/* Shared desktop section navigation. Existing scene geometry is retained. */
:root{--desktop-nav-height:80px}
.desktop-header-space{height:var(--header-height)}
.site-header.desktop-section-header{position:fixed;inset:0 0 auto;z-index:200;height:var(--desktop-nav-height);display:flex;align-items:center;padding:0 clamp(24px,3vw,56px);gap:24px;border-bottom:1px solid #dce5ef;background:rgba(255,255,255,.98)}
.desktop-section-header .brand{width:56px;height:56px}
.site-header.desktop-section-header nav{margin:0;flex:1;min-width:0;width:auto;padding:0;gap:clamp(8px,1vw,20px);font:400 clamp(11px,.9vw,16px)/1.2 gaude,sans-serif;text-transform:uppercase}
.desktop-section-header nav a{display:flex;align-items:center;min-height:44px;white-space:nowrap;text-decoration:none!important;letter-spacing:-.015em}
.desktop-section-header nav a:hover,.desktop-section-header nav a[aria-current]{color:#094bcc}
.desktop-section-header .header-store-slot{width:140px;align-self:center}
.desktop-section-header .header-store{width:140px;margin:0}
@media(max-width:1399px){.desktop-section-header .header-store-slot{display:none}}
/* Each pinned chapter keeps its readable area below the persistent navigation. */
.home-act>.home-stage{top:var(--desktop-nav-height);height:min(calc(100svh - var(--desktop-nav-height)),var(--native-height))}
.foundations-act>.foundations-stage{top:var(--desktop-nav-height);height:min(calc(100svh - var(--desktop-nav-height)),var(--foundations-height))}
.profile-act>.profile-stage{top:var(--desktop-nav-height);height:min(calc(100svh - var(--desktop-nav-height)),var(--profile-height))}
.depth-act:not([data-mode=flow])>.depth-stage{top:var(--desktop-nav-height);height:min(calc(100svh - var(--desktop-nav-height)),var(--scene-height))}
@media(prefers-reduced-motion:reduce){.home-act>.home-stage,.foundations-act>.foundations-stage,.profile-act>.profile-stage,.depth-act:not([data-mode=flow])>.depth-stage{top:0;height:auto}}
@media print{.desktop-section-header{display:none}.desktop-header-space{display:none}}

.desktop-menu-toggle{display:none}
@media(max-width:1100px){
 .site-header.desktop-section-header{justify-content:space-between;background:#e6f0ff}
 .desktop-menu-toggle{display:grid;align-content:center;gap:8px;width:48px;height:48px;padding:10px;border:0;background:transparent;color:#084acb;cursor:pointer}
 .desktop-menu-toggle span{height:2px;background:currentColor;width:28px}
 .desktop-menu-toggle[aria-expanded=true] span:first-child{transform:translateY(5px) rotate(45deg)}
 .desktop-menu-toggle[aria-expanded=true] span:last-child{transform:translateY(-5px) rotate(-45deg)}
 .site-header.desktop-section-header nav{display:none;position:fixed;inset:80px 0 auto;padding:24px 40px 32px;background:#e6f0ff;max-height:calc(100svh - 80px);overflow-y:auto;grid-template-columns:repeat(2,minmax(0,1fr));gap:0 36px;box-sizing:border-box;font-size:24px}
 .site-header.desktop-section-header[data-menu-open=true] nav{display:grid}
 .desktop-section-header nav a{min-height:72px;padding:12px 0;border-bottom:1px solid #bdcee5;white-space:normal}
}