:root {
  --ink: #0b1220;
  --paper: #f4f6fa;
  --muted: #3f4b5e;
  --line: rgba(11, 18, 32, 0.12);
  --sky: #0369a1;
  --sky-deep: #075985;
  --ok: #047857;
  --radius: 1rem;
  --nav-h: 5.25rem;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --fg: var(--ink);
  --fg-muted: var(--muted);
  --bg: var(--paper);
  --card: #fff;
  --btn: var(--ink);
  --btn-fg: #fff;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  height: 100dvh;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  overflow: hidden;
  -webkit-font-smoothing: antialiased;
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #f4f1ea;
    --fg-muted: rgba(244, 241, 234, 0.72);
    --bg: #0b1220;
    --card: rgba(255, 255, 255, 0.06);
    --line: rgba(244, 241, 234, 0.14);
    --btn: #38bdf8;
    --btn-fg: #0b1220;
    --sky: #7dd3fc;
    --ok: #34d399;
  }
}

html[data-scheme="dark"] {
  --fg: #f4f1ea;
  --fg-muted: rgba(244, 241, 234, 0.72);
  --bg: #0b1220;
  --card: rgba(255, 255, 255, 0.06);
  --line: rgba(244, 241, 234, 0.14);
  --btn: #38bdf8;
  --btn-fg: #0b1220;
  --sky: #7dd3fc;
  --ok: #34d399;
}

html[data-scheme="light"] {
  --fg: var(--ink);
  --fg-muted: var(--muted);
  --bg: var(--paper);
  --card: #fff;
  --line: rgba(11, 18, 32, 0.12);
  --btn: var(--ink);
  --btn-fg: #fff;
  --sky: #0369a1;
  --ok: #047857;
}

.deck { position: relative; z-index: 1; height: 100%; width: 100%; }

.slide {
  position: absolute;
  inset: 0;
  display: none;
  padding: clamp(1.25rem, 4vw, 3rem);
  padding-bottom: calc(var(--nav-h) + env(safe-area-inset-bottom, 0px) + 0.75rem);
  align-items: center;
  justify-content: center;
  overflow-x: hidden;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
  color: var(--fg);
}

.slide.is-active {
  display: flex;
  animation: rise 420ms var(--ease) both;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (prefers-reduced-motion: reduce) {
  .slide.is-active { animation: none; }
}

.frame {
  width: min(42rem, 100%);
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

.kicker {
  font-size: 0.95rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--sky);
}

h1 {
  font-size: clamp(2rem, 6vw, 3.15rem);
  line-height: 1.1;
  font-weight: 750;
  letter-spacing: -0.03em;
}

h2 {
  font-size: clamp(1.55rem, 4vw, 2.15rem);
  line-height: 1.15;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.lead, p, li {
  font-size: clamp(1.15rem, 2.4vw, 1.4rem);
  line-height: 1.45;
  color: var(--fg-muted);
}

.lead { color: var(--fg); font-weight: 500; }

.steps {
  list-style: none;
  display: grid;
  gap: 0.75rem;
}

.steps li {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.95rem 1.1rem;
  color: var(--fg);
  display: grid;
  grid-template-columns: 2.4rem 1fr;
  gap: 0.85rem;
  align-items: start;
}

.num {
  width: 2.4rem;
  height: 2.4rem;
  border-radius: 999px;
  background: var(--btn);
  color: var(--btn-fg);
  display: grid;
  place-items: center;
  font-weight: 800;
  font-size: 1.15rem;
}

.note {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.1rem;
  color: var(--fg);
}

a.guide-link {
  color: var(--sky);
  font-weight: 750;
  text-decoration: underline;
  text-underline-offset: 0.18em;
  text-decoration-thickness: 0.12em;
}

a.guide-link:hover,
a.guide-link:focus-visible {
  color: var(--sky-deep);
}

.steps li:has(> a.guide-link) {
  padding: 0;
}

.steps li > a.guide-link {
  display: grid;
  grid-template-columns: 2.4rem 1fr;
  gap: 0.85rem;
  align-items: center;
  padding: 0.95rem 1.1rem;
  color: var(--fg);
  text-decoration: none;
  font-weight: 650;
  border-radius: inherit;
}

.steps li > a.guide-link:hover,
.steps li > a.guide-link:focus-visible {
  background: color-mix(in srgb, var(--sky) 14%, var(--card));
  color: var(--fg);
}

.nav {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 5;
  height: calc(var(--nav-h) + env(safe-area-inset-bottom, 0px));
  padding: 0.7rem 1rem calc(0.7rem + env(safe-area-inset-bottom, 0px));
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 0.75rem;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  border-top: 1px solid var(--line);
  backdrop-filter: blur(14px);
}

.progress {
  font-size: 1.05rem;
  font-weight: 650;
  color: var(--fg);
  text-align: center;
  white-space: nowrap;
}

.nav-btn {
  min-height: 3.15rem;
  padding: 0 1.15rem;
  border: 0;
  border-radius: 999px;
  font: inherit;
  font-size: 1.15rem;
  font-weight: 750;
  cursor: pointer;
  background: var(--card);
  color: var(--fg);
  border: 1px solid var(--line);
}

.nav-btn:disabled {
  opacity: 0.38;
  cursor: not-allowed;
}

.nav-btn--next {
  background: var(--btn);
  color: var(--btn-fg);
  border-color: transparent;
  justify-self: end;
}

.nav-btn--back { justify-self: start; }