:root{--primary: #2563eb;--primary-light: #3b82f6;--primary-bg: #eff6ff;--bg: #f8fafc;--sidebar-bg: #1e293b;--sidebar-text: #e2e8f0;--text: #1e293b;--text-secondary: #64748b;--border: #e2e8f0;--white: #ffffff;--assistant-bg: #f1f5f9;--user-bg: #2563eb;--user-text: #ffffff;--shadow: 0 1px 3px rgba(0,0,0,.08);--radius: 12px}*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;background:var(--bg);color:var(--text);height:100vh;overflow:hidden}#root{height:100%}.app{display:flex;height:100vh}.sidebar{width:280px;background:var(--sidebar-bg);color:var(--sidebar-text);display:flex;flex-direction:column;transition:width .3s,transform .3s;flex-shrink:0}.sidebar.collapsed{width:0;overflow:hidden}.sidebar-header{padding:24px 20px 12px;border-bottom:1px solid rgba(255,255,255,.1)}.logo{display:flex;align-items:center;gap:10px}.logo-icon{font-size:28px}.logo-text{font-size:22px;font-weight:700;letter-spacing:1px}.logo-sub{font-size:12px;color:#94a3b8;margin-top:6px}.sidebar-actions{padding:16px 20px}.btn-new-chat{width:100%;padding:10px;border:1px solid rgba(255,255,255,.2);background:transparent;color:var(--sidebar-text);border-radius:8px;cursor:pointer;font-size:14px;display:flex;align-items:center;justify-content:center;gap:8px;transition:all .2s}.btn-new-chat:hover{background:#ffffff1a}.chat-history{flex:1;overflow-y:auto;padding:0 20px}.chat-history h3{font-size:12px;text-transform:uppercase;color:#94a3b8;margin-bottom:12px;letter-spacing:1px}.history-empty{font-size:13px;color:#64748b}.history-item{padding:10px 12px;border-radius:8px;cursor:pointer;font-size:13px;margin-bottom:4px;transition:background .2s;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.history-item:hover{background:#ffffff14}.sidebar-footer{padding:16px 20px;border-top:1px solid rgba(255,255,255,.1);font-size:11px;color:#64748b;line-height:1.8}.main{flex:1;display:flex;flex-direction:column;min-width:0}.topbar{height:56px;display:flex;align-items:center;padding:0 20px;border-bottom:1px solid var(--border);background:var(--white);gap:12px}.topbar h2{font-size:16px;font-weight:600}.btn-toggle{width:36px;height:36px;border:none;background:transparent;cursor:pointer;border-radius:8px;display:flex;align-items:center;justify-content:center;color:var(--text-secondary)}.btn-toggle:hover{background:var(--bg)}.chat-container{flex:1;overflow-y:auto;padding:20px 24px}.welcome{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:60vh;text-align:center;padding:40px 20px}.welcome-icon{font-size:64px;margin-bottom:16px;animation:float 3s ease-in-out infinite}@keyframes float{0%,to{transform:translateY(0)}50%{transform:translateY(-10px)}}.welcome h1{font-size:28px;margin-bottom:8px}.welcome-desc{color:var(--text-secondary);font-size:15px;line-height:1.8;margin-bottom:32px;max-width:480px}.suggestions{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;max-width:540px;width:100%}.suggestion-chip{padding:14px 16px;border:1px solid var(--border);background:var(--white);border-radius:10px;cursor:pointer;font-size:14px;text-align:left;transition:all .2s;color:var(--text);display:flex;align-items:center;gap:8px}.suggestion-chip:hover{border-color:var(--primary);background:var(--primary-bg);box-shadow:var(--shadow)}.message{display:flex;gap:12px;margin-bottom:24px;animation:slideUp .3s ease-out}@keyframes slideUp{0%{opacity:0;transform:translateY(10px)}to{opacity:1;transform:translateY(0)}}.avatar{width:36px;height:36px;border-radius:8px;display:flex;align-items:center;justify-content:center;font-size:18px;flex-shrink:0}.ai-avatar{background:#dbeafe}.user-avatar{background:#ddd6fe}.message-content{flex:1;min-width:0}.bubble{padding:14px 18px;border-radius:var(--radius);line-height:1.8;font-size:15px}.message.assistant .bubble{background:var(--white);border:1px solid var(--border)}.message.user .bubble{background:var(--user-bg);color:var(--user-text)}.message.user{flex-direction:row-reverse}.message.user .message-content{display:flex;flex-direction:column;align-items:flex-end}.formatted-answer p{margin-bottom:6px}.formatted-answer .answer-section-title{font-weight:700;color:var(--primary);margin:12px 0 6px;font-size:15px}.formatted-answer .answer-item{padding-left:4px}.sources{margin-top:8px;display:flex;align-items:center;gap:6px;flex-wrap:wrap}.sources-label{font-size:12px;color:var(--text-secondary)}.source-tag{display:inline-block;padding:3px 10px;background:var(--primary-bg);color:var(--primary);border-radius:20px;font-size:12px;border:1px solid #bfdbfe;cursor:default}.related{margin-top:12px}.related-label{font-size:12px;color:var(--text-secondary);display:block;margin-bottom:8px}.related-chips{display:flex;flex-wrap:wrap;gap:6px}.related-chip{padding:8px 14px;background:var(--bg);border:1px solid var(--border);border-radius:20px;cursor:pointer;font-size:13px;color:var(--text);transition:all .2s}.related-chip:hover{border-color:var(--primary);color:var(--primary);background:var(--primary-bg)}.chat-input{padding:16px 24px 20px;border-top:1px solid var(--border);background:var(--white)}.input-wrapper{display:flex;gap:10px;align-items:center;background:var(--bg);border:1px solid var(--border);border-radius:var(--radius);padding:6px;transition:border-color .2s}.input-wrapper:focus-within{border-color:var(--primary);box-shadow:0 0 0 3px #2563eb1a}.input-wrapper input{flex:1;padding:10px 12px;border:none;background:transparent;font-size:15px;outline:none;color:var(--text)}.input-wrapper input::placeholder{color:#94a3b8}.btn-send{width:42px;height:42px;border:none;background:var(--primary);color:#fff;border-radius:10px;cursor:pointer;display:flex;align-items:center;justify-content:center;transition:all .2s;flex-shrink:0}.btn-send:hover{background:var(--primary-light)}.btn-send:disabled{background:#94a3b8;cursor:not-allowed}.input-hint{text-align:center;font-size:11px;color:#94a3b8;margin-top:8px}.typing-dots{display:flex;gap:4px;padding:4px 0}.typing-dots span{width:8px;height:8px;background:#94a3b8;border-radius:50%;animation:bounce 1.4s infinite ease-in-out both}.typing-dots span:nth-child(1){animation-delay:0s}.typing-dots span:nth-child(2){animation-delay:.16s}.typing-dots span:nth-child(3){animation-delay:.32s}@keyframes bounce{0%,80%,to{transform:scale(.6)}40%{transform:scale(1)}}.spinner{width:18px;height:18px;border:2px solid rgba(255,255,255,.3);border-top-color:#fff;border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}@media (max-width: 768px){.sidebar{position:fixed;left:0;top:0;bottom:0;z-index:200;width:280px;transform:translate(-100%);transition:transform .25s ease;box-shadow:none}.sidebar.open{transform:translate(0);box-shadow:4px 0 20px #0000004d}.sidebar-overlay{display:none;position:fixed;top:0;right:0;bottom:0;left:0;background:#0006;z-index:199;transition:opacity .25s}.sidebar-overlay.visible{display:block}.topbar{height:48px;padding:0 12px}.topbar h2{font-size:15px}.chat-container{padding:10px 12px}.welcome{min-height:50vh;padding:24px 12px}.welcome-icon{font-size:48px}.welcome h1{font-size:22px}.welcome-desc{font-size:14px;margin-bottom:20px}.suggestions{grid-template-columns:1fr;gap:8px}.suggestion-chip{padding:12px 14px;font-size:13px}.message{gap:8px;margin-bottom:16px}.avatar{width:30px;height:30px;font-size:15px;border-radius:6px}.bubble{padding:10px 14px;font-size:14px;line-height:1.7}.formatted-answer p{font-size:14px}.sources{margin-top:6px;gap:4px}.sources-label{font-size:11px}.source-tag{font-size:11px;padding:2px 8px}.related{margin-top:8px}.related-label{font-size:11px}.related-chip{font-size:12px;padding:7px 12px}.chat-input{padding:8px 10px 12px}.input-wrapper{padding:4px;border-radius:10px}.input-wrapper input{font-size:16px;padding:8px 10px}.btn-send{width:38px;height:38px;border-radius:8px}.input-hint{font-size:10px;margin-top:6px}.sidebar-header{padding:18px 16px 10px}.logo-text{font-size:18px}.sidebar-actions{padding:12px 16px}.chat-history{padding:0 16px}.chat-history h3{font-size:11px}.history-item{font-size:12px;padding:8px 10px}}@media (max-width: 400px){.topbar h2{font-size:14px}.welcome h1{font-size:20px}.welcome-icon{font-size:40px}.bubble{padding:8px 12px;font-size:13px}.avatar{width:26px;height:26px;font-size:13px}.message{gap:6px;margin-bottom:12px}.suggestion-chip{padding:10px 12px;font-size:12px}}