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

header {
    padding: 1px;
    color: white;
    background-color: black;
    clear: left;
    text-align: center;
}

footer {
    padding: 5px;
    color: white;
    background-color: green;
    clear: left;
}

.column {
   float: center;
   width: 25%;
   margin-bottom: 16px;
   padding: 0 8px;
}

.card {
   box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
}

.button {
   border: none;
   outline: 0;
   display: inline-block;
   padding: 8px;
   color: white;
   background-color: #000;
   text-align: center;
   cursor: pointer;
   width: 100px;
}

.button:hover {
   background-color: #3e8e41;
}

.dropbtn {
    background-color: black;
    color: white;
    padding: 16px;
    font-size: 16px;
    border: none;
    cursor: pointer;
}

.dropdown {
    position: relative;
    display: inline-block;
}

.dropdown-content {
    display: none;
    position: absolute;
    background-color: #f9f9f9;
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
}

.dropdown-content a {
    color: black;
    padding: 12px 16px;
    text-decoration: none;
    display: block;
}

.dropdown-content a:hover {background-color: #f1f1f1}

.dropdown:hover .dropdown-content {
    display: block;
}

.dropdown:hover .dropbtn {
    background-color: #3e8e41;
}

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: 0px;
    padding: 1em;
    overflow: hidden;
}