/* Arena PLM shell · green nav + tree rail · 2 pages */
:root[data-system="arena"], body[data-system="arena"] {
  --shell-bg: #00803e;
  --shell-bg-hover: #006c34;
  --shell-fg: #ffffff;
  --shell-accent: #00a651;
  --shell-rail-bg: #f5f9f5;
  --shell-rail-fg: #1a1a1a;
  --shell-rail-active: #00803e;
  --shell-header-h: 40px;
  --shell-rail-w: 0;            /* Arena leaf pages use the native .arena-top tab nav, not a shell rail */
}
body[data-system="arena"] {
  margin: 0;
  padding-top: 0;        /* Arena native .arena-top IS the system header — no W2 shell header */
  padding-left: 0;
  font-family: -apple-system, "Segoe UI", "Helvetica Neue", sans-serif;
  background: #fafbfa; font-size: 12.5px;
}
body[data-system="arena"] .shell-rail   { display: none !important; }
body[data-system="arena"] .shell-header { display: none !important; }
body[data-system="arena"] .shell-footer { display: none !important; }
body[data-system="arena"] .shell-header {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--shell-header-h); background: var(--shell-bg);
  color: var(--shell-fg);
  display: flex; align-items: center; padding: 0 16px;
  font-size: 13px; z-index: 100;
  box-shadow: 0 1px 3px rgba(0,0,0,0.18);
}
body[data-system="arena"] .shell-logo { font-weight: 700; }
body[data-system="arena"] .shell-search {
  flex: 1; max-width: 460px; margin-left: 16px;
  background: rgba(255,255,255,0.16);
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 3px; padding: 5px 10px; color: #fff; font-size: 12.5px;
}
body[data-system="arena"] .shell-right {
  margin-left: auto; display: flex; align-items: center; gap: 14px;
}
body[data-system="arena"] .shell-rail {
  position: fixed; top: var(--shell-header-h); bottom: 0; left: 0;
  width: var(--shell-rail-w); background: var(--shell-rail-bg);
  color: var(--shell-rail-fg);
  border-right: 1px solid #cfdcd0;
  overflow-y: auto; padding: 10px 0;
}
body[data-system="arena"] .shell-rail .nav-link {
  display: block; padding: 5px 16px; color: var(--shell-rail-fg);
  text-decoration: none;
}
body[data-system="arena"] .shell-rail .nav-link::before {
  content: '\25B8'; margin-right: 6px; color: var(--shell-rail-active); opacity: 0.6;
}
body[data-system="arena"] .shell-rail .nav-link:hover { background: #ebf3ec; }
body[data-system="arena"] .shell-rail .nav-link.active {
  background: white; font-weight: 600; color: var(--shell-rail-active);
}
body[data-system="arena"] .shell-status {
  background: rgba(255,255,255,0.16); padding: 3px 10px;
  border-radius: 999px; font-size: 11.5px;
  display: inline-flex; align-items: center; gap: 6px;
}
body[data-system="arena"] .shell-status .dot {
  width: 7px; height: 7px; border-radius: 50%; background: #4ade80;
}
body[data-system="arena"] .shell-footer {
  padding: 12px 22px; border-top: 1px solid #cfdcd0;
  font-size: 11px; color: #4b6354; text-align: center;
}
/* NOTE: legacy .arena-top (Arena tabs Items/BOMs/Changes/Manufacturers/Documents/Quality + ITAR Workspace pill) intentionally NOT hidden. */