:root{--bg:#071024;--card:#081428;--accent:#06b6d4;--muted:#94a3b8;--text:#e6eef6}
*{box-sizing:border-box}
body{margin:0;font-family:Inter,system-ui,Segoe UI,Roboto,Arial;background:linear-gradient(180deg,var(--bg) 0%,#091027 100%);color:var(--text);min-height:100vh;display:grid;place-items:center;padding:20px}
.card{width:100%;max-width:920px;background:linear-gradient(180deg,rgba(255,255,255,0.02),transparent);border-radius:12px;padding:22px;box-shadow:0 8px 30px rgba(2,6,23,0.6);border:1px solid rgba(255,255,255,0.04)}
header{display:flex;justify-content:space-between;align-items:center;margin-bottom:8px}
h1{margin:0;font-size:20px}
.lead{color:var(--muted);margin:0 0 14px}
label{display:block;margin:10px 0 6px;color:var(--muted);font-size:13px}
input[type=number]{width:120px;padding:8px;border-radius:8px;border:1px solid rgba(255,255,255,0.06);background:transparent;color:var(--text)}
textarea{width:100%;padding:12px;border-radius:8px;border:1px solid rgba(255,255,255,0.04);background:rgba(255,255,255,0.02);color:var(--text);resize:vertical;font-family:ui-monospace,Roboto Mono,monospace}
.controls{display:flex;gap:8px;flex-wrap:wrap;margin:12px 0}
button{padding:10px 12px;border-radius:10px;border:0;background:var(--accent);color:#032226;font-weight:600;cursor:pointer}
.preview{margin-top:8px;background:rgba(255,255,255,0.02);padding:10px;border-radius:8px;color:var(--muted);font-family:ui-monospace,monospace;white-space:pre-wrap;font-size:13px}
.footer{margin-top:14px;color:var(--muted);font-size:13px;text-align:right}
@media (max-width:520px){.card{padding:16px}h1{font-size:18px}}