:root{--bg: #f5f4ed;--bg-elev: #ffffff;--panel: #eceae0;--accent: #d97757;--accent-hover: #c5664a;--text: #1f1e1d;--text-muted: #6b6862;--border: #e3e0d5;--user-bubble: #eae9e1;--marx-bubble: #ffffff;--error: #b91c1c;--font-serif: "Source Serif Pro", "Source Serif 4", "Noto Serif SC", "Songti SC", Georgia, serif;--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;--radius: 18px;--maxw: 768px}*{box-sizing:border-box}html,body,#root{height:100%;margin:0;padding:0}body{background:var(--bg);color:var(--text);font-family:var(--font-sans);font-size:15px;line-height:1.65;-webkit-font-smoothing:antialiased}.app-shell{display:flex;flex-direction:column;height:100vh;height:100dvh}.app-header{flex:0 0 auto;border-bottom:1px solid var(--border);background:#f5f4edd9;backdrop-filter:saturate(140%) blur(8px);position:sticky;top:0;z-index:10}.header-inner{max-width:var(--maxw);margin:0 auto;padding:14px 20px;display:flex;align-items:center;justify-content:space-between;gap:12px}.header-brand{display:flex;align-items:center;gap:12px;min-width:0}.brand-mark{font-size:26px;color:var(--accent);line-height:1}.brand-text{display:flex;flex-direction:column;min-width:0}.brand-title{font-family:var(--font-serif);font-weight:600;font-size:16px;letter-spacing:.01em}.brand-sub{font-size:12px;color:var(--text-muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.reset-btn{background:transparent;border:1px solid var(--border);color:var(--text-muted);padding:6px 14px;border-radius:999px;font-size:13px;cursor:pointer;transition:all .15s}.reset-btn:hover{border-color:var(--accent);color:var(--accent)}.chat-main{flex:1 1 auto;overflow-y:auto;padding:0 20px}.welcome{max-width:var(--maxw);margin:0 auto;padding:14vh 0 6vh;text-align:center}.welcome-title{font-family:var(--font-serif);font-size:44px;font-weight:600;margin:0 0 18px;letter-spacing:.02em}.welcome-quote{font-family:var(--font-serif);font-style:italic;color:var(--text);font-size:17px;margin:0 auto 12px;max-width:540px}.welcome-hint{color:var(--text-muted);font-size:13px;margin:0 auto 32px;max-width:460px}.suggestions{display:grid;grid-template-columns:repeat(2,1fr);gap:10px;max-width:560px;margin:0 auto}.suggestion-chip{background:var(--bg-elev);border:1px solid var(--border);color:var(--text);padding:12px 14px;border-radius:12px;font-size:13.5px;text-align:left;cursor:pointer;transition:all .15s;font-family:inherit}.suggestion-chip:hover:not(:disabled){border-color:var(--accent);color:var(--accent);transform:translateY(-1px)}.suggestion-chip:disabled{opacity:.5;cursor:not-allowed}.messages{max-width:var(--maxw);margin:0 auto;padding:28px 0 40px;display:flex;flex-direction:column;gap:22px}.message{display:flex;gap:14px;align-items:flex-start}.message-user{flex-direction:row-reverse}.avatar{flex:0 0 auto;width:32px;height:32px;border-radius:50%;display:grid;place-items:center;font-size:14px;font-weight:600;background:var(--panel);color:var(--text)}.message-user .avatar{background:var(--accent);color:#fff}.bubble-wrap{max-width:calc(100% - 60px);display:flex;flex-direction:column;gap:4px}.message-user .bubble-wrap{align-items:flex-end}.bubble-name{font-size:12px;color:var(--text-muted);padding:0 4px}.bubble{padding:14px 18px;border-radius:var(--radius);font-size:15px;line-height:1.75;word-wrap:break-word;overflow-wrap:anywhere}.bubble-user{background:var(--user-bubble);color:var(--text);border-top-right-radius:6px}.bubble-marx{background:var(--marx-bubble);border:1px solid var(--border);border-top-left-radius:6px}.bubble-content{display:block}.bubble-text{margin:0;font-family:var(--font-sans);white-space:pre-wrap;font-size:inherit;line-height:inherit;color:inherit;background:none;border:0;padding:0}.cursor{display:inline-block;color:var(--accent);animation:blink 1s steps(2,start) infinite;margin-left:1px}@keyframes blink{to{opacity:0}}.bubble-placeholder{color:var(--text-muted);font-style:italic}.reasoning{margin:0 0 12px;padding:8px 12px;background:var(--panel);border-left:2px solid var(--text-muted);border-radius:6px;font-size:13px;color:var(--text-muted)}.reasoning>summary{cursor:pointer;font-weight:500;color:var(--text-muted);user-select:none;list-style:none}.reasoning>summary::-webkit-details-marker{display:none}.reasoning>summary:before{content:"▸ ";display:inline-block;transition:transform .15s}.reasoning[open]>summary:before{transform:rotate(90deg)}.reasoning-text{margin:8px 0 0;font-size:12.5px;line-height:1.6;opacity:.85}.typing-indicator{display:inline-flex;gap:4px;padding:4px;margin-left:46px}.typing-indicator span{width:7px;height:7px;border-radius:50%;background:var(--text-muted);opacity:.4;animation:bounce 1.2s infinite ease-in-out}.typing-indicator span:nth-child(2){animation-delay:.15s}.typing-indicator span:nth-child(3){animation-delay:.3s}@keyframes bounce{0%,60%,to{transform:translateY(0);opacity:.4}30%{transform:translateY(-4px);opacity:.9}}.error-banner{max-width:var(--maxw);margin:16px auto 0;padding:10px 14px;background:#fdecec;border:1px solid #f5c2c2;color:var(--error);border-radius:10px;font-size:13px}.chat-input-footer{flex:0 0 auto;border-top:1px solid var(--border);background:var(--bg);padding:14px 20px 18px}.chat-input-form{max-width:var(--maxw);margin:0 auto}.input-row{display:flex;align-items:flex-end;gap:10px;background:var(--bg-elev);border:1px solid var(--border);border-radius:22px;padding:8px 8px 8px 18px;transition:border-color .15s,box-shadow .15s}.input-row:focus-within{border-color:var(--accent);box-shadow:0 0 0 3px #d9775726}.chat-textarea{flex:1;border:0;outline:0;resize:none;background:transparent;font-family:inherit;font-size:15px;line-height:1.6;color:var(--text);padding:8px 0;max-height:160px;overflow-y:auto}.chat-textarea::placeholder{color:var(--text-muted)}.chat-textarea:disabled{opacity:.6}.send-btn{flex:0 0 auto;background:var(--accent);color:#fff;border:0;padding:8px 18px;border-radius:16px;font-size:14px;font-weight:500;cursor:pointer;transition:background .15s,transform .1s}.send-btn:hover:not(:disabled){background:var(--accent-hover)}.send-btn:active:not(:disabled){transform:scale(.96)}.send-btn:disabled{background:var(--border);color:var(--text-muted);cursor:not-allowed}.stop-btn{background:var(--text)}.stop-btn:hover{background:#000}.input-hint{margin-top:8px;text-align:center;font-size:11.5px;color:var(--text-muted)}@media (max-width: 600px){.welcome-title{font-size:32px}.suggestions{grid-template-columns:1fr}.brand-sub{display:none}.bubble-wrap{max-width:calc(100% - 50px)}}