:root {
  --bg-top: #f6f1e7;
  --bg-bottom: #ece4d5;
  --ink: #152238;
  --ink-soft: #41556f;
  --paper: rgba(255, 252, 246, 0.88);
  --paper-strong: rgba(255, 252, 246, 0.96);
  --line: rgba(21, 34, 56, 0.1);
  --accent-a: #db5a42;
  --accent-b: #0f7c82;
  --accent-c: #dd9b29;
  --shadow: 0 32px 70px rgba(18, 29, 46, 0.16);
  --radius: 32px;
  --font-body: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", sans-serif;
  --font-display: "M PLUS 1p", "Noto Sans JP", "Hiragino Sans", "Yu Gothic", sans-serif;
  --font-ui: "Noto Sans JP", "Hiragino Sans", "Yu Gothic", sans-serif;
  --font-mono: "IBM Plex Mono", "SFMono-Regular", Consolas, monospace;
  --step-width: 1180px;
  --step-height: 720px;
}

* {
  box-sizing: border-box;
}

html,
body {
  width: 100%;
  height: 100%;
  overflow: hidden;
}

body {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-body);
  background:
    radial-gradient(circle at 15% 18%, rgba(219, 90, 66, 0.18), transparent 24%),
    radial-gradient(circle at 83% 14%, rgba(15, 124, 130, 0.16), transparent 22%),
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px),
    linear-gradient(180deg, var(--bg-top), var(--bg-bottom));
  background-size: auto, auto, 30px 30px, 30px 30px, auto;
}

a {
  color: var(--accent-b);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  padding: 0.12em 0.4em;
  border-radius: 999px;
  background: rgba(21, 34, 56, 0.08);
}

.fallback-message {
  display: none;
}

.impress-not-supported .fallback-message {
  display: block;
  width: min(680px, calc(100vw - 48px));
  margin: 10vh auto;
  padding: 28px 32px;
  border-radius: 24px;
  background: var(--paper-strong);
  box-shadow: var(--shadow);
  line-height: 1.7;
}

.impress-supported .fallback-message {
  display: none;
}

#hud {
  position: fixed;
  inset: 22px 22px auto 22px;
  z-index: 20;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  pointer-events: none;
}

.hud-chip {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  border-radius: 999px;
  background: rgba(255, 252, 246, 0.78);
  backdrop-filter: blur(10px);
  box-shadow: 0 10px 25px rgba(18, 29, 46, 0.08);
  font-family: var(--font-ui);
}

.hud-chip-right {
  margin-left: auto;
}

.hud-label {
  color: var(--ink-soft);
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

#impress {
  pointer-events: none;
}

.step {
  width: var(--step-width);
  min-height: var(--step-height);
  padding: 46px 50px;
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: var(--radius);
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.62), rgba(255, 255, 255, 0.22)),
    var(--paper);
  box-shadow: var(--shadow);
  pointer-events: auto;
  opacity: 0.2;
  transition:
    opacity 400ms ease,
    box-shadow 400ms ease;
}

.step.active {
  opacity: 1;
  box-shadow: 0 36px 90px rgba(18, 29, 46, 0.2);
}

.impress-on-overview .step {
  opacity: 0.82;
}

.impress-on-overview .overview-step,
.impress-on-overview .overview-step.active {
  width: 0;
  min-height: 0;
  padding: 0;
  opacity: 0;
  border: 0;
  box-shadow: none;
  pointer-events: none;
}

.step.hero {
  background:
    radial-gradient(circle at top right, rgba(221, 155, 41, 0.22), transparent 28%),
    linear-gradient(135deg, rgba(255, 255, 255, 0.74), rgba(255, 255, 255, 0.3)),
    var(--paper-strong);
}

.overview-step {
  background: transparent;
  border: 0;
  box-shadow: none;
}

.eyebrow {
  margin: 0 0 16px;
  color: var(--accent-b);
  font-family: var(--font-display);
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.22;
}

h1,
h2 {
  font-family: var(--font-display);
  letter-spacing: -0.015em;
}

h1 {
  max-width: 14.5ch;
  font-size: 3.45rem;
  font-weight: 800;
}

h2 {
  max-width: 24ch;
  font-size: 2.22rem;
  font-weight: 800;
  margin-bottom: 22px;
}

h3 {
  font-size: 1.16rem;
  font-weight: 700;
  margin-bottom: 12px;
}

p,
li,
td,
th {
  font-size: 1.05rem;
  line-height: 1.74;
}

.lead {
  max-width: 42ch;
  margin-top: 18px;
  color: var(--ink-soft);
  font-size: 1.18rem;
  font-weight: 500;
  line-height: 1.72;
}

.lead.narrow {
  max-width: 50ch;
}

h1,
h2,
h3,
.eyebrow,
.lead,
.quote,
.footnote strong {
  text-wrap: balance;
}

p,
li,
td,
th,
.body-text,
.stack-item span,
.stat-card span,
.loop-node p,
.footnote {
  text-wrap: pretty;
}

.hero-grid,
.split,
.cards-grid,
.stats-row,
.merge-board {
  display: grid;
}

.hero-grid {
  grid-template-columns: 1.18fr 0.82fr;
  gap: 28px;
  align-items: center;
}

.hero-stack {
  display: grid;
  gap: 18px;
}

.callout {
  padding: 18px 20px;
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid rgba(21, 34, 56, 0.08);
}

.callout.warning {
  border-left: 8px solid var(--accent-a);
}

.callout-title {
  display: inline-block;
  margin-bottom: 8px;
  font-family: var(--font-ui);
  font-size: 0.88rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.meta-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 7px 12px;
  border-radius: 999px;
  background: rgba(15, 124, 130, 0.12);
  color: var(--accent-b);
  font-family: var(--font-ui);
  font-size: 0.84rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.pill.light {
  background: rgba(21, 34, 56, 0.08);
  color: var(--ink);
}

.cards-grid {
  gap: 18px;
}

.cards-grid.three {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.cards-grid.two {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.compact-grid {
  margin-top: 28px;
}

.card,
.panel,
.source-card,
.stat-card,
.loop-node,
.loop-center-note {
  padding: 20px 22px;
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.64);
  border: 1px solid rgba(21, 34, 56, 0.08);
}

.card,
.panel,
.source-card,
.stat-card,
.loop-node,
.loop-center-note {
  box-shadow: 0 14px 28px rgba(18, 29, 46, 0.06);
}

.card-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  margin-bottom: 14px;
  border-radius: 16px;
  background: rgba(21, 34, 56, 0.08);
  font-family: var(--font-display);
  font-size: 0.92rem;
  font-weight: 800;
}

.accent-a .card-index {
  background: rgba(219, 90, 66, 0.14);
  color: var(--accent-a);
}

.accent-b .card-index {
  background: rgba(15, 124, 130, 0.14);
  color: var(--accent-b);
}

.accent-c .card-index {
  background: rgba(221, 155, 41, 0.16);
  color: #9f6908;
}

.split {
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.narrow-gap {
  gap: 18px;
}

.tone {
  background:
    radial-gradient(circle at top right, rgba(15, 124, 130, 0.12), transparent 32%),
    rgba(255, 255, 255, 0.68);
}

.body-text {
  margin: 0;
  color: var(--ink-soft);
}

.quote {
  margin: 0 0 16px;
  font-size: 1.2rem;
  font-weight: 700;
  line-height: 1.68;
}

.feature-list,
.ordered-list {
  margin: 0;
  padding-left: 1.2em;
}

.feature-list.compact li,
.ordered-list li {
  margin-bottom: 8px;
}

.stack-list {
  display: grid;
  gap: 12px;
}

.stack-item {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  padding: 12px 14px;
  border-radius: 18px;
  background: rgba(21, 34, 56, 0.06);
}

.stack-item span {
  color: var(--ink-soft);
  text-align: right;
}

.merge-board {
  grid-template-columns: 1fr auto 1fr auto 1.15fr;
  gap: 14px;
  align-items: center;
}

.merge-plus,
.merge-arrow {
  font-family: var(--font-display);
  font-size: 2.6rem;
  font-weight: 800;
  color: var(--accent-a);
  text-align: center;
}

.source-card.final {
  background:
    radial-gradient(circle at top right, rgba(221, 155, 41, 0.16), transparent 28%),
    rgba(255, 255, 255, 0.72);
}

.stats-row {
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 20px;
}

.stat-card {
  display: grid;
  gap: 6px;
  text-align: center;
}

.stat-card strong {
  font-family: var(--font-display);
  font-size: 1.18rem;
}

.table-panel {
  padding-bottom: 16px;
}

.check-table {
  width: 100%;
  border-collapse: collapse;
  overflow: hidden;
  border-radius: 18px;
}

.check-table th,
.check-table td {
  padding: 11px 10px;
  text-align: left;
  border-bottom: 1px solid rgba(21, 34, 56, 0.08);
}

.check-table th {
  font-size: 0.94rem;
  background: rgba(21, 34, 56, 0.06);
}

.check-table td {
  font-size: 0.9rem;
}

.check-table code {
  white-space: nowrap;
  font-size: 0.8em;
}

.loop-grid {
  display: grid;
  grid-template-columns: 1.25fr 0.22fr 1.45fr 0.22fr 1.2fr;
  gap: 12px 10px;
  margin-top: 14px;
  align-items: stretch;
}

.loop-node {
  display: grid;
  gap: 8px;
  min-height: 142px;
  align-content: start;
}

.loop-node span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 46px;
  height: 46px;
  border-radius: 18px;
  background: rgba(219, 90, 66, 0.15);
  color: var(--accent-a);
  font-family: var(--font-display);
  font-size: 1.24rem;
  font-weight: 800;
}

.loop-node strong {
  font-size: 1.12rem;
}

.loop-node p,
.loop-center-note p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.68;
}

.loop-node.emphasis {
  background:
    radial-gradient(circle at top right, rgba(15, 124, 130, 0.12), transparent 30%),
    rgba(255, 255, 255, 0.72);
}

.loop-node.final-step span {
  background: rgba(15, 124, 130, 0.16);
  color: var(--accent-b);
}

.node-1 {
  grid-column: 1;
  grid-row: 1;
}

.connector-1 {
  grid-column: 2;
  grid-row: 1;
}

.node-2 {
  grid-column: 3;
  grid-row: 1;
}

.connector-2 {
  grid-column: 4;
  grid-row: 1;
}

.node-3 {
  grid-column: 5;
  grid-row: 1;
}

.node-5 {
  grid-column: 1;
  grid-row: 2;
}

.connector-3 {
  grid-column: 2;
  grid-row: 2;
}

.loop-center-note {
  grid-column: 3;
  grid-row: 2;
  display: grid;
  gap: 10px;
  place-items: center;
  text-align: center;
  background:
    radial-gradient(circle at top right, rgba(221, 155, 41, 0.16), transparent 30%),
    rgba(255, 255, 255, 0.72);
}

.connector-4 {
  grid-column: 4;
  grid-row: 2;
}

.node-4 {
  grid-column: 5;
  grid-row: 2;
}

.loop-connector {
  align-self: center;
  justify-self: center;
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--ink-soft);
}

.footnote {
  margin: 16px 0 0;
  color: var(--ink-soft);
  text-align: center;
  font-size: 0.96rem;
  line-height: 1.7;
}

.footnote.strong {
  font-size: 1.04rem;
}

.closing h2 {
  max-width: 20ch;
}

.cards-grid.three .card p {
  font-size: 0.98rem;
}

.cards-grid.three .card h3,
.cards-grid.two .card h3,
.panel h3,
.source-card h3 {
  text-wrap: balance;
}

.cards-grid.three .card p,
.cards-grid.two .card p,
.panel p,
.source-card p,
.body-text,
.feature-list li,
.ordered-list li,
.check-table td {
  max-width: 40ch;
}

.table-panel .check-table td {
  max-width: none;
}

@media (max-width: 1280px) {
  .step {
    width: 1060px;
    min-height: 680px;
    padding: 40px 42px;
  }

  h1 {
    font-size: 3rem;
  }

  h2 {
    font-size: 1.96rem;
  }

  p,
  li,
  td,
  th {
    font-size: 0.98rem;
  }
}