body {
  font-family: system-ui, sans-serif;
  margin: 0;
  background: #f4f6f9;
  color: #222;
}

.hero {
  padding: 3rem;
  background: linear-gradient(135deg, #e3f2fd, #ffffff);
  text-align: center;
}

.explainer {
  max-width: 1000px;
  margin: auto;
  padding: 2rem;
}

/* Cards */
.card {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
  padding: 2rem;
  margin-bottom: 3rem;
  border-radius: 16px;
  background: white;
  box-shadow: 0 10px 30px rgba(0,0,0,0.05);
}

.card-text h2 {
  margin-top: 0;
}

.card-viz {
  display: flex;
  justify-content: center;
  align-items: flex-start;
}

/* Themes */
.data-card {
  background: linear-gradient(180deg, #eef5ff, #ffffff);
}

.prior-card {
  background: linear-gradient(180deg, #fff4d6, #ffffff);
}

.likelihood-card {
  background: linear-gradient(180deg, #e9f7ef, #ffffff);
}

.posterior-card {
  background: linear-gradient(180deg, #fff0e6, #ffffff);
}

/* Coins */
.coin-container {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.coin {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  font-weight: bold;
  display: flex;
  align-items: center;
  justify-content: center;
}

.coin.heads {
  background: #4caf50;
  color: white;
}

.coin.tails {
  background: #f44336;
  color: white;
}

/* Canvas appearance */
canvas {
  background: #fafafa;
  border: 1px solid #ddd;
  border-radius: 8px;
}

/* Responsive */
@media (max-width: 900px) {
  .card {
    grid-template-columns: 1fr;
  }
}
.overlay-card {
  background: linear-gradient(180deg, #eef7f1, #ffffff);
}
.legend {
  display: flex;
  gap: 16px;
  font-size: 14px;
  margin-top: 8px;
}

.legend .prior { color: #3f51b5; }
.legend .likelihood { color: #e91e63; }
.legend .posterior { color: #009688; }
.controls {
  margin-top: 12px;
  display: flex;
  gap: 12px;
  align-items: center;
}

.controls label {
  display: flex;
  gap: 8px;
  align-items: center;
}
/* ===== Sampling Controls ===== */
.controls {
  margin-top: 12px;
  display: flex;
  gap: 14px;
  align-items: center;
  flex-wrap: wrap;
}

.controls label {
  display: flex;
  gap: 8px;
  align-items: center;
  font-size: 14px;
}

.controls input[type="range"] {
  cursor: pointer;
}

.controls button {
  padding: 6px 12px;
  border: none;
  border-radius: 4px;
  background: #009688;
  color: white;
  cursor: pointer;
}

.controls button:hover {
  background: #00796b;
}
/* ===== Trace Plot ===== */
#trace canvas {
  border: 1px solid #ddd;
  background: #fafafa;
}
.hdi-text {
  margin-top: 8px;
  font-size: 14px;
  color: #00695c;
  font-weight: 500;
}
/* ===================== SCROLL STORY: STEP VISIBILITY ===================== */

/* Hide all steps by default */
#scrolly section {
  opacity: 0;
  transform: translateY(40px);
  transition: opacity 0.6s ease, transform 0.6s ease;
  min-height: 80vh; /* CRITICAL */
}


/* Show first step initially */
#scrolly section[data-step="1"] {
  opacity: 1;
  transform: translateY(0);
  pointer-events: auto;
}