body {
  font-family: Arial, sans-serif;
  background:#f4f6f8;
  margin:0;
  color:#333;
}
header {
  background:#1b1f24;
  color:#fff;
  padding:20px;
}
nav a {
  color:#fff;
  margin-right:15px;
  text-decoration:none;
}
.container {
  padding:30px;
}
.card {
  background:#fff;
  padding:20px;
  margin-bottom:15px;
  border-radius:6px;
}
.notice {
  background:#fff3cd;
}
footer {
  text-align:center;
  padding:20px;
  font-size:13px;
  color:#777;
}