:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;color:#111827;background:#f5f7fb;font-synthesis:none;text-rendering:optimizeLegibility}*{box-sizing:border-box}body{margin:0;min-width:320px;min-height:100vh}button,textarea{font:inherit}button{cursor:pointer}button:disabled{cursor:not-allowed;opacity:.55}.app-shell{min-height:100vh;display:grid;grid-template-columns:290px minmax(0,1fr)}.sidebar{display:flex;flex-direction:column;min-height:100vh;padding:22px 16px;background:#111827;color:#f9fafb}.brand{display:flex;align-items:center;gap:12px;padding:0 8px 24px}.brand-mark{display:grid;place-items:center;width:38px;height:38px;border-radius:11px;background:#f9fafb;color:#111827;font-size:13px;font-weight:800}.brand strong,.brand span{display:block}.brand span{margin-top:2px;color:#9ca3af;font-size:12px}.new-button{display:flex;align-items:center;justify-content:center;gap:8px;width:100%;padding:11px 14px;border:1px solid #374151;border-radius:10px;background:#1f2937;color:#fff;font-weight:650}.new-button:hover{background:#283548}.new-button span{font-size:20px;line-height:1}.conversation-list{display:flex;flex:1;flex-direction:column;gap:5px;margin-top:20px;overflow-y:auto}.conversation-item{display:grid;gap:5px;width:100%;padding:10px 12px;border:0;border-radius:9px;background:transparent;color:#d1d5db;text-align:left}.conversation-item:hover,.conversation-item.active{background:#1f2937;color:#fff}.conversation-item span{overflow:hidden;font-size:14px;font-weight:600;text-overflow:ellipsis;white-space:nowrap}.conversation-item time{color:#6b7280;font-size:11px}.sidebar-footer{display:flex;align-items:center;gap:8px;padding:16px 8px 0;border-top:1px solid #253045;color:#9ca3af;font-size:12px}.status-dot{width:8px;height:8px;border-radius:999px;background:#34d399;box-shadow:0 0 0 3px #34d3991f}.chat-panel{display:grid;min-width:0;min-height:100vh;grid-template-rows:auto minmax(0,1fr) auto auto}.chat-header{display:flex;align-items:center;justify-content:space-between;gap:20px;min-height:82px;padding:16px 28px;border-bottom:1px solid #e5e7eb;background:#ffffffe5;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px)}.chat-header h1{max-width:650px;margin:0;overflow:hidden;font-size:19px;text-overflow:ellipsis;white-space:nowrap}.chat-header p{margin:4px 0 0;color:#6b7280;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:11px}.header-actions{display:flex;gap:8px}.header-actions button{padding:8px 12px;border:1px solid #d1d5db;border-radius:8px;background:#fff;color:#374151;font-size:13px;font-weight:600}.header-actions .danger{color:#b42318}.messages{width:min(920px,100%);margin:0 auto;padding:38px 32px 24px;overflow-y:auto}.center-state,.welcome-card{margin:15vh auto 0;color:#6b7280;text-align:center}.welcome-card{max-width:520px;padding:34px;border:1px solid #e5e7eb;border-radius:18px;background:#fff;box-shadow:0 14px 40px #1118270f}.welcome-icon{display:grid;place-items:center;width:48px;height:48px;margin:0 auto 18px;border-radius:14px;background:#111827;color:#fff;font-size:22px}.welcome-card h2{margin:0 0 10px;color:#111827;font-size:22px}.welcome-card p{margin:0;line-height:1.65}.message{display:grid;grid-template-columns:38px minmax(0,1fr);gap:13px;margin-bottom:24px}.message.user{grid-template-columns:minmax(0,1fr) 38px}.message.user .avatar{grid-column:2}.message.user .bubble{grid-row:1;grid-column:1;justify-self:end;background:#111827;color:#fff}.avatar{display:grid;place-items:center;width:36px;height:36px;border:1px solid #e5e7eb;border-radius:10px;background:#fff;color:#374151;font-size:11px;font-weight:800}.bubble{width:fit-content;max-width:min(720px,88%);padding:13px 16px;border:1px solid #e5e7eb;border-radius:14px;background:#fff;line-height:1.6;white-space:pre-wrap;box-shadow:0 4px 14px #1118270a}.typing{display:flex;gap:5px;align-items:center;min-height:46px}.typing span{width:6px;height:6px;border-radius:999px;background:#9ca3af;animation:pulse 1s infinite ease-in-out}.typing span:nth-child(2){animation-delay:.15s}.typing span:nth-child(3){animation-delay:.3s}@keyframes pulse{0%,80%,to{opacity:.35;transform:translateY(0)}40%{opacity:1;transform:translateY(-3px)}}.error-banner{width:min(856px,calc(100% - 64px));margin:0 auto 10px;padding:10px 13px;border:1px solid #fecaca;border-radius:9px;background:#fef2f2;color:#b42318;font-size:13px}.composer{position:relative;width:min(856px,calc(100% - 64px));margin:0 auto 24px;padding:8px 58px 24px 14px;border:1px solid #d1d5db;border-radius:15px;background:#fff;box-shadow:0 12px 35px #11182717}.composer textarea{width:100%;max-height:180px;padding:5px 0;resize:vertical;border:0;outline:0;color:#111827;line-height:1.5}.composer button{position:absolute;right:12px;bottom:16px;display:grid;place-items:center;width:36px;height:36px;border:0;border-radius:10px;background:#111827;color:#fff;font-size:20px;font-weight:700}.composer small{position:absolute;bottom:7px;left:14px;color:#9ca3af;font-size:10px}@media(max-width:760px){.app-shell{grid-template-columns:1fr}.sidebar{min-height:auto;padding:12px}.brand,.sidebar-footer{display:none}.conversation-list{flex-direction:row;margin-top:10px;overflow-x:auto}.conversation-item{min-width:170px}.chat-panel{min-height:calc(100vh - 120px)}.chat-header{padding:14px 18px}.messages{padding:26px 18px 18px}.composer,.error-banner{width:calc(100% - 28px)}.header-actions button{padding:7px 9px}}