:root{--blue: #2563eb;--bg: #f4f6fb;--card: #ffffff;--text: #1f2937;--muted: #6b7280;--err: #dc2626}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text)}.appbar{background:var(--blue);color:#fff;padding:14px 16px;font-size:18px;font-weight:600}.langswitch{position:fixed;top:10px;right:10px;display:flex;gap:4px}.langswitch button{width:auto;padding:4px 8px;font-size:12px;background:#ffffffd9;color:var(--blue);border:1px solid var(--blue);border-radius:6px}.langswitch button:disabled{background:var(--blue);color:#fff;opacity:1}main{padding:24px 16px;display:flex;justify-content:center}.card{background:var(--card);width:100%;max-width:420px;padding:24px;border-radius:16px;box-shadow:0 2px 12px #0000000f;display:flex;flex-direction:column;gap:14px}.card h1{font-size:22px;margin:0 0 4px}input{width:100%;padding:14px;font-size:16px;border:1px solid #d1d5db;border-radius:10px}button{width:100%;padding:14px;font-size:16px;font-weight:600;color:#fff;background:var(--blue);border:none;border-radius:10px;cursor:pointer}button.link,.card a{background:none;color:var(--blue);text-decoration:none;font-weight:500;text-align:center}.langrow{display:grid;grid-template-columns:1fr 1fr;gap:8px}.langrow button{background:#eef2ff;color:var(--blue)}.langrow button.on{background:var(--blue);color:#fff}.err{color:var(--err);margin:0;font-size:14px}.ok{color:#16a34a;font-size:32px;text-align:center;margin:4px 0 0}.invite{background:#f0f9ff;padding:12px;border-radius:10px;word-break:break-all;font-size:14px}