/* Global site navigation — single source of truth. Linked by every content page
   AFTER its inline <style> so these rules win the cascade and unify the nav across
   the site. Uses design-system vars with hard fallbacks so it renders even on a
   page that doesn't define them. */
nav{position:fixed;top:0;left:0;right:0;z-index:100;padding:1rem 2rem;display:flex;align-items:center;justify-content:space-between;background:rgba(2,6,23,0.85);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);border-bottom:1px solid var(--border,rgba(30,41,59,0.5))}
.nav-logo{font-weight:700;font-size:1.1rem;letter-spacing:-.02em;color:var(--fg,#f1f5f9);text-decoration:none}
.nav-logo span{color:var(--ext,#a78bfa)}
.nav-links{display:flex;gap:1.75rem;align-items:center}
.nav-links a{font-size:.85rem;color:var(--fg2,#94a3b8);font-weight:500;text-decoration:none;transition:color .2s}
.nav-links a:hover{color:var(--fg,#f1f5f9)}
.nav-cta{background:var(--ext,#a78bfa);color:var(--bg,#020617)!important;padding:.45rem 1.1rem;border-radius:6px;font-weight:600;font-size:.85rem}
.nav-cta:hover{background:var(--fg,#f1f5f9)}
.nav-login{border:1px solid var(--border,rgba(30,41,59,0.5));color:var(--fg,#f1f5f9)!important;padding:.45rem 1.1rem;border-radius:6px;font-weight:600;font-size:.85rem}
.nav-login:hover{border-color:var(--ext,#a78bfa);color:var(--ext,#a78bfa)!important}
/* Login + Connect stay visible on mobile (the two key actions); other links collapse. */
@media(max-width:768px){nav{padding:.8rem 1rem}.nav-links{gap:.7rem}.nav-links a:not(.nav-cta):not(.nav-login){display:none}}

/* Perception dropdown — groups the machine-perception pages (structured perception /
   SiFR / snapshots) under one nav item so crawlers reach all three from the global nav
   on every content page. Real anchors; CSS-only reveal (hover + keyboard focus-within). */
.nav-group{position:relative;display:flex;align-items:center}
.nav-group-label{cursor:pointer}
.nav-group-label::after{content:" \25BE";font-size:.75em;opacity:.7}
.nav-dropdown{position:absolute;top:100%;left:0;display:flex;flex-direction:column;gap:.7rem;min-width:184px;padding:.9rem 1rem;background:rgba(2,6,23,0.97);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);border:1px solid var(--border,rgba(30,41,59,0.5));border-radius:8px;box-shadow:0 8px 24px rgba(0,0,0,.35);opacity:0;visibility:hidden;transition:opacity .18s ease,visibility .18s ease}
.nav-group:hover>.nav-dropdown,.nav-group:focus-within>.nav-dropdown{opacity:1;visibility:visible}
@media(max-width:768px){.nav-group{display:none}}