:root{--bg-primary: #0a0a0a;--bg-secondary: #141414;--bg-tertiary: #1e1e1e;--bg-hover: #252525;--bg-user-bubble: #1a3a2a;--bg-assistant-bubble: transparent;--text-primary: #e8e4df;--text-secondary: #9a958e;--text-tertiary: #6b6660;--text-accent: #d4a574;--text-user: #b8d8c8;--border-primary: #2a2a2a;--border-accent: #3d3024;--accent: #c8956c;--accent-dim: #8b6544;--accent-glow: rgba(200, 149, 108, .15);--success: #5a9a6e;--warning: #c49a3c;--error: #b85450;--font-serif: "Noto Serif SC", "Songti SC", "SimSun", serif;--font-mono: "JetBrains Mono", "Menlo", monospace;--font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;--max-width: 680px;--radius-sm: 8px;--radius-md: 14px;--radius-lg: 20px;--safe-top: env(safe-area-inset-top, 0px);--safe-bottom: env(safe-area-inset-bottom, 0px)}*,*:before,*:after{margin:0;padding:0;box-sizing:border-box}html{font-size:16px;-webkit-text-size-adjust:100%;-webkit-tap-highlight-color:transparent}body{font-family:var(--font-sans);background:var(--bg-primary);color:var(--text-primary);line-height:1.7;overflow-x:hidden;-webkit-font-smoothing:antialiased}.app{display:flex;flex-direction:column;height:100dvh;max-width:var(--max-width);margin:0 auto}.header{display:flex;align-items:center;justify-content:space-between;padding:calc(var(--safe-top) + 12px) 20px 12px;border-bottom:1px solid var(--border-primary);background:var(--bg-primary);position:sticky;top:0;z-index:100}.header-brand{display:flex;align-items:baseline;gap:10px}.header-title{font-family:var(--font-serif);font-size:1.25rem;font-weight:700;color:var(--text-primary);letter-spacing:.05em}.header-subtitle{font-size:.75rem;color:var(--text-tertiary);letter-spacing:.02em}.header-usage{font-size:.75rem;color:var(--text-secondary);background:var(--bg-tertiary);padding:4px 12px;border-radius:100px;border:1px solid var(--border-primary)}.header-usage strong{color:var(--accent);font-weight:600}.chat-area{flex:1;overflow-y:auto;padding:16px 16px 8px;scroll-behavior:smooth;-webkit-overflow-scrolling:touch}.chat-area::-webkit-scrollbar{width:4px}.chat-area::-webkit-scrollbar-thumb{background:var(--border-primary);border-radius:2px}.welcome{display:flex;flex-direction:column;align-items:center;justify-content:center;height:100%;text-align:center;padding:40px 24px;animation:fadeIn .6s ease}.welcome-icon{font-size:3rem;margin-bottom:20px;opacity:.8}.welcome h2{font-family:var(--font-serif);font-size:1.5rem;font-weight:600;color:var(--text-primary);margin-bottom:12px}.welcome p{color:var(--text-secondary);font-size:.9rem;line-height:1.8;max-width:320px}.welcome-tips{margin-top:32px;display:flex;flex-direction:column;gap:10px;width:100%;max-width:360px}.welcome-tip{background:var(--bg-secondary);border:1px solid var(--border-primary);border-radius:var(--radius-md);padding:14px 18px;text-align:left;font-size:.85rem;color:var(--text-secondary);cursor:pointer;transition:all .2s}.welcome-tip:active{background:var(--bg-tertiary);border-color:var(--accent-dim);transform:scale(.98)}.welcome-tip .tip-label{font-size:.7rem;color:var(--text-tertiary);margin-bottom:4px;text-transform:uppercase;letter-spacing:.08em}.message{margin-bottom:20px;animation:slideUp .3s ease}.message-user{display:flex;justify-content:flex-end}.message-user .bubble{background:var(--bg-user-bubble);color:var(--text-user);border-radius:var(--radius-md) var(--radius-md) 4px var(--radius-md);padding:12px 16px;max-width:85%;font-size:.9rem;line-height:1.6;word-break:break-word}.message-user .bubble img{max-width:200px;border-radius:var(--radius-sm);margin-bottom:8px;display:block}.message-assistant{display:flex;justify-content:flex-start}.message-assistant .bubble{max-width:100%;width:100%;font-size:.9rem;line-height:1.85;color:var(--text-primary)}.bubble h1,.bubble h2,.bubble h3,.bubble h4{font-family:var(--font-serif);color:var(--text-accent);margin:24px 0 12px;line-height:1.4}.bubble h1{font-size:1.2rem}.bubble h2{font-size:1.1rem}.bubble h3{font-size:1rem}.bubble p{margin-bottom:12px}.bubble strong{color:var(--accent);font-weight:600}.bubble em{color:var(--text-secondary);font-style:italic}.bubble ul,.bubble ol{padding-left:20px;margin-bottom:12px}.bubble li{margin-bottom:6px}.bubble blockquote{border-left:3px solid var(--accent-dim);padding:8px 16px;margin:12px 0;color:var(--text-secondary);background:var(--bg-secondary);border-radius:0 var(--radius-sm) var(--radius-sm) 0}.bubble code{font-family:var(--font-mono);font-size:.82rem;background:var(--bg-tertiary);padding:2px 6px;border-radius:4px;color:var(--accent)}.bubble pre{background:var(--bg-secondary);border:1px solid var(--border-primary);border-radius:var(--radius-sm);padding:14px;margin:12px 0;overflow-x:auto;-webkit-overflow-scrolling:touch}.bubble pre code{background:none;padding:0;font-size:.8rem;line-height:1.5;color:var(--text-primary)}.bubble hr{border:none;border-top:1px solid var(--border-primary);margin:20px 0}.bubble table{width:100%;border-collapse:collapse;margin:12px 0;font-size:.85rem}.bubble th,.bubble td{border:1px solid var(--border-primary);padding:8px 12px;text-align:left}.bubble th{background:var(--bg-tertiary);font-weight:600;color:var(--text-accent)}.katex-display{overflow-x:auto;overflow-y:hidden;padding:8px 0;-webkit-overflow-scrolling:touch}.katex{font-size:1em}.thinking{display:flex;align-items:center;gap:8px;padding:8px 0;color:var(--text-tertiary);font-size:.85rem}.thinking-dots{display:flex;gap:4px}.thinking-dots span{width:5px;height:5px;background:var(--accent-dim);border-radius:50%;animation:pulse 1.4s ease-in-out infinite}.thinking-dots span:nth-child(2){animation-delay:.2s}.thinking-dots span:nth-child(3){animation-delay:.4s}.artifact-frame{width:100%;border:1px solid var(--border-primary);border-radius:var(--radius-sm);margin:12px 0;background:#fff;min-height:300px}.input-area{padding:8px 12px calc(var(--safe-bottom) + 10px);border-top:1px solid var(--border-primary);background:var(--bg-primary)}.input-row{display:flex;align-items:flex-end;gap:8px;max-width:var(--max-width);margin:0 auto}.input-textarea{flex:1;background:var(--bg-secondary);border:1px solid var(--border-primary);border-radius:var(--radius-md);padding:12px 16px;color:var(--text-primary);font-family:var(--font-sans);font-size:.9rem;line-height:1.5;resize:none;outline:none;min-height:44px;max-height:120px;transition:border-color .2s}.input-textarea:focus{border-color:var(--accent-dim)}.input-textarea::placeholder{color:var(--text-tertiary)}.input-btn{width:44px;height:44px;border:none;border-radius:var(--radius-md);cursor:pointer;display:flex;align-items:center;justify-content:center;transition:all .2s;flex-shrink:0}.btn-camera{background:var(--bg-secondary);border:1px solid var(--border-primary);color:var(--text-secondary)}.btn-camera:active{background:var(--bg-tertiary)}.btn-send{background:var(--accent);color:var(--bg-primary)}.btn-send:disabled{opacity:.3;cursor:not-allowed}.btn-send:not(:disabled):active{transform:scale(.94)}.btn-stop{background:var(--error);color:#fff}.image-preview{display:flex;align-items:center;gap:8px;padding:8px 12px;margin-bottom:4px}.image-preview img{width:56px;height:56px;object-fit:cover;border-radius:var(--radius-sm);border:1px solid var(--border-primary)}.image-preview .remove-image{background:none;border:none;color:var(--text-tertiary);font-size:1.2rem;cursor:pointer;padding:4px}.limit-banner{background:linear-gradient(135deg,var(--bg-tertiary),var(--bg-secondary));border:1px solid var(--border-accent);border-radius:var(--radius-md);padding:20px;margin:20px 16px;text-align:center}.limit-banner h3{font-family:var(--font-serif);color:var(--accent);margin-bottom:8px;font-size:1rem}.limit-banner p{color:var(--text-secondary);font-size:.85rem;margin-bottom:16px;line-height:1.6}.limit-banner .btn-subscribe{background:var(--accent);color:var(--bg-primary);border:none;border-radius:100px;padding:10px 28px;font-size:.9rem;font-weight:600;cursor:pointer;transition:transform .15s}.limit-banner .btn-subscribe:active{transform:scale(.96)}.btn-new-chat{background:none;border:1px solid var(--border-primary);color:var(--text-secondary);border-radius:var(--radius-sm);padding:6px 12px;font-size:.75rem;cursor:pointer;transition:all .2s}.btn-new-chat:active{background:var(--bg-tertiary);color:var(--text-primary)}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}@keyframes pulse{0%,to{opacity:.3;transform:scale(.8)}50%{opacity:1;transform:scale(1)}}@media (min-width: 680px){.app{border-left:1px solid var(--border-primary);border-right:1px solid var(--border-primary)}}