:root {
  --tutorial-hero-width: 900px;
  --tutorial-line-width: 2px;
  --tutorial-marker-size: 54px;
  --tutorial-summary-min: 132px;
  --tutorial-card-min: 210px;
  --tutorial-chapter-gap: clamp(22px, 4vw, 42px);
  --tutorial-content-gap: clamp(56px, 8vw, 88px);
  --tutorial-small-gap: 10px;
  --tutorial-medium-gap: 18px;
  --tutorial-large-gap: 30px;
}

.tutorial-hero {
  position: relative;
  overflow: hidden;
  background:
    radial-gradient(circle at 14% 25%, var(--color-error-glow), transparent 28%),
    radial-gradient(circle at 86% 70%, var(--color-accent-glow), transparent 30%),
    var(--color-bg);
}

.tutorial-hero::after {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(var(--color-grid) 1px, transparent 1px),
    linear-gradient(90deg, var(--color-grid) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: linear-gradient(to bottom, transparent, var(--color-text) 28%, transparent);
  -webkit-mask-image: linear-gradient(to bottom, transparent, var(--color-text) 28%, transparent);
  pointer-events: none;
}

.tutorial-hero .reading-wrap {
  max-width: calc(var(--tutorial-hero-width) + (var(--gutter) * 2));
  position: relative;
  z-index: 1;
  text-align: center;
}

.tutorial-hero h1 {
  margin-right: auto;
  margin-left: auto;
}

.tutorial-hero .lead {
  max-width: var(--reading-width);
  margin-right: auto;
  margin-left: auto;
}

.text-link,
.tutorial-prose a:not(.button) {
  color: var(--color-accent-dark);
  text-decoration: underline;
  text-decoration-color: var(--color-accent);
  text-underline-offset: 3px;
}

.tutorial-summary {
  margin-top: var(--tutorial-large-gap);
  padding: 14px;
  overflow-x: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--tutorial-small-gap);
  background: var(--color-bg);
  box-shadow: var(--shadow-card);
  scrollbar-width: thin;
  -webkit-overflow-scrolling: touch;
}

.summary-item {
  min-width: var(--tutorial-summary-min);
  min-height: 48px;
  padding: 8px 12px;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  background: var(--color-panel);
  color: var(--color-text);
  font-weight: 740;
  white-space: nowrap;
}

.summary-index {
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 800;
}

.summary-arrow {
  flex-shrink: 0;
  color: var(--color-warn);
  font-family: var(--font-mono);
  font-weight: 800;
}

.tutorial-platform-note {
  margin-top: 26px;
  margin-bottom: 0;
  text-align: left;
}

.tutorial-nav-section {
  padding-top: 24px;
  padding-bottom: 24px;
  overflow: visible;
  border-top: 1px solid var(--color-border-soft);
  border-bottom: 1px solid var(--color-border-soft);
  background: var(--color-panel);
}

.tutorial-content {
  padding-top: clamp(56px, 8vw, 92px);
}

.tutorial-prose {
  display: grid;
  gap: var(--tutorial-content-gap);
}

.tutorial-chapter {
  display: grid;
  grid-template-columns: var(--tutorial-marker-size) minmax(0, 1fr);
  gap: var(--tutorial-chapter-gap);
  scroll-margin-top: calc(var(--nav-height) + 88px);
}

.chapter-marker {
  position: relative;
  display: flex;
  justify-content: center;
}

.chapter-marker::after {
  content: "";
  position: absolute;
  top: var(--tutorial-marker-size);
  bottom: calc(var(--tutorial-content-gap) * -1);
  left: 50%;
  width: var(--tutorial-line-width);
  transform: translateX(-50%);
  background: linear-gradient(to bottom, var(--color-accent), var(--color-border-soft));
}

.tutorial-chapter:last-child .chapter-marker::after {
  display: none;
}

.chapter-marker span {
  width: var(--tutorial-marker-size);
  height: var(--tutorial-marker-size);
  flex-shrink: 0;
  border: 1px solid var(--color-accent);
  border-radius: var(--radius-md);
  display: grid;
  place-items: center;
  position: relative;
  z-index: 1;
  background: var(--color-bg);
  color: var(--color-accent-dark);
  box-shadow: 0 8px 20px var(--color-accent-glow);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 800;
}

.chapter-label {
  margin-bottom: 8px;
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 760;
  letter-spacing: 0.08em;
}

.chapter-content h2 {
  font-size: clamp(28px, 4vw, 42px);
}

.chapter-content > p {
  color: var(--color-muted);
}

.chapter-content > p + p {
  margin-top: var(--tutorial-medium-gap);
}

.checkpoint {
  margin-top: 28px;
  padding: 20px 22px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  position: relative;
  background: var(--color-panel);
}

.checkpoint::before {
  content: "";
  position: absolute;
  top: 20px;
  left: -6px;
  width: 11px;
  height: 11px;
  border: 2px solid var(--color-bg);
  border-radius: var(--radius-pill);
  background: var(--color-warn);
}

.checkpoint-title {
  margin-bottom: 6px;
  color: var(--color-text);
  font-weight: 780;
}

.checkpoint p {
  color: var(--color-muted);
}

.mode-comparison {
  margin-top: var(--tutorial-large-gap);
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.mode-comparison article {
  min-width: 0;
  padding: 20px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  background: var(--color-bg);
  box-shadow: var(--shadow-card);
}

.mode-code {
  margin-bottom: 12px;
  padding: 5px 9px;
  border-radius: var(--radius-pill);
  display: inline-flex;
  background: var(--color-accent-soft);
  color: var(--color-accent-dark);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 800;
}

.mode-comparison h3 {
  margin-bottom: 8px;
  font-size: 18px;
}

.mode-comparison p {
  color: var(--color-muted);
  font-size: 13px;
}

.verification-grid {
  margin-top: var(--tutorial-large-gap);
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.verification-item {
  min-width: 0;
  padding: 18px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: flex-start;
  gap: 14px;
  background: var(--color-bg);
  box-shadow: var(--shadow-card);
}

.verification-status {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
  border-radius: var(--radius-sm);
  display: grid;
  place-items: center;
  background: var(--color-accent);
  color: var(--color-white);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 800;
}

.verification-item h3 {
  margin-bottom: 5px;
  font-size: 17px;
}

.verification-item p {
  color: var(--color-muted);
  font-size: 13px;
}

.chapter-content .download-guide-card {
  margin-top: 36px;
}

@media (max-width: 768px) {
  .tutorial-summary {
    justify-content: flex-start;
  }

  .mode-comparison {
    grid-template-columns: 1fr;
  }

  .verification-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  :root {
    --tutorial-marker-size: 42px;
    --tutorial-chapter-gap: 14px;
  }

  .tutorial-hero .lead {
    font-size: 16px;
  }

  .tutorial-summary {
    margin-top: 22px;
    border-radius: var(--radius-lg);
  }

  .summary-item {
    min-width: 116px;
  }

  .tutorial-chapter {
    grid-template-columns: var(--tutorial-marker-size) minmax(0, 1fr);
  }

  .chapter-marker span {
    border-radius: var(--radius-sm);
    font-size: 11px;
  }

  .chapter-content h2 {
    font-size: clamp(25px, 7vw, 32px);
  }

  .checkpoint {
    padding: 17px 17px 17px 19px;
  }

  .verification-item {
    padding: 16px;
  }
}

@media (max-width: 360px) {
  .tutorial-chapter {
    grid-template-columns: 1fr;
  }

  .chapter-marker {
    justify-content: flex-start;
  }

  .chapter-marker::after {
    display: none;
  }
}