styles.css

html {
  scroll-behavior: smooth;
  overflow-x: hidden;
}
body {
  margin: 0;
  padding: 0;
  font-size: 16px;
  color: #808988;
  font-family: 'Montserrat', sans-serif;
}
body * { box-sizing: border-box; }
a { text-decoration: none; }
a:hover { text-decoration: underline; }
img {
  width: auto;
  max-width: 100%;
}

html[lang="en"] .lang-pl {
  display: none;
}
html[lang="en"] .lang-en {
  display: inline;
}
html[lang="pl"] .lang-pl {
  display: inline;
}
html[lang="pl"] .lang-en {
  display: none;
}

#myVideo {
  position: fixed;
  right: 0;
  top: 0;
  min-height: 100%;
  min-width: 100%;
}
.main-container {
  position: relative;
  min-height: 100%;
}
header {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  padding: 36px;
  background-color: rgba(0, 0, 0, .5);
  color: #FFFFFF;
  text-align: center;
}
header a {
  color: #FFFFFF;
}
header img.logo-image {
  width: 112px;
  opacity: .6;
}
.lang-switcher {
  align-self: flex-end;
  padding-bottom: 6px;
}
.lang-switcher a {
  text-transform: uppercase;
  font-size: 14px;
  display: inline-block;
  margin-left: 6px;
  font-family: 'Lato', sans-serif;
  font-weight: 700;
}
.lang-switcher a.active {
  color: #3BC7FF;
}
.soon-text {
  font-family: 'Lato', sans-serif;
  font-weight: 700;
  font-size: 30px;
  color: #3BC7FF;
  letter-spacing: 30px;
  position: relative;
  top: 24px;
}
.share-lock-title {
  font-size: 120px;
}
.share-lock-title img {
  vertical-align: top;
  max-width: 880px;
  width: 100%;
}
.learn-more {
  padding-bottom: 42px;
}
.social-networks a {
  display: inline-block;
  margin: 0 6px;
}
.social-networks a img {
  width: 32px;
  height: 32px;
}
.to-subscribe {
  color: #FFFFFF;
  font-size: 50px;
  line-height: 24px;
  padding-top: 24px;
}
.to-subscribe a:hover {
  text-decoration: none;
}
.subscription-container {
  background-color: #FFFFFF;
  padding: 120px 0;
}
.subscription-box {
  width: 850px;
  margin: 0 auto;
  text-align: center;
}
.subscription-box h1.slogan {
  font-family: 'Montserrat', sans-serif;
  font-weight: 400;
  margin: 0 0 24px 0;
  color: #171D1C;
  font-size: 24px;
}
.subscription-box h1.slogan span.blue-text {
  color: #3BC7FF;
}
.subscription-box h2.sub-slogan {
  font-family: 'Montserrat', sans-serif;
  font-weight: 400;
  margin: 0 0 36px 0;
  font-size: 16px;
  line-height: 28px;
}
form {
  margin: 0;
}
form label {
  display: block;
  position: relative;
}
form label::before {
  display: block;
  content: "";
  background-color: #E0E0E4;
  width: 1px;
  height: 30px;
  position: absolute;
  left: 42px;
  top: 14px;
}
form input.email-input {
  display: block;
  border: 1px solid #E0E0E4;
  line-height: 56px;
  box-shadow: none;
  border-radius: 5px;
  color: #808988;
  width: 100%;
  padding: 0 0 0 48px;
  outline: none;
  font-family: 'Montserrat', sans-serif;
  font-size: 14px;
  background: url("./assets/images/icn_email.png") no-repeat 15px 50%;
  margin-bottom: 36px;
}
form button.action-button {
  background-color: #3BC7FF;
  border: none;
  border-radius: 20px;
  color: #FFFFFF;
  font-family: 'Montserrat', sans-serif;
  font-weight: 700;
  text-transform: uppercase;
  box-shadow: none;
  outline: none;
  line-height: 40px;
  padding: 0 36px;
  margin: 0;
  cursor: pointer;
}
form .success-text,
form .error-text{
  margin: 6px 0 24px 0;
  display: none;
  border-radius: 5px;
  padding: 8px 18px;
}
form .success-text {
  border: 1px solid #2ec100;
  color: #2ec100;
}
form .error-text {
  border: 1px solid #9b0500;
  color: #9b0500;
}
form .success-text.show,
form .error-text.show{
  display: block;
}
footer {
  background-color: #09131F;
  padding: 18px 0;
  color: #FFFFFF;
  font-family: 'Lato', sans-serif;
  font-weight: 700;
  font-size: 14px;
}
footer .footer-container {
  display: flex;
  align-items: center;
  max-width: 1100px;
  margin: 0 auto;
}
footer .footer-container a {
  margin: 0 6px;
}

@media (max-width: 1111px) {
  .subscription-container, header, footer {
    padding-left: 24px;
    padding-right: 24px;
  }
  .subscription-box {
    width: 100%;
  }
  .share-lock-title {
    font-size: 34px;
  }
}

@media (max-width: 610px) {
  #myVideo {
    display: none;
  }
  header {
    background: transparent url("./assets/images/mobile_bg.png") no-repeat 0 0;
    background-size: cover;
    position: relative;
  }
  header::before {
    display: block;
    content: '';
    position: absolute;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: 0;
    background-color: rgba(0, 0, 0, .5);
  }
  header > * {
    position: relative;
  }
}

@media (max-width: 555px) {
  header img.logo-image {
    width: 81px;
  }
  .soon-text {
    font-size: 24px;
    letter-spacing: 18px;
  }
  footer .footer-container {
    flex-wrap: wrap;
  }
}

@media (max-width: 390px) {
  header {
    padding-top: 18px;
    padding-bottom: 18px;
  }
  .soon-text {
    font-size: 21px;
    letter-spacing: 12px;
  }
  .learn-more {
    padding-bottom: 30px;
  }
  .to-subscribe {
    padding-top: 12px;
  }
}