.site-header {
  position: fixed;
  top: 0;
  left: 0;
  z-index: 5;

  width: 100%;
  padding: clamp(1rem, 2vw, 1.5rem) clamp(1.25rem, 4vw, 4rem);

  display: flex;
  align-items: center;
  justify-content: space-between;

  box-sizing: border-box;
}

.logo-header {
  display: flex;
  align-items: center;
  justify-content: center;

  width: clamp(4.25rem, 7.25vw, 6.75rem);

  transition: filter 0.3s ease;
}

.logo-header:hover {
  filter: drop-shadow(0 0 5px var(--cosmic-cyan))
    drop-shadow(0 0 10px var(--cosmic-cyan));
}

.menu-ouvert-header,
.menu-ferme-header {
  position: absolute;
  top: 0;
  z-index: 6;

  display: block;

  padding: 20vh 10vw 100vh;

  background-image: linear-gradient(
    135deg,
    rgba(36, 59, 155, 0.88) 0%,
    rgba(36, 59, 155, 0.68) 25%,
    rgba(122, 63, 255, 0.48) 55%,
    rgba(18, 18, 18, 0.95) 100%
  );

  transition: right 0.5s ease;
}

.menu-ouvert-header {
  right: 0;
}

.menu-ferme-header {
  right: -100%;
}

.ul-header {
  display: flex;
  flex-direction: column;

  margin: 0;
  padding: 0;

  text-align: center;
  list-style: none;
}

.nav-header ul li {
  margin-bottom: 3vh;
}

.a-header {
  color: var(--white-star);

  font-size: 0.7rem;
  font-weight: 700;

  text-decoration: none;

  transition: text-shadow 0.3s ease;
}

.a-header:hover {
  text-shadow:
    0 0 5px var(--white-star),
    0 0 10px var(--white-star),
    0 0 20px var(--white-star);
}

.a-header:focus-visible,
.logo-header:focus-visible,
.btn-menu-header:focus-visible {
  outline: 3px solid var(--cosmic-cyan);
  outline-offset: 5px;
}

.btn-menu-header {
  z-index: 7;

  padding: 0;

  border: none;
  background: none;

  color: var(--white-star);
  font-size: clamp(1.5rem, 2vw, 2.2rem);
  
  transition: text-shadow 0.3s ease;
}

.btn-menu-header:hover {
  text-shadow:
    0 0 5px var(--white-star),
    0 0 10px var(--white-star),
    0 0 20px var(--white-star);
}


@media (min-width: 375px) {
  .nav-header ul li {
    margin-bottom: 5vh;
  }

  .a-header {
    font-size: 1rem;
  }
}

@media (min-width: 768px) {
  .site-header {
    padding-inline: clamp(2rem, 4vw, 4rem);
  }

  .nav-header ul li {
    margin-bottom: 6.5vh;
  }

  .a-header {
    font-size: 1.2rem;
  }
}

@media (min-width: 1280px) {
  .a-header {
    font-size: 1.3rem;
  }
}

@media (min-width: 1920px) {
  .site-header {
    padding-inline: 4rem;
  }

  .a-header {
    font-size: 1.5rem;
  }
}