:root{--bg: #0f1116;--panel: #171a21;--panel-2: #1e222b;--border: #2a2f3a;--text: #e6e8ee;--muted: #8a91a0;--accent: #4f8cff;--user: #253048}*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--text)}.app{display:flex;height:100vh}.sidebar{width:260px;flex-shrink:0;background:var(--panel);border-right:1px solid var(--border);display:flex;flex-direction:column;padding:12px}.new-chat{background:var(--accent);color:#fff;border:none;border-radius:8px;padding:10px;font-weight:600;cursor:pointer}.conv-list{flex:1;overflow-y:auto;margin-top:12px}.conv-item{display:flex;align-items:center;justify-content:space-between;gap:6px;padding:9px 10px;border-radius:8px;cursor:pointer;color:var(--muted)}.conv-item:hover{background:var(--panel-2)}.conv-item.active{background:var(--panel-2);color:var(--text)}.conv-title{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:14px}.conv-del{background:none;border:none;color:var(--muted);cursor:pointer;font-size:18px;line-height:1;opacity:0;padding:0 4px}.conv-item:hover .conv-del{opacity:1}.sidebar-foot{font-size:12px;padding-top:8px;border-top:1px solid var(--border)}.muted{color:var(--muted);font-size:13px}.chat{flex:1;display:flex;flex-direction:column;min-width:0}.chat-header{display:flex;align-items:center;justify-content:space-between;padding:14px 20px;border-bottom:1px solid var(--border)}.subtitle{color:var(--muted);font-weight:400;font-size:13px}.chat-header select{background:var(--panel-2);color:var(--text);border:1px solid var(--border);border-radius:6px;padding:6px 8px}.messages{flex:1;overflow-y:auto;padding:24px}.empty{color:var(--muted);text-align:center;margin-top:15vh}.empty .hint{font-size:13px}.msg{max-width:780px;margin:0 auto 22px}.msg .role{font-size:12px;color:var(--muted);margin-bottom:4px}.msg .content{white-space:pre-wrap;line-height:1.55}.msg.user .content{background:var(--user);padding:12px 14px;border-radius:10px;display:inline-block}.cursor{color:var(--accent);animation:blink 1s steps(2) infinite}@keyframes blink{50%{opacity:0}}.sources{margin-top:10px;display:flex;flex-wrap:wrap;gap:6px;align-items:center}.sources-label{font-size:12px;color:var(--muted)}.chip{background:var(--panel-2);border:1px solid var(--border);color:var(--accent);border-radius:999px;padding:2px 10px;font-size:12px;text-decoration:none}.chip:hover{border-color:var(--accent)}.composer{display:flex;gap:10px;padding:16px 24px;border-top:1px solid var(--border)}.composer input{flex:1;background:var(--panel-2);border:1px solid var(--border);border-radius:10px;padding:12px 14px;color:var(--text);font-size:15px}.composer input:focus{outline:none;border-color:var(--accent)}.composer button{background:var(--accent);color:#fff;border:none;border-radius:10px;padding:0 22px;font-weight:600;cursor:pointer}.composer button:disabled{opacity:.5;cursor:default}