h1{
    color: rgb(211, 191, 211);
    border: rgb(128, 117, 117) solid 1px;
    text-align: center;
    background-color: rgb(13, 58, 74);
    font-size: 2em;
    text-transform: uppercase;
    text-decoration: underline;
}
h2{
    text-align: center;
    text-decoration: underline;
}
html {
    background: url(https://img.tripi.vn/cdn-cgi/image/width=700,height=700/https://gcs.tripi.vn/public-tripi/tripi-feed/img/482605IQX/anh-mo-ta.png);
    background-size: cover;
    background-repeat: no-repeat;
}
div{
    border: 1px solid black;
}
#main{
    background-color: rgba(89, 194, 171, 0.5);
    font-size: 20px;
    font-weight: bold;
    padding: 10px;
    text-align: center;
}
#main img{
    display: block;
    margin: 20px auto;
    margin-top: 20px;
    border: 2px solid black;
    border-radius: 20px 0 20px 0 ;
}
#top{
    text-align: center;
    margin-bottom: 20px;
    font-size:2em;
}
#footer{
    text-align: center;
    font-size: 1.2em;
    margin-top: 20px;
    background-color: rgba(152, 168, 165, 0.5);
}
#sidebar{
    background-color: rgba(200, 217, 252, 0.5);
    font-size: 18px;
    padding: 10px;
    margin-top: 10px;
    text-align: center;
    border: 2px dashed;
}
#sidebar img{
    max-width: 100%;
    margin-top: 20px;
}