/* ============================================================
   html-presentation engine.css — IMMUTABLE ENGINE STYLES
   Do not modify. AI writes only inside template.html SLIDES markers.
   ============================================================ */

/* --- Reset & Base ----------------------------------------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  overflow: hidden;
  width: 100%;
  height: 100%;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: var(--body-size);
  line-height: var(--body-lh);
  -webkit-font-smoothing: antialiased;
}

/* --- CSS Custom Properties --------------------------------- */
:root {
  /* Canvas */
  --stage-w: 1920px;
  --stage-h: 1080px;

  /* Colors */
  --bg: #ffffff;
  --fg: #0f172a;
  --accent: #2563eb;
  --muted: #64748b;
  --code-bg: #0f172a;
  --code-fg: #e2e8f0;
  --border: #e2e8f0;

  /* Fonts */
  --font-sans: 'Pretendard', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;

  /* Type scale */
  --h1-size: 80px;
  --h2-size: 48px;
  --body-size: 32px;
  --h1-lh: 1.15;
  --body-lh: 1.5;

  /* Layout */
  --slide-pad: 96px;
  --radius: 12px;
  --shadow: 0 10px 40px rgba(0,0,0,0.08);

  /* Navigation */
  --nav-bg: #ffffff;
  --nav-fg: #0f172a;
  --nav-active-bg: #eff6ff;
}

[data-theme="dark"] {
  --bg: #0f172a;
  --fg: #f1f5f9;
  --accent: #60a5fa;
  --muted: #94a3b8;
  --code-bg: #020617;
  --code-fg: #e2e8f0;
  --border: #1e293b;
  --nav-bg: #1e293b;
  --nav-fg: #f1f5f9;
  --nav-active-bg: #1e40af;
}

/* --- Viewport & Stage ------------------------------------- */
.viewport {
  position: fixed;
  inset: 0;
  overflow: hidden;
  background: color-mix(in srgb, var(--bg) 60%, #888 40%);
}

.stage {
  position: absolute;
  left: 50%;
  top: 50%;
  width: var(--stage-w);
  height: var(--stage-h);
  transform-origin: center center;
  transform: translate(-50%, -50%);
  background: var(--bg);
  box-shadow: var(--shadow);
  overflow: hidden;
}

/* --- Deck & Slides ---------------------------------------- */
.deck {
  position: absolute;
  inset: 0;
}

.deck > section {
  position: absolute;
  inset: 0;
  padding: var(--slide-pad);
  display: none;
  flex-direction: column;
  overflow: hidden;
}

.deck > section.active {
  display: flex;
}

/* Debug mode: overflow detection */
.deck > section[data-overflow] {
  outline: 3px solid red;
  outline-offset: -3px;
}

/* --- Layout: cover ---------------------------------------- */
section[data-layout="cover"] {
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 24px;
  background: linear-gradient(135deg, var(--bg) 0%, color-mix(in srgb, var(--accent) 8%, var(--bg)) 100%);
}

section[data-layout="cover"] h1 {
  font-size: var(--h1-size);
  line-height: var(--h1-lh);
  font-weight: 800;
  color: var(--fg);
  max-width: 1400px;
}

section[data-layout="cover"] .subtitle {
  font-size: var(--h2-size);
  color: var(--muted);
  font-weight: 400;
  max-width: 1200px;
}

/* --- Layout: section -------------------------------------- */
section[data-layout="section"] {
  align-items: flex-start;
  justify-content: center;
  gap: 16px;
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 6%, var(--bg)) 0%, var(--bg) 100%);
}

section[data-layout="section"] .section-num {
  font-size: 140px;
  font-weight: 900;
  color: color-mix(in srgb, var(--accent) 18%, var(--bg));
  line-height: 1;
  margin-bottom: -20px;
  font-variant-numeric: tabular-nums;
}

section[data-layout="section"] h1 {
  font-size: var(--h1-size);
  line-height: var(--h1-lh);
  font-weight: 800;
  color: var(--fg);
  border-left: 6px solid var(--accent);
  padding-left: 32px;
}

/* --- Layout: bullets -------------------------------------- */
section[data-layout="bullets"] {
  gap: 0;
}

section[data-layout="bullets"] > header {
  margin-bottom: 48px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 32px;
}

section[data-layout="bullets"] > header h1 {
  font-size: var(--h1-size);
  line-height: var(--h1-lh);
  font-weight: 800;
  color: var(--fg);
}

section[data-layout="bullets"] > header .subtitle {
  font-size: var(--h2-size);
  color: var(--muted);
  font-weight: 400;
  margin-top: 8px;
}

section[data-layout="bullets"] > ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 20px;
  flex: 1;
  justify-content: center;
}

section[data-layout="bullets"] > ul li {
  font-size: var(--body-size);
  line-height: var(--body-lh);
  padding-left: 36px;
  position: relative;
  color: var(--fg);
}

section[data-layout="bullets"] > ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 16px;
  height: 4px;
  background: var(--accent);
  border-radius: 2px;
}

/* --- Layout: two-col -------------------------------------- */
section[data-layout="two-col"] {
  flex-direction: row;
  flex-wrap: wrap;
  gap: 0;
}

section[data-layout="two-col"] > header {
  width: 100%;
  flex: none;
  margin-bottom: 40px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 28px;
}

section[data-layout="two-col"] > header h1 {
  font-size: var(--h1-size);
  line-height: var(--h1-lh);
  font-weight: 800;
  color: var(--fg);
}

section[data-layout="two-col"] > .col {
  flex: 1;
  min-width: 0;
  padding: 32px 40px;
  background: color-mix(in srgb, var(--border) 30%, var(--bg));
  border-radius: var(--radius);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

section[data-layout="two-col"] > .col:first-of-type {
  margin-right: 24px;
  border-right: 3px solid var(--accent);
}

section[data-layout="two-col"] > .col h2 {
  font-size: var(--h2-size);
  font-weight: 700;
  color: var(--accent);
}

section[data-layout="two-col"] > .col ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

section[data-layout="two-col"] > .col ul li {
  font-size: var(--body-size);
  line-height: var(--body-lh);
  padding-left: 28px;
  position: relative;
  color: var(--fg);
}

section[data-layout="two-col"] > .col ul li::before {
  content: '▸';
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* --- Layout: statement ------------------------------------ */
section[data-layout="statement"] {
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 32px;
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 5%, var(--bg)) 0%, var(--bg) 100%);
}

section[data-layout="statement"] blockquote {
  font-size: 68px;
  font-weight: 800;
  line-height: 1.2;
  color: var(--fg);
  max-width: 1400px;
  position: relative;
  padding: 0 80px;
}

section[data-layout="statement"] blockquote::before {
  content: '\201C';
  position: absolute;
  left: 0;
  top: -20px;
  font-size: 160px;
  color: var(--accent);
  opacity: 0.3;
  line-height: 1;
  font-family: Georgia, serif;
}

section[data-layout="statement"] cite {
  font-size: var(--body-size);
  color: var(--muted);
  font-style: italic;
}

/* --- Layout: image ---------------------------------------- */
section[data-layout="image"] {
  gap: 0;
}

section[data-layout="image"] > header {
  margin-bottom: 40px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 28px;
  flex: none;
}

section[data-layout="image"] > header h1 {
  font-size: var(--h1-size);
  line-height: var(--h1-lh);
  font-weight: 800;
  color: var(--fg);
}

section[data-layout="image"] > figure {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 0;
  gap: 16px;
}

section[data-layout="image"] > figure img {
  flex: 1;
  min-height: 0;
  max-width: 100%;
  object-fit: contain;
  border-radius: var(--radius);
}

section[data-layout="image"] > figure figcaption {
  font-size: 26px;
  color: var(--muted);
  text-align: center;
}

/* --- Layout: code ----------------------------------------- */
section[data-layout="code"] {
  gap: 0;
}

section[data-layout="code"] > header {
  margin-bottom: 40px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 28px;
  flex: none;
}

section[data-layout="code"] > header h1 {
  font-size: var(--h1-size);
  line-height: var(--h1-lh);
  font-weight: 800;
  color: var(--fg);
}

section[data-layout="code"] > pre {
  flex: 1;
  min-height: 0;
  overflow: auto;
  background: var(--code-bg);
  border-radius: var(--radius);
  padding: 48px 56px;
  font-family: var(--font-mono);
  font-size: 26px;
  line-height: 1.7;
  color: var(--code-fg);
}

section[data-layout="code"] > pre code {
  font-family: inherit;
  font-size: inherit;
  background: none;
  padding: 0;
  color: inherit;
}

/* --- Layout: end ------------------------------------------ */
section[data-layout="end"] {
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 48px;
  background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 8%, var(--bg)) 0%, var(--bg) 100%);
}

section[data-layout="end"] h1 {
  font-size: var(--h1-size);
  font-weight: 800;
  line-height: var(--h1-lh);
  color: var(--fg);
}

section[data-layout="end"] .meta {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 12px 32px;
  text-align: left;
  font-size: var(--body-size);
}

section[data-layout="end"] .meta dt {
  color: var(--muted);
  font-weight: 600;
}

section[data-layout="end"] .meta dd {
  color: var(--fg);
}

/* --- Progress Bar ----------------------------------------- */
.progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 3px;
  width: 0%;
  background: var(--accent);
  z-index: 11;
  transition: width 0.2s ease;
  pointer-events: none;
}

/* --- Slide Counter ---------------------------------------- */
.counter {
  position: fixed;
  top: 10px;
  right: 16px;
  font-size: 14px;
  color: var(--muted);
  font-family: var(--font-mono);
  z-index: 11;
  pointer-events: none;
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  padding: 4px 10px;
  border-radius: 100px;
}

/* --- Nav Toggle Button ------------------------------------ */
.nav-toggle {
  position: fixed;
  top: 8px;
  left: 12px;
  z-index: 12;
  background: color-mix(in srgb, var(--bg) 90%, transparent);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--fg);
  font-size: 18px;
  width: 36px;
  height: 36px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.15s;
}

.nav-toggle:hover {
  background: var(--nav-active-bg);
  color: var(--accent);
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* --- Side Navigation -------------------------------------- */
.sidenav {
  position: fixed;
  left: 0;
  top: 0;
  bottom: 0;
  width: 320px;
  background: var(--nav-bg);
  border-right: 1px solid var(--border);
  transform: translateX(-100%);
  transition: transform 0.2s ease;
  z-index: 10;
  overflow-y: auto;
  box-shadow: 4px 0 20px rgba(0,0,0,0.1);
}

.sidenav.open {
  transform: translateX(0);
}

.sidenav-list {
  list-style: none;
  padding: 56px 0 24px;
}

.sidenav-list li {
  display: flex;
}

.sidenav-list li a {
  display: flex;
  align-items: center;
  gap: 12px;
  width: 100%;
  padding: 12px 20px;
  font-size: 16px;
  color: var(--nav-fg);
  text-decoration: none;
  transition: background 0.1s;
  border-left: 3px solid transparent;
}

.sidenav-list li a:hover {
  background: var(--nav-active-bg);
}

.sidenav-list li a.active {
  background: var(--nav-active-bg);
  border-left-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

.sidenav-list li a .nav-num {
  font-size: 13px;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  min-width: 24px;
}

/* --- Footer (auto-injected by engine.js) ------------------ */
.footer {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 56px;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 18px;
  color: var(--muted);
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  border-top: 1px solid color-mix(in srgb, var(--border) 50%, transparent);
  z-index: 5;
  pointer-events: auto;
  font-family: var(--font-sans);
}

.footer-credit {
  letter-spacing: 0.02em;
}

.footer-links {
  display: flex;
  gap: 16px;
}

.footer-links a {
  color: var(--muted);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  transition: color 0.15s, background 0.15s;
}

.footer-links a:hover {
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
}

.footer-links a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.footer-links svg {
  display: block;
}

/* --- Utility: common inline elements ---------------------- */
strong { font-weight: 700; }
em { font-style: italic; }
a { color: var(--accent); text-decoration: underline; }