/* ============================================================
   TOP BAR
   ============================================================ */
.topbar {
  position: sticky; top: 0; z-index: 50;
  border-bottom: 1px solid var(--rule);
  background: color-mix(in oklab, var(--bg) 80%, transparent);
  backdrop-filter: blur(10px);
}
.topbar-inner {
  max-width: 1360px; margin: 0 auto;
  padding: 14px 28px;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
}
.brand {
  display: flex; align-items: center; gap: 14px;
  font-weight: 600; letter-spacing: -0.01em;
  font-size: 14.5px; color: var(--ink);
}
.brand img.gch-mark {
  height: 36px; width: auto; display: block;
}
.brand .pipe { width: 1px; height: 26px; background: var(--rule); }
.brand .product {
  display: flex; flex-direction: column; line-height: 1.05;
}
.brand .product .nm {
  font-weight: 600; font-size: 14.5px;
  letter-spacing: -0.01em; color: var(--ink);
}
.brand .product .sub {
  font-family: "Geist Mono", monospace;
  font-size: 10.5px; font-weight: 400; color: var(--muted);
  letter-spacing: 0.08em; text-transform: uppercase;
  margin-top: 3px;
}
.top-nav {
  display: flex; gap: 4px; align-items: center;
  font-family: "Geist Mono", monospace;
  font-size: 11.5px; letter-spacing: 0.04em;
}
.top-nav a {
  padding: 8px 12px; border-radius: 8px;
  color: var(--ink-2);
  transition: background .15s, color .15s;
}
.top-nav a:hover { background: var(--paper-2); color: var(--ink); }
.top-nav a.active {
  color: var(--ink); background: var(--paper-2);
  box-shadow: inset 0 0 0 1px var(--rule);
}
.theme-switch {
  display: flex; gap: 0; align-items: center;
  border: 1px solid var(--rule); border-radius: 999px;
  padding: 3px; background: var(--paper);
}
.theme-switch button {
  border: none; background: transparent;
  padding: 5px 10px; border-radius: 999px;
  font-family: "Geist Mono", monospace;
  font-size: 10.5px; letter-spacing: 0.06em;
  color: var(--muted);
}
.theme-switch button.active {
  background: var(--ink); color: var(--bg);
}