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

.header{
  background:#111827;
  padding:15px;
  font-size:24px;
  font-weight:bold;
}

.sidebar{
  width:220px;
  background:#1e293b;
  height:100vh;
  position:fixed;
  padding-top:20px;
}

.sidebar a{
  display:block;
  color:white;
  text-decoration:none;
  padding:12px 20px;
}

.sidebar a:hover{
  background:#334155;
}

.main{
  margin-left:240px;
  padding:20px;
}

.card{
  background:#1e293b;
  padding:15px;
  border-radius:10px;
  margin-bottom:15px;
}