html { 
    font-family: Helvetica; 
    display: inline-block; 
    margin: 0px auto; 
    text-align: center;
}
body{
    margin-top: 50px;
} 
h1 {
    color: #444444;
    margin: 50px auto 30px;
} 
h3 {
    color: #444444;
    margin-bottom: 50px;
}
.button {
    display: block;
    width: 180px;
    background-color: #1abc9c;
    border: none;
    color: white;
    padding: 13px 30px;
    text-decoration: none;
    font-size: 25px;
    margin: 0px auto 35px;
    cursor: pointer;
    border-radius: 4px;
}
.button-on {
    background-color: #1abc9c;
}
.button-on:active {
    background-color: #16a085;
}
.button-off {
    background-color: #34495e;
}
.button-off:active {
    background-color: #2c3e50;
}
p {font-size: 14px;
    color: #888;
    margin-bottom: 10px;
}