body { font-family: Arial, sans-serif; margin: 0; background: #f7f7fb; color: #222; }
header { background: #111827; padding: 1rem; }
nav a { color: white; margin-right: 1rem; text-decoration: none; }
main { max-width: 860px; margin: 2rem auto; background: white; padding: 2rem; border-radius: 12px; box-shadow: 0 10px 30px rgba(0,0,0,0.08); }
input, textarea, button { display: block; width: 100%; margin: 0.75rem 0; padding: 0.75rem; }
button { width: auto; cursor: pointer; }
.error { color: #b91c1c; }