.container { display: flex; }
.nav { width: 200px; padding: 5px; background: #f5f5f5; }
.content { flex: 1; padding: 5px; }
.nav a { display: block; padding: 5px 0; }
.nav-heading1 {
    background: #b6fcb6;
    color: #000;
    padding: 1px;
    margin-bottom: 1px;
    border-radius: 1px;
    font-weight: bold;
    text-align: center;
}