:root{font-family:Inter,system-ui,-apple-system,Segoe UI,Roboto,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;color:#1f2937;background-color:#f3f4f6}*{box-sizing:border-box}body{margin:0}.page{min-height:100vh;display:grid;place-items:center;padding:16px}.card{width:100%;max-width:960px;background:#fff;border-radius:12px;padding:24px;box-shadow:0 8px 30px #00000014}h1{margin:0 0 8px;font-size:clamp(24px,4vw,30px)}.toolbar{display:flex;justify-content:space-between;align-items:center;gap:12px}.form,.actions,.tabs{display:flex;gap:8px;flex-wrap:wrap;margin:12px 0}input,button,textarea{border:1px solid #d1d5db;border-radius:8px;padding:8px 10px;font:inherit}button{background:#111827;color:#fff;cursor:pointer}.json-area{width:100%;min-height:150px}.result{margin:0;background:#111827;color:#e5e7eb;padding:12px;border-radius:8px;overflow:auto;max-height:360px}.error{color:#b91c1c}