:root{color-scheme:dark;font-family:Inter,ui-sans-serif,system-ui,sans-serif;background:#0c0f14;color:#eef2ff}*{box-sizing:border-box}body{margin:0;min-height:100vh}button,input,textarea{font:inherit}button{border:0;border-radius:12px;padding:.75rem 1rem;background:#7c3aed;color:#fff;cursor:pointer}button:disabled{opacity:.5;cursor:not-allowed}.auth-card{max-width:440px;margin:12vh auto;padding:2rem;border:1px solid #283244;border-radius:24px;background:#121826;box-shadow:0 20px 60px #0008}.auth-card form{display:grid;gap:.75rem}input,textarea{width:100%;border:1px solid #334155;border-radius:14px;background:#0f172a;color:#f8fafc;padding:.85rem}.error{color:#fca5a5}.chat-shell{display:grid;grid-template-columns:280px minmax(0,1fr);min-height:100vh}.sidebar{border-right:1px solid #1f2937;padding:1rem;background:#090d14}.sidebar nav{display:grid;gap:.5rem;margin-top:1rem}.sidebar nav button{background:#111827;text-align:left}.sidebar nav button.active{background:#312e81}.chat-pane{display:grid;grid-template-rows:auto 1fr auto;gap:1rem;padding:1.5rem;max-height:100vh}.message-list{overflow:auto;display:flex;flex-direction:column;gap:1rem;padding-right:.5rem}.empty-state{align-self:center;justify-self:center;color:#94a3b8}.message{max-width:76ch;padding:1rem;border-radius:18px;white-space:pre-wrap;line-height:1.5}.message.user{margin-left:auto;background:#1d4ed8}.message.assistant{margin-right:auto;background:#111827;border:1px solid #263244}.thinking-panel{margin-bottom:.75rem;color:#9ca3af;background:#1f2937;border-radius:12px;padding:.75rem}.thinking-panel summary{cursor:pointer;font-weight:700}.composer{display:grid;grid-template-columns:1fr auto;gap:.75rem}.composer textarea{min-height:72px;resize:vertical}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@media(max-width:760px){.chat-shell{grid-template-columns:1fr}.sidebar{display:none}}