body { font-family: Arial, sans-serif; margin: 0; padding: 0; background: #f9f9f9; }
#app { display: flex; justify-content: center; align-items: center; height: 100vh; }
.card { background: white; padding: 2rem; border-radius: 12px; box-shadow: 0 2px 6px rgba(0,0,0,0.1); text-align: center; }
button { margin: 0.5rem; padding: 0.6rem 1rem; border: none; border-radius: 6px; background: #0070f3; color: white; cursor: pointer; }
button:hover { background: #0059c1; }