body {
    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #2c3e50;
    color: #fff;
}
.selected {
    background-color: #2980b9;
}
.logo {
    width: 25;
    height: 25;
}

header {
    background-color: #3e4982;
    color: #fff;
    padding: 20px;
    text-align: center;
}

header h1 {
    margin: 0;
}

.container {
    display: flex;
}

nav {
    background-color: #34495e;
    width: 200px;
    padding: 20px;
    text-align: center;
}

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

nav li a {
    color: #fff;
    text-decoration: none;
    padding: 10px 0;
    display: block;
}

nav li a:hover {
    background-color: #2980b9;
}

main {
    padding: 20px;
    flex-grow: 1;
}