header {
  z-index: 9999;
  position: fixed;
  top: 0;
  bottom: auto;
  right: 0;
  left: 0;
  width: 100%;
  background-color: var(--c1);
}

header .flex-box {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: nowrap;
}

header .flex-box .logo {
  width: 9.51684vw;
}

header .flex-box nav ul {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: nowrap;
}