:root {
  color-scheme: dark;
  --bg: #050912;
  --bg-gradient: radial-gradient(circle at top, rgba(58, 92, 180, 0.35), transparent 60%),
    radial-gradient(circle at bottom, rgba(196, 82, 138, 0.25), transparent 55%);
  --card-shadow: rgba(0, 0, 0, 0.35);
  --text-main: #f6f8ff;
  --text-muted: #a9b3d6;
  --accent: #ff7f5d;
  --glass: rgba(8, 14, 30, 0.78);
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  min-height: 100vh;
  background: var(--bg);
  background-image: var(--bg-gradient);
  font-family: 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont, 'Roboto', sans-serif;
  color: var(--text-main);
  overflow: hidden;
}

.content {
  position: relative;
  z-index: 2;
  max-width: 640px;
  margin: 0 auto;
  padding: 10vh 2rem 4rem;
  text-align: center;
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 1rem;
}

h1 {
  font-size: clamp(2.8rem, 8vw, 4.5rem);
  line-height: 1.1;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
}

.tagline {
  font-size: 1.25rem;
  color: var(--accent);
  margin-bottom: 2.5rem;
}

.how-to {
  background: var(--glass);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 18px;
  padding: 2rem;
  text-align: left;
  box-shadow: 0 25px 60px rgba(0, 0, 0, 0.3);
}

.how-to h2 {
  font-size: 1.5rem;
  margin-bottom: 1.25rem;
}

.how-to ul {
  list-style: none;
  color: var(--text-muted);
  padding-left: 0;
  display: grid;
  gap: 0.75rem;
  font-size: 1rem;
  line-height: 1.7;
}

.how-to li {
  padding-left: 1.25rem;
  position: relative;
}

.how-to li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.75em;
  width: 0.5rem;
  height: 0.5rem;
  border-radius: 999px;
  background: var(--accent);
  transform: translateY(-50%);
}

.subtext {
  margin-top: 2.5rem;
  color: var(--text-muted);
  letter-spacing: 0.2em;
  text-transform: uppercase;
  font-size: 0.85rem;
}

.cards-layer {
  position: fixed;
  inset: 0;
  overflow: hidden;
  z-index: 1;
  pointer-events: none;
}

.card {
  position: absolute;
  width: 140px;
  aspect-ratio: 2 / 3;
  background-size: cover;
  background-position: center;
  filter: drop-shadow(0 25px 20px var(--card-shadow));
  opacity: 0.8;
  animation: drift 22s linear infinite;
}

.card::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: 10px;
  box-shadow: inset 0 0 30px rgba(0, 0, 0, 0.25);
}

.card-a {
  background-image: url('cards/ace_of_spades.png');
  top: 10%;
  left: 12%;
  animation-duration: 36s;
  animation-delay: -3s;
}

.card-b {
  background-image: url('cards/queen_of_hearts.png');
  top: 65%;
  left: 8%;
  animation-duration: 42s;
  animation-delay: -8s;
}

.card-c {
  background-image: url('cards/jack_of_clubs.png');
  top: 20%;
  right: 10%;
  animation-duration: 40s;
  animation-delay: -12s;
}

.card-d {
  background-image: url('cards/king_of_diamonds.png');
  top: 70%;
  right: 12%;
  animation-duration: 44s;
  animation-delay: -5s;
}

.card-e {
  background-image: url('cards/10_of_spades.png');
  top: 45%;
  left: 35%;
  animation-duration: 48s;
  animation-delay: -15s;
}

.card-f {
  background-image: url('cards/ace_of_clubs.png');
  top: 55%;
  right: 32%;
  animation-duration: 41s;
  animation-delay: -10s;
}

@keyframes drift {
  0% {
    transform: translate3d(0, 0, 0) rotate(0deg) scale(1);
  }
  25% {
    transform: translate3d(40px, -60px, 0) rotate(8deg) scale(1.05);
  }
  50% {
    transform: translate3d(-30px, -20px, 0) rotate(-5deg) scale(1.03);
  }
  75% {
    transform: translate3d(20px, 35px, 0) rotate(4deg) scale(1.02);
  }
  100% {
    transform: translate3d(-25px, 50px, 0) rotate(-6deg) scale(0.99);
  }
}

@media (max-width: 720px) {
  .content {
    padding-top: 6vh;
  }

  .card {
    width: 90px;
  }

  .how-to {
    padding: 1.5rem;
  }
}