body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
}

main p,
main li {
  font-size: 1.1em;
  text-align: justify;
}

main li {
  margin: 0 0 0.5em;
}

nav>ul>li:hover {
  background: rgba(83, 150, 167, 0.5);
  transition: all 0.5s;
}

h2 {
  font-size: 1.5em;
}

.sticky-header {
  background-color: #2c3e50;
}

nav {
  position: sticky;
  top: 0;
  z-index: 1000;
}

img {
  max-width: 100%;
}

.header-background {
  position: relative;
  height: 300px;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  text-align: center;
  padding:0 5%;
}

.header-background::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url('images/data-transfer.jpeg');
  background-size: cover;
  background-position: center;
  filter: brightness(76%) blur(3px) contrast(110%);
  z-index: 1;
}

.header-background h1 {
  position: relative;
  z-index: 2;
  font-size: 4em;
}

nav {
  background-color: #2c3e50;
}

nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  margin: 0;
  padding: 0;
  justify-content: center;
}

nav li {
  margin: 0;
}

nav a {
  font-size: 1.1em;
  display: block;
  padding: 15px 20px;
  color: #ecf0f1;
  text-decoration: none;
}

nav li.active a {
  background-color: #12856e;
  color: #fff;
}

main {
  padding: 1em 60em;
}

footer {
  background-color: #2c3e50;
  color: white;
  text-align: center;
  padding: 15px;
  margin-top: 30px;
}

.sign {
  display: flex;
  flex-direction: row;
  flex-wrap: nowrap;
  justify-content: space-between;
  align-items: flex-start;
}

.sign p.address {
  width: 50%;
}

.menu-btn {
  visibility: hidden;
  display: none;
}

@media (max-width: 2600px) {
  main {
    padding: 1em 55em;
  }
}

@media (max-width: 2600px) {
  main {
    padding: 1em 46em;
  }
}

@media (max-width: 2300px) {
  main {
    padding: 1em 37em;
  }
}

@media (max-width: 2000px) {
  .header-background h1 {
    font-size: 3.5em;
  }

  main {
    padding: 1em 28em;
  }
}

@media (max-width: 1700px) {
  .header-background h1 {
    font-size: 3em;
  }

  main {
    padding: 1em 20em;
  }
}

@media (max-width: 1500px) {
  main {
    padding: 1em 15em;
  }
}

@media (max-width: 1200px) {
  .header-background h1 {
    font-size: 2.7em;
  }
  main {
    padding: 1em 8em;
  }

  .sign p.address {
    width: 45%;
  }
}

@media (max-width: 900px) {
  .header-background h1 {
    font-size: 2.2em;
  }

  main {
    padding: 1em 3em;
  }
}

@media (max-width: 750px) {
  .sign {
    flex-direction: column;
  }

  .sign>p.address {
    width: 100%;
  }
}

@media (max-width: 650px) {
  .header-background h1 {
    font-size: 1.8em;
  }
}
@media (max-width: 600px) {
  .menu-btn {
    visibility: visible;
    display: flex;
    order: 3;
    flex-flow: row nowrap;
    align-items: center;
    justify-content: right;
    align-self: center;
  }

  nav {
    visibility: hidden;
    display: none;
  }

  nav ul {
    flex-direction: column;
  }

  .photo-gallery {
    flex-direction: column;
    align-items: center;
  }

  nav a {
    font-size: 1em;
  }

  main {
    padding: 1em;
  }

  #menu_toggle:checked~nav {
    visibility: visible;
    display: block;
  }
}