:root{--bg:#f7f7f8;--panel:#fff;--text:#171717;--muted:#737378;--line:#e6e6e9;--soft:#f1f1f3;--danger:#b42318;--radius:18px}*{box-sizing:border-box}body{margin:0;font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,Arial;background:var(--bg);color:var(--text)}button,input,textarea,select{font:inherit}.hidden{display:none!important}.app{height:100vh;display:grid;grid-template-columns:278px 1fr}.sidebar{background:#f2f2f4;border-right:1px solid var(--line);display:flex;flex-direction:column;min-width:0}.sidebar-head{height:66px;display:flex;align-items:center;gap:10px;padding:0 16px}.logo,.brand-mark{display:grid;place-items:center;background:#111;color:#fff;border-radius:12px;font-weight:800}.logo{width:36px;height:36px}.brand-mark{width:50px;height:50px;margin:auto}.new-chat{margin:6px 12px 12px;padding:12px 14px;border:1px solid #ddd;border-radius:12px;background:#fff;text-align:left;cursor:pointer}.conversations{overflow:auto;padding:0 8px;flex:1}.conversation{width:100%;border:0;background:transparent;padding:10px 12px;border-radius:11px;display:flex;gap:8px;align-items:center;justify-content:space-between;cursor:pointer;color:inherit;text-align:left}.conversation span{white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.conversation small{font-size:9px;color:#999;white-space:nowrap}.conversation:hover,.conversation.active{background:#fff}.sidebar-foot{padding:12px;border-top:1px solid var(--line);display:flex;justify-content:space-between;align-items:center;font-size:13px}.sidebar-foot small{display:block;color:#8a8a90;font-size:10px;margin-top:2px}.ghost,.icon-btn{border:0;background:transparent;cursor:pointer}.main{display:grid;grid-template-rows:66px 1fr auto;min-width:0;background:#fff;position:relative}.topbar{border-bottom:1px solid var(--line);display:flex;align-items:center;gap:14px;padding:0 18px}.chat-title{min-width:120px}.topbar small{display:block;color:var(--muted);font-size:10px;margin-top:2px}.model-controls{display:flex;gap:7px;margin-left:auto}.model-controls select{background:#fff;color:inherit;border:1px solid #ddd;border-radius:10px;padding:8px 9px;max-width:145px}.tools{display:flex;gap:6px}.tools button,.modal-actions button,.auth-actions button{border:1px solid #ddd;background:#111;color:#fff;border-radius:10px;padding:8px 11px;cursor:pointer}.tools button{background:#fff;color:#222}.tools .danger-lite{color:var(--danger)}.messages{overflow:auto;padding:36px max(24px,calc((100% - 900px)/2));scroll-behavior:smooth}.hero{text-align:center;margin:14vh auto 0;color:#27272a}.hero-icon{font-size:38px}.hero h2{font-size:30px;margin:10px 0}.hero p{color:var(--muted)}.msg{display:flex;margin:0 0 27px}.msg.user{justify-content:flex-end}.bubble{max-width:84%;line-height:1.62;font-size:15px;min-width:0}.user .bubble{background:var(--soft);padding:11px 15px;border-radius:18px}.assistant .bubble{width:100%;max-width:100%}.message-content p{margin:0 0 12px}.message-content h1,.message-content h2,.message-content h3{line-height:1.25;margin:20px 0 10px}.message-content h1{font-size:24px}.message-content h2{font-size:20px}.message-content h3{font-size:17px}.message-content ul{padding-left:23px}.message-content pre{overflow:auto;background:#171717;color:#f5f5f5;padding:14px;border-radius:12px}.inline-code{background:#f0f0f2;padding:2px 5px;border-radius:5px}.message-actions{opacity:0;transition:.15s;margin-top:6px}.msg:hover .message-actions{opacity:1}.message-actions button{border:0;background:transparent;color:#777;padding:3px 0;cursor:pointer;font-size:12px}.generated{max-width:560px;width:100%;border-radius:16px;border:1px solid var(--line)}.download-link{display:inline-block;margin-top:7px;color:#555;font-size:12px}.artifact{display:flex;gap:11px;align-items:center;width:min(430px,100%);border:1px solid var(--line);padding:13px 15px;border-radius:13px;text-decoration:none;color:inherit;background:#fafafa}.artifact span{display:flex;flex-direction:column}.artifact small{color:#888;text-transform:uppercase;font-size:10px;margin-top:2px}.muted{color:#888}.composer-wrap{padding:12px max(18px,calc((100% - 900px)/2)) 18px}.composer{border:1px solid #d9d9dd;border-radius:23px;padding:10px;display:flex;align-items:flex-end;gap:8px;box-shadow:0 8px 30px rgba(0,0,0,.05)}.composer textarea{border:0;outline:0;resize:none;flex:1;max-height:180px;padding:10px;background:transparent}.attach-btn,.send,.stop{width:40px;height:40px;border-radius:50%;display:grid;place-items:center;border:0;background:#f0f0f2;cursor:pointer}.send{background:#111;color:#fff}.stop{background:#111;color:#fff}.hint{display:block;text-align:center;color:#888;margin-top:8px;font-size:11px}.attachments{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:8px}.chip{font-size:12px;padding:7px 9px 7px 11px;border-radius:999px;background:#f0f0f2;display:flex;align-items:center;gap:7px}.chip button{border:0;background:transparent;cursor:pointer;font-size:16px;color:#777}.auth-wrap{min-height:100vh;display:grid;place-items:center;background:#f7f7f8}.auth-card{width:min(420px,92vw);padding:32px;background:#fff;border:1px solid var(--line);border-radius:22px;box-shadow:0 18px 60px rgba(0,0,0,.08);text-align:center}.auth-card input{width:100%;padding:13px 14px;margin:7px 0;border:1px solid #ddd;border-radius:10px}.auth-actions{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-top:10px}.secondary{background:#fff!important;color:#222!important}.error{color:var(--danger);font-size:13px;margin-top:10px}.modal{position:fixed;z-index:50;inset:0;background:rgba(0,0,0,.38);display:grid;place-items:center;padding:20px}.modal-card{background:#fff;border-radius:18px;padding:22px;width:min(580px,95vw)}.modal-card textarea{width:100%;border:1px solid #ddd;border-radius:12px;padding:12px}.modal-help{color:#777;font-size:13px}.image-options{display:flex;gap:8px;margin-top:10px}.image-options select{flex:1;padding:9px;border:1px solid #ddd;border-radius:10px;background:#fff}.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:12px}.drop-hint{position:absolute;z-index:30;inset:80px 30px 115px;border:2px dashed #999;border-radius:24px;background:rgba(255,255,255,.93);display:grid;place-items:center;font-size:22px;font-weight:700}.icon-btn{display:none}@media(max-width:1050px){.tools button:nth-child(n+4){display:none}.model-controls select{max-width:120px}}@media(max-width:800px){.app{grid-template-columns:1fr}.sidebar{position:fixed;z-index:40;inset:0 auto 0 0;width:280px;transform:translateX(-100%);transition:.2s}.sidebar.open{transform:none}.icon-btn{display:block}.topbar{padding:0 10px;gap:7px}.chat-title small{display:none}.tools{display:none}.model-controls{gap:4px}.model-controls select{max-width:110px;padding:7px 5px}.messages{padding:28px 16px}.composer-wrap{padding:10px 12px 14px}.bubble{max-width:94%}.assistant .bubble{max-width:100%}}