/* Frisson lesson. All rules scoped under .fr-* */
.fr-track { display: flex; flex-direction: column; gap: 8px; }
.fr-fig { position: relative; border-radius: 16px; background: var(--surface); border: 1px solid var(--line); padding: 6px 4px 4px; }
.fr-svg { display: block; width: 100%; height: auto; overflow: visible; }
.fr-ax { fill: var(--faint); font: 700 11px var(--sans); letter-spacing: .08em; text-transform: uppercase; }
.fr-base { stroke: var(--line-strong); stroke-width: 1; stroke-dasharray: 3 3; }
.fr-curve { fill: none; stroke: var(--violet-bright); stroke-width: 2.4; stroke-linejoin: round; stroke-linecap: round; filter: drop-shadow(0 0 4px rgba(169,155,255,.55)); }
.fr-ghost { fill: none; stroke: var(--dim); stroke-width: 1.4; stroke-dasharray: 3 3; opacity: .55; }
.fr-seg rect { fill: var(--raised); stroke: var(--line); }
.fr-seg.hold rect { fill: #262046; }
.fr-seg.arr rect { fill: #2c2413; stroke: rgba(252,192,80,.35); }
.fr-seg .n { fill: var(--text); font: 700 11.5px var(--sans); }
.fr-seg rect, .fr-seg text { transition: x .15s, width .15s; }
.fr-head { stroke: #fff; stroke-width: 1.5; opacity: 0; }
.fr-lane { fill: var(--bg); stroke: var(--line); }
.fr-na { fill: var(--gold); }
.fr-cd, .fr-na { filter: drop-shadow(0 0 3px rgba(252,192,80,.5)); }
.fr-ln { fill: var(--text); font: 700 11px var(--sans); letter-spacing: .02em; paint-order: stroke; stroke: rgba(10,14,26,.8); stroke-width: 2.5px; }
.fr-chill { opacity: 0; transform-box: fill-box; }
.fr-chill circle { fill: var(--gold); }
.fr-chill path { stroke: var(--gold); stroke-width: 2; stroke-linecap: round; }
.fr-chill text { fill: var(--gold); font: 800 11px var(--sans); letter-spacing: .08em; text-transform: uppercase; }
.fr-chill.on { opacity: 1; animation: frPop .5s cubic-bezier(.34,1.56,.64,1) both; }
@keyframes frPop { from { opacity: 0; } 40% { opacity: 1; } }
.fr-track .gauge .gt i { transition: none; }
.fr-sp .gt i { background: var(--gold); }
.fr-cap { font-size: 12px; line-height: 1.35; color: var(--dim); }

.fr-body .gt i { transition: width .35s cubic-bezier(.2,.8,.2,1); }
.fr-body.up .gt i { background: var(--gold); box-shadow: 0 0 8px rgba(252,192,80,.5); }
.fr-exp { display: flex; flex-direction: column; gap: 6px; }
.fr-e { display: flex; justify-content: space-between; align-items: center; gap: 8px; padding: 8px 12px; border-radius: 12px; background: var(--surface); border: 1px solid var(--line); font-size: 13px; transition: border-color .3s, background .3s; }
.fr-e span { color: var(--dim); font-weight: 600; }
.fr-e b { font: 600 13px var(--mono); color: var(--text); white-space: nowrap; }
.fr-exp.hit .rule { border-color: var(--gold); background: #2c2413; }
.fr-exp.hit .rule b { color: var(--gold); }
.fr-exp.hit .mem b { color: var(--faint); }

/* tappable segments over the track */
.fr-zone { position: absolute; border-radius: 10px; border: 1.5px dashed rgba(169,155,255,.55); background: rgba(123,92,253,.08); transition: background .2s, border-color .2s, opacity .3s; }
.fr-zone:active { background: rgba(123,92,253,.2); }
.fr-zone.right { border: 2px solid var(--mint); background: rgba(63,214,154,.14); }
.fr-zone.wrong { border: 2px solid var(--red); background: rgba(216,85,85,.14); }
.fr-zone.off { opacity: .25; }
.fr-zone.locked { pointer-events: none; }

@media (max-height: 700px) {
  .fr-track { gap: 6px; }
  .fr-cap { font-size: 12px; }
}