body{
    font-family: Arial, sans-serif;
    background:#f4f7fb;
    color:#0f172a;
}

.rb-nav{
    background:#0b0f3a;
    padding:15px 0;
}

.rb-logo{
    color:white;
    font-size:24px;
    font-weight:700;
    text-decoration:none;
}

.rb-btn{
    background:#2563eb;
    color:white;
    padding:10px 18px;
    border-radius:8px;
    text-decoration:none;
}

.rb-card{
    background:white;
    border-radius:15px;
    padding:25px;
    box-shadow:0 10px 30px rgba(0,0,0,0.08);
}

.rb-sidebar{
    width:250px;
    min-height:100vh;
    background:#0b0f3a;
    color:white;
    padding:25px;
}

.rb-sidebar a{
    display:block;
    color:white;
    text-decoration:none;
    margin:14px 0;
}