* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Hiragino Sans",
    "Noto Sans JP", Meiryo, sans-serif;
  background-color: #f3f4f6;
  color: #1f2937;
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: #2563eb;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: #1d4ed8;
}

.container {
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  padding: 0 16px;
}

header {
  background-color: #111827;
  color: #ffffff;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 0;
}

.site-title {
  margin: 0;
  font-size: 1.5rem;
}

nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin: 0;
  padding: 0;
  justify-content: center;
}

nav a {
  color: #ffffff;
}

nav a:hover {
  color: #93c5fd;
}

main {
  flex: 1;
  padding: 28px 0 40px;
}

.legal-links {
  padding: 0 0 18px;
}

.legal-links ul {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 16px;
  margin: 0;
  padding: 0;
}

.legal-links a {
  color: #2563eb;
}

.legal-links a:hover {
  color: #1d4ed8;
}

.app-intro {
  margin-bottom: 24px;
}

.notice {
  display: inline-block;
  margin: 0 0 10px;
  padding: 4px 10px;
  border-radius: 999px;
  background-color: #fef3c7;
  color: #92400e;
  font-size: 0.85rem;
  font-weight: 700;
}

.app-intro h2 {
  margin: 0 0 8px;
  font-size: 1.8rem;
}

.app-intro p {
  margin: 0;
}

.features {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.feature-card {
  background-color: #ffffff;
  border-radius: 12px;
  box-shadow: 0 4px 10px rgba(15, 23, 42, 0.08);
  padding: 16px;
}

.feature-card img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 8px;
  margin-bottom: 12px;
}

.feature-card h3 {
  margin: 0 0 8px;
  font-size: 1.1rem;
}

.feature-card p {
  margin: 0;
}

.single-page {
  background-color: #ffffff;
  border-radius: 12px;
  box-shadow: 0 4px 10px rgba(15, 23, 42, 0.08);
  padding: 24px;
}

.single-page h2 {
  margin-top: 0;
}

footer {
  margin-top: auto;
  background-color: #111827;
  border-top: 1px solid #1f2937;
  padding: 18px 0 24px;
}

footer .container {
  display: block;
  text-align: center;
}

.footer-contact {
  margin: 0 0 6px;
  color: #cbd5e1;
  font-size: 0.92rem;
}

.copyright {
  margin: 0;
  color: #ffffff;
  font-size: 0.95rem;
  text-align: center;
}

@media (max-width: 768px) {
  header .container {
    padding-left: 24px;
    padding-right: 24px;
  }

  .header-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  nav ul {
    justify-content: flex-start;
  }

  .features {
    grid-template-columns: 1fr;
  }

  .legal-links ul {
    justify-content: center;
  }

  .copyright {
    text-align: center;
  }
}