.button{
    background-color:#2ba1e8; /* Green */
    border: none;
    color: white;
    padding: 13px 79px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 24px;
    margin: 4px 2px;
    cursor: pointer;
    font-family: 'Open Sans', sans-serif;
}

.button1 {
    width: 50%;
  
    
}
.button2 {width: 50%;}
.button3 {width: 50%;}

div.container {
    width: 100%;
    border: 1px solid gray;
}

header, footer {
    padding: 1em;
    color: rgb(0, 0, 0);
    background-color: rgb(255, 255, 255);
    clear: left;
    text-align: center;
}

nav {
    float: left;
    max-width: 160px;
    margin: 0;
    padding: 1em;
}

nav ul {
    list-style-type: none;
    padding: 0;
}
   
nav ul a {
    text-decoration: none;
}

article {
    margin-left: 170px;
    border-left: 1px solid gray;
    padding: 1em;
    overflow: hidden;
}
ul {
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: rgb(66, 65, 65);
}

li {
    float: left;
    border-right:1px solid rgb(255, 255, 255);
}

li:last-child {
    border-right: none;
}

li a {
    display: block;
    color: rgb(255, 255, 255);
    text-align: center;
    padding: 14px 16px;
    text-decoration: none;
    font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji","Segoe UI Symbol";
    
}

li a:hover:not(.active) {
    background-color: rgb(0, 0, 0);
}

.active {
    background-color: rgb(0, 0, 0);
}