*{box-sizing:border-box}body{margin:0;font-family:system-ui,Segoe UI,Roboto,Arial,sans-serif;padding:0 16px;color:#111}
.wrap{margin:40px auto}
.card{border:1px solid #e5e7eb;border-radius:12px;padding:16px;margin:14px 0;background:#fff}
h1,h2,h3{margin:8px 0 14px}
.btn{display:inline-block;border:1px solid #111;background:#111;color:#fff;border-radius:10px;padding:10px 16px;text-decoration:none;cursor:pointer}
.btn.secondary{background:#fff;color:#111}
.input{width:100%;padding:10px;border:1px solid #d1d5db;border-radius:8px;margin:6px 0}
.err{color:#b00020;font-weight:600}
.note{color:#555}
.code{font-size:28px;font-weight:800;letter-spacing:0.14em;font-family:ui-monospace,Consolas,monospace}
.header{display:flex;justify-content:space-between;align-items:center}
.small{font-size:12px;color:#6b7280}