header {
  background-color: #004080;
  padding: 20px 60px;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 70px;
  z-index: 1001;

  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
}

header span {
  color: #fff;
  font-size: 1.4rem;
  font-weight: 600;
  text-align: left;
}

header div a {
  text-decoration: none;
}

header img {
  margin-left: 10px;
  max-height: 50px;
}

header nav {
  display: flex;
  gap: 25px;
}

header nav a {
  font-size: 1.2rem;
  color: #fff;
  font-weight: bold;
  text-decoration: none;
  position: relative;
  transition: color 0.3s ease, transform 0.3s ease;
}

header nav a::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -5px;
  width: 0;
  height: 2px;
  background-color: #ffd700;
  transition: width 0.3s ease;
}

header nav a:hover {
  color: #ffd700;
}

header nav a:hover::after {
  width: 100%;
}

.hamburger {
  display: none;
}

@media screen and (max-width: 768px) {
  header {
    padding: 20px 30px;
    height: 90px;
  }

  header div {
    width: 200px;
  }

  .hamburger {
    display: block;
    cursor: pointer;
    font-size: 2rem;
    color: #fff;
  }

  .menu a:not(.hamburger) {
    display: none;
  }

  .menu.responsive {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: #004080;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    row-gap: 50px;
    z-index: 1000;
  }

  .menu.responsive a:not(.hamburger) {
    display: block;
    color: #fff;
    font-size: 2rem;
    text-align: center;
  }
}