body { font-family: sans-serif; margin: 0; padding: 20px; background: #f4f4f4; color: #333; transition: background 0.3s, color 0.3s; }
nav { background: #333; padding: 10px; margin-bottom: 20px; border-radius: 5px; display: flex; align-items: center; justify-content: space-between; transition: background 0.3s; }
nav h1 { color: white; margin: 0; font-size: 1.5em; }
.nav-right { display: flex; align-items: center; gap: 10px; }
nav a { color: white; text-decoration: none; margin-right: 15px; cursor: pointer; }
.hidden { display: none; }
.card { background: white; padding: 20px; border-radius: 5px; margin-bottom: 10px; box-shadow: 0 2px 5px rgba(0,0,0,0.1); transition: background 0.3s, color 0.3s; }
input, textarea { width: 100%; padding: 10px; margin: 5px 0; box-sizing: border-box; }
button { background: #007bff; color: white; padding: 10px 15px; border: none; cursor: pointer; transition: background 0.3s; }
button.danger { background: #dc3545; }
#chat-messages { height: 300px; overflow-y: scroll; border: 1px solid #ccc; padding: 10px; margin-bottom: 10px; background: #fff; transition: background 0.3s, border-color 0.3s; }
.message { margin-bottom: 5px; padding: 5px; background: #e9ecef; border-radius: 3px; transition: background 0.3s; }
.my-message { background: #d1ecf1; text-align: right; }
#dark-mode-toggle { background: none; border: none; font-size: 1.5em; cursor: pointer; transition: transform 0.3s; }
#dark-mode-toggle:hover { transform: scale(1.1); }

/* Dark mode */
body.dark { background: #121212; color: #e0e0e0; }
body.dark nav { background: #1e1e1e; }
body.dark .card { background: #1e1e1e; color: #e0e0e0; }
body.dark #chat-messages { background: #1e1e1e; border-color: #333; }
body.dark .message { background: #2e2e2e; }
body.dark .my-message { background: #3e3e3e; }