:root{
  --bg:#f7f7f8; --panel:#ffffff; --panel-2:#ffffff; --line:#e5e6ea;
  --text:#1b1c1f; --muted:#6b7076; --dim:#9096a0;
  --accent:#0b63f6; --accent-soft:#eaf1ff; --accent-line:#cfe0ff;
  --radius:16px;
  color-scheme:light;
}
*{box-sizing:border-box}
html,body{height:100%}
body{
  margin:0; background:var(--bg); color:var(--text);
  font:15px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Inter,system-ui,sans-serif;
  -webkit-font-smoothing:antialiased; overflow:hidden;
}
button,input,textarea{font:inherit;color:inherit}
button{cursor:pointer;border:0;background:none}
a{color:var(--accent);text-decoration:none}
.muted{color:var(--muted)}
[hidden]{display:none !important}

/* layout */
#app{display:grid;grid-template-columns:264px 1fr;height:100dvh}
#sidebar{
  display:flex;flex-direction:column;gap:2px;padding:18px 12px;
  background:var(--panel);border-right:1px solid var(--line);min-height:0;
}
.brand{display:flex;align-items:center;gap:10px;padding:4px 8px 18px}
.logo{width:30px;height:30px;object-fit:contain;flex:none}
.logo-lg{width:56px;height:56px;margin-bottom:16px}
.brand strong{display:block;font-size:13px;letter-spacing:.16em}
.brand small{display:block;font-size:10px;letter-spacing:.14em;color:var(--dim);text-transform:uppercase}

.modes{display:flex;flex-direction:column;gap:2px;margin-bottom:14px}
.mode{display:flex;align-items:center;padding:9px 12px;border-radius:11px;color:var(--muted);text-align:left;font-size:14px}
.mode:hover{background:#f3f4f6;color:var(--text)}
.mode.active{background:var(--accent-soft);color:var(--accent);font-weight:550}

.section-head{display:flex;align-items:center;justify-content:space-between;padding:6px 10px;font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:var(--dim)}
.section-head button{width:22px;height:22px;border-radius:7px;color:var(--muted);font-size:16px;line-height:1}
.section-head button:hover{background:#f1f2f4;color:var(--text)}

.conv-list{flex:1;overflow-y:auto;min-height:0;padding:2px 0 10px;scrollbar-width:thin}
.conv{display:block;width:100%;text-align:left;padding:9px 10px;border-radius:10px;color:var(--muted);font-size:13px;line-height:1.35;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.conv:hover{background:#f4f5f7;color:var(--text)}
.conv.active{background:#eef1f5;color:var(--text)}
.conv .kind{display:inline-block;font-size:9px;letter-spacing:.1em;text-transform:uppercase;color:var(--accent);margin-right:6px;opacity:.75}

.side-foot{display:flex;gap:6px;padding:10px 4px 0;border-top:1px solid var(--line)}
.side-foot .ghost{flex:1}

#main{display:flex;flex-direction:column;min-width:0;min-height:0}
.topbar{display:flex;align-items:center;gap:10px;padding:12px 18px;border-bottom:1px solid var(--line);background:rgba(247,247,248,.85);backdrop-filter:blur(8px)}
.mode-label{flex:1;font-size:12px;letter-spacing:.14em;text-transform:uppercase;color:var(--dim)}
.icon{width:34px;height:34px;border-radius:10px;color:var(--muted);display:grid;place-items:center}
.icon:hover{background:#eceef2;color:var(--text)}
#menuBtn{display:none}

.view{flex:1;min-height:0;display:flex;flex-direction:column}
.messages{flex:1;overflow-y:auto;padding:26px 20px 8px;scroll-behavior:smooth}
.messages-inner{max-width:760px;margin:0 auto;display:flex;flex-direction:column;gap:22px}
.empty{max-width:600px;margin:9vh auto 0;text-align:center}
.empty h1{font-size:28px;letter-spacing:-.02em;margin:0 0 6px;font-weight:600}
.chips{display:flex;flex-wrap:wrap;gap:8px;justify-content:center;margin-top:22px}
.chip{padding:8px 13px;border-radius:999px;border:1px solid var(--line);color:var(--muted);font-size:13px;background:var(--panel)}
.chip:hover{border-color:var(--accent-line);color:var(--text);background:#fff}

.msg{display:flex;flex-direction:column;gap:6px}
.msg .who{font-size:10px;letter-spacing:.14em;text-transform:uppercase;color:var(--dim)}
.msg.user{align-items:flex-end}
.msg.user .who{color:var(--accent)}
.msg .bubble{max-width:100%;white-space:pre-wrap;overflow-wrap:anywhere}
.msg.user .bubble{background:#eef0f3;border-radius:18px 18px 6px 18px;padding:11px 15px;max-width:85%}
.msg.assistant .bubble{font-size:15.2px}
.bubble p{margin:0 0 12px}
.bubble p:last-child{margin-bottom:0}
.bubble h1,.bubble h2,.bubble h3{margin:18px 0 8px;line-height:1.3}
.bubble h1{font-size:21px}.bubble h2{font-size:18px}.bubble h3{font-size:16px;color:var(--accent)}
.bubble ul,.bubble ol{margin:0 0 12px;padding-left:20px}
.bubble li{margin:3px 0}
.bubble code{background:#f2f3f5;border:1px solid var(--line);padding:1px 5px;border-radius:5px;font-size:13px}
.bubble pre{background:#f7f8fa;border:1px solid var(--line);padding:12px;border-radius:10px;overflow-x:auto;margin:0 0 12px}
.bubble pre code{background:none;border:0;padding:0}
.bubble blockquote{margin:0 0 12px;padding-left:12px;border-left:2px solid var(--accent-line);color:var(--muted)}
.msg-tools{display:flex;gap:8px;opacity:0;transition:opacity .15s}
.msg:hover .msg-tools{opacity:1}
.msg-tools button{font-size:11px;color:var(--dim);padding:2px 6px;border-radius:6px}
.msg-tools button:hover{color:var(--text);background:#f0f1f4}
.cursor{display:inline-block;width:7px;height:15px;background:var(--accent);vertical-align:-2px;animation:blink 1s steps(2) infinite;border-radius:1px}
@keyframes blink{50%{opacity:0}}

.composer{display:flex;gap:10px;align-items:flex-end;padding:14px 20px 18px;max-width:800px;width:100%;margin:0 auto}
#input{flex:1;resize:none;max-height:220px;padding:12px 14px;border-radius:14px;border:1px solid var(--line);background:var(--panel);line-height:1.5;outline:none;box-shadow:0 1px 2px rgba(16,24,40,.04)}
#input:focus{border-color:var(--accent-line);box-shadow:0 0 0 3px rgba(11,99,246,.08)}
.send{padding:12px 20px;border-radius:13px;background:var(--accent);color:#fff;font-weight:600;letter-spacing:.01em}
.send:hover{background:#0a58da}
.send:disabled{opacity:.45}
.ghost{padding:8px 12px;border-radius:9px;border:1px solid var(--line);color:var(--muted);background:var(--panel)}
.ghost:hover{color:var(--text);border-color:#c9ccd4}
.primary{background:var(--accent);color:#fff;font-weight:600;padding:8px 14px;border-radius:9px}
.small{font-size:12.5px}
.danger{color:#c0392b;border-color:rgba(192,57,43,.25)}

/* notes */
.notes-layout{flex:1;display:grid;grid-template-columns:300px 1fr;min-height:0}
.notes-list-wrap{border-right:1px solid var(--line);display:flex;flex-direction:column;min-height:0;background:var(--panel)}
.notes-actions{display:flex;gap:8px;padding:14px;align-items:center}
.notes-actions input{flex:1;min-width:0;padding:7px 10px;border-radius:8px;border:1px solid var(--line);background:var(--bg);font-size:13px;outline:none}
.notes-list{flex:1;overflow-y:auto;padding:0 8px 16px}
.note-item{display:block;width:100%;text-align:left;padding:10px 12px;border-radius:10px;color:var(--muted)}
.note-item:hover{background:#f4f5f7}
.note-item.active{background:#eef1f5;color:var(--text)}
.note-item strong{display:block;font-size:13px;color:var(--text);font-weight:550;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.note-item span{display:block;font-size:11.5px;color:var(--dim);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;margin-top:2px}
.note-editor{display:flex;flex-direction:column;gap:10px;padding:18px;min-height:0}
.note-editor input,.note-editor textarea{border:1px solid var(--line);background:var(--panel);border-radius:10px;padding:11px 13px;outline:none;width:100%}
#noteTitle{font-size:17px;font-weight:600}
#noteTags{font-size:12.5px;color:var(--muted)}
#noteBody{flex:1;resize:none;line-height:1.65;font-size:14.5px;min-height:200px}
.note-buttons{display:flex;gap:8px}

/* dialog */
dialog{border:1px solid var(--line);border-radius:18px;background:var(--panel);color:var(--text);padding:0;width:min(420px,92vw);box-shadow:0 24px 70px rgba(16,24,40,.18)}
dialog::backdrop{background:rgba(20,24,33,.35);backdrop-filter:blur(3px)}
.dlg-body{padding:22px;display:flex;flex-direction:column;gap:12px}
.dlg-body h2{margin:0;font-size:17px;font-weight:600}
.dlg-body label{font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:var(--dim)}
.dlg-body input{padding:10px 12px;border-radius:9px;border:1px solid var(--line);background:var(--bg);outline:none;width:100%}
.dlg-actions{display:flex;gap:8px;justify-content:flex-end;margin-top:6px}
.dlg-note{font-size:12px;color:var(--dim);line-height:1.5}
#toast{position:fixed;left:50%;bottom:24px;transform:translate(-50%,20px);background:#1b1c1f;color:#fff;padding:9px 16px;border-radius:10px;font-size:13px;opacity:0;transition:.2s;pointer-events:none;z-index:50}
#toast.show{opacity:1;transform:translate(-50%,0)}

/* login */
.login-wrap{min-height:100dvh;display:grid;place-items:center;padding:24px;background:var(--bg)}
.login-card{width:min(400px,100%);background:var(--panel);border:1px solid var(--line);border-radius:20px;padding:30px 26px;box-shadow:0 20px 60px rgba(16,24,40,.08)}
.login-card h1{font-size:22px;margin:0 0 4px;letter-spacing:-.01em}
.login-card p{margin:0 0 22px;color:var(--muted);font-size:13.5px}
.login-card form{display:flex;flex-direction:column;gap:12px}
.login-card label{font-size:11px;letter-spacing:.1em;text-transform:uppercase;color:var(--dim)}
.login-card input{width:100%;padding:12px 13px;border-radius:10px;border:1px solid var(--line);background:var(--bg);outline:none}
.login-card input:focus{border-color:var(--accent-line);box-shadow:0 0 0 3px rgba(11,99,246,.08)}
.login-card button{padding:12px;border-radius:11px;background:var(--accent);color:#fff;font-weight:600;margin-top:6px}
.err{color:#c0392b;font-size:13px;min-height:18px}

@media (max-width:780px){
  #app{grid-template-columns:1fr}
  #sidebar{position:fixed;inset:0 auto 0 0;width:272px;z-index:40;transform:translateX(-100%);transition:transform .22s ease;box-shadow:20px 0 60px rgba(16,24,40,.12)}
  #app.nav-open #sidebar{transform:none}
  #app.nav-open::after{content:"";position:fixed;inset:0;background:rgba(20,24,33,.25);z-index:35}
  #menuBtn{display:grid}
  .messages{padding:18px 14px 4px}
  .composer{padding:10px 12px 16px}
  .notes-layout{grid-template-columns:1fr}
  .notes-list-wrap{border-right:0;border-bottom:1px solid var(--line);max-height:38vh}
  .topbar{padding:10px 12px}
}

/* ---------- sidebar v2 ---------- */
#app{grid-template-columns:252px 1fr}
#sidebar{width:252px;padding:14px 10px 10px;gap:0;background:#fbfbfc;border-right:1px solid #ececef}
.brand{padding:2px 6px 14px;gap:9px}
.brand .logo{width:24px;height:24px}
.brand .wordmark{font-size:14.5px;font-weight:600;letter-spacing:-.01em}
.brand strong,.brand small{display:none}

.new-chat{display:flex;align-items:center;gap:8px;width:100%;padding:8px 11px;border-radius:10px;background:#fff;border:1px solid var(--line);color:var(--text);font-size:13.5px;font-weight:550;margin-bottom:14px;box-shadow:0 1px 2px rgba(16,24,40,.04)}
.new-chat:hover{border-color:#d3d7de}
.new-chat svg{opacity:.6}

.modes{gap:1px;margin-bottom:16px}
.mode{padding:7px 9px;gap:9px;font-size:13.5px;border-radius:9px;color:#4a4f57}
.mode svg{width:16px;height:16px;flex:none;opacity:.55}
.mode:hover{background:#f2f3f5}
.mode.active{background:#eceff3;color:var(--text);font-weight:550}
.mode.active svg{opacity:1;color:var(--accent)}

.section-head{padding:2px 9px 6px;font-size:11px;letter-spacing:.02em;color:#9aa0a8;text-transform:none;font-weight:550}
.conv{padding:7px 9px;border-radius:8px;font-size:13px;display:flex;align-items:center;gap:8px}
.conv .dot{width:5px;height:5px;border-radius:50%;flex:none;background:#c6cad1}
.conv .dot.lyrics{background:#0b63f6}
.conv .dot.memory{background:#8b5cf6}
.conv .dot.notes{background:#10b981}
.conv .ctitle{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.conv.active{background:#e9edf2}
.conv-list{padding:0 0 8px}

.side-foot{border-top:1px solid #ececef;padding:8px 2px 0}
.account{display:flex;align-items:center;gap:9px;width:100%;padding:6px 8px;border-radius:9px;text-align:left}
.account:hover{background:#f1f2f4}
.avatar{width:24px;height:24px;border-radius:50%;background:#e7ebf0;color:#3b414a;font-size:11px;font-weight:600;display:grid;place-items:center;flex:none}
.acct-mail{font-size:12px;color:var(--muted);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.push-left{margin-right:auto}

.attach-chip{display:flex;align-items:center;gap:6px;padding:3px;border:1px solid var(--line);border-radius:10px;background:var(--panel);flex:none}
.attach-chip img{width:36px;height:36px;object-fit:cover;border-radius:7px;display:block}
.attach-chip button{width:18px;height:18px;border-radius:50%;background:#eef0f3;color:#6b7076;font-size:12px;line-height:1;display:grid;place-items:center}