/* Basic reset */
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
}

:root {
  /* Default: Dark theme */
  --bg: #0b1020;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --primary: #60a5fa;
  --accent: #22d3ee;

  --border: rgba(148,163,184,0.2);
  --card-border: rgba(148,163,184,0.2);
  --image-border: rgba(148,163,184,0.25);
  --panel-border: rgba(148,163,184,0.2);

  --card-bg: linear-gradient(180deg, rgba(15,23,42,0.9), rgba(15,23,42,0.6));
  --badge-bg: rgba(15,23,42,0.5);
  --panel-bg: rgba(15,23,42,0.7);
  --code-bg: rgba(2,6,23,0.6);
  --code-text: #e5e7eb;

  /* --- Compare layout & badges --- */
  --hot-bg: linear-gradient(180deg, rgba(239,68,68,0.18), rgba(234,88,12,0.14));
  --hot-border: rgba(251,113,133,0.5);
  --cold-bg: linear-gradient(180deg, rgba(59,130,246,0.18), rgba(34,211,238,0.14));
  --cold-border: rgba(96,165,250,0.5);
}

:root[data-theme="light"] {
  --bg: #f8fafc;
  --text: #0f172a;
  --muted: #334155;
  --border: rgba(15,23,42,0.12);
  --card-border: rgba(15,23,42,0.12);
  --image-border: rgba(15,23,42,0.12);
  --panel-border: rgba(15,23,42,0.12);

  --card-bg: linear-gradient(180deg, rgba(255,255,255,0.95), rgba(255,255,255,0.85));
  --badge-bg: rgba(255,255,255,0.75);
  --panel-bg: rgba(255,255,255,0.85);
  --code-bg: rgba(2,6,23,0.06);
  --code-text: #0f172a;
}

/* Book media layout */
.book-media { display: grid; grid-template-columns: 280px 1fr; gap: 20px; align-items: start; }
.book-media img { width: 100%; height: auto; object-fit: cover; border-radius: 12px; border: 1px solid var(--image-border); box-shadow: 0 10px 24px rgba(0,0,0,0.35); }
.book-meta h3 { margin-top: 0; margin-bottom: 8px; }
@media (max-width: 820px) { .book-media { grid-template-columns: 1fr; } }

/* Deck layout */
.deck {
  position: relative;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
}
.slide {
  position: absolute;
  inset: 0;
  padding: 60px 80px;
  display: none;
  flex-direction: column;
  justify-content: center;
  background: radial-gradient(1200px 800px at 80% -10%, rgba(34,211,238,0.08), transparent),
              radial-gradient(900px 700px at -10% 100%, rgba(96,165,250,0.1), transparent),
              var(--bg);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity .35s ease, transform .35s ease;
}
.slide.active {
  display: flex;
  opacity: 1;
  transform: none;
}

/* Center slide titles */
.slide > h1,
.slide > h2 { text-align: center; }

/* Comparison slides */
.slide.compare .cols {
  display: grid;
  gap: 20px;
}
.slide.compare.phase-1 .cols { grid-template-columns: 1fr 1fr; }
.slide.compare.phase-2 .cols { grid-template-columns: 1fr 1fr; }

.slide.compare .col {
  border-radius: 16px;
  padding: 20px 22px;
  border: 1px solid var(--border);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.03), 0 10px 30px rgba(0,0,0,0.25);
  backdrop-filter: blur(2px);
  transition: all .35s ease;
}
.slide.compare .col.hot {
  background: var(--hot-bg);
  border-color: var(--hot-border);
}
.slide.compare .col.cold {
  background: var(--cold-bg);
  border-color: var(--cold-border);
}

/* Keep two equal columns at all times on compare slides */
.slide.compare .cols { grid-template-columns: 1fr 1fr; }
.slide.compare.phase-1 .cols { grid-template-columns: 1fr 1fr; }

/* Cold column is hidden but keeps layout space in phase-1 */
.slide.compare.phase-1 .col.cold {
  opacity: 0;
  transform: translateY(8px) scale(0.98);
  pointer-events: none;
}
.slide.compare.phase-2 .col.cold { opacity: 1; transform: none; }

h1, h2, h3 { color: var(--text); margin: 0 0 16px; line-height: 1.1; }
h1 { font-size: clamp(56px, 7.5vw, 96px); font-weight: 800; letter-spacing: -0.025em; }
h2 { font-size: clamp(48px, 6vw, 80px); font-weight: 800; letter-spacing: -0.02em; }
h3 { font-size: 28px; font-weight: 700; }

p, li { color: var(--text); font-size: 22px; line-height: 1.6; }
.small { color: var(--muted); font-size: 16px; }

hr { border: 0; border-top: 1px solid var(--border); margin: 24px 0; }

/* Cards */
.card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 20px 24px;
  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

/* Bullets */
ul { list-style: none; padding: 0; margin: 0; }
li { position: relative; padding-left: 28px; margin: 8px 0; }
li::before {
  content: '';
  position: absolute;
  left: 0; top: 12px;
  width: 10px; height: 10px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--primary), var(--accent));
  box-shadow: 0 0 12px rgba(34,211,238,0.5);
}

/* Help */
.help {
  position: fixed;
  bottom: 14px; left: 50%; transform: translateX(-50%);
  color: var(--muted);
  font-size: 14px;
  background: var(--panel-bg);
  border: 1px solid var(--panel-border);
  border-radius: 999px;
  padding: 8px 14px;
}

/* Overview grid */
.overview .slide {
  display: block !important;
  position: static !important;
  height: auto;
  min-height: 160px;
  padding: 16px;
  opacity: 1;
  transform: none;
}
.overview .deck {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(480px, 1fr));
  gap: 18px;
  padding: 22px;
  overflow: auto;
}

/* Overview: show only slide titles as cards */
.overview .slide { min-height: 160px; padding: 16px; opacity: 1; transform: none; }
/* keep only titles visible */
.overview .slide > :not(h1):not(h2) { display: none !important; }
.overview .slide > h1,
.overview .slide > h2 {
  display: block;
  text-align: center;
  font-size: clamp(22px, 2.4vw, 30px);
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  padding: 14px 16px;
  margin: 0;
  box-shadow: 0 10px 30px rgba(0,0,0,0.25);
}

/* Overview UI/UX tweaks: smaller centered title card */
.overview .slide {
  display: flex !important;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.overview .slide > h1,
.overview .slide > h2 {
  width: min(90%, 720px);
  padding: 12px 14px;
  border-radius: 12px;
  cursor: pointer;
  transition: transform .18s ease, box-shadow .2s ease, border-color .2s ease;
}
.overview .slide:hover > h1,
.overview .slide:hover > h2,
.overview .slide:focus-within > h1,
.overview .slide:focus-within > h2 {
  border-color: var(--primary);
  box-shadow: 0 14px 34px rgba(0,0,0,0.35), 0 0 0 3px rgba(96,165,250,0.15) inset;
  transform: translateY(-2px);
}

/* Images */
.slide img { max-width: 100%; border-radius: 12px; border: 1px solid var(--image-border); }

/* Code blocks (if any) */
pre, code { background: var(--code-bg); color: var(--code-text); }
pre { padding: 16px; border-radius: 12px; overflow: auto; }
code { padding: 2px 6px; border-radius: 6px; }

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  border: 1px solid var(--panel-border);
  background: var(--badge-bg);
}
.badge .icon { font-size: 16px; }

/* Section titles spacing in compare cards */
.slide.compare h3 { margin-top: 0; margin-bottom: 10px; }
.slide.compare ul { margin-top: 10px; }

/* Reveal for practical/notes block in compare slides */
.slide.compare .notes-block {
  opacity: 0;
  transform: translateY(8px) scale(0.98);
  transition: opacity .35s ease, transform .35s ease;
}
.mt-16 { margin-top: 16px !important; }
.mt-20-center { margin-top: 20px !important; text-align: center !important; }
.mt-12-center { margin-top: 12px !important; text-align: center !important; }
.w-260 { width: 260px !important; height: auto !important; }
.slide.compare.phase-3 .notes-block {
  opacity: 1;
  transform: none;
}

/* Compact variant: title and description inline in notes-block */
.slide.compare .notes-block.compact li { margin: 6px 0; }
.slide.compare .notes-block.compact li .li-title,
.slide.compare .notes-block.compact li .li-desc { display: inline; }
.slide.compare .notes-block.compact li .li-title {
  font-size: 22px;
  font-weight: 800;
  margin-right: 6px;
}
.slide.compare .notes-block.compact li .li-desc { font-size: 20px; opacity: 0.95; }
.slide.compare .notes-block.compact li .li-title::after { content: ': '; }

/* List item title/description formatting */
li .li-title {
  display: block;
  font-size: 24px;
  font-weight: 800;
  letter-spacing: -0.01em;
  margin-bottom: 6px;
  color: var(--text);
}
li .li-desc {
  display: block;
  font-size: 20px;
  line-height: 1.6;
  color: var(--text);
  opacity: 0.95;
}
/* Slightly larger in compare columns */
.slide.compare li .li-title { font-size: 26px; }
.slide.compare li .li-desc { font-size: 20px; }

/* Agenda layout: centered card and larger items */
.slide.agenda .card,
.slide.narrow .card {
  width: min(1100px, 90vw);
  margin: 24px auto 0;
}
.slide.agenda li {
  font-size: clamp(24px, 3vw, 32px);
  line-height: 1.6;
}

/* Overview layout refinements: denser grid and smaller title cards */
.overview .deck {
  /* show more cards per row on wide screens */
  grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
}
/* smaller slide tile height */
.overview .slide { min-height: 130px; }
/* narrower title bar and slightly smaller type */
.overview .slide > h1,
.overview .slide > h2 {
  width: min(88%, 640px);
  font-size: clamp(20px, 2vw, 26px);
  padding: 10px 12px;
  border-radius: 10px;
}

/* Intro slide refinements */
.slide.intro { align-items: center; }
.slide.intro h1 { margin-bottom: 10px; }
.slide.intro .subtitle {
  margin: 0 0 18px;
  font-size: clamp(28px, 3.2vw, 40px);
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
  text-align: center;
  background: linear-gradient(90deg, rgba(34,211,238,0.24), rgba(96,165,250,0.24));
  -webkit-background-clip: text;
  background-clip: text;
  color: var(--text);
}
.slide.intro .card { width: min(1100px, 92vw); margin: 10px auto 0; text-align: left; }
.slide.intro .card p { font-size: clamp(20px, 2.2vw, 26px); }
.slide.intro h1 {
  background: linear-gradient(90deg, rgba(34,211,238,0.18), rgba(96,165,250,0.18));
  -webkit-background-clip: text;
  background-clip: text;
  color: var(--text);
}

/* QR inline on intro card */
.slide.intro .qr-inline {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-top: 12px;
}
.slide.intro .qr-inline img {
  width: 160px;
  height: auto;
  border-radius: 8px;
  border: 1px solid var(--image-border);
}
.slide.intro .qr-inline .small { margin: 0; }

/* Intro slide date */
.slide.intro .date {
  margin: 4px 0 8px;
  text-align: center;
  color: var(--muted);
}

/* Theme toggle button */
#theme-toggle {
  position: fixed;
  top: 12px;
  right: 12px;
  z-index: 1000;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 999px;
  border: 1px solid var(--panel-border);
  background: var(--panel-bg);
  color: var(--text);
  box-shadow: 0 6px 18px rgba(0,0,0,0.25);
  cursor: pointer;
  user-select: none;
}
#theme-toggle:hover { transform: translateY(-1px); }
#theme-toggle:focus { outline: none; box-shadow: 0 0 0 3px rgba(96,165,250,0.35); }
#theme-toggle .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;
}

/* Mobile overrides: stack content vertically and enable page scroll */
@media (max-width: 820px) {
  .deck.mobile {
    display: block;
    width: 100vw;
    min-height: 100vh;
    height: auto;
    overflow-y: auto;
    overflow-x: hidden;
  }
  .deck.mobile .slide {
    position: relative;
    inset: auto;
    display: block !important; /* one slide per block */
    width: auto;
    min-width: 0;
    height: auto;
    min-height: 0;
    padding: 50px 10px; /* keep spacing between slides */
    opacity: 1;
    transform: none;
    scroll-snap-align: none;
  }
  /* Stack compare columns into single column */
  .deck.mobile .slide.compare .cols { grid-template-columns: 1fr !important; }
  .deck.mobile .slide.compare .col { margin-bottom: 12px; }
  /* Always reveal compare cold column and notes on mobile */
  .deck.mobile .slide.compare .col.cold { opacity: 1 !important; transform: none !important; pointer-events: auto !important; }
  .deck.mobile .slide.compare .notes-block { opacity: 1 !important; transform: none !important; }

  /* Reposition help above nav arrows to avoid overlap */
  .help { bottom: 72px; }

  /* Add spacing between slides */
  .deck.mobile .slide { padding: 50px 10px; }

  /* Hide quick actions bar on mobile */
  .help { display: none !important; }

  /* Typography scale for mobile */
  h1 { font-size: clamp(28px, 8vw, 40px); }
  h2 { font-size: clamp(24px, 6.5vw, 32px); }
  h3 { font-size: 20px; }
  p, li { font-size: 18px; line-height: 1.65; }
  .slide.agenda li { font-size: clamp(18px, 4.2vw, 22px); }
  .slide.intro .subtitle { font-size: clamp(18px, 4.5vw, 24px); }
  .slide.intro .qr-inline { justify-content: center; }

  /* Bullet sizing and spacing */
  li { padding-left: 22px; }
  li::before { width: 8px; height: 8px; top: 10px; }

  /* Title/desc sizing in list items */
  li .li-title { font-size: 20px; }
  li .li-desc { font-size: 18px; }
  .slide.compare li .li-title { font-size: 22px; }
  .slide.compare li .li-desc { font-size: 18px; }

  /* Badges */
  .badge { font-size: 12px; padding: 4px 8px; }
  
  /* Keep all phased content visible on mobile */
  .deck.mobile .phase-content { opacity: 1 !important; }
}

/* --- Phased content visibility (moved from inline) --- */
.phase-content { opacity: 0; transition: opacity 0.3s ease-in-out; }
.slide.phase-2 .phase-content.phase-2 { opacity: 1; }
.slide.phase-3 .phase-content.phase-2,
.slide.phase-3 .phase-content.phase-3 { opacity: 1; }
.slide.phase-4 .phase-content.phase-2,
.slide.phase-4 .phase-content.phase-3,
.slide.phase-4 .phase-content.phase-4 { opacity: 1; }
.slide.phase-5 .phase-content.phase-2,
.slide.phase-5 .phase-content.phase-3,
.slide.phase-5 .phase-content.phase-4,
.slide.phase-5 .phase-content.phase-5 { opacity: 1; }

/* --- Toolkit grid layout (moved from inline) --- */
.toolkit-grid {
  display: grid !important;
  grid-template-columns: repeat(3, minmax(0, 1fr)) !important;
  gap: 20px !important;
  margin-bottom: 20px !important;
}
.slide.narrow .toolkit-grid {
  max-width: 1400px;
  margin: 22px auto 0;
  gap: 22px !important;
}
.toolkit-grid .card {
  margin: 0 !important;
  padding: 20px !important;
  font-size: 1em !important;
  width: 100% !important;
  min-height: 140px;
  transition: transform .18s ease, box-shadow .2s ease, border-color .2s ease;
}
.toolkit-grid .card h3 {
  font-size: 24px !important;
  margin-bottom: 8px !important;
  font-weight: 700 !important;
}
.toolkit-grid .card ul { margin: 0 !important; padding-left: 16px !important; }
.toolkit-grid .card li {
  margin: 6px 0 !important;
  font-size: 18px !important;
  line-height: 1.5 !important;
  padding-left: 20px !important;
}
.toolkit-grid .card li::before { width: 8px !important; height: 8px !important; top: 10px !important; }
.toolkit-grid .card p { font-size: 20px !important; margin: 8px 0 !important; line-height: 1.55 !important; }

/* Hover/focus polish */
.toolkit-grid .card:hover,
.toolkit-grid .card:focus-within {
  transform: translateY(-2px);
  border-color: var(--primary);
  box-shadow: 0 14px 34px rgba(0,0,0,0.35), 0 0 0 3px rgba(96,165,250,0.15) inset;
}

/* Single card layout for phase-2 */
/* Keep cards horizontal on desktop; stack on mobile */
@media (max-width: 820px) {
  .toolkit-grid { grid-template-columns: 1fr !important; }
}

/* Medium breakpoint: 2 columns */
@media (min-width: 821px) and (max-width: 1199px) {
  .toolkit-grid { grid-template-columns: repeat(2, 1fr) !important; }
}

/* CTA accent card */
.card.card-cta {
  border-color: var(--primary);
  background: linear-gradient(180deg, rgba(96,165,250,0.12), rgba(34,211,238,0.10));
}