body, html{
    margin: 0px;
    padding: 0px;
    font-family: sans-serif;
    background-color: #F3F3F3;
}

.main{
    width: 80%;
    max-width: 1140px;
    min-width: 540px;
    margin: 60px auto 30px;
    background-color: #FFFFFF;
    box-shadow: 0px 1px 5px rgba(0,0,0,0.1);
    border-radius: 2px;
    padding: 30px;
    line-height: 120%;
}

nav{
    width: 100%;
    background-color: #FFFFFF;
    box-shadow: 0px 1px 5px rgba(0,0,0,0.1), 0px 1px 0px rgba(0,0,0,0.3);
    position: fixed;
    top: 0px;
    z-index: 100;
}
nav a{
    width: 20%;
    display: block;
    float: left;
    text-decoration: none;
    border-bottom: 4px solid transparent;
    text-align: center;
    padding: 10px 0px 6px 0px;
    color: black;
    transition: border-bottom 0.3s ease;
}
nav a:hover{
    border-bottom: 4px solid grey;
    text-decoration: none;
}
nav a:active{
    border-bottom: 4px solid #00BCD4;
    text-decoration: none;
}

img{
    display: inline-block;
    max-height: 100%;
    max-width: 100%;
    margin: 10px auto;
}

.selected{
    border-bottom: 4px solid #00BCD4;
    font-weight: bold;
}

a{
    text-decoration: none;
    color: #00BCD4;
}
a:hover, a:active{
    text-decoration: underline;
}

h3 a{
    color: #ffffff;
    background: #00BCD4;
    height: 40px;
    line-height: 40px;
    display: block;
    text-align: center;
    width: 30%;
    margin: 30px auto;
    border-radius: 2px;
    border: 2px solid #00BCD4;
    transition: background 0.3s ease, color 0.3s ease;
    text-decoration: none;
}

h3 a:hover, h3 a:active{
    color: #00BCD4;
    background: #ffffff;
    text-decoration: none;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}

.down{
    width: 40%;
    max-width: 600px;
    min-width: 300px;
    
}

.down h3 a{
    width: auto;
}

.youtube-player { display: block; margin: 10px auto; }