:root { --bg:#0f172a; --card:#111827; --text:#e5e7eb; --muted:#9ca3af; }
* { box-sizing:border-box; }
body { margin:0; font-family:system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial; background:var(--bg); color:var(--text); }
.container { max-width:880px; margin:40px auto; padding:0 16px; }
h1 { font-size:28px; margin-bottom:12px; }
.card { background:var(--card); border:1px solid #1f2937; border-radius:12px; padding:16px; margin:16px 0; }
textarea { width:100%; padding:12px; border-radius:8px; border:1px solid #374151; background:#0b1220; color:var(--text); }
button { margin-top:10px; padding:10px 16px; border:0; border-radius:8px; background:#2563eb; color:white; cursor:pointer; }
button:disabled { opacity:.6; cursor:not-allowed; }
.hidden { display:none; }
pre { background:#0b1220; border:1px solid #1f2937; border-radius:8px; padding:12px; white-space:pre-wrap; }
footer { margin-top:16px; color:var(--muted); font-size:14px; }