body {
  margin: 0;
  font-family: "ビルの谷間と高架下", Arial, sans-serif;
  overflow-x: hidden;
}

header {
  background-color: #3b4140;
  color: white;
  padding: 15px 20px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

.logo-img {
  max-height: 40px;
  width: auto;
  vertical-align: middle;
  color: white;
  margin-left: -160px;
}

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

.logo {
  display: flex;
  align-items: center;
  height: 100%;
}

.hamburger-menu {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 30px;
  height: 25px;
  cursor: pointer;
  position: relative;
  z-index: 1000;
}

.hamburger-menu .bar {
  width: 100%;
  height: 3px;
  background-color: white;
  transition: all 0.3s ease;
}

.nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
}

.nav-links li {
  margin-left: 20px;
}

.nav-links a {
  color: white;
  text-decoration: none;
  font-size: 18px;
  padding: 5px 0;
  transition: color 0.3s ease;
}

.nav-links a:hover {
  color: #69d7d2;
}