body {
  font-family: 'Noto Sans JP', sans-serif;
  margin: 0;
  background-color: #f5f7fa;
  color: #333;
  line-height: 1.6;
}

header {
  background-color: #002147;
  color: white;
  padding: 10px 0;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.header-container {
  display: flex;
  flex-direction: column;
  align-items: center;
}

header h1 {
  margin: 0;
  font-size: 1.5em;
}

nav ul {
  list-style: none;
  display: flex;
  gap: 15px;
  padding: 0;
  margin: 10px 0 0;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: bold;
}

nav a:hover {
  text-decoration: underline;
}

main {
  max-width: 900px;
  margin: auto;
  padding: 20px;
}

.card {
  background: white;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
  padding: 20px;
  margin-bottom: 20px;
}

.card h2 {
  margin-top: 0;
  color: #002147;
}

footer {
  background-color: #002147;
  color: white;
  text-align: center;
  padding: 10px;
  margin-top: 20px;
  font-size: 0.9em;
}

@media (max-width: 600px) {
  nav ul {
    flex-direction: column;
    align-items: center;
  }
}

.highlight {
  font-size: 1.6em;
  color: #002147;
  border-left: 6px solid #FFD700; /* 金色のラインで強調 */
  padding-left: 10px;
}