body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background-color: var(--bg);
  color: var(--text);
  transition: background 0.3s, color 0.3s;
}

:root {
  --bg: #f4f4f4;
  --text: #222;
}

.dark {
  --bg: #121212;
  --text: #eee;
}

header {
  background: #3498db;
  color: white;
  text-align: center;
  padding: 1.5em 1em;
  box-shadow: 0 4px 6px rgba(0,0,0,0.1);
}

section {
  padding: 2em;
  max-width: 800px;
  margin: auto;
}

#status {
  background: rgba(52,152,219,0.1);
  border-left: 5px solid #3498db;
  padding: 1em;
  margin-top: 1em;
}

footer {
  text-align: center;
  padding: 1em;
  background: #222;
  color: #aaa;
  margin-top: 2em;
}