0,255,0,0.5); */
}
header td {
    padding-left: 5vmin;
    vertical-align: middle;
}
header button {
    display:block;
    background-color: transparent;
    border: 0.3vmin solid white;
    padding: 0.4vmin;
    margin:0;
    border-radius: 1vmin; 
    color: white;
    font-family: 'Arial';
    font-size: 2.5vmin;
    text-transform: uppercase;
    cursor: pointer;
}
header button:hover  {
    background-color: rgba(255, 255, 255, 0.5);
    outline:0;
}
header button:focus  {
    background-color: rgba(255, 255, 255, 0.5);
    outline:0;
}
header button:active {
    background-color: rgba(255, 255, 255, 1);
    color: black;
}


footer {
    position:absolute;
    bottom:0;
    text-align:center;
    font-size: 2.353vmin; /* std 16px */
    width: 100%;
    padding: 0;
    margin: 2vmin 0 0 0;
    height: 6vmin;
    background-color: rgba(0,0,0,0.7);
    color: white;
    /* background-color: rgba(255,0,0,0.5); */

}

footer p {
    margin: 1.471vmin; /* 10px */
    padding:0;
}