:root {
  color-scheme: light;
  --bg: #f5f7f8;
  --surface: #ffffff;
  --text: #162126;
  --muted: #5b6a72;
  --line: #d8e0e4;
  --accent: #007c89;
  --accent-dark: #005d68;
  --warning-bg: #fff7df;
  --warning-line: #eed48a;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", "YuGothic", "Meiryo", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-size: 16px;
  line-height: 1.8;
}

img {
  max-width: 100%;
  display: block;
}

a {
  color: var(--accent-dark);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 14px max(18px, calc((100vw - 1120px) / 2));
  background: rgba(255, 255, 255, 0.94);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.brand {
  color: var(--text);
  font-weight: 800;
  font-size: 1.25rem;
  white-space: nowrap;
}

.nav {
  display: flex;
  gap: 6px;
  overflow-x: auto;
  white-space: nowrap;
}

.nav a {
  color: var(--muted);
  font-weight: 700;
  padding: 8px 10px;
  border-radius: 6px;
}

.nav a[aria-current="page"] {
  color: var(--accent-dark);
  background: #e4f3f5;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(240px, 360px);
  gap: 48px;
  align-items: center;
  max-width: 1120px;
  margin: 0 auto;
  padding: 56px 20px 48px;
}

.hero-text h1,
.document h1 {
  margin: 0 0 18px;
  font-size: clamp(2rem, 5vw, 4.4rem);
  line-height: 1.15;
}

.hero-text p,
.section p {
  color: var(--muted);
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--accent-dark);
  font-weight: 800;
  letter-spacing: 0;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 26px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 10px 18px;
  border-radius: 6px;
  font-weight: 800;
}

.button.primary {
  color: #ffffff;
  background: var(--accent);
}

.button.secondary {
  color: var(--accent-dark);
  border: 1px solid var(--accent);
  background: #ffffff;
}

.phone-shot {
  margin: 0;
}

.phone-shot img {
  width: min(100%, 320px);
  margin: 0 auto;
  border-radius: 8px;
  border: 1px solid #111;
  box-shadow: 0 20px 42px rgba(22, 33, 38, 0.2);
}

.section {
  max-width: 1120px;
  margin: 0 auto;
  padding: 42px 20px;
}

.section h2 {
  margin: 0 0 16px;
  font-size: clamp(1.5rem, 3vw, 2.3rem);
  line-height: 1.3;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 14px;
}

.feature-grid article,
.faq-list details {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 18px;
}

.feature-grid h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
}

.feature-grid p {
  margin: 0;
}

.screenshots {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.screenshots figure {
  margin: 0;
}

.screenshots img {
  width: 100%;
  border-radius: 8px;
  border: 1px solid #1b1b1b;
  background: #000000;
}

.screenshots figcaption {
  margin-top: 8px;
  color: var(--muted);
  font-weight: 700;
  text-align: center;
}

.notice {
  margin-bottom: 24px;
  background: var(--warning-bg);
  border: 1px solid var(--warning-line);
  border-radius: 8px;
}

.page {
  min-height: calc(100vh - 170px);
}

.document {
  max-width: 840px;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 8px;
  margin-top: 32px;
  margin-bottom: 32px;
  padding: 34px 28px;
}

.document h2 {
  margin-top: 34px;
  font-size: 1.45rem;
}

.document ul {
  padding-left: 1.3em;
}

.faq-list {
  display: grid;
  gap: 12px;
}

.faq-list summary {
  cursor: pointer;
  font-weight: 800;
}

.faq-list p {
  margin-bottom: 0;
}

.site-footer {
  max-width: 1120px;
  margin: 0 auto;
  padding: 28px 20px 42px;
  color: var(--muted);
  border-top: 1px solid var(--line);
}

.site-footer p {
  margin: 4px 0;
}

@media (max-width: 820px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 28px;
    padding-top: 36px;
  }

  .feature-grid,
  .screenshots {
    grid-template-columns: 1fr;
  }

  .screenshots img {
    width: min(100%, 340px);
    margin: 0 auto;
  }

  .document {
    margin-top: 18px;
    padding: 26px 20px;
  }
}

@media (max-width: 460px) {
  body {
    font-size: 15px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .button {
    width: 100%;
  }
}