:root{
  --bg:#F3F6F9; --sidebar:#E9EEF3; --surface:#FFFFFF; --text:#14202B; --muted:#5F6D7A;
  --border:#D5DDE5; --accent:#0676B8; --accent-hover:#055F95; --accent-ink:#FFFFFF; --code-bg:#F8FAFC; --bubble:#E1E8EF;
  --hover:rgba(20,32,43,.06); --shadow:0 1px 2px rgba(20,32,43,.06),0 4px 16px rgba(20,32,43,.07);
  --danger:#B3261E; --glow:none;
  --hl-kw:#8B3FA8; --hl-str:#2F7A3B; --hl-com:#7C8894; --hl-num:#B0521D; --hl-fn:#0B63B6; --hl-type:#9A6700;
  --serif: "Iowan Old Style","Palatino Linotype",Palatino,"Book Antiqua",Georgia,ui-serif,serif;
  --sans: ui-sans-serif,system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono: ui-monospace,"JetBrains Mono","SF Mono",Menlo,Consolas,"Liberation Mono",monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#0B141D; --sidebar:#07101A; --surface:#121E2A; --text:#E4EDF4; --muted:#8C9CAB;
    --border:#20303F; --accent:#22C3FA; --accent-hover:#5BD3FB; --accent-ink:#03121C; --code-bg:#070E15; --bubble:#172634;
    --hover:rgba(120,200,255,.07); --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px rgba(0,0,0,.35);
    --danger:#F2A7A1; --glow:0 0 18px rgba(34,195,250,.35);
    --hl-kw:#C792EA; --hl-str:#9CCB8A; --hl-com:#6C7D8C; --hl-num:#F2A86F; --hl-fn:#6FD3FF; --hl-type:#E3C27A;
    color-scheme: dark;
  }
}
:root[data-theme="dark"]{
  --bg:#0B141D; --sidebar:#07101A; --surface:#121E2A; --text:#E4EDF4; --muted:#8C9CAB;
  --border:#20303F; --accent:#22C3FA; --accent-hover:#5BD3FB; --accent-ink:#03121C; --code-bg:#070E15; --bubble:#172634;
  --hover:rgba(120,200,255,.07); --shadow:0 1px 2px rgba(0,0,0,.4),0 8px 24px rgba(0,0,0,.35);
  --danger:#F2A7A1; --glow:0 0 18px rgba(34,195,250,.35);
  --hl-kw:#C792EA; --hl-str:#9CCB8A; --hl-com:#6C7D8C; --hl-num:#F2A86F; --hl-fn:#6FD3FF; --hl-type:#E3C27A;
  color-scheme: dark;
}
*{box-sizing:border-box}
html,body{height:100%;margin:0}
body{background:var(--bg);color:var(--text);font:15px/1.5 var(--sans);-webkit-font-smoothing:antialiased}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
button:focus-visible,textarea:focus-visible,input:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
svg{flex:none}

.app{display:flex;height:100%;overflow:hidden}

/* ---------- sidebar ---------- */
.sidebar{width:272px;flex:none;background:var(--sidebar);border-right:1px solid var(--border);display:flex;flex-direction:column;transition:margin-left .2s ease}
.app.sb-closed .sidebar{margin-left:-272px}
.sb-top{display:flex;align-items:center;justify-content:space-between;padding:14px 12px 8px 16px}
.brand{display:flex;align-items:center;gap:10px;font:650 16px/1 var(--sans);letter-spacing:.01em}
.mark{width:30px;height:30px;border-radius:8px;background:#050d16;object-fit:cover;flex:none;box-shadow:0 0 0 1px rgba(34,195,250,.25)}
.icon-btn{width:32px;height:32px;border-radius:8px;display:grid;place-items:center;color:var(--muted)}
.icon-btn:hover{background:var(--hover);color:var(--text)}
.new-chat{margin:6px 10px 14px;display:flex;align-items:center;gap:10px;padding:8px 10px;border-radius:10px;font-weight:500}
.new-chat .plus{width:24px;height:24px;border-radius:50%;background:var(--accent);color:var(--accent-ink);display:grid;place-items:center}
.new-chat:hover{background:var(--hover)}
.sb-label{padding:0 18px 6px;font-size:12.5px;color:var(--muted)}
.conv-list{flex:1;overflow-y:auto;padding:0 8px 12px}
.conv{display:flex;align-items:center;border-radius:8px;position:relative}
.conv:hover,.conv.active{background:var(--hover)}
.conv.active{background:var(--border)}
.conv-title{flex:1;min-width:0;text-align:left;padding:7px 10px;font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.conv-tools{display:none;padding-right:4px}
.conv:hover .conv-tools,.conv.active .conv-tools,.conv:focus-within .conv-tools{display:flex}
.conv-tools .icon-btn{width:26px;height:26px}
.conv input{flex:1;margin:3px 4px;padding:4px 6px;border:1px solid var(--accent);border-radius:6px;background:var(--surface);color:var(--text);font:inherit;font-size:14px}
.conv-empty{padding:8px 10px;color:var(--muted);font-size:13.5px}
.sb-foot{border-top:1px solid var(--border);padding:12px 16px;font-size:12.5px;color:var(--muted);display:flex;flex-direction:column;gap:5px}
.engine{display:flex;align-items:center;gap:8px}
.dot{width:7px;height:7px;border-radius:50%;background:var(--muted);flex:none}
.dot.ok{background:#3E9B57}.dot.warm{background:#D4A53C}.dot.bad{background:var(--danger)}

/* ---------- main ---------- */
.main{flex:1;min-width:0;display:flex;flex-direction:column;position:relative}
.topbar{position:absolute;inset:0 0 auto 0;height:52px;display:flex;align-items:center;gap:6px;padding:0 12px;z-index:5;background:linear-gradient(var(--bg) 70%,transparent)}
.topbar .title{flex:1;min-width:0;text-align:center;font-size:14px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.app:not(.sb-closed) #openSb{visibility:hidden}
.scroller{flex:1;overflow-y:auto;padding:60px 20px 24px;scroll-behavior:auto}
.thread{max-width:768px;margin:0 auto;display:flex;flex-direction:column;gap:28px}
.main.is-empty{justify-content:center}
.main.is-empty .scroller{flex:0 0 auto;overflow:visible;padding-top:0}
.main.is-empty .thread{display:none}
.main:not(.is-empty) .empty{display:none}
.empty{text-align:center;padding:0 20px 28px}
.empty h1{font:400 clamp(30px,4.2vw,42px)/1.15 var(--serif);letter-spacing:-.015em;margin:0;display:inline-flex;align-items:center;gap:14px}
.empty h1 .mark{width:52px;height:52px;border-radius:14px;box-shadow:0 0 0 1px rgba(34,195,250,.3),var(--glow)}

/* messages */
.msg.user{display:flex;justify-content:flex-end}
.bubble{background:var(--bubble);border-radius:18px;padding:10px 16px;max-width:85%;white-space:pre-wrap;word-wrap:break-word}
.bubble .chips{margin-top:8px}
.msg.assistant{font:16.5px/1.65 var(--serif);min-width:0}
.md>*:first-child{margin-top:0}.md>*:last-child{margin-bottom:0}
.md p,.md ul,.md ol{margin:0 0 .85em}
.md h1,.md h2,.md h3,.md h4{font-family:var(--sans);line-height:1.3;margin:1.3em 0 .5em;letter-spacing:-.01em}
.md h1{font-size:1.35em}.md h2{font-size:1.2em}.md h3{font-size:1.05em}
.md li{margin:.25em 0}
.md a{color:var(--accent)}
.md blockquote{margin:0 0 .9em;padding-left:14px;border-left:3px solid var(--border);color:var(--muted)}
.md table{border-collapse:collapse;margin:0 0 1em;font:14px/1.45 var(--sans);display:block;overflow-x:auto}
.md th,.md td{border:1px solid var(--border);padding:6px 10px;text-align:left}
.md th{background:var(--hover)}
.md :not(pre)>code{font:.86em var(--mono);background:var(--hover);border:1px solid var(--border);padding:.1em .35em;border-radius:5px}
.md hr{border:0;border-top:1px solid var(--border);margin:1.4em 0}

.codeblock{margin:0 0 1em;border:1px solid var(--border);border-radius:12px;overflow:hidden;background:var(--code-bg);font-family:var(--sans)}
.cb-head{display:flex;align-items:center;justify-content:space-between;padding:5px 6px 5px 14px;border-bottom:1px solid var(--border);font-size:12.5px;color:var(--muted)}
.cb-head .acts{display:flex;gap:2px}
.cb-btn{display:flex;align-items:center;gap:5px;padding:4px 8px;border-radius:6px;font-size:12.5px;color:var(--muted)}
.cb-btn:hover{background:var(--hover);color:var(--text)}
.codeblock pre{margin:0;padding:14px 16px;overflow-x:auto;font:13.5px/1.6 var(--mono);tab-size:4}
.codeblock code{font:inherit;background:none;border:0;padding:0}

.thinking{margin:0 0 14px;border:1px solid var(--border);border-radius:12px;font:14px/1.55 var(--sans);background:var(--surface)}
.thinking summary{cursor:pointer;list-style:none;padding:9px 14px;color:var(--muted);display:flex;align-items:center;gap:8px;user-select:none}
.thinking summary::-webkit-details-marker{display:none}
.thinking summary .chev{transition:transform .15s}
.thinking[open] summary .chev{transform:rotate(90deg)}
.thinking-body{padding:0 14px 12px;color:var(--muted);white-space:pre-wrap;max-height:340px;overflow-y:auto}

.msg-actions{display:flex;align-items:center;gap:2px;margin-top:8px;font:12.5px var(--sans);color:var(--muted);opacity:0;transition:opacity .15s}
.msg.assistant:hover .msg-actions,.msg.assistant.last .msg-actions,.msg-actions:focus-within{opacity:1}
.msg-actions .meta{margin-left:8px;display:flex;gap:10px}
.msg-actions .icon-btn{width:28px;height:28px}
.err{font:14px/1.5 var(--sans);color:var(--danger);border:1px solid color-mix(in srgb,var(--danger) 40%,transparent);border-radius:10px;padding:10px 12px;margin-top:6px}

.typing{display:inline-flex;gap:5px;padding:6px 0}
.typing i{width:7px;height:7px;border-radius:50%;background:var(--accent);animation:blink 1.2s infinite ease-in-out}
.typing i:nth-child(2){animation-delay:.15s}.typing i:nth-child(3){animation-delay:.3s}
@keyframes blink{0%,80%,100%{opacity:.25;transform:scale(.85)}40%{opacity:1;transform:scale(1)}}

/* ---------- composer ---------- */
.composer-wrap{padding:0 20px 14px}
.composer{max-width:768px;margin:0 auto;background:var(--surface);border:1px solid var(--border);border-radius:20px;box-shadow:var(--shadow);padding:12px 12px 10px 16px;transition:border-color .15s}
.composer:focus-within{border-color:color-mix(in srgb,var(--accent) 45%,var(--border))}
.composer.drag{border-color:var(--accent);border-style:dashed}
.composer textarea{width:100%;border:0;outline:0;resize:none;background:transparent;color:var(--text);font:15.5px/1.5 var(--sans);max-height:260px;min-height:26px;padding:2px 0}
.composer textarea::placeholder{color:var(--muted)}
.composer-bar{display:flex;align-items:center;gap:6px;margin-top:8px;margin-left:-6px}
.spacer{flex:1}
.pill{display:flex;align-items:center;gap:6px;height:32px;padding:0 10px;border-radius:9px;border:1px solid var(--border);font-size:13px;color:var(--muted)}
.pill:hover:not(:disabled){background:var(--hover);color:var(--text)}
.pill[aria-pressed="true"]{color:var(--accent);border-color:color-mix(in srgb,var(--accent) 50%,var(--border));background:color-mix(in srgb,var(--accent) 9%,transparent)}
.pill:disabled{opacity:.4;cursor:not-allowed}
.model-picker{position:relative}
.model-btn{display:flex;align-items:center;gap:6px;height:32px;padding:0 10px;border-radius:9px;font-size:13.5px;color:var(--muted)}
.model-btn:hover{background:var(--hover);color:var(--text)}
.menu{position:absolute;right:0;bottom:40px;width:300px;background:var(--surface);border:1px solid var(--border);border-radius:14px;box-shadow:var(--shadow);padding:6px;z-index:20}
.main.is-empty .menu{bottom:auto;top:40px}
.menu-item{width:100%;display:flex;gap:10px;text-align:left;padding:9px 10px;border-radius:9px}
.menu-item:hover,.menu-item:focus-visible{background:var(--hover)}
.menu-item .mi-body{flex:1;min-width:0}
.menu-item .mi-name{font-size:14px;font-weight:500;display:flex;align-items:center;gap:7px}
.menu-item .mi-desc{font-size:12.5px;color:var(--muted);margin-top:1px}
.menu-item .check{color:var(--accent);visibility:hidden;margin-top:2px}
.menu-item[aria-checked="true"] .check{visibility:visible}
.send{width:34px;height:34px;border-radius:10px;background:var(--accent);color:var(--accent-ink);display:grid;place-items:center}
.send:hover:not(:disabled){background:var(--accent-hover);box-shadow:var(--glow)}
.send:disabled{opacity:.35;cursor:default}
.chips{display:flex;flex-wrap:wrap;gap:6px}
#fileChips:not(:empty){margin-bottom:10px}
.chip{display:inline-flex;align-items:center;gap:6px;max-width:240px;padding:4px 6px 4px 9px;border:1px solid var(--border);border-radius:8px;font:12.5px var(--sans);background:var(--bg)}
.chip span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.chip small{color:var(--muted)}
.chip button{width:18px;height:18px;border-radius:4px;display:grid;place-items:center;color:var(--muted)}
.chip button:hover{background:var(--hover)}
.hint{max-width:768px;margin:8px auto 0;text-align:center;font-size:12px;color:var(--muted)}
.main.is-empty .hint{visibility:hidden}

/* ---------- code panel ---------- */
.panel{width:min(46vw,760px);flex:none;border-left:1px solid var(--border);background:var(--surface);display:flex;flex-direction:column;min-width:0}
.panel[hidden]{display:none}
.panel-head{display:flex;align-items:center;gap:6px;padding:10px 10px 10px 18px;border-bottom:1px solid var(--border)}
.panel-head .ptitle{flex:1;min-width:0;font-weight:500;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.panel-head .ptitle small{color:var(--muted);font-weight:400;margin-left:6px}
.panel-body{flex:1;overflow:auto;background:var(--code-bg)}
.panel-body pre{margin:0;padding:18px 20px;font:13.5px/1.65 var(--mono);tab-size:4}
.panel-body code{font:inherit}

/* syntax colors */
.hljs-keyword,.hljs-selector-tag,.hljs-meta .hljs-keyword{color:var(--hl-kw)}
.hljs-string,.hljs-regexp,.hljs-addition,.hljs-template-string{color:var(--hl-str)}
.hljs-comment,.hljs-quote{color:var(--hl-com);font-style:italic}
.hljs-number,.hljs-literal,.hljs-symbol,.hljs-bullet{color:var(--hl-num)}
.hljs-title,.hljs-title.function_,.hljs-section,.hljs-name{color:var(--hl-fn)}
.hljs-type,.hljs-built_in,.hljs-class .hljs-title,.hljs-title.class_,.hljs-attr,.hljs-attribute{color:var(--hl-type)}
.hljs-deletion{color:var(--danger)}
.hljs-meta{color:var(--muted)}

.toast{position:fixed;left:50%;bottom:26px;transform:translateX(-50%);background:var(--text);color:var(--bg);padding:8px 14px;border-radius:9px;font-size:13.5px;z-index:50;opacity:0;transition:opacity .15s;pointer-events:none}
.toast.show{opacity:1}
.scrim{display:none}

@media (max-width:900px){
  .sidebar{position:fixed;inset:0 auto 0 0;z-index:30;box-shadow:var(--shadow)}
  .app.sb-closed .sidebar{margin-left:-280px}
  .app:not(.sb-closed) .scrim{display:block;position:fixed;inset:0;background:rgba(0,0,0,.3);z-index:25}
  .app:not(.sb-closed) #openSb{visibility:visible}
  .panel{position:fixed;inset:0;width:auto;z-index:40}
  .scroller{padding-left:14px;padding-right:14px}
  .composer-wrap{padding:0 10px 10px}
  .msg.assistant{font-size:16px}
}
@media (prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}

/* ================= shared components (multi-user) ================= */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:7px;height:36px;padding:0 14px;border-radius:9px;font-size:14px;font-weight:500;border:1px solid var(--border);background:var(--surface);color:var(--text)}
.btn:hover:not(:disabled){background:var(--hover)}
.btn:disabled{opacity:.5;cursor:default}
.btn.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.btn.primary:hover:not(:disabled){background:var(--accent-hover);border-color:var(--accent-hover)}
.btn.danger{color:var(--danger);border-color:color-mix(in srgb,var(--danger) 35%,var(--border))}
.btn.danger:hover:not(:disabled){background:color-mix(in srgb,var(--danger) 10%,transparent)}
.btn.small{height:30px;padding:0 10px;font-size:13px}
.field{display:flex;flex-direction:column;gap:6px;margin-bottom:14px}
.field label{font-size:13.5px;font-weight:500}
.field input[type=text],.field input[type=password]{height:40px;padding:0 12px;border:1px solid var(--border);border-radius:9px;background:var(--bg);color:var(--text);font:15px var(--sans)}
.field input:focus{outline:2px solid color-mix(in srgb,var(--accent) 55%,transparent);outline-offset:0;border-color:var(--accent)}
.field .help{font-size:12.5px;color:var(--muted)}
.check-row{display:flex;align-items:center;gap:8px;font-size:14px;margin-bottom:14px}
.check-row input{accent-color:var(--accent);width:16px;height:16px}
.form-err{color:var(--danger);font-size:13.5px;min-height:1.3em;margin:-4px 0 10px}
.inline-row{display:flex;gap:8px}
.inline-row input{flex:1;min-width:0}

dialog.modal{border:1px solid var(--border);border-radius:16px;background:var(--surface);color:var(--text);padding:0;width:min(440px,calc(100vw - 32px));box-shadow:var(--shadow)}
dialog.modal::backdrop{background:rgba(20,18,15,.45)}
.modal-body{padding:22px 24px 20px}
.modal h2{font:500 22px/1.25 var(--serif);margin:0 0 6px;letter-spacing:-.01em}
.modal p.sub{margin:0 0 18px;color:var(--muted);font-size:14px}
.modal-actions{display:flex;justify-content:flex-end;gap:8px;margin-top:6px}
.secret{display:flex;align-items:center;gap:8px;background:var(--bg);border:1px solid var(--border);border-radius:9px;padding:10px 12px;font:14px var(--mono);margin-bottom:10px;word-break:break-all}
.secret span{flex:1}

/* user menu in sidebar */
.user-row{position:relative;margin:4px -8px -4px}
.user-btn{width:100%;display:flex;align-items:center;gap:10px;padding:8px;border-radius:10px;text-align:left}
.user-btn:hover{background:var(--hover)}
.avatar{width:28px;height:28px;border-radius:50%;background:var(--text);color:var(--bg);display:grid;place-items:center;font:600 13px var(--sans);flex:none;text-transform:uppercase}
.user-btn .uname{flex:1;min-width:0;font-size:14px;color:var(--text);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.user-btn .role{font-size:12px;color:var(--muted)}
.user-menu{position:absolute;left:0;right:0;bottom:46px;background:var(--surface);border:1px solid var(--border);border-radius:12px;box-shadow:var(--shadow);padding:5px;z-index:20}
.user-menu a,.user-menu button{display:flex;width:100%;align-items:center;gap:10px;padding:8px 10px;border-radius:8px;font-size:14px;color:var(--text);text-decoration:none;text-align:left}
.user-menu a:hover,.user-menu button:hover{background:var(--hover)}
.user-menu hr{border:0;border-top:1px solid var(--border);margin:4px 2px}
.engine-list{display:flex;flex-direction:column;gap:5px;padding-bottom:8px}