:root {
  color-scheme: light;
  --ink: #14213d;
  --muted: #56657a;
  --line: #d8e6f2;
  --blue: #2f80ed;
  --blue-dark: #185abc;
  --mint: #45d6b5;
  --yellow: #f5c84c;
  --paper: #ffffff;
  --soft: #eef8fb;
  --soft-warm: #fff6d8;
  --shadow: 0 20px 60px rgba(33, 78, 127, 0.18);
  font-family:
    "Inter", "Noto Sans JP", "Yu Gothic UI", "Hiragino Sans", Meiryo, system-ui, sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at 8% 8%, rgba(69, 214, 181, 0.16), transparent 28rem),
    radial-gradient(circle at 90% 5%, rgba(245, 200, 76, 0.18), transparent 24rem),
    linear-gradient(180deg, #f7fcff 0%, #ffffff 46%, #f4fbf8 100%);
  color: var(--ink);
  line-height: 1.7;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 14px clamp(18px, 4vw, 56px);
  background: rgba(255, 255, 255, 0.82);
  border-bottom: 1px solid rgba(216, 230, 242, 0.78);
  backdrop-filter: blur(18px);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
}

.brand-mark {
  display: grid;
  width: 38px;
  height: 38px;
  place-items: center;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--blue), var(--mint));
  color: #fff;
  font-size: 14px;
  letter-spacing: 0;
}

nav {
  display: flex;
  align-items: center;
  gap: clamp(12px, 2.4vw, 26px);
  color: var(--muted);
  font-size: 14px;
  font-weight: 700;
}

nav a {
  white-space: nowrap;
}

.nav-cta {
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--blue-dark);
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(320px, 520px);
  gap: clamp(28px, 5vw, 72px);
  align-items: center;
  min-height: calc(100vh - 68px);
  padding: clamp(36px, 7vw, 88px) clamp(18px, 5vw, 72px) clamp(26px, 5vw, 54px);
}

.hero-copy {
  max-width: 720px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--blue-dark);
  font-size: 13px;
  font-weight: 900;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  overflow-wrap: anywhere;
}

h1 {
  margin: 0;
  max-width: 10.5em;
  font-size: clamp(36px, 4.4vw, 58px);
  line-height: 1.08;
  letter-spacing: 0;
  white-space: nowrap;
}

.lead {
  max-width: 650px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: clamp(16px, 2vw, 19px);
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 30px;
}

.primary-button,
.secondary-button {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  justify-content: center;
  border-radius: 8px;
  padding: 12px 18px;
  font-weight: 900;
}

.primary-button {
  background: var(--blue);
  box-shadow: 0 12px 24px rgba(47, 128, 237, 0.24);
  color: #fff;
}

.primary-button:hover,
.primary-button:focus-visible {
  background: var(--blue-dark);
}

.secondary-button {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
}

.trust-row {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  max-width: 380px;
  margin: 34px 0 0;
}

.trust-row div {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 14px;
  background: rgba(255, 255, 255, 0.74);
}

.trust-row dt {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
}

.trust-row dd {
  margin: 2px 0 0;
  font-size: 18px;
  font-weight: 900;
}

.hero-visual {
  position: relative;
}

.hero-visual::before {
  position: absolute;
  inset: 7%;
  border-radius: 28px;
  background: linear-gradient(135deg, rgba(47, 128, 237, 0.18), rgba(69, 214, 181, 0.18));
  content: "";
  transform: rotate(-3deg);
}

.hero-visual img {
  position: relative;
  display: block;
  width: 100%;
  border: 1px solid rgba(255, 255, 255, 0.82);
  border-radius: 24px;
  box-shadow: var(--shadow);
}

.section,
.parent-band,
.cta-band {
  margin: 0 auto;
  padding: clamp(54px, 8vw, 92px) clamp(18px, 5vw, 72px);
}

.section-heading {
  max-width: 760px;
}

h2 {
  margin: 0;
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.18;
  letter-spacing: 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 18px;
  margin-top: 30px;
}

.subject-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  margin-top: 30px;
}

.subject-grid article {
  min-height: 190px;
  border-left: 5px solid var(--mint);
  border-radius: 8px;
  padding: 22px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 14px 36px rgba(33, 78, 127, 0.07);
}

.subject-grid strong {
  display: block;
  margin-bottom: 10px;
  font-size: 24px;
}

.subject-grid p {
  margin: 0;
  color: var(--muted);
}

.how-band {
  padding: clamp(54px, 8vw, 92px) clamp(18px, 5vw, 72px);
  background: #10213d;
  color: #fff;
}

.how-band .eyebrow {
  color: var(--yellow);
}

.how-band h2 {
  color: #fff;
}

.step-list {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin: 30px 0 0;
  padding: 0;
  list-style: none;
}

.step-list li {
  display: flex;
  gap: 16px;
  min-height: 180px;
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 8px;
  padding: 22px;
  background: rgba(255, 255, 255, 0.08);
}

.step-list span {
  display: grid;
  flex: 0 0 auto;
  width: 36px;
  height: 36px;
  place-items: center;
  border-radius: 8px;
  background: var(--yellow);
  color: #10213d;
  font-weight: 900;
}

.step-list h3 {
  margin-top: 0;
  color: #fff;
}

.step-list p {
  margin: 0;
  color: rgba(255, 255, 255, 0.74);
}

.example-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
  margin-top: 30px;
}

.example-list p {
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 18px 20px;
  background: #fff;
  color: var(--ink);
  font-weight: 800;
}

.feature-card {
  min-height: 230px;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 24px;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 14px 40px rgba(33, 78, 127, 0.08);
}

.feature-icon {
  display: grid;
  width: 42px;
  height: 42px;
  place-items: center;
  border-radius: 8px;
  background: var(--soft-warm);
  color: #8b6400;
  font-weight: 900;
}

h3 {
  margin: 18px 0 8px;
  font-size: 22px;
  line-height: 1.3;
}

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

.poe-card {
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.94), rgba(238, 248, 251, 0.92));
}

.parent-band {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(260px, 0.8fr);
  gap: 36px;
  align-items: center;
  background: linear-gradient(90deg, rgba(238, 248, 251, 0.92), rgba(255, 246, 216, 0.76));
}

.safety-section {
  background: rgba(238, 248, 251, 0.62);
}

.safety-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 28px;
  align-items: center;
  margin-top: 24px;
}

.safety-layout p {
  max-width: 800px;
  margin: 0;
  color: var(--muted);
  font-size: 17px;
}

.parent-band p {
  max-width: 760px;
  margin-top: 18px;
  font-size: 17px;
}

.parent-points {
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.parent-points li {
  border: 1px solid rgba(216, 230, 242, 0.86);
  border-radius: 8px;
  padding: 14px 16px;
  background: rgba(255, 255, 255, 0.78);
  font-weight: 800;
}

.cta-band {
  text-align: center;
}

.cta-band p {
  margin: 12px auto 24px;
}

footer {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 24px clamp(18px, 5vw, 72px);
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 13px;
}

@media (max-width: 860px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  nav {
    width: 100%;
    justify-content: space-between;
    overflow-x: auto;
  }

  .hero {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  h1 {
    max-width: 8em;
    white-space: normal;
    white-space: pre-line;
  }

  .hero-visual {
    max-width: 520px;
    margin: 0 auto;
  }

  .feature-grid,
  .subject-grid,
  .step-list,
  .example-list,
  .parent-band {
    grid-template-columns: 1fr;
  }

  .safety-layout {
    grid-template-columns: 1fr;
  }

  footer {
    flex-direction: column;
  }
}

@media (max-width: 520px) {
  .brand {
    font-size: 15px;
  }

  nav {
    font-size: 13px;
  }

  h1 {
    font-size: 36px;
  }

  .trust-row {
    grid-template-columns: 1fr;
  }

  .primary-button,
  .secondary-button {
    width: 100%;
  }
}