body { font-family: sans-serif; display: flex; flex-direction: column; justify-content: center; align-items: center; min-height: 100vh; margin: 0; }
#nav { display: flex; justify-content: center; align-items: center; }
#nav a { background-color: #007bff; color: white; padding: 10px 15px; margin-bottom: 15px; border: none; border-radius: 4px; cursor: pointer; font-size: 16px; width: 100%; }
#nav a:hover { background-color: #0056b3; }
.flash { color: red; }
.hidden { display: none; }