/* Achievement backgrounds live beneath the app shell and never receive input. */
@property --effect-accent { syntax: "<color>"; inherits: true; initial-value: #95a8ff; }
@property --effect-accent-light { syntax: "<color>"; inherits: true; initial-value: #d7defe; }
@property --effect-accent-dim { syntax: "<color>"; inherits: true; initial-value: rgba(149, 168, 255, .36); }
@property --effect-page { syntax: "<color>"; inherits: true; initial-value: #111720; }
@property --effect-surface { syntax: "<color>"; inherits: true; initial-value: #1b2430; }
:root { --background-layer-unzoom: 1; }
:root[data-font-size="small"] { --background-layer-unzoom: 1.1363636364; }
:root[data-font-size="large"] { --background-layer-unzoom: .8928571429; }
:root {
  --effect-accent: var(--accent);
  --effect-accent-light: color-mix(in srgb, var(--accent) 62%, white);
  --effect-accent-dim: color-mix(in srgb, var(--accent) 36%, transparent);
  --effect-page: var(--bg);
  --effect-surface: var(--surface);
}
#background-layer {
  position: fixed;
  z-index: 0;
  inset: 0;
  width: 100vw;
  height: auto;
  /* body zoom scales the UI; cancel it here so effects remain viewport-sized. */
  zoom: var(--background-layer-unzoom, 1);
  overflow: hidden;
  contain: strict;
  isolation: isolate;
  pointer-events: none;
}
.app-shell { position: relative; z-index: 1; }
#background-layer > div {
  position: absolute;
  inset: 0;
  overflow: hidden;
  opacity: 0;
  visibility: hidden;
  transition: opacity 240ms ease-out;
}
#background-layer[data-background="retro_grid"] .background-retro-grid,
#background-layer[data-background="starfield"] .background-starfield,
#background-layer[data-background="warp"] .background-warp,
#background-layer[data-background="plasma"] .background-plasma,
#background-layer[data-background="underwater"] .background-underwater { opacity: .8; visibility: visible; }

.background-retro-grid {
  background:
    radial-gradient(ellipse at 12% 18%, color-mix(in srgb, var(--effect-accent) 34%, transparent), transparent 48%),
    radial-gradient(ellipse at 88% 24%, color-mix(in srgb, var(--effect-accent-light) 34%, transparent), transparent 49%),
    radial-gradient(ellipse at 50% 53%, color-mix(in srgb, var(--effect-accent) 38%, transparent), transparent 62%),
    linear-gradient(180deg, rgba(14, 10, 32, .04), rgba(12, 9, 27, .16));
}
.background-retro-grid::before {
  position: absolute;
  inset: 8% -12% -14%;
  content: "";
  transform: perspective(700px) rotateX(66deg) scale(1.18);
  transform-origin: center 52%;
  background-image: linear-gradient(color-mix(in srgb, var(--effect-accent-light) 70%, transparent) 1.3px, transparent 1.3px),
    linear-gradient(90deg, color-mix(in srgb, var(--effect-accent-light) 62%, transparent) 1.3px, transparent 1.3px);
  background-size: 100% 34px, 58px 100%;
  mask-image: linear-gradient(to bottom, #000 0%, #000 100%);
}
.background-retro-grid::after {
  position: absolute; top: 46%; right: 0; left: 0; height: 2px;
  content: "";
  background: linear-gradient(90deg, transparent, color-mix(in srgb, var(--effect-accent-light) 72%, transparent) 22%, color-mix(in srgb, var(--effect-accent-light) 94%, transparent) 50%, color-mix(in srgb, var(--effect-accent-light) 72%, transparent) 78%, transparent);
  box-shadow: 0 0 24px color-mix(in srgb, var(--effect-accent-light) 72%, transparent), 0 0 55px var(--effect-accent-dim);
  filter: blur(3px);
}
.retro-road { position: absolute; inset: 46% 0 0; overflow: hidden; }
.retro-road > i {
  position: absolute; top: 0; left: 50%; width: 2px; height: 100vh;
  transform-origin: 50% 0;
  background: linear-gradient(to bottom, color-mix(in srgb, var(--effect-accent-light) 82%, transparent), color-mix(in srgb, var(--effect-accent) 36%, transparent) 64%, color-mix(in srgb, var(--effect-accent) 12%, transparent));
  box-shadow: 0 0 8px color-mix(in srgb, var(--effect-accent-light) 42%, transparent), 0 0 20px var(--effect-accent-dim);
}
.retro-road > i:nth-child(1) { transform: rotate(-42deg); }
.retro-road > i:nth-child(2) { transform: rotate(42deg); }
.retro-road > i:not(.retro-road-center)::after {
  position: absolute; top: -7vh; left: -4px; width: 10px; height: 8vh; content: "";
  border-radius: 999px;
  background: linear-gradient(to bottom, transparent, color-mix(in srgb, var(--effect-accent-light) 96%, white) 44%, var(--effect-accent-light) 76%, transparent);
  filter: drop-shadow(0 0 8px var(--effect-accent));
}
.retro-road > i:nth-child(2)::after { animation-delay: -2.2s; }
.retro-road > .retro-road-center {
  top: 0; width: 1px; height: 100%; transform: none; opacity: .68;
  background: repeating-linear-gradient(to bottom, color-mix(in srgb, var(--effect-accent-light) 82%, transparent) 0 10px, transparent 10px 27px);
  filter: drop-shadow(0 0 5px var(--effect-accent));
}
#background-layer[data-background="retro_grid"][data-motion="running"] .background-retro-grid::before {
  animation: retro-grid-drift 8s linear infinite;
}
#background-layer[data-background="retro_grid"][data-motion="running"] .retro-road > i::after {
  animation: retro-road-build 4.4s linear infinite;
}
#background-layer[data-background="retro_grid"][data-motion="running"] .retro-road > i:nth-child(2)::after { animation-delay: -2.2s; }
#background-layer[data-background="retro_grid"][data-motion="running"] .retro-road-center {
  animation: retro-center-lane 2.8s linear infinite;
}
@keyframes retro-grid-drift {
  from { transform: perspective(700px) rotateX(66deg) scale(1.18) translateY(0); }
  to { transform: perspective(700px) rotateX(66deg) scale(1.18) translateY(30px); }
}
@keyframes retro-road-build {
  0% { opacity: 0; transform: translateY(-7vh); }
  12% { opacity: .95; }
  82% { opacity: .78; }
  100% { opacity: 0; transform: translateY(60vh); }
}
@keyframes retro-center-lane { to { background-position: 0 27px; } }

.background-starfield {
  background:
    radial-gradient(ellipse at 8% 12%, color-mix(in srgb, var(--effect-accent) 30%, transparent), transparent 48%),
    radial-gradient(ellipse at 92% 27%, color-mix(in srgb, var(--effect-accent-light) 30%, transparent), transparent 48%),
    radial-gradient(ellipse at 78% 94%, color-mix(in srgb, var(--effect-accent) 23%, transparent), transparent 43%),
    radial-gradient(ellipse at 13% 84%, color-mix(in srgb, var(--effect-accent-light) 24%, transparent), transparent 46%),
    linear-gradient(145deg, rgba(7, 10, 25, .19), rgba(26, 18, 49, .18));
}
.background-static-stars { position: absolute; inset: 0; }
.background-static-stars {
  background-image: radial-gradient(1.2px 1.2px at 13% 18%, color-mix(in srgb, var(--effect-accent-light) 78%, transparent) 50%, transparent 100%),
    radial-gradient(1px 1px at 72% 11%, color-mix(in srgb, var(--effect-accent-light) 80%, transparent) 50%, transparent 100%),
    radial-gradient(1.4px 1.4px at 88% 62%, color-mix(in srgb, var(--effect-accent-light) 70%, transparent) 50%, transparent 100%),
    radial-gradient(1px 1px at 36% 76%, color-mix(in srgb, var(--effect-accent-light) 72%, transparent) 50%, transparent 100%),
    radial-gradient(1px 1px at 57% 42%, color-mix(in srgb, var(--effect-accent-light) 68%, transparent) 50%, transparent 100%),
    radial-gradient(1.3px 1.3px at 6% 58%, color-mix(in srgb, var(--effect-accent-light) 68%, transparent) 50%, transparent 100%),
    radial-gradient(1px 1px at 94% 87%, color-mix(in srgb, var(--effect-accent-light) 66%, transparent) 50%, transparent 100%);
  background-size: 179px 157px, 197px 171px, 223px 191px, 211px 183px, 167px 149px, 239px 203px, 191px 177px;
}
.background-stars-canvas { position: absolute; inset: 0; display: block; width: 100%; height: 100%; }
#background-layer[data-canvas="unavailable"] .background-stars-canvas { display: none; }

.background-warp {
  background:
    radial-gradient(ellipse at 50% 50%, rgba(7, 10, 27, .56) 0 6%, rgba(34, 21, 71, .14) 25%, transparent 58%),
    radial-gradient(ellipse at 8% 18%, color-mix(in srgb, var(--effect-accent) 30%, transparent), transparent 48%),
    radial-gradient(ellipse at 91% 82%, color-mix(in srgb, var(--effect-accent-light) 26%, transparent), transparent 48%),
    radial-gradient(ellipse at 85% 12%, color-mix(in srgb, var(--effect-accent) 22%, transparent), transparent 42%);
  perspective: 900px;
}
.warp-tunnel { position: absolute; inset: -12%; }
.warp-tunnel i {
  position: absolute; top: 50%; left: 50%; width: 132vmax; height: 132vmax;
  border: 1px solid color-mix(in srgb, var(--effect-accent) 34%, transparent); border-radius: 19%;
  transform: translate(-50%, -50%) rotate(45deg) scale(.22);
}
.warp-tunnel i:nth-child(2) { transform: translate(-50%, -50%) rotate(45deg) scale(.36); border-color: color-mix(in srgb, var(--effect-accent-light) 34%, transparent); }
.warp-tunnel i:nth-child(3) { transform: translate(-50%, -50%) rotate(45deg) scale(.5); border-color: color-mix(in srgb, var(--effect-accent) 30%, transparent); }
.warp-tunnel i:nth-child(4) { transform: translate(-50%, -50%) rotate(45deg) scale(.64); border-color: color-mix(in srgb, var(--effect-accent-light) 31%, transparent); }
.warp-tunnel i:nth-child(5) { transform: translate(-50%, -50%) rotate(45deg) scale(.78); border-color: color-mix(in srgb, var(--effect-accent) 28%, transparent); }
.warp-tunnel i:nth-child(6) { transform: translate(-50%, -50%) rotate(45deg) scale(.92); border-color: color-mix(in srgb, var(--effect-accent-light) 29%, transparent); }
.warp-beams { position: absolute; inset: 0; }
.warp-beams i {
  position: absolute; top: 50%; left: 50%; width: 2px; height: 120vmax; transform-origin: 50% 0;
  --beam-color: color-mix(in srgb, var(--effect-accent) 72%, white);
  opacity: .3;
  background: linear-gradient(to bottom, color-mix(in srgb, var(--beam-color) 46%, transparent), color-mix(in srgb, var(--beam-color) 66%, transparent) 27%, color-mix(in srgb, var(--beam-color) 8%, transparent) 76%, transparent);
}
#background-layer[data-background="warp"][data-motion="running"] .warp-beams i::after { animation: warp-lightfly var(--warp-spark-duration, 9s) linear var(--warp-spark-delay, 0s) infinite; }
.warp-beams i::before, .warp-beams i::after {
  position: absolute; top: 0; left: -5px; width: 10px; height: 10px; border-radius: 50%;
  content: ""; opacity: 0;
  background: radial-gradient(circle, white 0 12%, color-mix(in srgb, var(--beam-color) 82%, white) 35%, var(--beam-color) 56%, transparent 78%);
}
.warp-beams i::before { display: none; }
.warp-beams i:nth-child(1) { transform: rotate(0deg) translateY(-1vh); animation-delay: 0s; }
.warp-beams i:nth-child(2) { --beam-color: rgba(255,95,205,.9); transform: rotate(30deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.3), rgba(255,95,205,.55) 24%, rgba(255,95,205,.06) 76%, transparent); animation-delay: -.4s; }
.warp-beams i:nth-child(3) { --beam-color: rgba(126,108,255,.9); transform: rotate(60deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.3), rgba(126,108,255,.62) 28%, rgba(126,108,255,.08) 76%, transparent); animation-delay: -.8s; }
.warp-beams i:nth-child(4) { --beam-color: rgba(46,205,255,.92); transform: rotate(90deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.32), rgba(46,205,255,.58) 24%, rgba(46,205,255,.06) 76%, transparent); animation-delay: -1.2s; }
.warp-beams i:nth-child(5) { --beam-color: rgba(65,230,202,.9); transform: rotate(120deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.28), rgba(65,230,202,.55) 28%, rgba(65,230,202,.06) 76%, transparent); animation-delay: -1.6s; }
.warp-beams i:nth-child(6) { --beam-color: rgba(255,191,102,.9); transform: rotate(150deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.28), rgba(255,191,102,.58) 25%, rgba(255,191,102,.06) 76%, transparent); animation-delay: -2s; }
.warp-beams i:nth-child(7) { --beam-color: rgba(120,212,255,.9); transform: rotate(180deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.38), rgba(120,212,255,.58) 26%, rgba(120,212,255,.06) 76%, transparent); animation-delay: -2.4s; }
.warp-beams i:nth-child(8) { --beam-color: rgba(216,142,255,.9); transform: rotate(210deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.3), rgba(216,142,255,.56) 24%, rgba(216,142,255,.06) 76%, transparent); animation-delay: -2.8s; }
.warp-beams i:nth-child(9) { --beam-color: rgba(93,132,255,.9); transform: rotate(240deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.28), rgba(93,132,255,.58) 28%, rgba(93,132,255,.06) 76%, transparent); animation-delay: -3.2s; }
.warp-beams i:nth-child(10) { --beam-color: rgba(255,107,157,.9); transform: rotate(270deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.3), rgba(255,107,157,.56) 24%, rgba(255,107,157,.06) 76%, transparent); animation-delay: -3.6s; }
.warp-beams i:nth-child(11) { --beam-color: rgba(126,224,255,.9); transform: rotate(300deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.3), rgba(126,224,255,.58) 28%, rgba(126,224,255,.06) 76%, transparent); animation-delay: -4s; }
.warp-beams i:nth-child(12) { --beam-color: rgba(183,120,255,.9); transform: rotate(330deg) translateY(-1vh); background: linear-gradient(to bottom, rgba(255,255,255,.28), rgba(183,120,255,.58) 24%, rgba(183,120,255,.06) 76%, transparent); animation-delay: -4.4s; }
.warp-beams i::after { animation-delay: var(--ray-delay, 0s); }
.warp-beams i:nth-child(2) { --ray-delay: -.4s; }
.warp-beams i:nth-child(3) { --ray-delay: -.8s; }
.warp-beams i:nth-child(4) { --ray-delay: -1.2s; }
.warp-beams i:nth-child(5) { --ray-delay: -1.6s; }
.warp-beams i:nth-child(6) { --ray-delay: -2s; }
.warp-beams i:nth-child(7) { --ray-delay: -2.4s; }
.warp-beams i:nth-child(8) { --ray-delay: -2.8s; }
.warp-beams i:nth-child(9) { --ray-delay: -3.2s; }
.warp-beams i:nth-child(10) { --ray-delay: -3.6s; }
.warp-beams i:nth-child(11) { --ray-delay: -4s; }
.warp-beams i:nth-child(12) { --ray-delay: -4.4s; }
#background-layer[data-background="warp"][data-motion="running"] .warp-beams > i { animation: warp-line-flare var(--warp-flare-duration, 8s) ease-in-out var(--warp-flare-delay, 0s) infinite; }
.warp-beams i { background: linear-gradient(to bottom, color-mix(in srgb, var(--beam-color) 46%, transparent), color-mix(in srgb, var(--beam-color) 66%, transparent) 27%, color-mix(in srgb, var(--beam-color) 8%, transparent) 76%, transparent); }
.warp-beams i:nth-child(1) { --beam-color: color-mix(in srgb, var(--effect-accent) 72%, white); }
.warp-beams i:nth-child(2) { --beam-color: color-mix(in srgb, var(--effect-accent) 58%, white); }
.warp-beams i:nth-child(3) { --beam-color: color-mix(in srgb, var(--effect-accent) 78%, white); }
.warp-beams i:nth-child(4) { --beam-color: color-mix(in srgb, var(--effect-accent) 64%, white); }
.warp-beams i:nth-child(5) { --beam-color: color-mix(in srgb, var(--effect-accent) 86%, white); }
.warp-beams i:nth-child(6) { --beam-color: color-mix(in srgb, var(--effect-accent) 52%, white); }
.warp-beams i:nth-child(7) { --beam-color: color-mix(in srgb, var(--effect-accent) 74%, white); }
.warp-beams i:nth-child(8) { --beam-color: color-mix(in srgb, var(--effect-accent) 58%, white); }
.warp-beams i:nth-child(9) { --beam-color: color-mix(in srgb, var(--effect-accent) 82%, white); }
.warp-beams i:nth-child(10) { --beam-color: color-mix(in srgb, var(--effect-accent) 64%, white); }
.warp-beams i:nth-child(11) { --beam-color: color-mix(in srgb, var(--effect-accent) 76%, white); }
.warp-beams i:nth-child(12) { --beam-color: color-mix(in srgb, var(--effect-accent) 54%, white); }
.warp-beams i::after { animation-delay: var(--warp-spark-delay, 0s); }
@keyframes warp-line-flare {
  0%, 100% { opacity: .2; }
  36% { opacity: .34; }
  48% { opacity: 1; }
  58% { opacity: .68; }
  74% { opacity: .28; }
}
@keyframes warp-lightfly {
  0%, 5%, 100% { opacity: 0; transform: translateY(-3vh); }
  8% { opacity: 1; }
  24% { opacity: .92; transform: translateY(94vmax); }
  30% { opacity: 0; transform: translateY(110vmax); }
}

.background-plasma {
  background:
    radial-gradient(ellipse at 5% 14%, rgba(255, 48, 104, .25), transparent 48%),
    radial-gradient(ellipse at 94% 15%, rgba(70, 109, 255, .27), transparent 48%),
    radial-gradient(ellipse at 88% 92%, rgba(59, 229, 203, .22), transparent 48%),
    radial-gradient(ellipse at 12% 88%, rgba(224, 73, 197, .23), transparent 48%);
}
.background-plasma i {
  position: absolute; width: 110vw; height: 115vh; border-radius: 50%;
  opacity: .76;
}
.background-plasma i:nth-child(1) {
  top: 50%; left: 50%; width: 120vmax; height: 120vmax; margin: -60vmax; opacity: .68;
  background: conic-gradient(from 18deg at 50% 50%, color-mix(in srgb, #ff365b 72%, var(--accent)), color-mix(in srgb, #ffa641 72%, var(--accent)), color-mix(in srgb, #efe548 72%, var(--accent)), color-mix(in srgb, #56e47c 72%, var(--accent)), color-mix(in srgb, #2dd3e0 72%, var(--accent)), color-mix(in srgb, #417cff 72%, var(--accent)), color-mix(in srgb, #a252ff 72%, var(--accent)), color-mix(in srgb, #f442ca 72%, var(--accent)), color-mix(in srgb, #ff365b 72%, var(--accent)));
}
.background-plasma i:nth-child(2) {
  top: -13%; right: -21%; opacity: .62;
  background: radial-gradient(ellipse at 24% 38%, rgba(50,196,255,.78), transparent 61%), radial-gradient(ellipse at 76% 62%, rgba(126,83,255,.7), transparent 58%);
}
.background-plasma i:nth-child(3) {
  bottom: -24%; left: -15%; opacity: .58;
  background: radial-gradient(ellipse at 33% 58%, rgba(255,69,143,.74), transparent 60%), radial-gradient(ellipse at 72% 36%, rgba(71,236,169,.68), transparent 60%);
}
#background-layer[data-background="plasma"][data-motion="running"] .background-plasma i { will-change: transform; }
#background-layer[data-background="plasma"][data-motion="running"] .background-plasma i:nth-child(1) { will-change: transform, rotate; animation: plasma-drift-one 34s ease-in-out infinite alternate, plasma-spectrum-shift 20s linear infinite; }
#background-layer[data-background="plasma"][data-motion="running"] .background-plasma i:nth-child(2) { animation: plasma-drift-two 29s ease-in-out infinite alternate; }
#background-layer[data-background="plasma"][data-motion="running"] .background-plasma i:nth-child(3) { animation: plasma-drift-three 38s ease-in-out infinite alternate; }
@keyframes plasma-drift-one { to { transform: translate3d(4vw, 3vh, 0) scale(1.08); } }
@keyframes plasma-drift-two { to { transform: translate3d(-5vw, 4vh, 0) scale(1.1); } }
@keyframes plasma-drift-three { to { transform: translate3d(5vw, -4vh, 0) scale(1.08); } }
@keyframes plasma-spectrum-shift { to { rotate: 1turn; } }

.background-underwater {
  --underwater-top: color-mix(in srgb, var(--effect-accent-light) 85%, var(--surface));
  --underwater-mid: color-mix(in srgb, var(--effect-accent) 62%, var(--bg));
  --underwater-side: color-mix(in srgb, var(--effect-accent-light) 36%, var(--bg));
  --underwater-depth: color-mix(in srgb, var(--bg) 88%, var(--effect-accent));
  background:
    radial-gradient(ellipse at 50% -10%, var(--underwater-top), transparent 47%),
    radial-gradient(ellipse at 12% 78%, var(--underwater-mid), transparent 52%),
    radial-gradient(ellipse at 88% 48%, var(--underwater-side), transparent 48%),
    linear-gradient(180deg, color-mix(in srgb, var(--bg) 44%, var(--effect-accent) 56%), var(--underwater-depth) 88%);
}
:root:not([data-theme^="dark-"]) .background-underwater {
  --underwater-top: color-mix(in srgb, var(--accent) 26%, var(--surface));
  --underwater-mid: color-mix(in srgb, var(--accent-deep) 36%, var(--bg));
  --underwater-side: color-mix(in srgb, var(--accent) 28%, var(--bg));
  --underwater-depth: color-mix(in srgb, var(--accent-deep) 38%, var(--bg));
  background:
    radial-gradient(ellipse at 50% -10%, var(--underwater-top), transparent 47%),
    radial-gradient(ellipse at 12% 78%, var(--underwater-mid), transparent 52%),
    radial-gradient(ellipse at 88% 48%, var(--underwater-side), transparent 48%),
    linear-gradient(180deg, var(--underwater-top), var(--underwater-depth) 88%);
}
.underwater-caustics {
  position: absolute; inset: -24%; opacity: .42;
  background:
    repeating-conic-gradient(from 18deg at 53% 34%, transparent 0deg 6deg,
      color-mix(in srgb, var(--effect-accent-light) 24%, transparent) 6.4deg 7deg,
      transparent 7.5deg 14deg),
    radial-gradient(ellipse at 52% 35%, color-mix(in srgb, var(--effect-accent-light) 40%, transparent), transparent 48%);
  mask-image: radial-gradient(ellipse at 50% 32%, #000 0 22%, transparent 74%);
}
.underwater-rays { position: absolute; inset: 0; overflow: hidden; }
.underwater-rays i {
  position: absolute; top: -15vh; left: 50%; width: clamp(44px, 8vw, 170px); height: 112vh;
  transform-origin: 50% 0; opacity: .31; filter: blur(8px);
  background: linear-gradient(180deg, color-mix(in srgb, var(--effect-accent-light) 58%, transparent),
    color-mix(in srgb, var(--effect-accent) 18%, transparent) 46%, transparent 88%);
  mask-image: linear-gradient(90deg, transparent, #000 44% 58%, transparent);
}
.underwater-rays i:nth-child(1) { --ray-angle: -38deg; }
.underwater-rays i:nth-child(2) { --ray-angle: -20deg; width: 12vw; opacity: .24; }
.underwater-rays i:nth-child(3) { --ray-angle: -4deg; width: 15vw; opacity: .28; }
.underwater-rays i:nth-child(4) { --ray-angle: 18deg; width: 10vw; opacity: .24; }
.underwater-rays i:nth-child(5) { --ray-angle: 37deg; width: 8vw; }
#background-layer[data-background="underwater"][data-motion="running"] .underwater-caustics {
  will-change: transform;
  animation: underwater-caustic-drift 23s ease-in-out infinite alternate;
}
#background-layer[data-background="underwater"][data-motion="running"] .underwater-rays i {
  will-change: transform, opacity;
  animation: underwater-ray-sway 13s ease-in-out var(--ray-delay, 0s) infinite alternate;
}
#background-layer[data-background="underwater"][data-motion="running"] .underwater-bubbles i {
  will-change: transform, opacity;
  animation: underwater-bubble-rise var(--bubble-duration, 17s) linear var(--bubble-delay, 0s) infinite;
}
.underwater-rays i:nth-child(1) { --ray-delay: -3s; }
.underwater-rays i:nth-child(2) { --ray-delay: -8s; }
.underwater-rays i:nth-child(3) { --ray-delay: -5s; }
.underwater-rays i:nth-child(4) { --ray-delay: -10s; }
.underwater-rays i:nth-child(5) { --ray-delay: -1s; }
.underwater-bubbles { position: absolute; inset: 0; overflow: hidden; }
.underwater-bubbles i {
  position: absolute; bottom: -8vh; left: var(--bubble-left, 50%); width: var(--bubble-size, 9px); height: var(--bubble-size, 9px);
  border: 1px solid color-mix(in srgb, var(--effect-accent-light) 62%, transparent); border-radius: 50%;
  opacity: 0; box-shadow: inset 1px 1px 2px rgba(255,255,255,.62), 0 0 8px color-mix(in srgb, var(--effect-accent-light) 35%, transparent);
}
.underwater-bubbles i:nth-child(1) { --bubble-left: 8%; --bubble-size: 8px; --bubble-duration: 19s; --bubble-delay: -8s; --bubble-drift: 18px; }
.underwater-bubbles i:nth-child(2) { --bubble-left: 19%; --bubble-size: 13px; --bubble-duration: 23s; --bubble-delay: -17s; --bubble-drift: -16px; }
.underwater-bubbles i:nth-child(3) { --bubble-left: 34%; --bubble-size: 6px; --bubble-duration: 16s; --bubble-delay: -5s; --bubble-drift: 24px; }
.underwater-bubbles i:nth-child(4) { --bubble-left: 53%; --bubble-size: 11px; --bubble-duration: 21s; --bubble-delay: -13s; --bubble-drift: -20px; }
.underwater-bubbles i:nth-child(5) { --bubble-left: 68%; --bubble-size: 7px; --bubble-duration: 18s; --bubble-delay: -3s; --bubble-drift: 14px; }
.underwater-bubbles i:nth-child(6) { --bubble-left: 78%; --bubble-size: 15px; --bubble-duration: 25s; --bubble-delay: -19s; --bubble-drift: -25px; }
.underwater-bubbles i:nth-child(7) { --bubble-left: 91%; --bubble-size: 9px; --bubble-duration: 20s; --bubble-delay: -11s; --bubble-drift: 16px; }
.underwater-bubbles i:nth-child(8) { --bubble-left: 43%; --bubble-size: 5px; --bubble-duration: 15s; --bubble-delay: -7s; --bubble-drift: -12px; }
@keyframes underwater-caustic-drift {
  from { transform: translate3d(-2%, -1%, 0) rotate(-3deg) scale(1); }
  to { transform: translate3d(2%, 2%, 0) rotate(4deg) scale(1.06); }
}
@keyframes underwater-ray-sway {
  from { transform: translateX(-50%) rotate(calc(var(--ray-angle) - 2deg)); opacity: .18; }
  to { transform: translateX(-50%) rotate(calc(var(--ray-angle) + 2deg)); opacity: .48; }
}
@keyframes underwater-bubble-rise {
  0% { transform: translate3d(0, 10vh, 0) scale(.7); opacity: 0; }
  12% { opacity: .56; }
  84% { opacity: .42; }
  100% { transform: translate3d(var(--bubble-drift), -112vh, 0) scale(1.18); opacity: 0; }
}

.background-settings { margin-top: 21px; padding-top: 18px; border-top: 1px solid var(--line); }
.background-settings-heading h4 { margin: 0; font-size: 13px; font-weight: 750; }
.background-settings-heading p { margin: 4px 0 13px; color: var(--muted); font-size: 10px; line-height: 1.5; }
.background-disclosure { overflow: hidden; border: 1px solid var(--line); border-radius: 13px; background: color-mix(in srgb, var(--surface) 84%, transparent); backdrop-filter: blur(8px) saturate(1.12); -webkit-backdrop-filter: blur(8px) saturate(1.12); }
.background-disclosure > summary { display: flex; align-items: center; justify-content: space-between; gap: 12px; min-height: 54px; padding: 10px 13px; list-style: none; cursor: pointer; }
.background-disclosure > summary::-webkit-details-marker { display: none; }
.background-disclosure > summary > span:first-child { display: grid; gap: 2px; }
.background-disclosure > summary small { color: var(--muted); font-size: 9px; }
.background-disclosure > summary strong { color: var(--text); font-size: 11px; }
.background-disclosure-chevron { color: var(--accent); font-size: 16px; transition: transform .18s ease; }
.background-disclosure[open] .background-disclosure-chevron { transform: rotate(180deg); }
.background-disclosure-content { padding: 0 10px 10px; }
.background-disclosure-content .background-motion-control { margin-bottom: 10px !important; }
.background-motion-control { position: relative; display: flex !important; align-items: center; justify-content: space-between; gap: 12px; min-height: 52px; margin: 0 0 12px !important; padding: 9px 11px; border: 1px solid var(--line); border-radius: 12px; background: color-mix(in srgb, var(--surface) 92%, transparent); cursor: pointer; text-transform: none !important; letter-spacing: normal !important; }
.background-motion-control > span:first-child { display: grid; gap: 2px; }
.background-motion-control strong { color: var(--text); font-size: 10px; font-weight: 700; }
.background-motion-control small { color: var(--muted); font-size: 9px; font-weight: 500; }
.background-motion-control input { position: absolute; width: 1px; height: 1px; opacity: 0; }
.background-motion-switch { position: relative; width: 37px; height: 22px; flex: 0 0 37px; border-radius: 999px; background: var(--line); transition: background .18s ease; }
.background-motion-switch::after { position: absolute; top: 3px; left: 3px; width: 16px; height: 16px; border-radius: 50%; content: ""; background: var(--surface); box-shadow: 0 1px 4px rgba(0,0,0,.18); transition: transform .18s ease; }
.background-motion-control input:checked + .background-motion-switch { background: var(--accent); }
.background-motion-control input:checked + .background-motion-switch::after { transform: translateX(15px); }
.background-motion-control input:focus-visible + .background-motion-switch { outline: 2px solid var(--accent); outline-offset: 3px; }
.background-choices { display: grid; gap: 9px; }
.background-option { display: grid; grid-template-columns: minmax(0, 1fr); gap: 8px; width: 100%; min-width: 0; padding: 9px; border: 1px solid var(--line); border-radius: 14px; background: color-mix(in srgb, var(--surface) 84%, transparent); color: var(--text); text-align: left; cursor: pointer; backdrop-filter: blur(8px) saturate(1.1); -webkit-backdrop-filter: blur(8px) saturate(1.1); transition: border-color .2s ease, transform .16s ease, background-color .2s ease; }
.background-option:hover:not(:disabled), .background-option:focus-visible { border-color: var(--accent); }
.background-option[aria-pressed="true"] { border-color: var(--accent); box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--accent) 44%, transparent); }
.background-option:disabled { opacity: 1; cursor: default; }
.background-option:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.background-preview { position: relative; display: block; height: 66px; overflow: hidden; border: 1px solid rgba(255,255,255,.12); border-radius: 9px; background: linear-gradient(140deg, #111626, #211a37); isolation: isolate; }
.background-preview::before, .background-preview::after { position: absolute; inset: 0; content: ""; pointer-events: none; }
.background-preview[data-preview="normal"] { background: radial-gradient(ellipse at 82% 25%, color-mix(in srgb, var(--accent) 25%, transparent), transparent 72%), linear-gradient(135deg, var(--bg), var(--surface-soft)); }
.background-preview[data-preview="locked"] { display: grid; place-items: center; background: linear-gradient(135deg, var(--bg), var(--accent-soft)); color: var(--accent-deep); font-size: 28px; font-weight: 750; }
.background-preview[data-preview="locked"]::before, .background-preview[data-preview="locked"]::after { content: none; }
.background-preview[data-preview="retro_grid"] { background: radial-gradient(ellipse at 18% 25%, color-mix(in srgb, var(--accent) 48%, transparent), transparent 45%), radial-gradient(ellipse at 83% 25%, color-mix(in srgb, var(--effect-accent-light) 38%, transparent), transparent 46%), var(--bg); }
.background-preview[data-preview="retro_grid"]::before { inset: 14% -10% -20%; background-image: linear-gradient(color-mix(in srgb, var(--effect-accent-light) 64%, transparent) 1px, transparent 1px), linear-gradient(90deg, color-mix(in srgb, var(--effect-accent-light) 56%, transparent) 1px, transparent 1px); background-size: 100% 10px, 22px 100%; transform: perspective(120px) rotateX(57deg) scale(1.45); transform-origin: center 52%; mask-image: linear-gradient(to bottom, #000, #000); }
.background-preview[data-preview="retro_grid"]::after { top: 46%; height: 1px; background: linear-gradient(90deg, transparent, color-mix(in srgb, var(--effect-accent-light) 80%, transparent) 24%, color-mix(in srgb, var(--effect-accent-light) 100%, transparent) 50%, color-mix(in srgb, var(--effect-accent-light) 80%, transparent) 78%, transparent); box-shadow: 0 0 10px var(--effect-accent); }
.background-preview[data-preview="starfield"] { background: radial-gradient(ellipse at 12% 15%, color-mix(in srgb, var(--accent) 38%, transparent), transparent 54%), radial-gradient(ellipse at 88% 83%, color-mix(in srgb, var(--effect-accent-light) 32%, transparent), transparent 55%), var(--bg); }
.background-preview[data-preview="starfield"]::before { background-image: radial-gradient(1px 1px at 14% 30%, color-mix(in srgb, var(--effect-accent-light) 90%, transparent) 55%, transparent), radial-gradient(1px 1px at 74% 20%, color-mix(in srgb, var(--effect-accent-light) 75%, transparent) 55%, transparent), radial-gradient(1px 1px at 56% 72%, color-mix(in srgb, var(--effect-accent-light) 85%, transparent) 55%, transparent), radial-gradient(1px 1px at 88% 63%, color-mix(in srgb, var(--effect-accent-light) 78%, transparent) 55%, transparent), radial-gradient(1px 1px at 26% 82%, color-mix(in srgb, var(--effect-accent-light) 70%, transparent) 55%, transparent), radial-gradient(1px 1px at 44% 12%, color-mix(in srgb, var(--effect-accent-light) 95%, transparent) 55%, transparent); background-size: 44px 39px, 52px 44px, 47px 41px, 55px 48px, 49px 42px, 59px 51px; }
.background-preview[data-preview="warp"] { background: radial-gradient(ellipse at center, var(--bg) 0 9%, color-mix(in srgb, var(--accent) 40%, var(--bg)) 38%, color-mix(in srgb, var(--accent) 32%, var(--surface)) 76%); }
.background-preview[data-preview="warp"]::before { inset: -70%; border: 1px solid color-mix(in srgb, var(--effect-accent-light) 72%, transparent); transform: rotate(45deg) scale(.65); box-shadow: 0 0 0 12px color-mix(in srgb, var(--accent) 16%, transparent), 0 0 0 26px color-mix(in srgb, var(--effect-accent-light) 17%, transparent), 0 0 0 45px color-mix(in srgb, var(--accent) 15%, transparent); }
.background-preview[data-preview="warp"]::after { background: repeating-conic-gradient(from 0deg at 50% 50%, transparent 0deg 28deg, color-mix(in srgb, var(--effect-accent-light) 62%, transparent) 28.5deg 29deg, transparent 30deg 58deg, color-mix(in srgb, var(--accent) 52%, transparent) 58.5deg 59deg, transparent 60deg); mask-image: radial-gradient(ellipse, transparent 0 7%, #000 13% 70%, transparent 78%); }
.background-preview[data-preview="plasma"] { background: conic-gradient(from 18deg at 50% 50%, #ff466a, #ffad49, #e8e55a, #4ce6a0, #43d3ea, #5579ff, #a04cff, #f240c4, #ff466a); }
.background-preview[data-preview="plasma"]::before { inset: -28%; background: radial-gradient(ellipse at 20% 35%, rgba(73,174,255,.82), transparent 43%), radial-gradient(ellipse at 78% 66%, rgba(255,79,179,.75), transparent 46%), radial-gradient(ellipse at 49% 52%, rgba(105,255,157,.42), transparent 48%); filter: blur(12px); mix-blend-mode: screen; }
.background-preview[data-preview="underwater"] {
  background: radial-gradient(ellipse at 50% -4%, color-mix(in srgb, var(--accent) 70%, var(--surface)), transparent 56%),
    linear-gradient(180deg, color-mix(in srgb, var(--accent) 32%, var(--bg)), var(--bg) 90%);
}
.background-preview[data-preview="underwater"]::before {
  background: repeating-conic-gradient(from 10deg at 51% 12%, transparent 0deg 8deg,
    color-mix(in srgb, var(--effect-accent-light) 42%, transparent) 8.5deg 9.4deg, transparent 10deg 17deg);
  mask-image: radial-gradient(ellipse at 52% 12%, #000, transparent 74%);
}
.background-preview[data-preview="underwater"]::after {
  background-image: radial-gradient(5px 5px at 17% 82%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 72%, transparent) 47% 60%, transparent 68%),
    radial-gradient(7px 7px at 43% 97%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 66%, transparent) 48% 58%, transparent 67%),
    radial-gradient(4px 4px at 76% 74%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 76%, transparent) 48% 60%, transparent 68%),
    radial-gradient(6px 6px at 89% 106%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 70%, transparent) 48% 59%, transparent 68%);
}
/* Light palettes get their own bright preview surfaces and deeper, readable effect lines. */
:root:not([data-theme^="dark-"]) .background-preview[data-preview="normal"] {
  background-color: color-mix(in srgb, var(--surface) 82%, var(--accent-soft));
  background-image: linear-gradient(135deg, color-mix(in srgb, var(--surface) 85%, var(--accent-soft)),
    color-mix(in srgb, var(--surface) 72%, var(--accent-soft)) 55%, color-mix(in srgb, var(--surface) 88%, var(--accent-soft)));
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="retro_grid"] {
  background-color: color-mix(in srgb, var(--surface) 82%, var(--accent-soft));
  background-image: radial-gradient(ellipse at 18% 25%, color-mix(in srgb, var(--accent) 19%, transparent), transparent 48%),
    radial-gradient(ellipse at 83% 25%, color-mix(in srgb, var(--accent) 16%, transparent), transparent 48%),
    linear-gradient(135deg, color-mix(in srgb, var(--surface) 88%, var(--accent-soft)), color-mix(in srgb, var(--surface) 75%, var(--accent-soft)));
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="retro_grid"]::before {
  background-image: linear-gradient(color-mix(in srgb, var(--accent-deep) 44%, transparent) 1px, transparent 1px),
    linear-gradient(90deg, color-mix(in srgb, var(--accent-deep) 38%, transparent) 1px, transparent 1px);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="retro_grid"]::after {
  background: linear-gradient(90deg, transparent, color-mix(in srgb, var(--accent-deep) 36%, transparent) 24%,
    color-mix(in srgb, var(--accent-deep) 52%, transparent) 50%, color-mix(in srgb, var(--accent-deep) 36%, transparent) 78%, transparent);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="starfield"] {
  background-color: color-mix(in srgb, var(--surface) 80%, var(--accent-soft));
  background-image: radial-gradient(ellipse at 12% 15%, color-mix(in srgb, var(--accent) 16%, transparent), transparent 54%),
    radial-gradient(ellipse at 88% 83%, color-mix(in srgb, var(--accent) 12%, transparent), transparent 55%),
    linear-gradient(145deg, color-mix(in srgb, var(--surface) 86%, var(--accent-soft)), color-mix(in srgb, var(--surface) 72%, var(--accent-soft)));
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="starfield"]::before {
  background-image: radial-gradient(1.2px 1.2px at 14% 30%, color-mix(in srgb, var(--accent-deep) 82%, transparent) 55%, transparent),
    radial-gradient(1px 1px at 74% 20%, color-mix(in srgb, var(--accent-deep) 72%, transparent) 55%, transparent),
    radial-gradient(1.4px 1.4px at 56% 72%, color-mix(in srgb, var(--accent-deep) 78%, transparent) 55%, transparent),
    radial-gradient(1px 1px at 88% 63%, color-mix(in srgb, var(--accent-deep) 74%, transparent) 55%, transparent),
    radial-gradient(1px 1px at 26% 82%, color-mix(in srgb, var(--accent-deep) 70%, transparent) 55%, transparent),
    radial-gradient(1.3px 1.3px at 44% 12%, color-mix(in srgb, var(--accent-deep) 84%, transparent) 55%, transparent);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="warp"] {
  background-color: color-mix(in srgb, var(--surface) 80%, var(--accent-soft));
  background-image: radial-gradient(ellipse at center, color-mix(in srgb, var(--surface) 96%, var(--accent-soft)) 0 9%,
    color-mix(in srgb, var(--surface) 73%, var(--accent-soft)) 38%, color-mix(in srgb, var(--surface) 66%, var(--accent-soft)) 76%);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="warp"]::before {
  border-color: color-mix(in srgb, var(--accent-deep) 45%, transparent);
  box-shadow: 0 0 0 12px color-mix(in srgb, var(--accent) 10%, transparent),
    0 0 0 26px color-mix(in srgb, var(--accent-deep) 13%, transparent), 0 0 0 45px color-mix(in srgb, var(--accent) 10%, transparent);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="warp"]::after {
  background: repeating-conic-gradient(from 0deg at 50% 50%, transparent 0deg 28deg,
    color-mix(in srgb, var(--accent-deep) 42%, transparent) 28.5deg 29deg, transparent 30deg 58deg,
    color-mix(in srgb, var(--accent) 35%, transparent) 58.5deg 59deg, transparent 60deg);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="underwater"] {
  background-color: color-mix(in srgb, var(--surface) 78%, var(--accent-soft));
  background-image: radial-gradient(ellipse at 50% -4%, color-mix(in srgb, var(--accent) 26%, transparent), transparent 56%),
    linear-gradient(180deg, color-mix(in srgb, var(--surface) 72%, var(--accent-soft)), color-mix(in srgb, var(--surface) 66%, var(--accent-soft)) 90%);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="underwater"]::before {
  background: repeating-conic-gradient(from 10deg at 51% 12%, transparent 0deg 8deg,
    color-mix(in srgb, var(--accent-deep) 34%, transparent) 8.5deg 9.4deg, transparent 10deg 17deg);
}
:root:not([data-theme^="dark-"]) .background-preview[data-preview="underwater"]::after {
  background-image: radial-gradient(5px 5px at 17% 82%, transparent 40%, color-mix(in srgb, var(--accent-deep) 60%, transparent) 47% 60%, transparent 68%),
    radial-gradient(7px 7px at 43% 97%, transparent 40%, color-mix(in srgb, var(--accent-deep) 55%, transparent) 48% 58%, transparent 67%),
    radial-gradient(4px 4px at 76% 74%, transparent 40%, color-mix(in srgb, var(--accent-deep) 65%, transparent) 48% 60%, transparent 68%);
}
.background-option-copy { display: grid; gap: 3px; min-width: 0; }
.background-option-title { display: flex; align-items: center; justify-content: space-between; gap: 8px; font-size: 11px; font-weight: 750; }
.background-option-state { color: var(--accent-deep); font-size: 9px; font-weight: 700; white-space: nowrap; }
.background-option-requirement { margin: 0; color: var(--muted); font-size: 9px; line-height: 1.45; }
.background-progress-row { display: flex; align-items: center; gap: 8px; margin-top: 2px; }
.background-progress-row[hidden] { display: none !important; }
.background-progress-row progress { display: block; width: 100%; height: 5px; overflow: hidden; border: 0; border-radius: 999px; background: var(--surface-soft); accent-color: var(--accent); }
.background-progress-row progress::-webkit-progress-bar { border-radius: 999px; background: var(--surface-soft); }
.background-progress-row progress::-webkit-progress-value { border-radius: 999px; background: linear-gradient(90deg, var(--accent), color-mix(in srgb, var(--accent) 58%, #81d6ff)); }
.background-progress-row progress::-moz-progress-bar { border-radius: 999px; background: var(--accent); }
.background-progress-label { flex: 0 0 auto; color: var(--muted); font-size: 9px; font-variant-numeric: tabular-nums; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="retro_grid"]::before { animation: preview-grid-drift 7s linear infinite; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="starfield"]::before { animation: preview-stars-pan 20s linear infinite; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="warp"]::before { animation: preview-warp-pulse 7s ease-in-out infinite alternate; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="plasma"]::before { animation: preview-plasma-flow 10s ease-in-out infinite alternate; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="underwater"]::before { animation: preview-water-caustics 11s ease-in-out infinite alternate; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="underwater"]::after { animation: preview-water-bubbles 8s ease-in-out infinite alternate; }
@keyframes preview-grid-drift { to { background-position: 0 14px, 0 0; } }
@keyframes preview-stars-pan { to { background-position: 65px 54px, 0 72px, 81px 0, 0 59px; } }
@keyframes preview-warp-pulse { to { transform: rotate(45deg) scale(.67); opacity: .68; } }
@keyframes preview-plasma-flow { to { transform: translate3d(4%, -3%, 0) scale(1.07); } }
@keyframes preview-water-caustics { to { transform: translate3d(2%, 1%, 0) rotate(3deg) scale(1.05); } }
@keyframes preview-water-bubbles { to { transform: translateY(-4px); opacity: .65; } }
.background-preview[data-preview="plasma"]::after { inset: -32%; opacity: .48; background: conic-gradient(from 10deg at 50% 50%, transparent 0 10%, rgba(255,255,255,.52) 12%, transparent 17% 37%, rgba(255,255,255,.36) 39%, transparent 44% 72%, rgba(255,255,255,.46) 74%, transparent 80%); filter: blur(7px); mix-blend-mode: screen; }
html[data-background-motion="running"] .background-preview.is-visible[data-preview="plasma"]::after { animation: preview-plasma-orbit 12s linear infinite; }
@keyframes preview-plasma-orbit { to { transform: rotate(1turn); } }

/* Let the selected effect softly show through the app's panels without washing out text. */
.view .card {
  background-color: color-mix(in srgb, var(--surface) 86%, transparent);
  backdrop-filter: blur(9px) saturate(1.12);
  -webkit-backdrop-filter: blur(9px) saturate(1.12);
}
:root:not([data-theme^="dark-"]) .view .card {
  background: linear-gradient(105deg,
    color-mix(in srgb, var(--surface) 74%, transparent) 0%,
    color-mix(in srgb, var(--accent) 2%, color-mix(in srgb, var(--surface) 72%, transparent)) 52%,
    color-mix(in srgb, var(--accent) 3%, color-mix(in srgb, var(--surface) 70%, transparent)) 100%);
  backdrop-filter: blur(11px) saturate(1.16);
  -webkit-backdrop-filter: blur(11px) saturate(1.16);
}
.live-card, .week-nav, .day-tabs, .lesson-card {
  background: linear-gradient(105deg,
    color-mix(in srgb, var(--surface) 89%, transparent) 0%,
    color-mix(in srgb, var(--accent) 5%, color-mix(in srgb, var(--surface) 86%, transparent)) 52%,
    color-mix(in srgb, var(--accent) 13%, color-mix(in srgb, var(--surface) 82%, transparent)) 100%);
  backdrop-filter: blur(8px) saturate(1.1);
  -webkit-backdrop-filter: blur(8px) saturate(1.1);
}
:root:not([data-theme^="dark-"]) .live-card,
:root:not([data-theme^="dark-"]) .week-nav,
:root:not([data-theme^="dark-"]) .day-tabs,
:root:not([data-theme^="dark-"]) .lesson-card {
  background: linear-gradient(105deg,
    color-mix(in srgb, var(--surface) 76%, transparent) 0%,
    color-mix(in srgb, var(--accent) 2%, color-mix(in srgb, var(--surface) 74%, transparent)) 52%,
    color-mix(in srgb, var(--accent) 3%, color-mix(in srgb, var(--surface) 72%, transparent)) 100%);
  backdrop-filter: blur(10px) saturate(1.14);
  -webkit-backdrop-filter: blur(10px) saturate(1.14);
}
:root:not([data-theme^="dark-"]) .background-disclosure,
:root:not([data-theme^="dark-"]) .background-motion-control,
:root:not([data-theme^="dark-"]) .background-option {
  background-color: color-mix(in srgb, var(--surface) 86%, transparent);
  backdrop-filter: blur(10px) saturate(1.14);
  -webkit-backdrop-filter: blur(10px) saturate(1.14);
}
.lesson-card.current::before { background: var(--accent); }
.lesson-card.current::after { display: none; }
:root:not([data-theme^="dark-"]) .bottom-nav { background: color-mix(in srgb, var(--surface) 86%, transparent); }
.bottom-nav {
  background: color-mix(in srgb, var(--nav-bg) 95%, transparent);
  backdrop-filter: blur(14px) saturate(1.16);
  -webkit-backdrop-filter: blur(14px) saturate(1.16);
}
.notification-shortcut {
  border: 1px solid var(--line);
  background: color-mix(in srgb, var(--surface) 86%, transparent);
  box-shadow: 0 2px 9px rgba(24, 30, 44, .08);
}
.notification-shortcut:hover { background: color-mix(in srgb, var(--surface) 95%, transparent); }
.bottom-nav .nav-button { border: 1px solid transparent; }
.bottom-nav .nav-button.active {
  border-color: var(--accent-line);
  background: color-mix(in srgb, var(--accent-soft) 90%, var(--surface));
  box-shadow: inset 0 1px 0 rgba(255,255,255,.28);
}

.background-unlock-dialog {
  inset: 0; width: min(calc(100% - 28px), 540px); max-height: min(calc(100dvh - 28px), 680px);
  margin: auto; padding: 24px; border: 1px solid var(--line); border-radius: 24px;
  box-shadow: 0 16px 48px rgba(0,0,0,.24); text-align: center;
}
.background-unlock-dialog .sheet-heading { text-align: left; }
.background-unlock-preview { height: 108px; margin: 14px 0; overflow: hidden; border: 1px solid var(--line); border-radius: 14px; background: radial-gradient(ellipse at 25% 20%, rgba(82,111,242,.5), transparent 44%), radial-gradient(ellipse at 78% 70%, rgba(194,86,220,.42), transparent 42%), #111421; }
.background-unlock-preview-underwater {
  position: relative; isolation: isolate;
  background: radial-gradient(ellipse at 50% 0%, color-mix(in srgb, var(--effect-accent-light) 72%, var(--surface)), transparent 58%),
    radial-gradient(ellipse at 15% 70%, color-mix(in srgb, var(--accent) 52%, var(--bg)), transparent 58%),
    linear-gradient(180deg, color-mix(in srgb, var(--accent) 56%, var(--bg)), var(--bg) 90%);
}
.background-unlock-preview-underwater::before,
.background-unlock-preview-underwater::after { position: absolute; inset: 0; content: ""; pointer-events: none; }
.background-unlock-preview-underwater::before {
  inset: -18% -6%; opacity: .6;
  background: repeating-conic-gradient(from 18deg at 50% -8%, transparent 0deg 7deg,
    color-mix(in srgb, var(--effect-accent-light) 66%, white) 7.5deg 8deg, transparent 8.5deg 15deg),
    radial-gradient(ellipse at 50% 0%, color-mix(in srgb, var(--effect-accent-light) 56%, transparent), transparent 62%);
  mask-image: linear-gradient(to bottom, #000 4%, transparent 88%);
  animation: unlock-water-shimmer 8s ease-in-out infinite alternate;
}
.background-unlock-preview-underwater::after {
  opacity: .78;
  background-image:
    radial-gradient(7px 7px at 14% 75%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 88%, white) 50% 58%, transparent 68%),
    radial-gradient(5px 5px at 31% 57%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 84%, white) 50% 58%, transparent 68%),
    radial-gradient(9px 9px at 52% 83%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 82%, white) 50% 58%, transparent 68%),
    radial-gradient(6px 6px at 77% 62%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 88%, white) 50% 58%, transparent 68%),
    radial-gradient(4px 4px at 89% 80%, transparent 40%, color-mix(in srgb, var(--effect-accent-light) 86%, white) 50% 58%, transparent 68%);
}
@keyframes unlock-water-shimmer { to { transform: translate3d(1%, 3%, 0); } }
.background-unlock-dialog > button { width: 100%; margin-top: 8px; }
.background-unlock-dialog > button:first-of-type { margin-top: 0; }
.background-unlock-dialog::backdrop { background: rgba(6,8,17,.62); backdrop-filter: blur(4px); }
:root:not([data-theme^="dark-"]) .background-unlock-preview-underwater { background: radial-gradient(ellipse at 50% 0%, color-mix(in srgb, var(--accent) 26%, var(--surface)), transparent 58%), linear-gradient(180deg, var(--bg), color-mix(in srgb, var(--accent-deep) 38%, var(--bg)) 90%); }
:root:not([data-theme^="dark-"]) .background-unlock-preview-underwater::before { opacity: .48; }

/* Keep native sheets legible while letting the selected effect show through their edges. */
dialog.sheet { background-color: color-mix(in srgb, var(--surface) 88%, transparent); backdrop-filter: blur(14px) saturate(1.12); -webkit-backdrop-filter: blur(14px) saturate(1.12); }
:root:not([data-theme^="dark-"]) dialog.sheet { background-color: color-mix(in srgb, var(--surface) 62%, transparent); }
dialog.sheet::backdrop { background: rgba(8,10,18,.54); backdrop-filter: blur(2px); }
#background-layer[data-motion="paused"] *,
#background-layer[data-motion="paused"] .background-retro-grid::before,
#background-layer[data-motion="paused"] .retro-road > i::after,
#background-layer[data-motion="paused"] .retro-road-center,
#background-layer[data-motion="paused"] .warp-tunnel,
#background-layer[data-motion="paused"] .warp-beams,
#background-layer[data-motion="paused"] .warp-beams i::before,
#background-layer[data-motion="paused"] .warp-beams i::after,
#background-layer[data-motion="paused"] .background-plasma i,
#background-layer[data-motion="paused"] .background-underwater *,
html[data-background-motion="paused"] .background-preview::before,
html[data-background-motion="paused"] .background-preview::after,
html[data-background-motion="paused"] .background-preview.is-visible[data-preview="plasma"] { animation-play-state: paused !important; }
html[data-background-motion="paused"] .background-preview.is-visible[data-preview="underwater"]::before,
html[data-background-motion="paused"] .background-preview.is-visible[data-preview="underwater"]::after { animation-play-state: paused !important; }
@media (prefers-reduced-motion: reduce) {
  #background-layer *, #background-layer *::before, #background-layer *::after,
  .background-preview, .background-preview::before, .background-preview::after { animation: none !important; transition: none !important; }
}
@media (max-width: 355px) {
  .background-option { padding: 7px; }
  .background-preview { height: 58px; }
  .background-option-title { font-size: 10px; }
}

/* Alpha surfaces preserve the glass effect without re-blurring moving pixels
   beneath every nested card on every animation frame. */
.view .card, :root:not([data-theme^="dark-"]) .view .card,
.live-card, .week-nav, .day-tabs, .lesson-card, .bottom-nav,
.background-option, .background-disclosure, .background-motion-control,
:root:not([data-theme^="dark-"]) .background-option,
:root:not([data-theme^="dark-"]) .background-disclosure,
:root:not([data-theme^="dark-"]) .background-motion-control,
:root:not([data-theme^="dark-"]) .live-card,
:root:not([data-theme^="dark-"]) .week-nav,
:root:not([data-theme^="dark-"]) .day-tabs,
:root:not([data-theme^="dark-"]) .lesson-card,
:root:not([data-theme^="dark-"]) .bottom-nav {
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

/* Light palettes need ink-toned detail, not white neon over a white page. */
:root:not([data-theme^="dark-"]) #background-layer {
  --effect-accent-light: var(--accent-deep);
}
:root:not([data-theme^="dark-"]) .background-retro-grid::before {
  background-image: linear-gradient(color-mix(in srgb, var(--accent-deep) 66%, transparent) 1.3px, transparent 1.3px),
    linear-gradient(90deg, color-mix(in srgb, var(--accent-deep) 60%, transparent) 1.3px, transparent 1.3px);
}
:root:not([data-theme^="dark-"]) .background-retro-grid::after { filter: none; }
:root:not([data-theme^="dark-"]) .warp-beams > i:nth-child(n) {
  --beam-color: color-mix(in srgb, var(--warp-hue, var(--accent-deep)) 74%, var(--accent-deep));
  background: linear-gradient(to bottom, color-mix(in srgb, var(--beam-color) 78%, transparent),
    color-mix(in srgb, var(--beam-color) 70%, transparent) 27%,
    color-mix(in srgb, var(--beam-color) 24%, transparent) 76%, transparent);
}
.warp-beams > i:nth-child(3n + 1) { --warp-hue: #197e98; }
.warp-beams > i:nth-child(3n + 2) { --warp-hue: #aa356b; }
.warp-beams > i:nth-child(3n) { --warp-hue: #6550b2; }
:root:not([data-theme^="dark-"]) .warp-beams i::after {
  width: 12px; height: 12px;
  background: radial-gradient(circle, var(--text) 0 16%, var(--beam-color) 22% 44%,
    color-mix(in srgb, var(--beam-color) 36%, transparent) 58%, transparent 78%);
}
:root:not([data-theme^="dark-"]) .warp-tunnel i:nth-child(n) { border-color: color-mix(in srgb, var(--accent-deep) 52%, transparent); }
:root:not([data-theme^="dark-"]) .background-warp {
  background: radial-gradient(ellipse at center, color-mix(in srgb, var(--accent-deep) 16%, transparent), transparent 58%);
}
:root:not([data-theme^="dark-"]) .underwater-caustics {
  opacity: .42;
  filter: blur(2px);
  background: repeating-conic-gradient(from 18deg at 53% 34%, transparent 0deg 6deg,
    color-mix(in srgb, var(--accent-deep) 34%, transparent) 6.4deg 7deg, transparent 7.5deg 14deg);
}
:root:not([data-theme^="dark-"]) .underwater-rays i {
  filter: blur(4px);
  background: linear-gradient(180deg, color-mix(in srgb, var(--accent-deep) 44%, transparent),
    color-mix(in srgb, var(--accent-deep) 22%, transparent) 46%, transparent 88%);
}
:root:not([data-theme^="dark-"]) .underwater-bubbles i {
  border: 1.5px solid color-mix(in srgb, var(--accent-deep) 90%, transparent);
  box-shadow: inset 1px 1px 2px color-mix(in srgb, var(--surface) 76%, transparent);
}

/* Keep the complete group code readable; move it below the title on tiny screens. */
.app-header .context-line { flex: 0 0 auto; max-width: none; }
.app-header .context-line strong { overflow: visible; text-overflow: clip; }
.bottom-nav { container-type: inline-size; width: min(calc(100% - 4px), 580px); gap: 0; padding: 4px; }
.bottom-nav .nav-button { grid-template-columns: minmax(0, 1fr); }
.bottom-nav .nav-button small {
  width: 100%; min-width: 0; text-align: center;
  font-size: clamp(9px, 2.9cqw, 13px); line-height: 1.25;
  letter-spacing: -.025em;
}
.bottom-nav:has(#admin-nav:not([hidden])) .nav-button small { font-size: clamp(8px, 2.5cqw, 12px); letter-spacing: -.04em; }
.bottom-nav:has(#admin-nav:not([hidden])) .nav-button { padding-inline: 0; }
.bottom-nav:has(#admin-nav:not([hidden])) { grid-template-columns: repeat(5, minmax(0, 1fr)); }

/* Theme-coloured framing separates the background chooser from its artwork. */
:root:not([data-theme^="dark-"]) .background-disclosure {
  background-color: color-mix(in srgb, var(--surface) 48%, transparent);
}
:root:not([data-theme^="dark-"]) .background-option {
  background: color-mix(in srgb, var(--accent-soft) 48%, var(--surface));
  border-color: color-mix(in srgb, var(--accent) 38%, var(--surface));
  box-shadow: 0 2px 7px color-mix(in srgb, var(--accent-deep) 8%, transparent);
}
:root:not([data-theme^="dark-"]) .background-option[aria-pressed="true"] {
  background: color-mix(in srgb, var(--accent-soft) 78%, var(--surface));
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
}
.background-preview { border: 1px solid color-mix(in srgb, var(--accent) 20%, transparent); }
.lesson-edited-badge {
  display: inline-flex; align-items: center; justify-self: start; grid-column: 1; grid-row: 3;
  width: fit-content; max-width: 100%; margin: 0; padding: 3px 7px;
  border: 1px solid var(--accent-line); border-radius: 6px;
  background: var(--accent-soft); color: var(--accent-deep);
  font-size: calc(9px * var(--type-scale)); font-weight: 650; line-height: 1.4;
}
.lesson-notices { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; grid-column: 1; grid-row: 3; }
.lesson-notices .lesson-override, .lesson-notices .lesson-status { margin: 0; }
.notification-delete { margin-top: 10px; }
.notification-body .notification-attachment { white-space: normal; overflow-wrap: anywhere; }
#preview-button {
  background: var(--button-bg); color: var(--button-text);
  border-color: var(--accent-line); box-shadow: 0 2px 8px rgba(0,0,0,.08);
}
@media (max-width: 380px) {
  .app-header { flex-wrap: wrap; }
  .app-header-title { flex: 1 1 calc(100% - 68px); }
  .app-header .context-line { margin-left: auto; }
}

/* Small screens keep the same scenes with fewer moving, full-screen layers. */
@media (max-width: 600px) {
  #background-layer[data-background="underwater"] .underwater-caustics {
    inset: 0; opacity: .24; will-change: auto; animation: none !important;
    background: radial-gradient(ellipse at 50% 0%, color-mix(in srgb, var(--effect-accent-light) 38%, transparent), transparent 56%);
    mask-image: none;
  }
  #background-layer[data-background="underwater"] .underwater-rays i {
    top: -8vh; width: 27vw; height: 100vh; filter: none; mask-image: none;
    background: radial-gradient(ellipse 50% 85% at 50% 0%, color-mix(in srgb, var(--effect-accent-light) 30%, transparent), transparent 100%);
  }
  #background-layer[data-background="underwater"] .underwater-rays i:nth-child(n+4),
  #background-layer[data-background="underwater"] .underwater-bubbles i:nth-child(n+5),
  #background-layer[data-background="warp"] .warp-beams i:nth-child(n+7),
  #background-layer[data-background="warp"] .warp-tunnel i:nth-child(n+5),
  #background-layer[data-background="plasma"] .background-plasma i:nth-child(3) { display: none; }
  #background-layer[data-background="underwater"] .underwater-bubbles i { box-shadow: none; }
  html[data-background-motion="running"] .background-preview.is-visible::before,
  html[data-background-motion="running"] .background-preview.is-visible::after { animation: none !important; }
}