body{
  display:grid;
  grid-template-columns:var(--sidebar-width, 340px) 4px 1fr;
  grid-template-rows:auto 1fr;
  grid-template-areas:
    "topbar topbar topbar"
    "sidebar drag stage";
  background:var(--bg);
  color:var(--text);
}

header{
  grid-area:topbar;
  display:flex;
  align-items:center;
  gap:12px;
  padding:10px 12px;
  border-bottom:1px solid #222532;
  background:var(--panel);
  position:sticky;
  top:0;
  z-index:10;
}
header .title{ font-weight:700; }
header .spacer{ flex:1; }

aside{
  grid-area:sidebar;
  padding:12px;
  background:var(--panel);
  overflow:auto;
  min-width:300px;
}

.sidebar-resizer{
  grid-area:drag;
  cursor:col-resize;
  background:#222532;
}

.sidebar-resizer:hover{ background:#333647; }