.sfb-root {
  --sfb-card-top: #faf9f4;
  --sfb-card-bottom: #efeee9;
  --sfb-card-ink: #20221f;
  --sfb-card-stroke: #858784;
  --sfb-card-hinge: #2a2b29;
  --sfb-card-radius: 1px;
  --sfb-card-weight: 700;
  display: block;
  width: 100%;
  min-width: 0;
  color: #20221f;
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
}

.sfb-root,
.sfb-root *,
.sfb-root *::before,
.sfb-root *::after {
  box-sizing: border-box;
}

.sfb-board {
  position: relative;
  width: 100%;
  aspect-ratio: var(--sfb-board-ratio, 1.75);
  overflow: hidden;
  border: 1px solid #aeb1ad;
  border-radius: 2px;
  background: linear-gradient(145deg, #d9dad7 0%, #c8cac6 54%, #b9bcb7 100%);
  box-shadow:
    inset 0 0 0 clamp(2px, 0.32vw, 4px) rgba(255, 255, 255, 0.48),
    inset 0 0 20px rgba(47, 51, 47, 0.18),
    0 24px 58px rgba(0, 0, 0, 0.24);
}

.sfb-grid {
  position: absolute;
  top: 50%;
  left: 50%;
  display: grid;
  width: var(--sfb-grid-width, 80%);
  height: var(--sfb-grid-height, 70%);
  grid-template-columns: repeat(var(--sfb-columns, 20), var(--sfb-bit-width, 1fr));
  grid-template-rows: repeat(var(--sfb-rows, 4), var(--sfb-bit-height, auto));
  gap: var(--sfb-row-gap, 7px) var(--sfb-column-gap, 3px);
  transform: translate(-50%, -50%);
  visibility: hidden;
}

.sfb-grid.sfb-ready {
  visibility: visible;
}

.sfb-bit {
  position: relative;
  width: var(--sfb-bit-width);
  height: var(--sfb-bit-height);
  border: 0;
  border-radius: var(--sfb-card-radius, 1px);
  background: var(--sfb-card-bottom, #efeee9);
  box-shadow:
    inset 0 0 0 var(--sfb-bit-stroke, 1px) var(--sfb-card-stroke, #858784),
    inset 0 1px 0 rgba(255, 255, 255, 0.35),
    0 1px 0 rgba(255, 255, 255, 0.45),
    0 3px 4px rgba(18, 20, 18, 0.25),
    0 7px 12px rgba(18, 20, 18, 0.1);
  perspective: 250px;
  transform-style: preserve-3d;
}

.sfb-bit::after {
  position: absolute;
  z-index: 8;
  top: 50%;
  right: -1px;
  left: -1px;
  height: 1px;
  background: var(--sfb-card-hinge, #2a2b29);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
  content: "";
  pointer-events: none;
}

.sfb-half {
  position: absolute;
  left: 0;
  width: 100%;
  height: 50%;
  overflow: hidden;
  backface-visibility: hidden;
  color: var(--sfb-card-ink, #20221f);
}

.sfb-top {
  top: 0;
  border-radius: var(--sfb-card-radius, 1px) var(--sfb-card-radius, 1px) 0 0;
  background:
    linear-gradient(rgba(255, 255, 255, 0.12), rgba(255, 255, 255, 0)),
    var(--sfb-card-top, #faf9f4);
}

.sfb-bottom {
  bottom: 0;
  border-radius: 0 0 var(--sfb-card-radius, 1px) var(--sfb-card-radius, 1px);
  background:
    linear-gradient(rgba(255, 255, 255, 0.05), rgba(0, 0, 0, 0.05)),
    var(--sfb-card-bottom, #efeee9);
}

.sfb-half[data-bit-color] {
  background: var(--sfb-solid-bit-color);
}

.sfb-glyph {
  position: absolute;
  left: 0;
  display: grid;
  width: 100%;
  height: 200%;
  place-items: center;
  color: var(--sfb-card-ink, #20221f);
  font-family: "Arial Narrow", "Helvetica Neue", Arial, sans-serif;
  font-size: var(--sfb-glyph-size, 1rem);
  font-weight: var(--sfb-card-weight, 700);
  line-height: 1;
}

.sfb-glyph.sfb-emoji {
  font-family: "Apple Color Emoji", "Segoe UI Emoji", sans-serif;
  font-size: calc(var(--sfb-glyph-size, 1rem) * 0.78);
  font-weight: 400;
}

.sfb-top .sfb-glyph {
  top: 0;
}

.sfb-bottom .sfb-glyph {
  top: -100%;
}

.sfb-flap-out,
.sfb-flap-in {
  z-index: 5;
  visibility: hidden;
  will-change: transform, filter;
}

.sfb-flap-out {
  transform-origin: center bottom;
}

.sfb-flap-in {
  transform: rotateX(90deg);
  transform-origin: center top;
}

.sfb-flap-out.sfb-reverse {
  transform-origin: center top;
}

.sfb-flap-in.sfb-reverse {
  transform: rotateX(-90deg);
  transform-origin: center bottom;
}

.sfb-bit.sfb-flipping .sfb-flap-out,
.sfb-bit.sfb-flipping .sfb-flap-in {
  visibility: visible;
}

@media (prefers-reduced-motion: reduce) {
  .sfb-root[data-respect-reduced-motion="true"] .sfb-flap-out,
  .sfb-root[data-respect-reduced-motion="true"] .sfb-flap-in {
    will-change: auto;
  }
}