.header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--color-bg);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.18);
}

.header_container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
  height: var(--header-height);
}

.logo_link {
  flex-shrink: 0;
}

.logo_img {
  width: 7.5rem;
  height: auto;
}

.light_theme .logo_img {
  filter: brightness(0.8) saturate(1.2);
}

.header_list {
  display: flex;
  gap: 2.5em;
}

.header_link {
  position: relative;
  display: inline-block;
  white-space: nowrap;
  color: var(--color-text);
  transition: color var(--transition);
}

.header_link::after,
.footer_link::after,
.footer_contact_text::after {
  content: "";
  position: absolute;
  bottom: -5px;
  left: 0;
  width: 100%;
  height: 1px;
  background-color: var(--color-accent);
  transform: scaleX(0);
  transform-origin: center;
  transition: transform var(--transition);
}

.menu_extra {
  display: none;
}

.header_actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.header_btn {
  padding: 0.75em 1em;
}

.icon_btn {
  position: relative;
  display: grid;
  place-items: center;
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  color: var(--color-accent);
  border: 1px solid var(--color-button-border);
  border-radius: 0.75em;
  transition:
    color var(--transition),
    background-color var(--transition),
    border-color var(--transition);
}

.theme_icon {
  grid-area: 1 / 1;
  transition:
    opacity var(--transition),
    transform var(--transition);
}

.theme_icon_moon,
.light_theme .theme_icon_sun {
  opacity: 0;
  transform: rotate(-90deg) scale(0.5);
}

.light_theme .theme_icon_moon {
  opacity: 1;
  transform: rotate(0deg) scale(1);
}

.burger_btn {
  display: none;
}

.burger_line {
  position: absolute;
  left: 50%;
  width: 20px;
  height: 1.5px;
  margin-left: -10px;
  border-radius: 1px;
  background-color: currentColor;
  transition:
    top var(--transition),
    transform var(--transition);
}

.burger_line:nth-child(1) {
  top: 17px;
}

.burger_line:nth-child(2) {
  top: 25px;
}

.burger_btn[aria-expanded="true"] .burger_line {
  top: 21px;
}

.burger_btn[aria-expanded="true"] .burger_line:nth-child(1) {
  transform: rotate(45deg);
}

.burger_btn[aria-expanded="true"] .burger_line:nth-child(2) {
  transform: rotate(-45deg);
}

.header_link[aria-current="page"],
.footer_link[aria-current="page"] {
  color: var(--color-accent);
}

.header_link[aria-current="page"]::after,
.footer_link[aria-current="page"]::after {
  transform: scaleX(1);
}

.footer_logo {
  width: clamp(200px, 22vw, 270px);
  height: auto;
}

@media (hover: hover) {
  .header_link:hover,
  .footer_link:hover,
  .footer_contact:hover {
    color: var(--color-accent);
  }

  .header_link:hover::after,
  .footer_link:hover::after,
  .footer_contact:hover .footer_contact_text::after {
    transform: scaleX(1);
  }

  .footer_contact:hover .footer_contact_text {
    color: var(--color-accent);
  }

  .footer_contact:hover .footer_contact_text::before {
    opacity: 0;
  }
}

@media (hover: none) {
  .header_link:active,
  .footer_link:active,
  .footer_contact:active {
    color: var(--color-accent);
  }

  .header_link:active::after,
  .footer_link:active::after,
  .footer_contact:active .footer_contact_text::after {
    transform: scaleX(1);
  }
}

@media (max-width: 1200px) {
  .header_list {
    gap: 1.5em;
  }
}

@media (max-width: 1024px) {
  .header_nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    width: 100%;
    height: calc(100dvh - var(--header-height));
    display: flex;
    flex-direction: column;
    padding: 1.5rem 1.5rem 2.5rem;
    overflow-y: auto;
    background: var(--color-bg);
    border-top: 1px solid var(--color-border);
    transform: translateX(100%);
    visibility: hidden;
    transition:
      transform 0.4s ease,
      visibility 0.4s;
  }

  .header_nav.active_menu {
    transform: translateX(0);
    visibility: visible;
  }

  .header_list {
    flex-direction: column;
    gap: 0;
  }

  .header_list li {
    border-bottom: 1px solid var(--color-border);
    opacity: 0;
    transform: translateX(1.5rem);
    transition:
      opacity 0.4s ease,
      transform 0.4s ease;
  }

  .active_menu .header_list li {
    opacity: 1;
    transform: translateX(0);
  }

  .active_menu .header_list li:nth-child(2) {
    transition-delay: 0.05s; 
  }

  .active_menu .header_list li:nth-child(3) {
    transition-delay: 0.1s; 
  }

  .active_menu .header_list li:nth-child(4) {
    transition-delay: 0.15s; 
  }

  .active_menu .header_list li:nth-child(5) {
    transition-delay: 0.2s; 
  }

  .header_link {
    display: block;
    width: 100%;
    padding: 1.25rem 0;
    text-align: center;
    font-family: var(--font-title);
    font-size: 2rem;
    line-height: 125%;
  }

  .header_link::after {
    bottom: -1px;
  }

  .menu_extra {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-block: auto;
    text-align: center;
  }

  .menu_note {
    font-family: var(--font-accent);
    font-style: italic;
    font-size: 1.125rem;
    color: var(--color-text-muted);
  }

  .menu_btn {
    text-align: center;
  }

  .burger_btn {
    display: grid;
  }
}

@media (max-width: 600px) {
  .header_btn {
    display: none;
  }
}

@media (max-width: 450px) {
  .header_actions {
    gap: 0.75rem;
  }

  .logo_img {
    width: 6.25rem;
  }

  .header_nav {
    padding: 1rem 1rem 2rem;
  }

  .header_link {
    font-size: 1.75rem;
  }
}

@media (max-width: 1024px) {
  body:has(.header_nav.active_menu) {
    padding-top: var(--header-height);
  }

  body:has(.header_nav.active_menu) .header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
  }
}