:root { --theme: #0b57d0; --bg: #ffffff; --text: #1f1f1f; }
body { margin:0; font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
        background: var(--bg); color: var(--text);}
.content { max-width: 720px; margin: 10vh auto; padding: 24px; text-align: center; }
button { background: var(--theme); color: white; border: none; border-radius: 12px; padding: 12px 18px; font-weight: 600; }
.hint { color:#666; margin-top:12px; }