body{
  font-family: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

.header {
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  transition: all 0.3s ease;
}
.logo-container {
  display: flex;
  justify-content: center;
  align-items: center;
}
.logo {
  background: linear-gradient(135deg, #0066cc, #0066cc);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-size: 1.5rem;
  font-weight: bold;
  color: #2563eb;
  text-decoration: none;
}
.hamburger {
  display: none;
  flex-direction: column;
  cursor: pointer;
  gap: 5px;
}
.hamburger span {
  width: 25px;
  height: 3px;
  background-color: #333;
  display: block;
}
.nav {
  padding: 1rem 2rem;
  background-color: white;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 2rem;
}
.nav-links a {
  text-decoration: none;
  color: #333;
  font-weight: 500;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  border-bottom: 2px solid transparent;
}
.nav-links a:hover {
  border-bottom-color: #1d4ed8;
}

.nav-links .cta-button {
  border: none;
  background: #0066cc;
  padding: 0.75rem 1.5rem;
  border-radius: 0.5rem;
  color: white;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: background-color 0.3s ease;
}
.nav-links .cta-button:hover {
  background-color: #1d4ed8;
  color: white;
}

.nav-links a.active {
  border-bottom: 2px solid #1d4ed8;
}

@media (max-width: 768px) {
  .hamburger {
    display: flex;
  }
  .nav-links {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: white;
    padding: 1rem;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);

    max-height: 0;
    overflow: hidden;
    opacity: 0;
    transition: max-height 0.4s ease, opacity 0.4s ease;
  }
  .nav-links.show {
    max-height: 500px; /* big enough for links */
    opacity: 1;
  }
}