:root {
  color-scheme: light;
  --ink: #173b3a;
  --muted: #526d6b;
  --paper: #fffdf5;
  --cream: #f8f2df;
  --mint: #d8f0e5;
  --sea: #31988f;
  --sea-dark: #1f716b;
  --coral: #eb826e;
  --sun: #f5c95f;
  --line: rgba(23, 59, 58, 0.12);
  font-family: Inter, ui-rounded, "SF Pro Rounded", "Hiragino Maru Gothic ProN",
    "Noto Sans JP", "Noto Sans SC", system-ui, sans-serif;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 8%, rgba(245, 201, 95, 0.32), transparent 24rem),
    radial-gradient(circle at 88% 18%, rgba(216, 240, 229, 0.9), transparent 28rem),
    var(--cream);
  line-height: 1.7;
}

a { color: var(--sea-dark); }
a:hover { color: var(--coral); }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem clamp(1rem, 4vw, 4rem);
  background: rgba(255, 253, 245, 0.92);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(16px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 900;
  text-decoration: none;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 2.5rem;
  height: 2.5rem;
  color: white;
  background: var(--sea);
  border-radius: 42% 58% 54% 46%;
  box-shadow: 0 7px 18px rgba(31, 113, 107, 0.24);
}

.header-tools,
.language-picker,
.page-nav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.page-nav a,
.language-picker button {
  padding: 0.48rem 0.72rem;
  color: var(--ink);
  background: transparent;
  border: 0;
  border-radius: 999px;
  font: inherit;
  font-size: 0.88rem;
  font-weight: 750;
  text-decoration: none;
  cursor: pointer;
}

.page-nav a:hover,
.language-picker button:hover,
.language-picker button[aria-pressed="true"] {
  color: white;
  background: var(--sea);
}

main { min-height: calc(100vh - 13rem); }

.hero,
.page-shell {
  width: min(1080px, calc(100% - 2rem));
  margin-inline: auto;
}

.hero {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  align-items: center;
  gap: clamp(2rem, 6vw, 6rem);
  min-height: 70vh;
  padding-block: clamp(4rem, 9vw, 8rem);
}

.eyebrow {
  margin: 0 0 0.6rem;
  color: var(--sea-dark);
  font-size: 0.86rem;
  font-weight: 900;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

h1 {
  max-width: 14ch;
  margin: 0;
  font-size: clamp(2.7rem, 8vw, 6.5rem);
  line-height: 0.98;
  letter-spacing: -0.055em;
}

.tagline {
  margin: 1.35rem 0 0;
  color: var(--coral);
  font-size: clamp(1.25rem, 2.6vw, 2rem);
  font-weight: 900;
}

.lede {
  max-width: 42rem;
  margin: 1.25rem 0 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.book-visual {
  position: relative;
  aspect-ratio: 4 / 3;
  min-height: 19rem;
}

.book-page {
  position: absolute;
  inset: 8% 5%;
  border: 0.8rem solid white;
  border-radius: 2rem;
  background:
    radial-gradient(circle at 68% 30%, var(--sun) 0 8%, transparent 8.5%),
    linear-gradient(155deg, #99d9d0 0 52%, #73b887 52% 72%, #edc87e 72%);
  box-shadow: 0 28px 58px rgba(23, 59, 58, 0.22);
  transform: rotate(3deg);
}

.book-page::before,
.book-page::after {
  position: absolute;
  content: "";
  border-radius: 50%;
  background: var(--paper);
}

.book-page::before { width: 28%; height: 30%; left: 17%; bottom: 22%; }
.book-page::after { width: 22%; height: 23%; right: 17%; bottom: 27%; background: var(--coral); }

.sound-wave {
  position: absolute;
  top: 0;
  right: 0;
  color: var(--sea-dark);
  font-size: clamp(2.8rem, 8vw, 5.8rem);
  font-weight: 900;
  letter-spacing: 0.04em;
  transform: rotate(-6deg);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  width: min(1080px, calc(100% - 2rem));
  margin: 0 auto 6rem;
}

.feature-card,
.legal-card {
  padding: clamp(1.4rem, 3vw, 2.3rem);
  background: rgba(255, 253, 245, 0.94);
  border: 1px solid rgba(255, 255, 255, 0.95);
  border-radius: 1.7rem;
  box-shadow: 0 15px 40px rgba(23, 59, 58, 0.08);
}

.feature-card strong {
  display: block;
  margin-bottom: 0.45rem;
  color: var(--sea-dark);
  font-size: 1.25rem;
}

.feature-card p { margin: 0; color: var(--muted); }

.page-shell { padding-block: clamp(3rem, 8vw, 6rem); }
.page-shell > header { margin-bottom: 2rem; }
.page-shell h1 { max-width: none; font-size: clamp(2.4rem, 6vw, 4.8rem); }
.updated { color: var(--muted); font-size: 0.92rem; }
.legal-card { max-width: 880px; }
.legal-card h2 { margin: 2rem 0 0.45rem; line-height: 1.25; }
.legal-card h2:first-child { margin-top: 0; }
.legal-card p, .legal-card li { color: #344f4d; }
.legal-card ul { padding-left: 1.3rem; }

.support-actions { display: flex; flex-wrap: wrap; gap: 0.8rem; margin-top: 1.6rem; }
.button {
  display: inline-block;
  padding: 0.75rem 1rem;
  color: white;
  background: var(--sea);
  border-radius: 999px;
  font-weight: 850;
  text-decoration: none;
}
.button.secondary { color: var(--ink); background: var(--mint); }

.site-footer {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  padding: 2rem clamp(1rem, 4vw, 4rem);
  color: var(--muted);
  background: rgba(255, 253, 245, 0.72);
  border-top: 1px solid var(--line);
  font-size: 0.88rem;
}

.site-footer nav { display: flex; flex-wrap: wrap; gap: 1rem; }
.site-footer a { font-weight: 750; text-decoration: none; }

[hidden] { display: none !important; }

@media (max-width: 760px) {
  .site-header { align-items: flex-start; }
  .header-tools { justify-content: flex-end; }
  .page-nav { display: none; }
  .hero { grid-template-columns: 1fr; min-height: auto; padding-top: 4rem; }
  .book-visual { min-height: 16rem; }
  .feature-grid { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}