:root{ --bg:#0f1117; --ink:#e5e7eb; --panel:#151824; --accent:#60a5fa; --outline:#243244 }
  *{box-sizing:border-box}
  html,body{height:100%;margin:0;background:var(--bg);color:var(--ink);font:500 15px/1.35 ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto}
  header{display:flex;align-items:center;justify-content:center;padding:8px;background:#0b0e14;border-bottom:1px solid var(--outline)}
  .menu{display:flex;gap:10px;align-items:center;flex-wrap:wrap}
  .btn{appearance:none;border:1px solid var(--outline);background:#0b0e14;color:var(--ink);padding:8px 12px;border-radius:10px;cursor:pointer}
  .btn[aria-pressed="true"]{border-color:var(--accent);box-shadow:0 0 0 2px color-mix(in srgb, var(--accent) 35%, transparent)}
  main{height:calc(100% - 44px);display:grid;grid-template-rows:1fr}
  iframe{width:100%;height:100%;border:0;background:#0f1117}