/* ============================================================ ATOM SPLIT */
.atom-scroll-track {
  position: relative;
  /* runway: spread + a centred hold so the nucleus stays mid-screen */
  height: 170vh;
  margin: 60px 0 40px;
}
.atom {
  position: sticky;
  top: 0;
  height: 100vh;            /* full viewport so nucleus locks at exact center */
  display: grid;
  place-items: center;
  --p: 0;
  --r: clamp(180px, 28vw, 320px);
}

/* concentric rings — atomic shells */
.atom-ring {
  position: absolute;
  border-radius: 50%;
  border: 1px dashed oklch(0.55 0.22 320 / 0.18);
  pointer-events: none;
  opacity: var(--p);
  transition: opacity 0.4s ease;
}
.atom-ring--1 {
  width: calc(var(--r) * 1.1 * var(--p));
  height: calc(var(--r) * 1.1 * var(--p));
  animation: atomRingSpin 30s linear infinite;
}
.atom-ring--2 {
  width: calc(var(--r) * 1.6 * var(--p));
  height: calc(var(--r) * 1.6 * var(--p));
  border-style: dotted;
  border-color: oklch(0.55 0.30 350 / 0.14);
  animation: atomRingSpin 50s linear infinite reverse;
}
.atom-ring--3 {
  width: calc(var(--r) * 2.2 * var(--p));
  height: calc(var(--r) * 2.2 * var(--p));
  border-color: oklch(0.55 0.22 290 / 0.10);
  animation: atomRingSpin 80s linear infinite;
}
@keyframes atomRingSpin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

/* spokes — light filaments from core to each cover */
.atom-spoke {
  position: absolute;
  left: 50%; top: 50%;
  width: calc(var(--r) * var(--p));
  height: 1px;
  background: linear-gradient(
    90deg,
    oklch(0.65 0.30 350 / 0.55),
    oklch(0.55 0.30 350 / 0.10) 70%,
    transparent
  );
  transform-origin: 0 50%;
  transform: rotate(var(--angle, 0deg));
  opacity: calc(var(--p) * 0.9);
  pointer-events: none;
  filter: drop-shadow(0 0 4px oklch(0.55 0.30 350 / 0.5));
}
.atom-spoke::after {
  content: "";
  position: absolute;
  right: 0; top: 50%;
  width: 4px; height: 4px;
  margin-top: -2px;
  border-radius: 50%;
  background: oklch(0.85 0.20 350);
  box-shadow: 0 0 10px oklch(0.65 0.30 350);
  opacity: var(--p);
}

/* core — the nucleus, locked to the exact center of the .atom box */
.atom-core {
  position: absolute;
  left: 50%; top: 50%;
  width: calc(60px + 70px * var(--p));
  height: calc(60px + 70px * var(--p));
  border-radius: 50%;
  background:
    radial-gradient(circle at 35% 30%, oklch(0.30 0.12 320), oklch(0.04 0.02 280) 70%);
  box-shadow:
    0 0 0 1px oklch(1 0 0 / 0.08),
    0 0 60px oklch(0.55 0.30 350 / calc(0.2 + 0.6 * var(--p))),
    0 0 calc(20px + 80px * var(--p)) oklch(0.55 0.30 290 / 0.4);
  z-index: 5;
  display: grid; place-items: center;
  transform: translate(-50%, -50%) scale(calc(0.55 + 0.45 * var(--p)));
  transform-origin: center;
  opacity: calc(0.25 + 0.75 * var(--p));
}
.atom-core__inner {
  position: absolute; inset: 12%;
  border-radius: 50%;
  background:
    radial-gradient(circle at 60% 40%, oklch(0.55 0.30 350 / 0.6), transparent 60%),
    radial-gradient(circle at 30% 70%, oklch(0.45 0.30 290 / 0.5), transparent 55%);
  filter: blur(2px);
  animation: atomCorePulse 2.4s ease-in-out infinite;
}
@keyframes atomCorePulse {
  0%, 100% { transform: scale(1);    opacity: 0.85; }
  50%      { transform: scale(1.15); opacity: 1; }
}
.atom-core__label {
  position: absolute;
  top: calc(100% + 14px);
  left: 50%;
  transform: translateX(-50%) translateY(calc(-30px * (1 - var(--p))));
  text-align: center;
  white-space: nowrap;
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  color: oklch(0.85 0.04 320);
  opacity: var(--p);
  display: flex; flex-direction: column; gap: 2px;
}
.atom-core__label em {
  font-style: normal;
  color: oklch(0.55 0.18 320);
  font-size: 9px;
  letter-spacing: 0.3em;
}

/* covers orbit */
.atom-cover {
  position: absolute;
  left: 50%; top: 50%;
  width: clamp(110px, 13vw, 160px);
  text-decoration: none;
  color: inherit;
  /* spiral-in: rotate by angle + (1-p)*180deg, translate by r*p, then unrotate */
  --swirl: calc((1 - var(--p)) * -200deg);
  --pos: calc(var(--angle) + var(--swirl));
  transform:
    translate(-50%, -50%)
    rotate(var(--pos))
    translate(calc(var(--r) * var(--p)))
    rotate(calc(-1 * var(--pos)));
  opacity: calc(var(--p) * var(--p));
  cursor: pointer;
  z-index: 3;
  /* stable compositor layer — prevents flicker on hover */
  transform-style: preserve-3d;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}
/* blur only when actually needed; flat filter when spread is complete */
.atom[style*="--p:0"] .atom-cover,
.atom-cover { filter: none; }
.atom-cover:hover { z-index: 3; }
.atom-cover__art {
  position: relative;
  width: 100%;
  aspect-ratio: 1;
  border-radius: 10px;
  overflow: hidden;
  background: var(--surface, #14101a);
  box-shadow:
    0 18px 50px oklch(0 0 0 / 0.6),
    0 0 0 1px oklch(1 0 0 / 0.08),
    0 0 30px oklch(0.55 0.30 350 / 0.25);
  transition: transform 0.4s cubic-bezier(.2,.8,.2,1), box-shadow 0.4s ease;
}
.atom-cover__art image-slot { width: 100%; height: 100%; }
.atom-cover:hover .atom-cover__art {
  box-shadow:
    0 24px 70px oklch(0 0 0 / 0.7),
    0 0 0 1px oklch(0.55 0.30 350 / 0.6),
    0 0 60px oklch(0.55 0.30 350 / 0.7);
}
.atom-cover__art::after {
  content: "▶";
  position: absolute; inset: 0;
  display: grid; place-items: center;
  font-size: 24px;
  color: #fff;
  background: oklch(0.05 0.02 290 / 0.55);
  opacity: 0;
  transition: opacity 0.3s ease;
}
.atom-cover:hover .atom-cover__art::after { opacity: 1; }
.atom-cover__title {
  margin-top: 10px;
  font-family: var(--font-display, 'Space Grotesk');
  font-size: 14px;
  font-weight: 600;
  letter-spacing: -0.01em;
  text-align: center;
  color: #fff;
}
.atom-cover__meta {
  margin-top: 4px;
  display: flex; gap: 8px; justify-content: center;
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: oklch(0.65 0.04 320);
}
.atom-cover__meta .lang {
  padding: 2px 6px;
  border: 1px solid oklch(0.55 0.30 350 / 0.4);
  border-radius: 3px;
  color: oklch(0.85 0.18 350);
}

/* hint */
.atom-hint {
  display: flex; align-items: center; gap: 14px;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.3em;
  text-transform: uppercase;
  color: oklch(0.65 0.04 320);
  opacity: calc(1 - var(--atom-p, 0));
  margin-bottom: 60px;
  transition: opacity 0.3s ease;
}
.atom-hint__line {
  width: 60px; height: 1px;
  background: linear-gradient(90deg, transparent, oklch(0.55 0.20 320), transparent);
}

@media (max-width: 700px) {
  .atom-scroll-track { height: 160vh; }
  .atom { height: 100vh; --r: 130px; }
  .atom-cover { width: 92px; }
  .atom-cover__title { font-size: 11px; }
}

/* ============================================================ DRIFT MARK */
.drift {
  position: fixed;
  z-index: 5;
  pointer-events: none;
  width: 240px; height: 240px;
  left: 0; top: 0;
  will-change: transform;
}
@media (max-width: 900px) {
  .drift { width: 150px; height: 150px; }
}
.drift svg {
  width: 100%; height: 100%;
  overflow: visible;
}

/* hide all variants by default; show the active one */
.drift .variant { display: none; }
.drift[data-variant="vinyl"] .variant--vinyl,
.drift:not([data-variant]) .variant--vinyl { display: block; }
.drift[data-variant="play"] .variant--play   { display: block; }
.drift[data-variant="auto"] .variant--auto   { display: block; }

/* ====== VINYL ====== */
.v-disc { animation: spin 5s linear infinite; transform-origin: 50% 50%; transform-box: fill-box; }
.v-shine { animation: spin 5s linear infinite; transform-origin: 50% 50%; transform-box: fill-box; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ====== PLAY ====== */
.p-ring {
  transform-origin: 50% 50%; transform-box: fill-box;
  animation: pulse-ring 2s ease-out infinite;
}
.p-circle {
  transform-origin: 50% 50%; transform-box: fill-box;
  animation: pulse-scale 2s ease-in-out infinite;
}
@keyframes pulse-ring {
  0%   { transform: scale(0.8); opacity: 0.6; }
  100% { transform: scale(1.6); opacity: 0; }
}
@keyframes pulse-scale {
  0%, 100% { transform: scale(1); }
  50%      { transform: scale(1.06); }
}

/* ====== AUTO ====== */
.drift[data-variant="auto"] {
  width: 200px; height: 110px;
}
@media (max-width: 900px) { .drift[data-variant="auto"] { width: 130px; height: 75px; } }
.a-body { animation: bob 0.5s ease-in-out infinite alternate; transform-origin: 50% 60%; transform-box: fill-box; }
.a-wheel { animation: spin 0.4s linear infinite; transform-box: fill-box; }
.a-headlight {
  animation: flicker 0.3s ease-in-out infinite alternate;
  transform-origin: center; transform-box: fill-box;
}
.a-smoke { animation: smoke 1.4s ease-out infinite; transform-origin: 50% 50%; transform-box: fill-box; }
@keyframes bob {
  from { transform: translateY(-1px) rotate(-0.6deg); }
  to   { transform: translateY(1px)  rotate(0.6deg); }
}
@keyframes flicker {
  from { opacity: 0.85; }
  to   { opacity: 1; }
}
@keyframes smoke {
  0%   { opacity: 0.6; transform: translate(0, 0) scale(0.6); }
  100% { opacity: 0;   transform: translate(-30px, -8px) scale(1.6); }
}