:root{--bg: #f4f5f7;--bg-grad-a: #fbfcfd;--bg-grad-b: #eef1f4;--surface: #ffffff;--surface-2: #f7f8fa;--surface-3: #f1f3f6;--border: #e6e8ee;--border-strong: #d7dbe3;--text: #14181f;--text-muted: #5b6675;--text-faint: #8a93a2;--accent: #0f766e;--accent-strong: #0b5f59;--accent-soft: #e7f2f0;--accent-line: #c9e3df;--danger: #b4382c;--danger-soft: #fcecea;--danger-line: #f3cfca;--shadow-xs: 0 1px 2px rgba(17, 24, 39, .05);--shadow-sm: 0 1px 2px rgba(17, 24, 39, .04), 0 2px 6px rgba(17, 24, 39, .05);--shadow-md: 0 6px 18px -6px rgba(17, 24, 39, .12), 0 2px 6px rgba(17, 24, 39, .05);--shadow-lg: 0 24px 50px -16px rgba(17, 24, 39, .22);--shadow-page: 0 1px 1px rgba(17, 24, 39, .06), 0 16px 40px -16px rgba(17, 24, 39, .28);--radius-lg: 18px;--radius: 13px;--radius-sm: 9px;--radius-pill: 999px;color-scheme:light;font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,PingFang SC,Microsoft YaHei,sans-serif;line-height:1.5;color:var(--text);background:var(--bg);font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}*{box-sizing:border-box}html,body,#root{width:100%;height:100%}body{margin:0;min-width:320px;min-height:100vh;overflow:hidden}button,textarea,input{font:inherit}button{border:0;background:none}::selection{background:var(--accent-soft);color:var(--accent-strong)}.messages,.preview-surface,.doc-switcher{scrollbar-width:thin;scrollbar-color:var(--border-strong) transparent}.messages::-webkit-scrollbar,.preview-surface::-webkit-scrollbar{width:10px;height:10px}.messages::-webkit-scrollbar-thumb,.preview-surface::-webkit-scrollbar-thumb{border:3px solid transparent;border-radius:var(--radius-pill);background-clip:padding-box;background-color:var(--border-strong)}.messages::-webkit-scrollbar-thumb:hover,.preview-surface::-webkit-scrollbar-thumb:hover{background-color:#c2c8d2}.app-shell{position:relative;display:grid;grid-template-columns:minmax(0,1fr) 432px;height:100vh;height:100dvh;min-height:0;overflow:hidden;background:radial-gradient(1200px 600px at 12% -10%,var(--bg-grad-a),transparent 60%),linear-gradient(180deg,var(--bg-grad-a),var(--bg-grad-b))}.app-shell.is-dragging:after{content:"Drop PDF to add";position:absolute;inset:14px;z-index:20;display:grid;place-items:center;border:2px dashed var(--accent-line);border-radius:var(--radius-lg);background:#e7f2f08c;backdrop-filter:blur(2px);color:var(--accent-strong);font-weight:600;font-size:15px;letter-spacing:.01em;pointer-events:none}.workspace{display:grid;grid-template-rows:auto minmax(0,1fr);min-width:0;height:100%;min-height:0;overflow:hidden}.preview-toolbar{display:flex;align-items:center;gap:14px;min-height:60px;padding:12px 22px;border-bottom:1px solid var(--border);background:#fff9;backdrop-filter:blur(10px)}.document-chip{display:flex;align-items:center;gap:9px;min-width:0;max-width:60%;padding:6px 12px 6px 10px;border:1px solid var(--border);border-radius:var(--radius-pill);background:var(--surface);box-shadow:var(--shadow-xs);color:var(--text)}.document-chip svg{flex:0 0 auto;color:var(--accent)}.document-chip span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-weight:600;font-size:13.5px}.document-chip b,.attachment-main b{flex:0 0 auto;display:inline-grid;place-items:center;min-width:22px;height:20px;padding:0 7px;border-radius:var(--radius-pill);color:var(--accent-strong);background:var(--accent-soft);font-size:11.5px;font-weight:600;line-height:1}.doc-switcher{display:flex;gap:6px;min-width:0;overflow-x:auto;padding-bottom:2px}.doc-tab{display:inline-flex;align-items:center;gap:6px;max-width:180px;padding:6px 11px;border:1px solid var(--border);border-radius:var(--radius-pill);background:var(--surface);color:var(--text-muted);font-size:12.5px;cursor:pointer;transition:color .15s,border-color .15s,background .15s}.doc-tab svg{flex:0 0 auto;opacity:.7}.doc-tab span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.doc-tab:hover{color:var(--text);border-color:var(--border-strong)}.doc-tab.is-active{color:var(--accent-strong);background:var(--accent-soft);border-color:var(--accent-line)}.preview-surface{min-height:0;padding:28px 24px 40px;overflow:auto}.pdf-scroll{display:flex;flex-direction:column;align-items:center;gap:24px;width:100%;min-height:100%}.pdf-page{position:relative;display:grid;justify-items:center;width:min(860px,100%)}.pdf-page-label{margin-top:9px;padding:2px 10px;border-radius:var(--radius-pill);color:var(--text-faint);background:var(--surface-3);font-size:12px;font-weight:600;font-variant-numeric:tabular-nums}.canvas-wrap{position:relative;display:grid;place-items:center;width:100%;min-height:0}.canvas-wrap canvas{display:block;max-width:100%;height:auto;border-radius:4px;background:#fff;box-shadow:var(--shadow-page)}.preview-status{display:grid;place-items:center;width:100%;min-height:240px;color:var(--text-faint)}.canvas-error{display:grid;place-items:center;padding:16px 18px;border:1px solid var(--danger-line);border-radius:var(--radius);background:var(--danger-soft);color:var(--danger);font-size:13px;text-align:center}.empty-preview{display:flex;flex-direction:column;align-items:center;gap:22px;width:min(420px,100%);margin:auto;padding:44px 32px;border:1px dashed var(--border-strong);border-radius:var(--radius-lg);background:linear-gradient(180deg,#ffffffe6,#f7f8fae6);box-shadow:var(--shadow-sm);cursor:pointer;text-align:center;transition:border-color .2s,box-shadow .2s,transform .2s}.empty-preview:hover{border-color:var(--accent-line);box-shadow:var(--shadow-md);transform:translateY(-1px)}.empty-preview-art{position:relative;display:grid;place-items:center;width:96px;height:96px;border-radius:22px;color:var(--accent);background:var(--accent-soft)}.empty-preview-badge{position:absolute;right:-6px;bottom:-6px;display:grid;place-items:center;width:32px;height:32px;border-radius:var(--radius-pill);color:#fff;background:var(--accent);box-shadow:0 8px 18px -6px #0f766e80}.empty-preview-copy{display:grid;gap:6px}.empty-preview-copy strong{color:var(--text);font-size:16px;font-weight:650}.empty-preview-copy span{color:var(--text-muted);font-size:13px;line-height:1.55}.chat-panel{display:flex;flex-direction:column;gap:14px;height:100%;min-height:0;overflow:hidden;padding:16px 16px 18px;border-left:1px solid var(--border);background:#ffffffc7;backdrop-filter:blur(12px)}.chat-header{display:flex;align-items:center;justify-content:space-between;gap:12px;min-height:40px;padding:2px 4px}.brand{display:flex;align-items:center;gap:9px}.brand-mark{display:grid;place-items:center;width:30px;height:30px;border-radius:9px;color:#fff;background:linear-gradient(150deg,var(--accent),var(--accent-strong));box-shadow:0 6px 14px -6px #0f766e99}.brand-name{color:var(--text);font-size:15px;font-weight:650;letter-spacing:-.01em}.quota-pill{display:inline-flex;align-items:center;gap:6px;min-height:30px;padding:4px 11px;border:1px solid var(--border);border-radius:var(--radius-pill);background:var(--surface);box-shadow:var(--shadow-xs)}.quota-pill svg{color:var(--accent)}.quota-pill span{color:var(--text);font-weight:650;font-size:13px;font-variant-numeric:tabular-nums}.messages{display:flex;flex:1;flex-direction:column;gap:10px;min-height:0;padding:6px 6px 2px;overflow-y:auto}.message{max-width:90%;padding:10px 13px;border-radius:14px;font-size:14px;line-height:1.5;word-break:break-word;animation:rise .22s ease}.message-text{white-space:pre-wrap}.message.user{align-self:flex-end;color:#fff;background:linear-gradient(160deg,var(--accent),var(--accent-strong));border-bottom-right-radius:5px;box-shadow:var(--shadow-sm)}.message.assistant{align-self:flex-start;color:var(--text);background:var(--surface);border:1px solid var(--border);border-bottom-left-radius:5px;box-shadow:var(--shadow-xs)}.message.assistant.is-error{border-color:var(--danger-line);background:var(--danger-soft);color:var(--danger)}.message.is-thinking{display:inline-flex;align-items:center;gap:8px;color:var(--text-muted)}.message.is-thinking svg{color:var(--accent)}.empty-chat{display:flex;flex:1;flex-direction:column;justify-content:center;gap:8px;padding:8px 10px}.empty-chat h1{margin:0;font-size:23px;font-weight:680;letter-spacing:-.02em;line-height:1.2;color:var(--text)}.empty-chat p{margin:0 0 8px;max-width:34ch;color:var(--text-muted);font-size:14px;line-height:1.55}.suggestions{display:flex;flex-wrap:wrap;gap:8px}.suggestion{padding:7px 13px;border:1px solid var(--border);border-radius:var(--radius-pill);background:var(--surface);color:var(--text-muted);font-size:13px;cursor:pointer;box-shadow:var(--shadow-xs);transition:color .15s,border-color .15s,background .15s,transform .15s}.suggestion:hover{color:var(--accent-strong);border-color:var(--accent-line);background:var(--accent-soft);transform:translateY(-1px)}.attachment-list{display:flex;flex-direction:column;gap:7px;margin-top:10px}.attachment-card{display:grid;grid-template-columns:minmax(0,1fr) auto;align-items:center;min-width:0;overflow:hidden;border:1px solid var(--border);border-radius:11px;background:var(--surface-2);transition:border-color .15s,background .15s}.message.user .attachment-card{border-color:#ffffff59;background:#ffffff29}.attachment-card.is-active{border-color:var(--accent-line);background:var(--accent-soft)}.attachment-main{display:grid;grid-template-columns:18px minmax(0,1fr) auto;align-items:center;gap:9px;min-width:0;min-height:42px;padding:8px 11px;color:var(--text);text-align:left;cursor:pointer}.message.user .attachment-main,.message.user .attachment-main svg{color:#fff}.message.user .attachment-main b{color:#fff;background:#ffffff38}.attachment-main svg{color:var(--accent)}.attachment-main span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:13px;font-weight:500}.attachment-download{display:inline-flex;align-items:center;justify-content:center;width:40px;height:40px;margin-right:3px;border-radius:9px;color:var(--accent);text-decoration:none;transition:background .15s,color .15s}.attachment-download:hover{background:var(--surface)}.message.user .attachment-download{color:#fff}.message.user .attachment-download:hover{background:#fff3}.composer{display:grid;grid-template-columns:40px minmax(0,1fr) 40px;align-items:end;gap:9px;padding:9px;border:1px solid var(--border-strong);border-radius:var(--radius-lg);background:var(--surface);box-shadow:var(--shadow-md);transition:border-color .15s,box-shadow .15s}.composer:focus-within{border-color:var(--accent-line);box-shadow:var(--shadow-md),0 0 0 4px var(--accent-soft)}.composer textarea{width:100%;min-height:40px;max-height:168px;resize:none;padding:9px 2px;border:0;color:var(--text);background:transparent;outline:none;line-height:1.5}.composer textarea::placeholder{color:var(--text-faint)}.composer-upload,.send-button{display:inline-flex;align-items:center;justify-content:center;width:40px;height:40px;border-radius:11px;cursor:pointer;transition:background .15s,color .15s,transform .1s,box-shadow .15s}.composer-upload{color:var(--text-muted);background:var(--surface-2);border:1px solid var(--border)}.composer-upload:hover:not(:disabled){color:var(--accent-strong);background:var(--accent-soft);border-color:var(--accent-line)}.send-button{color:#fff;background:linear-gradient(160deg,var(--accent),var(--accent-strong));box-shadow:0 8px 16px -8px #0f766eb3}.send-button:hover:not(:disabled){transform:translateY(-1px);box-shadow:0 12px 20px -8px #0f766eb3}.send-button:active:not(:disabled){transform:translateY(0)}.composer-upload:disabled,.send-button:disabled,.attachment-main:disabled{cursor:not-allowed;opacity:.5}.send-button:disabled{background:var(--surface-3);color:var(--text-faint);box-shadow:none}.spin{animation:spin .9s linear infinite}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}@keyframes spin{to{transform:rotate(360deg)}}@keyframes rise{0%{opacity:0;transform:translateY(6px)}to{opacity:1;transform:translateY(0)}}@media(prefers-reduced-motion:reduce){.message,.suggestion,.send-button,.empty-preview{animation:none;transition:none}}@media(max-width:1100px){.app-shell{grid-template-columns:1fr;grid-template-rows:minmax(0,56fr) minmax(0,44fr)}.chat-panel{grid-column:1 / -1;min-height:0;border-top:1px solid var(--border);border-left:0}}@media(max-width:760px){.app-shell{grid-template-rows:minmax(0,52fr) minmax(0,48fr)}.preview-surface{padding:16px 14px 28px}.document-chip{max-width:100%}.empty-chat h1{font-size:20px}}