:root{--bg: #0f1419;--panel: #1a2332;--border: #2d3a4f;--text: #e7ecf3;--muted: #8b9cb3;--accent: #3d8bfd;--user-msg: #1e3a5f;--agent-msg: #1a2e24}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text)}.login-page{min-height:100vh;display:grid;place-items:center}.login-card{background:var(--panel);padding:2rem;border-radius:12px;width:min(400px,92vw);border:1px solid var(--border)}.login-card h1{margin:0 0 .5rem;font-size:1.5rem}.login-card p{color:var(--muted);margin:0 0 1.5rem}.login-card label{display:block;margin-bottom:1rem;font-size:.85rem;color:var(--muted)}.login-card input{display:block;width:100%;margin-top:.35rem;padding:.6rem .75rem;border-radius:8px;border:1px solid var(--border);background:var(--bg);color:var(--text)}.login-card button[type=submit]{width:100%;padding:.75rem;background:var(--accent);color:#fff;border:none;border-radius:8px;font-weight:600;cursor:pointer}.app{display:grid;grid-template-columns:280px 1fr;height:100vh}.sidebar{border-right:1px solid var(--border);background:var(--panel);display:flex;flex-direction:column;overflow:hidden}.sidebar-header{padding:1rem;border-bottom:1px solid var(--border);display:flex;flex-direction:column;gap:.35rem}.user-badge{font-size:.8rem;color:var(--muted)}.link-btn{background:none;border:none;color:var(--accent);cursor:pointer;text-align:left;padding:0;font-size:.85rem}.new-chat{padding:.75rem;display:flex;flex-direction:column;gap:.5rem;border-bottom:1px solid var(--border)}.new-chat select,.new-chat button{padding:.5rem;border-radius:6px;border:1px solid var(--border);background:var(--bg);color:var(--text)}.new-chat button{background:var(--accent);border:none;color:#fff;font-weight:600;cursor:pointer}.session-list{list-style:none;margin:0;padding:0;overflow-y:auto;flex:1}.session-list button{width:100%;text-align:left;padding:.75rem 1rem;border:none;background:transparent;color:var(--text);cursor:pointer;border-bottom:1px solid var(--border)}.session-list button.active{background:#3d8bfd26}.session-title{display:block;font-size:.9rem}.session-meta{display:block;font-size:.75rem;color:var(--muted);margin-top:.25rem}.chat-main{display:flex;flex-direction:column;min-height:0}.chat-header{padding:1rem 1.25rem;border-bottom:1px solid var(--border)}.chat-header h2{margin:0;font-size:1.1rem}.chat-header span{font-size:.8rem;color:var(--muted)}.messages{flex:1;overflow-y:auto;padding:1rem 1.25rem;display:flex;flex-direction:column;gap:1rem}.msg{max-width:85%;padding:.75rem 1rem;border-radius:12px}.msg-user{align-self:flex-end;background:var(--user-msg)}.msg-assistant{align-self:flex-start;background:var(--agent-msg)}.msg-role{font-size:.7rem;color:var(--muted);margin-bottom:.35rem;text-transform:uppercase;letter-spacing:.04em}.msg-body{white-space:pre-wrap;line-height:1.5}.typing{color:var(--muted);font-style:italic}.composer{padding:1rem 1.25rem;border-top:1px solid var(--border);display:flex;gap:.75rem;align-items:flex-end}.composer textarea{flex:1;resize:vertical;padding:.75rem;border-radius:8px;border:1px solid var(--border);background:var(--bg);color:var(--text);font-family:inherit}.composer button{padding:.75rem 1.25rem;background:var(--accent);color:#fff;border:none;border-radius:8px;font-weight:600;cursor:pointer}.composer button:disabled{opacity:.5;cursor:not-allowed}.empty{flex:1;display:grid;place-items:center;color:var(--muted)}.error{color:#ff8a8a;font-size:.9rem}.error.banner{margin:0;padding:.5rem 1.25rem;background:#ff50501a}@media(max-width:768px){.app{grid-template-columns:1fr}.sidebar{display:none}}