header {
    position: sticky;
    top: 0;
    left: 0;
    right: 0;
    background: linear-gradient(135deg, var(--green) 60%, var(--yellow));
    color: var(--black);
    padding: 5px 30px;
    transition: transform 0.2s ease-in-out;
    z-index: 1000;
}

header.slide-up {
  transform: translateY(-100%);
}

header > div {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header nav ul {
    list-style: none;
    display: flex;
    gap: 50px;
    margin: 0;
    padding: 0;
}

header nav ul li a {
    color: var(--black);
    text-decoration: none;
    font-weight: bold;
}

header nav ul li a:hover {
    text-decoration: underline;
}

header .header-logo {
    height: 50px;
}


header .burger {
  display: none;
}

.header-overlay {
  display: none;
}

/* Burger menu */

.burger {
  position: relative;
  width: 35px;
  height: 25px;
  background: transparent;
  cursor: pointer;
  z-index: 7;
}

#burger {
  display: none;
}

.burger span {
  display: block;
  position: absolute;
  height: 3px;
  width: 100%;
  background: var(--black);
  border-radius: 9px;
  opacity: 1;
  left: 0;
  transform: rotate(0deg);
  transform-origin: left center;
  transition: 0.25s ease-in-out;
}

.burger span:nth-of-type(1) {
  top: 0px;
}

.burger span:nth-of-type(2) {
  top: 50%;
  transform: translateY(-50%);
}

.burger span:nth-of-type(3) {
  top: 100%;
  transform: translateY(-100%);
}

#burger:checked + .burger span:nth-of-type(1) {
  transform: rotate(45deg);
  left: 5px;
}

#burger:checked + .burger span:nth-of-type(2) {
  width: 0%;
  opacity: 0;
}

#burger:checked + .burger span:nth-of-type(3) {
  transform: rotate(-45deg);
  left: 5px;
}

@media (max-width: 768px) {

  header .burger {
    display: block;
  }

    header nav {
        display: none;
    }

  header nav::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 75%;
    height: 1px;
    background-color: white;
  }

  #burger:checked ~ nav {
    display: flex;
  }

  #burger:checked ~ nav ul {
    display: flex;
    flex-direction: column;
  }

  header:has(#burger:checked) .header-overlay {
    display: block;
    position: fixed;
    top: 67px;
    left: 0;
    width: 100%;
    height: 100vh;
    z-index: 5;
    background-color: rgba(0, 0, 0, 0.7);
  }

  header nav {
    position: fixed;
    top: 67px;
    left: 0;
    width: 100%;
    height: auto;
    background-color: rgba(30, 59, 36, 0.75);
    backdrop-filter: blur(50px);
    padding: 20px 0 20px 0;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    z-index: 6;
  }

  header nav ul li a {
      color: white;
      text-decoration: none;
      font-weight: bold;
  }

  header nav a {
    margin: 1rem 0;
  }
}