body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #111827;
  color: #f3f4f6;
}

.site-header {
  text-align: center;
  padding: 40px 20px;
  background: #0f172a;
  border-bottom: 1px solid #1f2937;
}

.site-header h1 {
  margin: 0 0 10px 0;
  font-size: 2.2rem;
}

.site-header p {
  margin: 0;
  color: #cbd5e1;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 24px;
}

.intro-card,
.step-card,
.step-navigation {
  background: #1f2937;
  border: 1px solid #374151;
  border-radius: 14px;
  padding: 20px;
  margin-bottom: 24px;
}

.step-links {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 12px;
}

.step-links a {
  display: block;
  color: #93c5fd;
  text-decoration: none;
  font-weight: 700;
}

.step-links a:hover {
  text-decoration: underline;
}

.demo-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 24px;
  align-items: start;
  margin-top: 20px;
}

.controls {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.controls label {
  font-weight: 700;
  margin-top: 4px;
}

.controls input,
.controls button {
  padding: 10px;
  border-radius: 8px;
  border: 1px solid #4b5563;
  background: #111827;
  color: #f9fafb;
}

.controls button {
  cursor: pointer;
  font-weight: 700;
  background: #2563eb;
  border: none;
}

.controls button:hover {
  background: #1d4ed8;
}

.preview {
  display: flex;
  justify-content: center;
  align-items: center;
}

#noiseCanvas,
#noiseCanvas2,
#noiseCanvas3 {
  width: 100%;
  max-width: 700px;
  aspect-ratio: 1 / 1;
  border: 1px solid #4b5563;
  border-radius: 10px;
  background: #000000;
  display: block;
}

.code-block {
  margin-top: 24px;
  background: #0b1220;
  border: 1px solid #374151;
  border-radius: 10px;
  overflow-x: auto;
}

.code-block pre {
  margin: 0;
  padding: 16px;
  color: #e5e7eb;
}

.step-wrapper,
.code-wrapper {
  background: #1f2937;
  border: 1px solid #374151;
  border-radius: 14px;
  margin-bottom: 24px;
  overflow: hidden;
}

.step-summary,
.code-summary {
  cursor: pointer;
  list-style: none;
  padding: 18px 20px;
  font-weight: 700;
  background: #172033;
  user-select: none;
}

.step-summary::-webkit-details-marker,
.code-summary::-webkit-details-marker {
  display: none;
}

.step-summary::before,
.code-summary::before {
  content: "▶";
  display: inline-block;
  margin-right: 10px;
  transition: transform 0.2s ease;
}

.step-wrapper[open] .step-summary::before,
.code-wrapper[open] .code-summary::before {
  transform: rotate(90deg);
}

.step-card {
  background: #1f2937;
  border-top: 1px solid #374151;
  padding: 20px;
  margin: 0;
}

.demo-wrapper {
  background: #1f2937;
  border: 1px solid #374151;
  border-radius: 14px;
  margin-top: 20px;
  margin-bottom: 24px;
  overflow: hidden;
}

.demo-summary {
  cursor: pointer;
  list-style: none;
  padding: 18px 20px;
  font-weight: 700;
  background: #172033;
  user-select: none;
}

.demo-summary::-webkit-details-marker {
  display: none;
}

.demo-summary::before {
  content: "▶";
  display: inline-block;
  margin-right: 10px;
  transition: transform 0.2s ease;
}

.demo-wrapper[open] .demo-summary::before {
  transform: rotate(90deg);
}

.demo-content {
  padding: 20px;
  border-top: 1px solid #374151;
}

input[type="range"] {
  width: 100%;
  margin-bottom: 10px;
  cursor: pointer;
}

/* Step 4 */

.step4-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
  align-items: start;
}

.step4-preview-column h4 {
  margin-top: 0;
  margin-bottom: 12px;
  text-align: center;
}

.comparison-wrapper {
  position: relative;
  width: 100%;
  max-width: 700px;
  margin: 0 auto;
}

#comparisonCanvas4,
#biomeCanvas4 {
  width: 100%;
  max-width: 700px;
  aspect-ratio: 1 / 1;
  border: 1px solid #4b5563;
  border-radius: 10px;
  background: #000000;
  display: block;
}

.comparison-slider-horizontal {
  width: 100%;
  max-width: 700px;
  margin: 16px auto 0 auto;
  display: block;
  appearance: none;
  background: transparent;
}

.comparison-slider-horizontal::-webkit-slider-runnable-track {
  height: 4px;
  background: rgba(255, 255, 255, 0.35);
  border-radius: 999px;
}

.comparison-slider-horizontal::-webkit-slider-thumb {
  appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 999px;
  background: #ffffff;
  border: 2px solid #111827;
  cursor: pointer;
  margin-top: -7px;
}

.comparison-slider-horizontal::-moz-range-track {
  height: 4px;
  background: rgba(255, 255, 255, 0.35);
  border-radius: 999px;
}

.comparison-slider-horizontal::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 999px;
  background: #ffffff;
  border: 2px solid #111827;
  cursor: pointer;
}

/* Responsive */

@media (max-width: 1000px) {
  .step4-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 800px) {
  .demo-layout {
    grid-template-columns: 1fr;
  }
}

.generate-button {
  display: block;
  margin: 16px auto 0 auto;
  padding: 10px 16px;
  border-radius: 8px;
  border: none;
  background: #2563eb;
  color: #ffffff;
  font-weight: 700;
  cursor: pointer;
}

.generate-button:hover {
  background: #1d4ed8;
}

.image-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.image-row img {
  width: 32%;
  border-radius: 10px;
}

.reference-list {
  padding-left: 20px;
}

.reference-list li {
  margin-bottom: 10px;
  line-height: 1.5;
}
.download-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 16px;
}

.download-button {
  display: inline-block;
  padding: 10px 14px;
  border-radius: 8px;
  background: #2563eb;
  color: #ffffff;
  text-decoration: none;
  font-weight: 700;
  border: none;
}

.download-button:hover {
  background: #1d4ed8;
}