:root{--bg: #f4f5f7;--panel: #ffffff;--text: #1c2330;--muted: #667085;--line: #e2e5ea;--accent: #1f5eff;--accent-2: #0f8a5f;--warn: #b54708;--err: #c01048;font-family:Segoe UI,system-ui,-apple-system,sans-serif;color:var(--text);background:var(--bg)}*{box-sizing:border-box}body{margin:0;background:var(--bg)}.top{display:flex;align-items:center;gap:24px;padding:12px 20px;background:#101828;color:#fff}.brand{font-weight:700;letter-spacing:.08em}nav{display:flex;gap:4px;flex-wrap:wrap}.tab{font:inherit;padding:6px 12px;border:0;border-radius:6px;font-size:14px;color:#d0d5dd;background:transparent;cursor:pointer}.tab:hover{color:#fff}.tab.active{background:#ffffff1f;color:#fff}.layout{display:grid;grid-template-columns:minmax(340px,460px) 1fr;gap:16px;padding:16px;height:calc(100vh - 52px)}.panel{background:var(--panel);border:1px solid var(--line);border-radius:10px}.form{padding:20px;overflow:auto}.form h1{margin:0 0 4px;font-size:20px}.muted{color:var(--muted);font-size:14px}.center{display:grid;place-items:center;height:100%}fieldset{border:1px solid var(--line);border-radius:8px;margin:14px 0;padding:10px 14px 14px}legend{padding:0 6px;font-weight:600;font-size:14px}.row{display:grid;grid-template-columns:1fr 1fr;gap:10px}.field{display:flex;flex-direction:column;gap:4px;margin-top:8px;font-size:13px;color:var(--muted)}.field input,.field select{font:inherit;font-size:15px;color:var(--text);padding:8px 10px;border:1px solid #cfd4dc;border-radius:6px;background:#fff}.field input:focus,.field select:focus{outline:2px solid var(--accent);outline-offset:-1px}.seg{display:flex;gap:6px}.seg button{flex:1;font:inherit;font-size:14px;padding:8px;border:1px solid #cfd4dc;border-radius:6px;background:#fff;cursor:pointer;color:var(--text)}.seg button.on{background:var(--accent);border-color:var(--accent);color:#fff}.check{display:flex;gap:8px;align-items:center;margin-top:12px;font-size:14px}.hint{margin:10px 0 0;font-size:13px;color:var(--muted)}.warn{color:var(--warn);font-size:13px}.err{color:var(--err);font-size:13px;white-space:pre-wrap}.actions{display:flex;gap:10px;margin-top:16px}.primary{flex:1;font:inherit;font-weight:600;padding:11px;border:0;border-radius:8px;background:var(--accent);color:#fff;cursor:pointer}.primary.alt{background:var(--accent-2)}.primary:disabled{opacity:.6;cursor:wait}.preview{overflow:hidden}.preview iframe{width:100%;height:100%;border:0;border-radius:10px}@media(max-width:860px){.layout{grid-template-columns:1fr;height:auto}.preview{height:80vh}}