body{
    font-family: "Times New Roman", Times, serif;
    margin:0;
}

/* Khung ngoài */
.container{
    width:80%;
    margin:auto;
    border:3px solid #444;
}

/* Header */
header{
    background:#5f6b75;
    color:white;
    text-align:center;
    padding:40px;
    font-size:35px;
}

/* Navigation */
nav{
    float:left;
    width:30%;
    height:300px;
    background:#e6e6e6;
    padding:20px;
    box-sizing:border-box;
}

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

nav ul li{
    margin-bottom:10px;
}

/* Article */
article{
    float:left;
    width:70%;
    height:300px;
    padding:20px;
    box-sizing:border-box;
    background:white;
}

/* Footer */
footer{
    clear:both;
    background:#5f6b75;
    color:white;
    text-align:center;
    padding:15px;
}