/* ============ Shell Grid ============ */
.shell{display:grid;grid-template-columns:280px 1fr;height:100vh;overflow:hidden}

/* ============ Sidebar ============ */
.sidebar{
  background:var(--win);
  backdrop-filter:blur(24px) saturate(180%);
  border-right:1px solid var(--border);
  display:flex;flex-direction:column;height:100vh;overflow:hidden;
}
.brand{padding:20px 20px 14px;border-bottom:1px solid var(--border-s);flex-shrink:0}
.brand-name{font-family:var(--font-serif);font-size:22px;font-weight:600;color:var(--text);letter-spacing:-.3px}

/* Sidebar Nav */
.sidenav{display:flex;padding:8px 10px 0;gap:2px;border-bottom:1px solid var(--border-s);flex-shrink:0}
.snbtn{
  flex:1;padding:10px 4px;font-size:13px;font-family:var(--font-body);
  color:var(--t3);background:none;border:none;border-radius:var(--r-xs);
  cursor:pointer;transition:all .15s;text-align:center;font-weight:400;
}
.snbtn:hover{background:rgba(0,0,0,.04);color:var(--text)}
[data-theme="dark"] .snbtn:hover{background:rgba(255,255,255,.06)}
.snbtn.on{background:var(--blue-s);color:var(--blue);font-weight:500}

/* Sidebar Panels */
.sp{display:none;flex-direction:column;flex:1;overflow:hidden}
.sp.on{display:flex}
.arena-scroll{flex:1;overflow-y:auto;padding:16px 14px 14px;scrollbar-width:thin}

/* ============ Main ============ */
.main{display:flex;flex-direction:column;height:100vh;overflow:hidden}

/* Conversation Wraps */
.conv-wrap{flex:1;overflow:hidden;position:relative;display:none}
.conv-wrap.on{display:flex;flex-direction:column}

/* ============ Model Bar ============ */
.model-bar{
  display:flex;align-items:center;gap:8px;padding:9px 16px;
  background:var(--win);border-bottom:1px solid var(--border);
  flex-shrink:0;overflow-x:auto;scrollbar-width:none;
  backdrop-filter:blur(20px);flex-wrap:wrap;
}
.model-bar::-webkit-scrollbar{display:none}
.model-bar .mlabel{margin-right:2px;white-space:nowrap;flex-shrink:0}
.model-select-group{display:flex;align-items:center;gap:6px;flex-shrink:0}
.model-select-group label{
  display:flex;align-items:center;gap:5px;
  font-size:11px;color:var(--t3);font-family:var(--font-ui);font-weight:600;
  letter-spacing:.3px;white-space:nowrap;
}
.provider-logo{
  width:18px;height:18px;flex-shrink:0;display:inline-flex;
  align-items:center;justify-content:center;border-radius:4px;
  background:var(--win-s);border:1px solid var(--border-s);
}
.provider-logo svg{width:12px;height:12px}
.model-select{
  padding:6px 28px 6px 10px;border-radius:var(--r-xs);
  border:1.5px solid var(--border);background:var(--win-s);
  font-size:12px;font-family:var(--font-body);color:var(--text);
  cursor:pointer;outline:none;appearance:none;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%236e6e73'/%3E%3C/svg%3E");
  background-repeat:no-repeat;background-position:right 10px center;
  min-width:155px;max-width:220px;transition:border-color .15s;
}
.model-select:focus{border-color:var(--blue);box-shadow:0 0 0 3px var(--blue-s)}
[data-theme="dark"] .model-select{background-color:rgba(34,34,40,.8)}

/* ============ Topstrip ============ */
.topstrip{
  display:flex;align-items:center;gap:6px;padding:0 14px;
  border-bottom:1px solid var(--border);background:var(--win);
  backdrop-filter:blur(20px);flex-shrink:0;min-height:42px;
}
/* topstrip-brand removed — no longer used */
.icon-btn{
  width:30px;height:30px;border-radius:var(--r-xs);background:none;
  border:1px solid var(--border);color:var(--t3);display:flex;
  align-items:center;justify-content:center;cursor:pointer;transition:all .15s;flex-shrink:0;
}
.icon-btn:hover{background:var(--border-s);color:var(--text)}
.icon-btn svg{width:15px;height:15px;stroke:currentColor;fill:none;stroke-width:1.7;stroke-linecap:round;stroke-linejoin:round}

/* ============ Tab Bar ============ */
.tab-bar{
  display:flex;gap:0;border-bottom:1px solid var(--border);
  background:var(--win);flex-shrink:0;overflow-x:auto;scrollbar-width:none;
}
.tab-bar::-webkit-scrollbar{display:none}
.tab-btn{
  display:flex;align-items:center;gap:5px;padding:8px 16px;
  font-size:12px;font-family:var(--font-body);color:var(--t3);
  background:none;border:none;border-bottom:2px solid transparent;
  cursor:pointer;white-space:nowrap;transition:all .15s;flex-shrink:0;position:relative;
}
.tab-btn:hover{color:var(--text);background:rgba(0,0,0,.02)}
.tab-btn.on{color:var(--text);font-weight:600;border-bottom-color:var(--blue)}
.tab-btn.state-checked{border-bottom-color:var(--rose);color:var(--text);font-weight:600}
.tab-btn.state-checked.on{border-bottom-color:var(--rose)}
.tab-name{display:inline-block}
.tab-ck{
  display:inline-flex;align-items:center;justify-content:center;
  width:14px;height:14px;border-radius:50%;font-size:10px;line-height:1;
  margin-left:6px;cursor:pointer;user-select:none;
  border:1.5px solid var(--t4);color:var(--t4);background:none;padding:0;
}
.tab-ck.on{background:var(--rose);border-color:var(--rose);color:#fff}

/* ============ Search Hint ============ */
.search-hint{font-size:11px;color:var(--t4);line-height:1.4;margin:4px 0 8px;font-family:var(--font-ui)}

/* ============ Labels ============ */
.mlabel{font-size:10.5px;font-weight:600;text-transform:uppercase;letter-spacing:.8px;color:var(--t4);font-family:var(--font-ui)}
.sec-block{margin-bottom:16px}
.sec-block .mlabel{margin-bottom:7px}

/* ============ Responsive ============ */
@media(max-width:900px){
  .shell{grid-template-columns:1fr}
  .sidebar{display:none}
}
@media(max-width:600px){
  .split-view{grid-template-columns:1fr !important}
}