/* Page background, header, navigation, containers, footer */

body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: -1;
  background: #000 url("../assets/images/bg-network.jpg") center / cover no-repeat;
}

.skip-link {
  position: absolute;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 10px 16px;
  background: var(--color-white);
  color: var(--color-navy);
  font: 700 14px/1.2 var(--font-display);
  transform: translateY(-200%);
}

.skip-link:focus {
  transform: none;
}

/* Header */

.site-header {
  --color-focus: var(--color-white);
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-height);
  background: var(--color-brand-blue);
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.7);
}

.site-header__inner {
  display: flex;
  align-items: flex-start;
  height: 100%;
  padding-left: max(20px, calc((100% - var(--content-width)) / 2 - 162px));
  padding-right: 20px;
}

.site-header__logo {
  flex: none;
  margin-top: 2px;
}

.site-header__logo img {
  width: 132px;
  height: 61px;
}

.site-header__tagline {
  width: 315px;
  margin: 16px 0 0 6px;
  font: 700 17px/21px var(--font-mono);
  color: var(--color-yellow);
}

.site-header__nav {
  margin-left: auto;
  margin-top: 20px;
}

.site-header__list {
  display: flex;
  list-style: none;
}

.site-header__link {
  display: block;
  padding: 0 20px;
  font: var(--weight-light) 14px/20px var(--font-display);
  color: var(--color-white);
  text-decoration: none;
  white-space: nowrap;
  transition: color var(--transition);
}

.site-header__link:hover,
.site-header__link:focus-visible,
.site-header__link[aria-current="page"] {
  color: var(--color-yellow);
}

.site-header__toggle {
  display: none;
}

@media (max-width: 1279px) {
  .site-header__link {
    padding: 0 14px;
  }
}

@media (max-width: 1199px) {
  .site-header__inner {
    align-items: center;
  }

  .site-header__logo {
    margin-top: 0;
  }

  .site-header__logo img {
    width: 96px;
    height: auto;
  }

  .site-header__tagline {
    width: auto;
    max-width: 220px;
    margin: 0 12px 0 8px;
    font-size: 12px;
    line-height: 1.35;
  }

  .site-header__toggle {
    position: relative;
    display: block;
    flex: none;
    width: 44px;
    height: 44px;
    margin-left: auto;
    padding: 0;
    background: transparent;
    border: 0;
    cursor: pointer;
  }

  .site-header__toggle-bar,
  .site-header__toggle-bar::before,
  .site-header__toggle-bar::after {
    position: absolute;
    left: 10px;
    width: 24px;
    height: 2px;
    background: var(--color-white);
    transition: transform var(--transition), opacity var(--transition);
  }

  .site-header__toggle-bar {
    top: 21px;
  }

  .site-header__toggle-bar::before,
  .site-header__toggle-bar::after {
    content: "";
    left: 0;
  }

  .site-header__toggle-bar::before {
    top: -8px;
  }

  .site-header__toggle-bar::after {
    top: 8px;
  }

  .site-header__toggle[aria-expanded="true"] .site-header__toggle-bar {
    background: transparent;
  }

  .site-header__toggle[aria-expanded="true"] .site-header__toggle-bar::before {
    transform: translateY(8px) rotate(45deg);
  }

  .site-header__toggle[aria-expanded="true"] .site-header__toggle-bar::after {
    transform: translateY(-8px) rotate(-45deg);
  }

  .site-header__nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    margin: 0;
    max-height: calc(100vh - var(--header-height));
    overflow-y: auto;
    background: var(--color-brand-blue);
    box-shadow: 0 5px 5px rgba(0, 0, 0, 0.4);
  }

  .site-header__nav.is-open {
    display: block;
  }

  .site-header__list {
    flex-direction: column;
  }

  .site-header__link {
    padding: 14px 24px;
    font-size: 16px;
    border-top: 1px solid rgba(255, 255, 255, 0.15);
  }
}

@media (max-width: 399px) {
  .site-header__tagline {
    display: none;
  }
}

/* Containers and strips */

main {
  display: block;
  overflow-x: clip;
}

.container {
  width: 100%;
  max-width: var(--content-width);
  margin: 0 auto;
}

.strip {
  background: var(--color-white);
}

.bg-gap {
  height: 160px;
}

@media (max-width: 1019px) {
  .container {
    padding-left: 20px;
    padding-right: 20px;
  }
}

@media (max-width: 767px) {
  .bg-gap {
    height: 80px;
  }
}

/* Footer */

.site-footer {
  background: var(--color-white);
}

.site-footer__inner {
  position: relative;
  padding-top: 24px;
  padding-bottom: 7px;
}

.site-footer__copy {
  margin-left: 21px;
  font: var(--weight-light) 14px/1.4 var(--font-display);
  letter-spacing: 0.04em;
  color: var(--color-dark);
}

.site-footer__copy a {
  text-decoration: none;
}

.site-footer__copy a:hover {
  text-decoration: underline;
}

.site-footer__social {
  position: absolute;
  left: 870px;
  top: 18px;
  display: flex;
  gap: 10px;
  list-style: none;
}

.site-footer__social a {
  display: block;
  border-radius: 50%;
}

.site-footer__social img {
  width: 30px;
  height: 30px;
}

@media (max-width: 1019px) {
  .site-footer__inner {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
    padding-top: 16px;
    padding-bottom: 16px;
  }

  .site-footer__copy {
    margin-left: 0;
  }

  .site-footer__social {
    position: static;
    flex: none;
  }
}

/* 404 page */

.error-page__inner {
  min-height: 420px;
  padding-top: 24px;
  padding-bottom: 60px;
}

.error-page__text {
  max-width: 600px;
  margin: 27px 0 24px 20px;
  font: 13px/1.7 var(--font-mono);
}

.error-page__inner .btn {
  margin-left: 20px;
}