/* Confidential folder: a dark sleeve with a thumb cut on its right edge and a cream letter peeking out behind it.
   Click: the letter slides out to the right (still behind the sleeve), swings back over the cover to land in front,
   then flips over with a 4deg cant. Click again: it flips back, slides out to the side and tucks itself in.
   Rewritten from useLayouts "Confidential Folder" (MIT, (c) 2025 Urvish Mali). Phases, transforms, curves and
   timings are the source's; content and cover art are ours. */
.cfolder {
  --cf-w: 320px;                     /* folder width; height follows 320:400 */
  --cf-k: 1;                         /* set by part.js: width / 320 (scales the thumb cut) */
  --cf-sleeve: oklch(.26 .01 260);
  --cf-paper: oklch(.962 .014 95);
  --cf-rule: oklch(.28 .02 95 / .14);
  --cf-ink: oklch(.24 .02 95);
  --cf-ink-soft: oklch(.42 .02 95);
  --cf-cover-ink: oklch(.94 .01 260);
  --cf-cover-soft: oklch(.68 .01 260);
  --cf-radius: 22px;                 /* sleeve */
  --cf-letter-radius: 18px;
  --cf-tuck: 15.6028%;               /* resting peek: 44px of a 282px letter */
  --cf-peek: 23.4043%;               /* hover peek: 66px */
  --cf-out: 117.0213%;               /* fully out to the side: 330px */
  --cf-lift: 36px;                   /* translateZ of the landed letter */
  --cf-land-scale: 1.05;
  --cf-cant: -4deg;                  /* turn of the revealed letter */
  --cf-tilt-ease: cubic-bezier(.32, .72, 0, 1);   /* 150ms hover tilt */

  position: relative;
  width: var(--cf-w);
  max-width: 100%;
  aspect-ratio: 320 / 400;
  perspective: 2000px;
  transform-style: preserve-3d;
  transition: transform 150ms var(--cf-tilt-ease);
  cursor: pointer;
  overflow: visible;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  outline: none;
}
.cfolder:focus-visible { outline: 2px solid rgb(255 255 255 / .7); outline-offset: 2px; border-radius: var(--cf-radius); }
.cfolder.is-front { z-index: 999; }

.cfolder__back {
  position: absolute; inset: 0; z-index: 1;
  border-radius: var(--cf-radius);
  overflow: hidden;
  background: var(--cf-sleeve);
  transform: translate3d(0, 0, 0);
  box-shadow: 0 0 0 1px rgb(255 255 255 / .08), 0 16px 32px -12px rgb(0 0 0 / .35);
  transition: box-shadow 150ms ease-out;
}
.cfolder.is-hover .cfolder__back { box-shadow: 0 0 0 1px rgb(255 255 255 / .1), 0 22px 44px -14px rgb(0 0 0 / .42); }
.cfolder.is-front .cfolder__back { box-shadow: 0 0 0 1px rgb(255 255 255 / .08), 0 28px 56px -16px rgb(0 0 0 / .5); }

/* the letter: 282 x 354 inside 320 x 400, inset 19 / 23 */
.cfolder__letter {
  position: absolute; z-index: 3;
  left: 5.9375%; top: 5.75%; width: 88.125%; height: 88.5%;
  border-radius: var(--cf-letter-radius);
  background: var(--cf-paper);
  transform-style: preserve-3d;
  transform: translate3d(var(--cf-tuck), 0, 2px) scale(.96) rotate(0deg) rotateY(0deg);
  transition: transform .35s cubic-bezier(.34, 1.3, .64, 1);
  box-shadow: 0 0 0 1px rgb(0 0 0 / .06), 0 2px 6px rgb(0 0 0 / .08);
}
.cfolder.is-hover[data-phase="tucked"] .cfolder__letter { transform: translate3d(var(--cf-peek), 0, 2px) scale(.97) rotate(0deg) rotateY(0deg); }
.cfolder[data-phase="extracting"] .cfolder__letter {
  transform: translate3d(var(--cf-out), -2px, 4px) scale(1) rotate(1deg) rotateY(0deg);
  transition: transform .42s cubic-bezier(.2, .85, .35, 1.15);
}
.cfolder[data-phase="landing"] .cfolder__letter {
  transform: translate3d(0, -2px, var(--cf-lift)) scale(var(--cf-land-scale)) rotate(0deg) rotateY(0deg);
  transition: transform .38s cubic-bezier(.2, .9, .35, 1.1);
}
.cfolder[data-phase="revealed"] .cfolder__letter {
  transform: translate3d(0, -2px, var(--cf-lift)) scale(var(--cf-land-scale)) rotate(var(--cf-cant)) rotateY(180deg);
  transition: transform .65s cubic-bezier(.34, 1.35, .64, 1), box-shadow .65s ease;
}
.cfolder[data-phase="unflipping"] .cfolder__letter {
  transform: translate3d(0, -2px, var(--cf-lift)) scale(var(--cf-land-scale)) rotate(0deg) rotateY(0deg);
  transition: transform .52s cubic-bezier(.34, 1.25, .64, 1), box-shadow .52s ease;
}
.cfolder[data-phase="aligning_side"] .cfolder__letter {
  transform: translate3d(var(--cf-out), -2px, 4px) scale(1) rotate(0deg) rotateY(0deg);
  transition: transform .35s cubic-bezier(.2, .85, .35, 1.15);
}
.cfolder[data-phase="sliding_in"] .cfolder__letter {
  transform: translate3d(var(--cf-tuck), 0, 2px) scale(.96) rotate(0deg) rotateY(0deg);
  transition: transform .42s cubic-bezier(.2, .85, .35, 1.15);
}
.cfolder.is-front .cfolder__letter { z-index: 999; box-shadow: 0 0 0 1px rgb(0 0 0 / .08), 0 24px 48px -12px rgb(0 0 0 / .35); }

.cfolder__face {
  position: absolute; inset: 0;
  overflow: hidden;
  border-radius: var(--cf-letter-radius);
  background: var(--cf-paper);
  color: var(--cf-ink);
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  transform: rotateY(0deg) translateZ(1px);
}
.cfolder__face--back { transform: rotateY(180deg) translateZ(1px); }

/* the cover: same sleeve colour, in front (translateZ 8px), with a round thumb cut on the right edge */
.cfolder__cover {
  --cf-cut: radial-gradient(circle calc(18px * var(--cf-k)) at 100% 50%, transparent calc(16.5px * var(--cf-k)), #000 calc(17.5px * var(--cf-k)));
  position: absolute; inset: 0; z-index: 10;
  overflow: hidden;
  pointer-events: none;
  border-radius: var(--cf-radius);
  background: var(--cf-sleeve);
  color: var(--cf-cover-ink);
  transform: translate3d(0, 0, 8px);
  box-shadow: inset 0 1px 0 rgb(255 255 255 / .06);
  -webkit-mask-image: var(--cf-cut);
  mask-image: var(--cf-cut);
}

@media (prefers-reduced-motion: reduce) {
  .cfolder, .cfolder__back, .cfolder .cfolder__letter { transition: none !important; }
}