:root {
  --paper: #eef1ef;
  --paper-2: #e6ebe7;
  --ink: #1d3a23;
  --ink-soft: #4a6450;
  --muted: #7d8d81;
  --line: rgba(29, 58, 35, 0.14);
  --serif: "Cormorant Garamond", "Iowan Old Style", Georgia, serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

em { font-style: italic; color: var(--ink-soft); }

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 400;
  line-height: 1.02;
  letter-spacing: -0.01em;
}

h1 { font-size: clamp(2.8rem, 6vw, 5.4rem); }
h2 { font-size: clamp(2.2rem, 4.4vw, 3.9rem); }
h3 { font-size: 1.9rem; }

.eyebrow {
  font-size: 0.72rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 1.4rem;
}

.lede {
  max-width: 26rem;
  margin-top: 1.5rem;
  color: var(--ink-soft);
  font-size: 1.02rem;
}

.btn {
  display: inline-block;
  margin-top: 2rem;
  padding: 0.9rem 1.6rem;
  border: 1px solid var(--ink);
  border-radius: 999px;
  background: var(--ink);
  color: var(--paper);
  font: 500 0.88rem var(--sans);
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: background 0.3s, color 0.3s;
}
.btn:hover { background: transparent; color: var(--ink); }
.btn-small { margin: 0; padding: 0.55rem 1.1rem; font-size: 0.8rem; }

/* Nav */
.nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.3rem clamp(1.2rem, 4vw, 3rem);
  background: linear-gradient(var(--paper) 40%, rgba(238, 241, 239, 0));
}
.brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 500;
}
.brand svg { width: 22px; height: 22px; fill: none; stroke: var(--ink); stroke-width: 1.6; stroke-linecap: round; }
.nav nav { display: flex; gap: 2.2rem; font-size: 0.88rem; color: var(--ink-soft); }
.nav nav a { position: relative; }
.nav nav a::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: -3px;
  height: 1px; background: var(--ink); transition: right 0.3s;
}
.nav nav a:hover::after { right: 0; }

/* Growth stage */
.grow { height: 100vh; min-height: 620px; position: relative; }

.stage {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: hidden;
}

#tree { position: absolute; inset: 0; width: 100%; height: 100%; display: block; touch-action: pan-y; }

.swatches {
  position: absolute;
  top: 6rem;
  right: clamp(1.2rem, 3vw, 3rem);
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  max-width: calc(100vw - 2.4rem);
  gap: 0.55rem;
  z-index: 2;
}
.swatch {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 0;
  background: var(--c);
  cursor: pointer;
  box-shadow: 0 0 0 1px rgba(29, 58, 35, 0.18);
  transition: transform 0.2s, box-shadow 0.2s;
}
.swatch:hover { transform: scale(1.12); }
.swatch[aria-checked="true"] { box-shadow: 0 0 0 2px var(--paper), 0 0 0 3.5px var(--ink); }
.swatch:focus-visible { outline: 2px solid var(--ink); outline-offset: 4px; }

.hint {
  position: absolute;
  left: 67%;
  bottom: 1.1rem;
  transform: translateX(-50%);
  font-size: 0.72rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
  opacity: 0;
  pointer-events: none;
  transition: opacity 1s;
}
.hint.show { opacity: 1; }

.chapters {
  position: absolute;
  left: clamp(1.2rem, 6vw, 6rem);
  top: 50%;
  transform: translateY(-50%);
  width: min(34rem, 40vw);
  pointer-events: none;
}

.chapter {
  position: absolute;
  top: 50%;
  left: 0;
  width: 100%;
  opacity: 0;
  transform: translateY(calc(-50% + 24px));
  transition: opacity 0.4s ease, transform 0.5s ease;
}
.chapter.active {
  transition: opacity 0.9s ease 0.45s, transform 1.1s cubic-bezier(0.2, 0.7, 0.2, 1) 0.45s;
  opacity: 1;
  transform: translateY(-50%);
  pointer-events: auto;
}

/* Age meter */
.meter {
  position: absolute;
  right: clamp(1.2rem, 3vw, 3rem);
  bottom: 2.6rem;
  width: 150px;
  font-size: 0.72rem;
  color: var(--muted);
}
.meter-label { letter-spacing: 0.22em; text-transform: uppercase; }
.meter-value {
  font-family: var(--serif);
  font-size: 3rem;
  line-height: 1.1;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}
.meter-value small { font-size: 0.9rem; margin-left: 0.3rem; color: var(--muted); font-family: var(--sans); }
.meter-track { height: 1px; background: var(--line); margin: 0.6rem 0 0.7rem; }
.meter-fill { height: 1px; width: 0; background: var(--ink); }
.meter-steps { list-style: none; display: flex; justify-content: space-between; }
.meter-steps li { transition: color 0.6s; }
.meter-steps li.on { color: var(--ink); }
.meter-fill { transition: width 0.2s linear; }

.replay {
  position: absolute;
  top: -2.4rem;
  left: 0;
  padding: 0;
  border: 0;
  background: none;
  font: 500 0.72rem var(--sans);
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.8s;
}
.replay.show { opacity: 1; pointer-events: auto; }
.replay:hover { text-decoration: underline; text-underline-offset: 4px; }

/* How it works */
.how {
  padding: 10rem clamp(1.2rem, 6vw, 6rem) 7rem;
  border-top: 1px solid var(--line);
}
.section-head { max-width: 40rem; margin-bottom: 5rem; }
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: clamp(1.5rem, 4vw, 4rem);
}
.step { border-top: 1px solid var(--ink); padding-top: 1.6rem; }
.step .num { font-family: var(--serif); font-style: italic; font-size: 1.3rem; color: var(--muted); }
.step h3 { margin: 0.6rem 0 0.9rem; }
.step p { color: var(--ink-soft); max-width: 22rem; }

/* Quote */
.quote {
  padding: 8rem clamp(1.2rem, 6vw, 6rem);
  background: var(--paper-2);
  text-align: center;
}
.quote blockquote {
  font-family: var(--serif);
  font-size: clamp(1.8rem, 3.4vw, 3rem);
  line-height: 1.2;
  max-width: 52rem;
  margin: 0 auto;
}

/* CTA */
.cta { padding: 9rem 1.2rem; text-align: center; }
.cta p { color: var(--ink-soft); margin-top: 1rem; }
.signup {
  margin: 2.4rem auto 0;
  display: flex;
  gap: 0.6rem;
  justify-content: center;
  flex-wrap: wrap;
  max-width: 30rem;
}
.signup input {
  flex: 1 1 14rem;
  padding: 0.9rem 1.3rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  font: inherit;
  color: var(--ink);
  outline: none;
}
.signup input:focus { border-color: var(--ink); }
.signup .btn { margin: 0; }
.signup .thanks { display: none; width: 100%; font-family: var(--serif); font-size: 1.4rem; font-style: italic; }
.signup.done input, .signup.done button { display: none; }
.signup.done .thanks { display: block; }

.footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 2rem clamp(1.2rem, 6vw, 6rem);
  border-top: 1px solid var(--line);
  font-size: 0.8rem;
  color: var(--muted);
}
.footer .brand { font-size: 1.3rem; color: var(--ink); }

@media (max-width: 860px) {
  .nav nav { display: none; }
  .chapters {
    top: auto;
    bottom: 1.4rem;
    left: 1.2rem;
    right: 1.2rem;
    width: auto;
    transform: none;
  }
  .chapter { top: auto; bottom: 0; transform: translateY(24px); }
  .chapter.active { transform: none; }
  .chapter .lede { font-size: 0.92rem; }
  .meter { top: 5.2rem; bottom: auto; width: 110px; }
  .meter-value { font-size: 2.2rem; }
  .meter-steps { display: none; }
  .replay { top: auto; bottom: -1.8rem; }
  .swatches {
  position: absolute;
  top: 6rem;
  right: clamp(1.2rem, 3vw, 3rem);
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  max-width: calc(100vw - 2.4rem);
  gap: 0.55rem;
  z-index: 2;
}
.swatch {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 0;
  background: var(--c);
  cursor: pointer;
  box-shadow: 0 0 0 1px rgba(29, 58, 35, 0.18);
  transition: transform 0.2s, box-shadow 0.2s;
}
.swatch:hover { transform: scale(1.12); }
.swatch[aria-checked="true"] { box-shadow: 0 0 0 2px var(--paper), 0 0 0 3.5px var(--ink); }
.swatch:focus-visible { outline: 2px solid var(--ink); outline-offset: 4px; }

.hint { left: 50%; bottom: auto; top: 64vh; }
  .steps { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .chapter { transition: none; }
}