:root {
    /* Core System Navigation Variables */
    --sys-nav-height: 0px;
    --safe-bottom: env(safe-area-inset-bottom, 0px);
    --usable-vh: 100vh;
    --real-vh: 100vh;

    /* Fallback for browsers that don't support env() */
    --sat: env(safe-area-inset-top, 0px);
    --sar: env(safe-area-inset-right, 0px);
    --sab: env(safe-area-inset-bottom, 0px);
    --sal: env(safe-area-inset-left, 0px);
}

/* Ensure no layout shifts during initial load */
body {
    min-height: var(--real-vh);
    padding-bottom: var(--safe-bottom);
}

/* Debug Overlay Styles */
#sys-nav-debug-overlay {
    position: fixed;
    top: 10px;
    right: 10px;
    background: rgba(0, 0, 0, 0.85);
    color: #00ff00;
    font-family: monospace;
    font-size: 10px;
    padding: 8px;
    border-radius: 4px;
    z-index: 999999;
    pointer-events: none;
    backdrop-filter: blur(4px);
    border: 1px solid rgba(0, 255, 0, 0.3);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.5);
    max-width: 200px;
}

#sys-nav-debug-overlay h3 {
    margin: 0 0 5px 0;
    border-bottom: 1px solid rgba(0, 255, 0, 0.3);
    padding-bottom: 2px;
    font-size: 11px;
    color: #fff;
}

#sys-nav-debug-overlay div {
    display: flex;
    justify-content: space-between;
    margin-bottom: 2px;
}

#sys-nav-debug-overlay span.val {
    color: #fff;
    font-weight: bold;
}