:root {
  color-scheme: light;
  --bg: #eef5ff;
  --ink: #0f172a;
  --muted: #64748b;
  --line: rgba(148, 163, 184, 0.34);
  --panel: rgba(255, 255, 255, 0.88);
  --blue: #1d4ed8;
  --blue-deep: #1e3a8a;
  --sky: #0284c7;
  --cyan: #0891b2;
  --indigo: #4f46e5;
  --shadow: 0 28px 80px rgba(15, 23, 42, 0.14);
}

html.dark {
  color-scheme: dark;
  --bg: #020617;
  --ink: #f8fafc;
  --muted: #94a3b8;
  --line: rgba(100, 116, 139, 0.52);
  --panel: rgba(15, 23, 42, 0.9);
  --blue: #60a5fa;
  --blue-deep: #93c5fd;
  --sky: #38bdf8;
  --cyan: #22d3ee;
  --indigo: #818cf8;
  --shadow: 0 28px 80px rgba(0, 0, 0, 0.34);
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    linear-gradient(135deg, rgba(37, 99, 235, 0.16), transparent 34%),
    linear-gradient(315deg, rgba(79, 70, 229, 0.12), transparent 32%),
    linear-gradient(180deg, #f8fafc, var(--bg));
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont,
    "Segoe UI", sans-serif;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

.deck-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px clamp(18px, 4vw, 48px);
  background: rgba(255, 255, 255, 0.78);
  border-bottom: 1px solid rgba(255, 255, 255, 0.86);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-weight: 900;
  text-decoration: none;
}

.brand-copy {
  display: grid;
  gap: 2px;
}

.brand-copy small {
  color: var(--muted);
  font-size: 0.62rem;
  font-weight: 900;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.brand-copy strong {
  font-size: 1rem;
  line-height: 1;
}

.brand-mark {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border-radius: 8px;
  background: var(--ink);
  color: #ffffff;
}

.header-actions,
.site-nav,
.deck-nav {
  display: inline-flex;
  align-items: center;
}

.header-actions {
  gap: 18px;
}

.theme-toggle {
  position: relative;
  display: inline-flex;
  width: 64px;
  height: 40px;
  flex: 0 0 64px;
  align-items: center;
  padding: 3px;
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  background: #ffffff;
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(15, 23, 42, 0.08);
}

.theme-toggle:focus-visible {
  outline: 4px solid rgba(125, 211, 252, 0.38);
  outline-offset: 1px;
}

.theme-toggle-track {
  position: relative;
  display: grid;
  width: 100%;
  height: 32px;
  grid-template-columns: 1fr 1fr;
  place-items: center;
  overflow: hidden;
  border-radius: 5px;
  background: #e2e8f0;
  color: #475569;
  font-size: 15px;
}

.theme-toggle-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: 26px;
  height: 26px;
  border-radius: 5px;
  background: #ffffff;
  box-shadow: 0 2px 8px rgba(15, 23, 42, 0.22);
  transition: transform 180ms ease, background-color 180ms ease;
}

.theme-toggle-sun,
.theme-toggle-moon {
  position: relative;
  z-index: 1;
  line-height: 1;
}

.dark .theme-toggle {
  border-color: #334155;
  background: #0f172a;
}

.dark .theme-toggle-track {
  background: #1e3a8a;
  color: #bfdbfe;
}

.dark .theme-toggle-thumb {
  transform: translateX(26px);
  background: #e2e8f0;
}

.dark body {
  background: linear-gradient(135deg, rgba(30, 64, 175, 0.22), transparent 34%),
    linear-gradient(315deg, rgba(79, 70, 229, 0.16), transparent 32%),
    linear-gradient(180deg, #020617, var(--bg));
}

.dark .deck-header {
  border-color: rgba(51, 65, 85, 0.82);
  background: rgba(2, 6, 23, 0.84);
}

.dark .brand-mark {
  background: #f8fafc;
  color: #0f172a;
}

.dark .site-nav,
.dark .mock-topbar {
  background: rgba(30, 41, 59, 0.9);
}

.dark .site-nav a {
  background: rgba(15, 23, 42, 0.72);
  color: #f8fafc;
}

.dark .site-nav a.active,
.dark .deck-nav button,
.dark .mock-cards article,
.dark .mock-textarea {
  background: #0f172a;
  color: #e2e8f0;
}

.dark .site-nav a.active {
  background: #1e3a8a;
  color: #dbeafe;
}

.dark .site-nav a:hover,
.dark .site-nav a:focus-visible {
  background: #172554;
  color: #ffffff;
}

.dark .lead,
.dark .mock-cards p,
.dark .problem-grid p,
.dark .feature-card p,
.dark .value-board p,
.dark .flow-diagram p {
  color: #cbd5e1;
}

.dark .hero-note span {
  border-color: rgba(96, 165, 250, 0.35);
  background: rgba(15, 23, 42, 0.82);
  color: #bfdbfe;
}

.dark .mock-window {
  border-color: #334155;
  background: rgba(2, 6, 23, 0.76);
}

.dark .feature-card.strong {
  background: linear-gradient(135deg, rgba(30, 64, 175, 0.3), rgba(15, 23, 42, 0.94));
}

.site-nav {
  gap: 4px;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(248, 250, 252, 0.86);
}

.site-nav a {
  min-height: 34px;
  padding: 8px 12px;
  border-radius: 6px;
  color: #475569;
  font-size: 0.84rem;
  font-weight: 900;
  text-decoration: none;
}

.site-nav a:hover,
.site-nav a:focus-visible {
  color: var(--blue);
  outline: none;
}

.site-nav a.active {
  background: #ffffff;
  color: var(--blue);
  box-shadow: 0 6px 18px rgba(15, 23, 42, 0.08);
}

.deck-nav {
  gap: 10px;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 900;
}

.deck-nav button {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #ffffff;
  color: var(--blue);
  cursor: pointer;
  font-size: 1.3rem;
  font-weight: 900;
  line-height: 1;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
}

.deck {
  height: 100vh;
  overflow-y: auto;
  scroll-snap-type: y mandatory;
}

.slide {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1.1fr);
  gap: clamp(28px, 5vw, 72px);
  min-height: 100vh;
  padding: clamp(96px, 11vh, 132px) clamp(18px, 5vw, 72px) clamp(34px, 6vh, 72px);
  scroll-snap-align: start;
}

.slide-copy {
  align-self: center;
  min-width: 0;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--blue);
  font-size: 0.74rem;
  font-weight: 950;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  letter-spacing: 0;
}

h1,
h2 {
  margin: 0;
  max-width: 760px;
  font-size: clamp(1.9rem, 3.6vw, 3.6rem);
  font-weight: 950;
  line-height: 1.12;
}

h3 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 950;
}

.lead {
  max-width: 680px;
  margin: 24px 0 0;
  color: #334155;
  font-size: clamp(1.05rem, 1.7vw, 1.35rem);
  line-height: 1.7;
}

.hero-note {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin-top: 28px;
}

.hero-note span {
  display: inline-flex;
  min-height: 34px;
  align-items: center;
  border-radius: 8px;
  border: 1px solid rgba(37, 99, 235, 0.18);
  background: rgba(255, 255, 255, 0.78);
  color: #1e3a8a;
  padding: 0 11px;
  font-size: 0.86rem;
  font-weight: 850;
}

.product-visual,
.problem-grid,
.flow-diagram,
.feature-layout,
.value-board {
  align-self: center;
}

.mock-window {
  overflow: hidden;
  border: 1px solid rgba(255, 255, 255, 0.88);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.mock-topbar {
  display: flex;
  gap: 7px;
  padding: 16px;
  border-bottom: 1px solid var(--line);
  background: rgba(248, 250, 252, 0.9);
}

.mock-topbar span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #94a3b8;
}

.mock-grid {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 18px;
  padding: 18px;
}

.mock-sidebar,
.mock-stage,
.problem-grid article,
.feature-card,
.value-board div,
.flow-diagram div {
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 16px 40px rgba(15, 23, 42, 0.08);
}

.mock-sidebar,
.mock-stage {
  padding: 18px;
}

.mock-label {
  margin-bottom: 10px;
  color: var(--muted);
  font-size: 0.68rem;
  font-weight: 950;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.mock-textarea {
  min-height: 112px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #f8fafc;
  color: #334155;
  font-size: 0.88rem;
  line-height: 1.6;
}

.mock-button {
  display: grid;
  min-height: 40px;
  margin-top: 12px;
  place-items: center;
  border-radius: 8px;
  background: var(--blue);
  color: #ffffff;
  font-size: 0.88rem;
  font-weight: 950;
}

.mock-funnel {
  display: grid;
  gap: 7px;
  margin-top: 22px;
}

.mock-funnel span {
  display: block;
  height: 8px;
  border-radius: 999px;
}

.mock-funnel span:nth-child(1) {
  width: 100%;
  background: var(--sky);
}

.mock-funnel span:nth-child(2) {
  width: 72%;
  background: var(--blue);
}

.mock-funnel span:nth-child(3) {
  width: 46%;
  background: var(--indigo);
}

.mock-stage h2 {
  margin: 0 0 18px;
  font-size: clamp(1.4rem, 2.5vw, 2.2rem);
  line-height: 1.16;
}

.mock-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.mock-cards article {
  min-height: 150px;
  padding: 16px;
  border: 1px solid rgba(37, 99, 235, 0.18);
  border-radius: 8px;
  background: #ffffff;
}

.mock-cards b {
  display: grid;
  width: 30px;
  height: 30px;
  margin-bottom: 12px;
  place-items: center;
  border-radius: 50%;
  background: #dbeafe;
  color: var(--blue);
}

.mock-cards span {
  display: block;
  margin-bottom: 8px;
  font-weight: 950;
}

.mock-cards p,
.problem-grid p,
.feature-card p,
.value-board p,
.flow-diagram p {
  margin: 0;
  color: #475569;
  line-height: 1.62;
}

.problem-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.problem-grid article,
.feature-card,
.value-board div {
  padding: 22px;
}

.problem-grid span,
.flow-diagram span {
  display: inline-grid;
  width: 36px;
  height: 36px;
  margin-bottom: 20px;
  place-items: center;
  border-radius: 50%;
  background: #dbeafe;
  color: var(--blue);
  font-weight: 950;
}

.flow-diagram {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.flow-diagram div {
  min-height: 270px;
  padding: 22px;
}

.flow-diagram strong,
.value-board strong {
  display: block;
  margin-bottom: 10px;
  font-size: 1.05rem;
  font-weight: 950;
}

.feature-layout {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 16px;
}

.feature-card.strong {
  grid-row: span 2;
  background:
    linear-gradient(135deg, rgba(37, 99, 235, 0.13), rgba(255, 255, 255, 0.9)),
    #ffffff;
}

.feature-card h3 {
  margin-bottom: 10px;
}

.value-board {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.value-board div {
  min-height: 220px;
}

.progress {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 20;
  height: 5px;
  background: rgba(148, 163, 184, 0.2);
}

.progress span {
  display: block;
  width: 20%;
  height: 100%;
  background: linear-gradient(90deg, var(--sky), var(--blue), var(--indigo));
  transition: width 180ms ease;
}

.progress span.progress-step-1 {
  width: 20%;
}

.progress span.progress-step-2 {
  width: 40%;
}

.progress span.progress-step-3 {
  width: 60%;
}

.progress span.progress-step-4 {
  width: 80%;
}

.progress span.progress-step-5 {
  width: 100%;
}

@media (max-width: 980px) {
  .slide {
    grid-template-columns: 1fr;
    gap: 26px;
  }

  h1,
  h2 {
    font-size: clamp(1.8rem, 7vw, 3rem);
  }

  .mock-grid,
  .problem-grid,
  .flow-diagram,
  .feature-layout,
  .value-board {
    grid-template-columns: 1fr;
  }

  .flow-diagram div {
    min-height: 180px;
  }
}

@media (max-width: 640px) {
  .deck-header {
    align-items: stretch;
    flex-direction: column;
    padding-top: 12px;
    padding-bottom: 12px;
  }

  .header-actions {
    align-items: stretch;
    flex-wrap: wrap;
    gap: 8px;
    justify-content: space-between;
  }

  .site-nav,
  .deck-nav {
    justify-content: space-between;
  }

  .deck-nav {
    flex-basis: 100%;
  }

  .site-nav a {
    padding-right: 9px;
    padding-left: 9px;
  }

  .slide {
    padding-top: 202px;
  }

  .mock-cards {
    grid-template-columns: 1fr;
  }
}