/* v31-atoms — scroll-scrubbed particle transition overlay (canvas created by v31-atoms.js; the micro-dust pass and
   the GPU point cloud in v31-atoms-cloud.js draw into the same canvas). z-index 845: above every section, under the
   menu (850), scroll bar (880) and header (900). Palette lock: blue + white only — soft white, pale blue, periwinkle,
   electric blue (no cyan, violet or magenta). */
:root{--atom-1:#f4f6ff;--atom-2:#7d8bff;--atom-3:#2f45ff;--atom-4:#c7cdff;--atom-5:#4f66ff;--atom-6:#6b80ff;--atom-7:#eceef4}
.atoms{position:fixed;left:0;top:0;width:100vw;height:100vh;z-index:845;pointer-events:none;display:block;visibility:hidden;contain:strict}
.atoms.on{visibility:visible}

/* while the veil sits behind the header, give the header its on-dark treatment */
html.atoms-dk .hd{--fl:#fff;--fc:#fff}
html.atoms-dk .hd::before{opacity:0}
html.atoms-dk .hd .hd__snd:not(.on),html.atoms-dk .hd .hd__menu{background:rgba(255,255,255,.1);color:#fff;box-shadow:inset 0 0 0 1px rgba(255,255,255,.14)}
html.atoms-dk .hd .hd__talk{background:#fff;color:var(--ink)}
html.atoms-dk .hd .hd__talk:hover{color:#fff}

/* chapter card: the next chapter's name over the settled shape (aria-hidden; the header label announces it) */
.atoms-ch{position:fixed;left:0;top:0;z-index:846;pointer-events:none;font-family:var(--fm,ui-monospace,monospace);font-size:.8rem;letter-spacing:.14em;text-transform:uppercase;white-space:nowrap;color:#c7cdff;opacity:0;visibility:hidden;transition:opacity .25s linear,visibility 0s linear .25s;text-shadow:0 0 18px rgba(79,102,255,.55)}
.atoms-ch.on{opacity:1;visibility:visible;transition:opacity .25s linear,visibility 0s}
.atoms-ch.ink{color:#2438f5;text-shadow:none}

@media (prefers-reduced-motion:reduce){.atoms,.atoms-ch{display:none}}
@media print{.atoms,.atoms-ch{display:none}}
/* travelling chrome M faded through every window (v31-atoms.js mFade; <html data-atoms="on">) — multiplies motion's inline opacity */
.mo-m.atoms-fade{filter:opacity(var(--atoms-m,1)) drop-shadow(0 18px 26px rgba(8,10,20,.22))}