*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}

body{

    font-family:Arial, sans-serif;
    background:white;
}

.container{

    width:980px;

    margin:30px auto;

    border:2px solid #66cc66;

    padding:15px;

    background:#eeeeee;
}

/* HEADER */

header{

    display:flex;

    align-items:center;

    border:2px solid black;

    background:white;

    padding:10px;
}

header img{

    width:110px;
    margin-right:20px;
}

header h2{

    font-size:28px;
}

/* MENU */

nav{

    margin:15px 0;
}

nav ul{

    display:flex;

    list-style:none;
}

nav li{

    flex:1;
}

nav a{

    display:block;

    text-align:center;

    text-decoration:none;

    color:white;

    background:linear-gradient(green,#222);

    padding:10px;

    font-size:16px;
}

nav a:hover{

    background:#339933;
}

/* CONTENT */

.content{

    display:flex;

    justify-content:space-between;
}

section{

    width:72%;

    border:1px solid blue;

    padding:10px;
}

.box{

    border:1px solid red;

    background:white;

    padding:15px;

    margin-bottom:15px;

    text-align:center;
}

.box h3{

    margin-bottom:8px;
}

aside{

    width:25%;

    background:#7FE7E7;

    border:1px solid red;

    padding:15px;

    text-align:center;
}

aside h3{

    margin-bottom:15px;
}

/* FOOTER */

footer{

    margin-top:20px;

    border-top:2px solid green;

    text-align:center;

    padding:15px;
}
.back{
    text-align:center;
    margin:35px 0;
}

.back a{

    display:inline-block;

    padding:12px 25px;

    background:linear-gradient(135deg,#4CAF50,#2E8B57);

    color:white;

    text-decoration:none;

    border-radius:30px;

    font-size:18px;

    font-weight:bold;

    box-shadow:0 5px 10px rgba(0,0,0,.2);

    transition:.3s;
}

.back a:hover{

    background:linear-gradient(135deg,#2E8B57,#4CAF50);

    transform:translateY(-3px);

    box-shadow:0 8px 18px rgba(0,0,0,.3);
}