/* E-LAB V11 • six primary navigation groups. All legacy lesson URLs remain unchanged. */
.site-header{z-index:80}
.site-header .nav-inner{gap:clamp(10px,1.05vw,18px);min-height:78px}
.site-header .logo-link img{width:clamp(132px,11.7vw,157px)}
.site-nav.elab-nav-v11{display:flex;flex:1;min-width:0;align-items:center;justify-content:flex-end;gap:clamp(4px,.5vw,11px)}
.site-nav.elab-nav-v11>.nav-top-link,.site-nav.elab-nav-v11 .nav-group>summary{display:flex;align-items:center;gap:5px;min-height:44px;padding:10px 8px;color:#d3e5f8;font-size:clamp(12px,.9vw,13px);font-weight:740;white-space:nowrap;border-radius:10px;line-height:1.25;cursor:pointer;transition:color .16s,background .16s}
.site-nav.elab-nav-v11>.nav-top-link:hover,.site-nav.elab-nav-v11 .nav-group>summary:hover,.site-nav.elab-nav-v11 .nav-group[open]>summary,.site-nav.elab-nav-v11 .nav-group.is-current>summary{color:#7cecff;background:#12416a}
.site-nav.elab-nav-v11>.nav-top-link.active{color:#7cecff}
.site-nav.elab-nav-v11>.nav-top-link.active:after{position:absolute;bottom:-4px;left:8px;right:8px;display:block;height:2px;margin:0;background:#49dfff;border-radius:2px}
.site-nav.elab-nav-v11>.nav-top-link{position:relative}
.site-nav.elab-nav-v11 .nav-group{position:relative;flex:0 0 auto}
.site-nav.elab-nav-v11 .nav-group>summary{list-style:none;user-select:none}
.site-nav.elab-nav-v11 .nav-group>summary::-webkit-details-marker{display:none}
.site-nav.elab-nav-v11 .nav-chevron{font-size:17px;font-weight:750;line-height:.8;color:#71dff7;transition:transform .15s}
.site-nav.elab-nav-v11 .nav-group[open] .nav-chevron{transform:rotate(180deg)}
.site-nav.elab-nav-v11 .nav-dropdown{position:absolute;top:calc(100% + 9px);left:0;min-width:258px;max-width:330px;padding:10px;background:#0b2749;border:1px solid #426d92;border-radius:16px;box-shadow:0 20px 50px #0008;display:grid;gap:2px;z-index:100}
.site-nav.elab-nav-v11 .nav-group:nth-last-child(-n+2) .nav-dropdown{left:auto;right:0}
.site-nav.elab-nav-v11 .nav-dropdown a{white-space:normal;display:block;border-radius:9px;padding:10px 12px;font-size:13px;font-weight:650;line-height:1.35;color:#e5f1ff;min-height:40px}
.site-nav.elab-nav-v11 .nav-dropdown a:hover,.site-nav.elab-nav-v11 .nav-dropdown a.active{background:#164e7e;color:#85f3ff}
.site-nav.elab-nav-v11 .nav-dropdown a:after{display:none!important}
.site-nav.elab-nav-v11 .nav-menu-label{font-size:10px;color:#8cc9ed;font-weight:900;letter-spacing:.09em;text-transform:uppercase;padding:9px 12px 6px}
.site-header .nav-main-cta{flex:0 0 auto;min-height:43px;padding:11px 15px;border-radius:999px;font-size:12px;box-shadow:0 5px 19px #1688fd44}
.site-header .nav-contact{display:none}
@media(max-width:1170px){
 .site-header .nav-inner{min-height:69px}
 .site-nav.elab-nav-v11{display:none;position:absolute;top:100%;left:0;right:0;min-width:0;max-height:calc(100dvh - 69px);overflow-y:auto;overscroll-behavior:contain;background:#081e3d;padding:12px 18px 22px;border-bottom:1px solid #4976a1;box-shadow:0 18px 40px #0007;flex-direction:column;align-items:stretch;gap:3px}
 .site-nav.elab-nav-v11.open{display:flex}
 .site-header .menu-toggle{display:block;margin-left:auto;flex:0 0 auto}
 .site-nav.elab-nav-v11>.nav-top-link,.site-nav.elab-nav-v11 .nav-group>summary{font-size:15px;min-height:49px;justify-content:space-between;width:100%;border-radius:11px;padding:12px 15px;border:1px solid transparent}
 .site-nav.elab-nav-v11 .nav-group{width:100%}
 .site-nav.elab-nav-v11 .nav-group>summary{border-color:#24476b;background:#0d2b4d}
 .site-nav.elab-nav-v11 .nav-group[open]>summary{border-color:#4b8cbb;border-radius:11px 11px 0 0}
 .site-nav.elab-nav-v11 .nav-dropdown,.site-nav.elab-nav-v11 .nav-group:nth-last-child(-n+2) .nav-dropdown{position:static;min-width:0;max-width:none;padding:5px 8px 9px;margin:0;border:1px solid #345a7c;border-top:0;border-radius:0 0 11px 11px;box-shadow:none;background:#0b2442}
 .site-nav.elab-nav-v11 .nav-dropdown a{min-height:44px;display:flex;align-items:center;padding:11px 13px}
 .site-header .nav-main-cta{margin-left:0}
}
@media(min-width:1171px){.site-header .menu-toggle{display:none}}
@media(max-width:450px){.site-header .nav-inner{gap:9px}.site-header .logo-link img{width:116px}.site-header .nav-main-cta{padding:10px 12px;font-size:11px;min-height:42px}.site-nav.elab-nav-v11{padding:10px 12px 19px}}
@media(prefers-reduced-motion:reduce){.site-nav.elab-nav-v11 *{transition:none!important}}