* { box-sizing: border-box; }
body { font-family: system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, 'Helvetica Neue', Arial, sans-serif; margin: 0; color: #111; background: #fafafa; }
.app { max-width: 720px; margin: 0 auto; padding: 24px; }
header h1 { margin: 0; font-size: 2rem; }
header p { color: #555; }
.controls { display: flex; gap: 12px; margin: 20px 0; }
button { padding: 10px 16px; border: 1px solid #ddd; background: white; border-radius: 10px; cursor: pointer; }
button:disabled { opacity: .5; cursor: not-allowed; }
.status { padding: 12px; background: #fff; border: 1px solid #eee; border-radius: 10px; }
footer { margin-top: 40px; color: #777; }