:root{color-scheme:dark;--bg:#101312;--panel:#171b19;--panel-strong:#202622;--text:#f2f5ef;--muted:#aeb7ac;--line:#303830;--accent:#7ccf90;--accent-strong:#f0c66a}*{box-sizing:border-box}body,html{margin:0;min-height:100%;background:var(--bg);color:var(--text);font-family:Arial,Helvetica,sans-serif}button,select,textarea{font:inherit}button{cursor:pointer}.shell{min-height:100vh;display:grid;grid-template-rows:auto 1fr}.topbar{border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:16px;padding:16px 22px;background:#121613}.brand{display:flex;flex-direction:column;gap:3px}.brand strong{font-size:18px}.brand span,.user{color:var(--muted);font-size:13px}.workspace{display:grid;grid-template-columns:300px 1fr;min-height:0}.sidebar{border-right:1px solid var(--line);padding:18px;background:var(--panel)}.sidebar h2{font-size:15px;margin:0 0 12px}.mode-list{display:grid;grid-gap:8px;gap:8px}.mode-button{border:1px solid var(--line);background:transparent;color:var(--text);padding:12px;border-radius:8px;text-align:left}.mode-button.active{border-color:var(--accent);background:#1c2a20}.chat{min-height:0;display:grid;grid-template-rows:1fr auto}.messages{overflow:auto;padding:24px;display:flex;flex-direction:column;gap:14px}.message{max-width:860px;border:1px solid var(--line);border-radius:8px;padding:14px 16px;white-space:pre-wrap;line-height:1.5}.message.user{align-self:flex-end;background:#24251b;border-color:#474126}.message.assistant{align-self:flex-start;background:var(--panel-strong)}.composer{border-top:1px solid var(--line);padding:16px;display:grid;grid-template-columns:1fr auto;grid-gap:12px;gap:12px;background:#121613}.composer textarea{min-height:54px;max-height:180px;resize:vertical;border:1px solid var(--line);border-radius:8px;background:var(--panel);color:var(--text);padding:13px}.send{width:54px;height:54px;border:0;border-radius:8px;color:#101312;background:var(--accent);display:grid;place-items:center}.send:disabled{opacity:.55;cursor:wait}.login{display:flex;align-items:center;gap:10px}@media (max-width:780px){.workspace{grid-template-columns:1fr}.sidebar{border-right:0;border-bottom:1px solid var(--line)}.topbar{align-items:flex-start;flex-direction:column}}