:root {
  color-scheme: dark;
  --bg: #080b10;
  --surface: #111722;
  --surface-2: #182131;
  --line: #273449;
  --line-strong: #3b506d;
  --text: #edf3f7;
  --muted: #9aaabd;
  --accent: #83a9ff;
  --accent-soft: rgba(131, 169, 255, 0.12);
  --monolith: #f2a65a;
  --services: #70d6a4;
  --warning: #e5be70;
  --radius: 8px;
  --content-width: 1180px;
  --font-body: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-display:
    ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  line-height: 1.6;
}

a {
  color: inherit;
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
}

button:focus-visible,
input:focus-visible,
a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

[hidden] {
  display: none !important;
}

.shell {
  width: min(var(--content-width), calc(100% - 32px));
  margin-inline: auto;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  z-index: 10;
  top: 8px;
  left: 8px;
  padding: 8px 12px;
  border-radius: 6px;
  background: var(--accent);
  color: #08101d;
  font-weight: 700;
  transform: translateY(-160%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-block: 20px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
}

.brand img {
  width: 34px;
  height: 34px;
  border-radius: 50%;
  object-fit: cover;
}

.brand span {
  display: grid;
  line-height: 1.05;
}

.brand small {
  margin-top: 4px;
  color: var(--muted);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.library-back {
  color: var(--muted);
  font-size: 0.9rem;
  text-decoration: none;
}

.library-back:hover {
  color: var(--text);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(260px, 0.8fr);
  gap: 40px;
  padding-block: 72px 64px;
}

.eyebrow,
.note-label,
.result-kicker,
.scenario-kicker {
  margin: 0;
  color: var(--accent);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

.hero h1 {
  max-width: 760px;
  margin: 12px 0 20px;
  font: 700 clamp(2.6rem, 7vw, 5.5rem) / 1.02 var(--font-display);
  letter-spacing: -0.05em;
}

.hero-lead,
.section-lead {
  max-width: 720px;
  margin: 0;
  color: var(--muted);
  font-size: clamp(1.05rem, 2vw, 1.3rem);
}

.hero-note {
  align-self: end;
  padding: 22px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--surface);
}

.hero-note strong {
  display: block;
  margin-top: 12px;
  font-size: 1.1rem;
}

.hero-note p {
  margin: 8px 0 0;
  color: var(--muted);
}

.section {
  padding-block: 64px;
  border-top: 1px solid var(--line);
}

.section h2 {
  max-width: 780px;
  margin: 8px 0 12px;
  font-size: clamp(1.8rem, 4vw, 3rem);
  line-height: 1.1;
  letter-spacing: -0.03em;
}

.section h3 {
  margin: 0;
  font-size: 1.2rem;
}

.lesson-progress {
  padding-block: 20px;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.lesson-progress ol {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 8px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.lesson-progress button {
  width: 100%;
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 0 12px;
  background: var(--surface);
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  text-align: left;
}

.lesson-progress button.is-current {
  border-color: var(--accent);
  color: var(--text);
  background: var(--accent-soft);
}

.lesson-progress button.is-complete {
  color: var(--text);
}

.lesson-progress button.is-complete::after {
  content: " ✓";
}

.js-ready [data-step-panel]:not(.is-active) {
  display: none;
}

.step-panel {
  max-width: 900px;
  margin-inline: auto;
}

.step-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-top: 28px;
}

.mode-grid,
.architecture-choice,
.primer-grid {
  display: grid;
  gap: 12px;
}

.mode-grid,
.architecture-choice {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border: 0;
  padding: 0;
  margin: 24px 0 12px;
}

.mode-option,
.architecture-option,
.event-choice,
.scenario-card,
.explain-card,
.event-result {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}

.mode-option,
.architecture-option,
.event-choice {
  min-height: 92px;
  padding: 18px;
  text-align: left;
  color: var(--text);
}

.mode-option {
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.mode-option input {
  flex: 0 0 auto;
  margin-top: 4px;
  accent-color: var(--accent);
}

.mode-option:has(input:checked),
.architecture-option.is-selected {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.mode-option strong,
.architecture-option strong,
.event-choice strong {
  display: block;
  font-size: 1.05rem;
}

.architecture-option span,
.event-choice span,
.mode-option small {
  display: block;
  margin-top: 6px;
  color: var(--muted);
}

.control-help {
  margin: 0;
  color: var(--muted);
}

.mode-actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-top: 24px;
}

.live-status {
  margin-top: 16px;
  color: var(--warning);
  font-family: var(--font-mono);
  font-size: 0.82rem;
}

.button {
  min-height: 44px;
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  padding: 0 16px;
  background: transparent;
  color: var(--text);
  font-weight: 700;
}

.button.primary {
  border-color: var(--accent);
  background: var(--accent);
  color: #08101d;
}

.button.secondary:hover,
.scenario-actions button:hover {
  border-color: var(--accent);
}

.primer-grid {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  margin-top: 20px;
}

.explain-card,
.scenario-card {
  padding: 22px;
}

.explain-card p,
.scenario-card > p:not(.scenario-kicker),
.story-rail p,
.takeaway p {
  margin: 10px 0 0;
  color: var(--muted);
}

.story-rail {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 1px;
  margin-top: 28px;
  border: 1px solid var(--line);
  background: var(--line);
}

.story-rail article {
  min-height: 130px;
  padding: 20px;
  background: var(--surface);
}

.story-rail strong {
  color: var(--accent);
  font-family: var(--font-mono);
}

.boundary-diagram {
  display: grid;
  min-height: 180px;
  place-items: center;
  margin-top: 28px;
  padding: 24px;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius);
  background: var(--surface);
  font-family: var(--font-mono);
}

.diagram-monolith,
.diagram-services {
  width: min(100%, 780px);
}

.diagram-monolith {
  display: grid;
  gap: 14px;
  padding: 36px;
  border: 2px solid var(--monolith);
  border-radius: 12px;
  color: var(--monolith);
  text-align: center;
}

.diagram-label {
  font-size: 0.76rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.diagram-services {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.diagram-services span {
  padding: 22px 10px;
  border: 2px solid var(--services);
  border-radius: 8px;
  color: var(--services);
  text-align: center;
}

.section-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
}

.section-heading.compact {
  align-items: center;
  margin-top: 28px;
}

.architecture-choice {
  margin-bottom: 40px;
}

.pressure-events {
  margin-top: 12px;
}

.event-results {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 16px;
}

.event-results:has(.empty-result) {
  grid-template-columns: 1fr;
}

.event-result {
  padding: 18px;
}

.event-result h4 {
  margin: 7px 0 8px;
  font-size: 1.15rem;
}

.event-result p:not(.result-kicker) {
  margin: 0;
  color: var(--muted);
}

.result-tradeoff {
  display: block;
  margin-top: 12px;
  color: var(--text);
  font-size: 0.9rem;
}

.architecture-summary {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  padding: 16px 18px;
  border-left: 2px solid var(--accent);
  background: var(--surface-2);
  color: var(--muted);
  font-size: 0.92rem;
}

.architecture-summary strong {
  color: var(--text);
}

.event-counterfactual {
  border-color: var(--warning);
}

.empty-result {
  margin: 0;
  padding: 18px;
  border: 1px dashed var(--line-strong);
  color: var(--muted);
}

.scenario-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 18px;
}

.scenario-actions button {
  border: 1px solid var(--line-strong);
  border-radius: 6px;
  background: transparent;
  color: var(--text);
  padding: 9px 12px;
}

.scenario-actions button.is-selected {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.architecture-option.is-selected::after,
.scenario-actions button.is-selected::after {
  display: block;
  margin-top: 6px;
  color: var(--accent);
  content: "Selected";
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.reflection-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
  margin-top: 24px;
}

.middle-path {
  margin-top: 16px;
}

.scenario-result {
  margin-top: 16px;
  padding-top: 16px;
  border-top: 1px solid var(--line);
}

.scenario-result p {
  margin: 8px 0 0;
  color: var(--muted);
}

.scenario-result strong {
  color: var(--text);
}

.takeaway {
  padding-bottom: 96px;
}

@media (max-width: 760px) {
  .hero,
  .mode-grid,
  .architecture-choice,
  .primer-grid,
  .story-rail,
  .event-results {
    grid-template-columns: 1fr;
  }

  .lesson-progress ol,
  .reflection-grid {
    grid-template-columns: 1fr;
  }

  .lesson-progress button {
    text-align: center;
  }

  .step-panel h2 {
    max-width: 18ch;
  }

  .step-actions {
    align-items: stretch;
    flex-direction: column;
  }

  .step-actions .button {
    width: 100%;
  }

  .section {
    padding-block: 44px;
  }

  .hero {
    padding-block: 48px 44px;
  }

  .section-heading,
  .mode-actions {
    align-items: flex-start;
    flex-direction: column;
  }

  .diagram-services,
  .architecture-summary {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}