:root{--bg:#0b0f19;--fg:#e5e7eb;--muted:#9aa3b2;--primary:#4f46e5;--panel:#0f172a;--bubble:#111827;--user:#1f2937;--think-w:360px;--think-h:120px;--think-pad:8px}
*{box-sizing:border-box}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,"Noto Sans","PingFang SC","Hiragino Sans GB","Microsoft YaHei",sans-serif;background:var(--bg);color:var(--fg)}
.app{width:100%;max-width:none;margin:0 auto;display:flex;flex-direction:column;height:100vh;min-height:100dvh;padding:16px;gap:12px}
  .header{font-weight:600;display:flex;align-items:center;justify-content:space-between;gap:8px}
  .header .title{font-weight:600}
  .header .actions{display:flex;gap:8px}
  .header .actions button{padding:6px 12px;border-radius:10px;border:1px solid #273043;background:#121a2e;color:var(--fg);cursor:pointer}
  .header .actions button:hover{background:#18213a}
  .main{display:flex;gap:12px;flex:1;min-height:0}
  .sidebar{width:clamp(200px,24vw,320px);background:var(--panel);border-radius:12px;display:flex;flex-direction:column;min-height:0}
  .sidebar-header{padding:10px;border-bottom:1px solid #1f2937}
  .sessions{flex:1;overflow-y:auto;padding:8px;display:flex;flex-direction:column;gap:6px}
  .session-item{padding:8px 10px;border-radius:10px;background:#0b1324;color:var(--fg);cursor:pointer;border:1px solid transparent;display:flex;align-items:center;justify-content:space-between;gap:8px}
  .session-item .title{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .session-item .close{border:1px solid #2a3552;background:#141d35;color:var(--fg);border-radius:8px;padding:0 8px;height:22px;line-height:20px;cursor:pointer}
  .session-item .close:hover{background:#1b2645}
  .session-item:hover{background:#0f1a33}
  .session-item.active{border-color:var(--primary);background:#111c39}
  .session-item.busy{border-color:#f59e0b;background:#111a2e}
  .session-item.busy .title::after{content:' •';color:#f59e0b}
  .content{flex:1;display:flex;flex-direction:column;min-width:0}
  .tabs{display:flex;gap:8px;padding:8px 8px 0;overflow-x:auto}
  .tab{padding:6px 10px;border-radius:10px 10px 0 0;background:#0b1324;border:1px solid #1f2937;border-bottom:0;color:var(--fg);white-space:nowrap;cursor:pointer;display:flex;align-items:center;gap:8px}
  .tab .title{max-width:160px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .tab .close{border:1px solid #2a3552;background:#141d35;color:var(--fg);border-radius:8px;padding:0 8px;height:22px;line-height:20px;cursor:pointer}
  .tab .close:hover{background:#1b2645}
  .tab.active{background:#111c39;border-color:var(--primary);color:#fff}
  .tab.busy{border-color:#f59e0b}
  .tab.busy .title::after{content:' •';color:#f59e0b}
  .chat{flex:1;overflow-y:auto;padding:12px;background:var(--panel);border-radius:12px;display:flex;flex-direction:column;gap:12px}
  .msg{display:flex;gap:8px}
  .msg.user{justify-content:flex-end}
  .bubble{max-width:80%;padding:10px 12px;border-radius:12px;line-height:1.6;background:var(--bubble);white-space:pre-wrap;word-break:break-word}
  .msg.user .bubble{background:var(--user)}
  .attachments{display:flex;gap:8px;flex-wrap:wrap;margin-top:6px}
  .attachments .thumb{width:96px;height:96px;border-radius:8px;object-fit:cover;border:1px solid #1f2937;background:#0b1324}
  .msg.user .attachments .thumb{border-color:#2b3a57}
  .file-chip{display:inline-flex;align-items:center;gap:6px;padding:4px 8px;border-radius:9999px;background:#0b1324;border:1px solid #1f2937;color:var(--fg);font-size:12px}
  .file-chip .name{max-width:160px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
  .think-block{color:var(--muted);font-size:13px;line-height:1.6;margin-bottom:6px;width:var(--think-w);max-width:var(--think-w);padding:var(--think-pad);box-sizing:border-box;border-radius:8px;background:transparent}
  .think-content{white-space:pre-wrap;word-break:break-word;overflow-wrap:anywhere;word-wrap:break-word;height:var(--think-h);overflow-y:auto;overflow-x:hidden;-ms-overflow-style:none;scrollbar-width:none}
  .think-content::-webkit-scrollbar{display:none;width:0;height:0}
  .thinking-label{display:block;color:var(--muted);font-weight:600;margin-bottom:4px}
  .answer-block{white-space:pre-wrap}
  @keyframes thinkingBlink{0%,100%{opacity:.5}50%{opacity:1}}
  .typing{display:inline-block;vertical-align:middle;margin-left:4px;animation:typingColor 1.2s linear infinite, typingBounce .8s ease-in-out infinite}
  .typing .dot{width:6px;height:6px;border-radius:50%;background:var(--muted);opacity:.4;animation:typingBlink 1.4s infinite both}
  .typing .dot:nth-child(2){animation-delay:.2s}
  .typing .dot:nth-child(3){animation-delay:.4s}
  @keyframes typingBlink{0%{opacity:.2;transform:translateY(0)}20%{opacity:1;transform:translateY(-2px)}40%{opacity:.2;transform:translateY(0)}100%{opacity:.2;transform:translateY(0)}}
  @keyframes typingColor{0%{color:#ef4444}33%{color:#f59e0b}66%{color:#22c55e}100%{color:#ef4444}}
  @keyframes typingBounce{0%,100%{transform:translateY(0)}50%{transform:translateY(-2px)}}
  .composer{display:flex;gap:8px;padding-bottom:calc(12px + env(safe-area-inset-bottom))}
  .composer input,.composer textarea{flex:1;padding:12px;border-radius:10px;border:1px solid #1f2937;background:#0b1324;color:var(--fg);font-size:16px;resize:none}
  .composer input[type="file"]{flex:0;padding:6px 8px;border-radius:10px;border:1px solid #273043;background:#121a2e;color:var(--fg)}
  .composer button{padding:0 16px;border-radius:10px;border:0;background:var(--primary);color:#fff;font-weight:600}
  .composer button:disabled,.composer input:disabled,.composer textarea:disabled{opacity:.6}

/* ========== Responsive ========== */
@media (max-width: 1200px){
  .app{padding:14px}
  .bubble{max-width:82%}
}

@media (max-width: 1024px){
  .app{padding:12px}
  .sidebar{width:clamp(180px,28vw,280px)}
  .bubble{max-width:85%}
}

@media (max-width: 768px){
  .app{padding:10px}
  .main{flex-direction:column}
  .sidebar{display:none}
  .tabs{padding:6px 6px 0}
  .tab .title{max-width:40vw}
  .chat{padding:10px}
  .bubble{max-width:92%}
  .think-block{width:100%}
  .composer input,.composer textarea{padding:14px}
  .composer{position:sticky;bottom:0;background:var(--bg);padding-top:8px}
  .composer button{padding:0 14px}
}
.composer button{padding:0 16px;border-radius:10px;border:0;background:var(--primary);color:#fff;font-weight:600}
.composer button:disabled,.composer input:disabled,.composer textarea:disabled{opacity:.6}