body{
    background-color:#f4f4f4;
    background-image:
    radial-gradient(#e6e6e6 1px, transparent 1px);

    background-size:20px 20px;

    font-family:Verdana, sans-serif;

    margin:0;
}

#container{
    width:900px;

    margin:40px auto;

    background:white;

    border:1px solid #bdbdbd;

    box-shadow:0px 0px 10px rgba(0,0,0,0.15);
}

#navbar{
    background:#d8e4ea;

    padding:10px;
}

#navbar ul{
    list-style:none;

    display:flex;

    gap:15px;

    margin:0;
    padding:0;
}

#navbar a{
    text-decoration:none;

    color:#3a76d8;

    font-weight:bold;
}

#flex{
    display:flex;
}

aside{
    width:220px;

    background:#f3f6f7;

    border-right:1px solid #d6d6d6;

    padding:15px;
}

main{
    flex:1;

    padding:20px;
}

h1{
    color:#3d4b55;
}

.sidebar-title{
    font-weight:bold;

    margin-top:15px;

    margin-bottom:10px;

    background:#d8e4ea;

    padding:5px;
}

.sidebar-link{
    display:block;

    color:#3a76d8;

    text-decoration:none;

    margin:8px 0;
}

.bannerimg{
  display: block;
  margin: 0 auto;
  
  width:100%;
  max-height:700px;

  border-radius:15px;
}