* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  overflow-x: hidden;
  background: white;
}

body {
  padding: 4px;
}

/* ===== GRID ===== */

.coins {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(90px, 1fr));
  grid-auto-rows: 60px;
  grid-auto-flow: dense;
  gap: 4px;
  width: 100%;
  align-items: stretch;
}

/* ===== CARDS ===== */

.coin {
  --card-radius: 3px;

  position: relative !important;
  overflow: visible !important;
  transform-origin: var(--origin-x, center) var(--origin-y, center);
  transition: transform 0.2s ease;
}

.coin.big {
  grid-column: span 4;
  grid-row: span 4;
}

.coin.medium {
  grid-column: span 2;
  grid-row: span 2;
}

.coin.small {
  grid-column: span 1;
  grid-row: span 1;
}

/* ===== DESKTOP HOVER SCALE ===== */

.coin.big.active-hover {
  transform: scale(1.25) !important;
  --card-radius: 6px;
}

.coin.medium.active-hover {
  transform: scale(2.5) !important;
  --card-radius: 3px;
}

.coin.small.active-hover {
  transform: scale(5) !important;
  --card-radius: 1.5px;
}

.coin.active-hover {
  z-index: 9999 !important;
}

.coin.active-hover .flip-inner {
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.4) !important;
}

/* ===== FLIP CARD ===== */

.flip-inner {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s ease;
  border-radius: var(--card-radius) !important;
}

.coin.flipped .flip-inner {
  transform: rotateY(180deg);
}

.flip-front,
.flip-back {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border-radius: var(--card-radius) !important;
  overflow: hidden !important;
  backface-visibility: hidden !important;
  -webkit-backface-visibility: hidden !important;
}

.flip-front {
  transform: rotateY(0deg);
  background: white;
}

.flip-front img {
  width: 100% !important;
  height: 100% !important;
  object-fit: cover !important;
  display: block !important;
  border-radius: var(--card-radius) !important;
}

.flip-back {
  transform: rotateY(180deg);
  background: #f3efe5;
  color: #222;
  padding: 8px;

  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;

  text-align: center;
  font-family: "Inter", sans-serif;
  font-size: 12px;
  line-height: 1.3;
}

.flip-back strong {
  margin-bottom: 4px;
  font-weight: 600;
}

/* ===== VISITED / NOT VISITED ===== */

.coin img.hide {
  opacity: 0.25 !important;
}

.coin:hover img.hide,
.coin.active-hover img.hide {
  opacity: 1 !important;
}

/* ===== BACK TEXT COMPENSATION ON DESKTOP HOVER ===== */

.coin.big.active-hover .flip-back {
  font-size: 15px;
}

.coin.medium.active-hover .flip-back {
  font-size: 7.5px;
}

.coin.small.active-hover .flip-back {
  font-size: 3.75px;
}

.coin.big.active-hover .flip-back strong {
  font-size: 16.5px;
}

.coin.medium.active-hover .flip-back strong {
  font-size: 9px;
}

.coin.small.active-hover .flip-back strong {
  font-size: 5.25px;
}

.photo-credit {
  margin-top: 6px;
  font-size: 0.5em;
  opacity: 0.3;
}

/* ===== MOBILE / TOUCH GRID ===== */

@media (max-width: 600px) {
  body {
    padding: 4px;
  }

  .coins {
    grid-template-columns: repeat(auto-fill, minmax(72px, 1fr));
    grid-auto-rows: 48px;
    gap: 4px;
  }
}

/* ===== MOBILE / TOUCH POPUP ===== */

@media (hover: none), (pointer: coarse) {
  .coin.active-hover {
    transform: none !important;
  }

  .coin.active-hover .flip-inner {
    box-shadow: none !important;
  }

  .mobile-popup {
    position: fixed;
    inset: 0;
    z-index: 999999;

    display: none;
    justify-content: center;
    align-items: center;

    padding: 10px;
    background: rgba(0, 0, 0, 0.65);

    pointer-events: auto;
  }

  .mobile-popup.show {
    display: flex;
    pointer-events: auto !important;
  }

  .mobile-popup-card {
    width: 96vw;
    max-width: 620px;
    aspect-ratio: 3 / 2;

    position: relative;
    overflow: hidden;

    border-radius: 14px;
    background: #f3efe5;
    box-shadow: 0 14px 35px rgba(0, 0, 0, 0.45);
  }

  .mobile-popup-front,
  .mobile-popup-back {
    position: absolute;
    inset: 0;

    width: 100%;
    height: 100%;

    border-radius: 14px;
    overflow: hidden;
  }

  .mobile-popup-front img {
    width: 100%;
    height: 100%;

    object-fit: cover;
    display: block;
    opacity: 1 !important;
  }

  .mobile-popup-back {
    display: none;

    background: #f3efe5;
    color: #222;
    padding: 18px;

    font-family: "Inter", sans-serif;
    font-size: 16px;
    line-height: 1.3;
    text-align: center;

    justify-content: center;
    align-items: center;
    flex-direction: column;
  }

  .mobile-popup-back strong {
    font-size: 19px;
    margin-bottom: 8px;
  }

  .mobile-popup-card.show-back .mobile-popup-front {
    display: none;
  }

  .mobile-popup-card.show-back .mobile-popup-back {
    display: flex;
  }
}

/* ===== TABLET TEXT ===== */

@media (min-width: 601px) and (max-width: 1024px) {
  .mobile-popup-back {
    font-size: 20px;
    line-height: 1.4;
    padding: 24px;
  }

  .mobile-popup-back strong {
    font-size: 24px;
    margin-bottom: 10px;
  }

  .mobile-popup-back .photo-credit {
    font-size: 12px;
    margin-top: 10px;
  }
}