@font-face {
  font-family: 'open_sansregular';
  src: url("/assets/fonts/OpenSans-Regular-webfont.ttf");
}

@font-face {
  font-family: 'open_sansbold';
  src: url("/assets/fonts/OpenSans-Bold-webfont.ttf");
}

@font-face {
  font-family: 'source_serif_regular';
  src: url("/assets/fonts/SourceSerif4-Regular.ttf");
}

@font-face {
  font-family: 'source_serif_bold';
  src: url("/assets/fonts/SourceSerif4-Bold.ttf");
}

:root {
  --measure: 70ch;
  --space-unit: 1em;
  --space-xxs:  calc(0.25 * var(--space-unit));
  --space-xs:   calc(0.5 * var(--space-unit));
  --space-sm:   calc(0.75 * var(--space-unit));
  --space-md:   calc(1.25 * var(--space-unit));
  --space-lg:   calc(2 * var(--space-unit));
  --space-xl:   calc(3.25 * var(--space-unit));
  --space-xxl:  calc(5.25 * var(--space-unit));

  --cotech-white: white;
  --cotech-black: #000000;
  --cotech-light-grey: #646464;
  --cotech-dark-grey: #222222;
  --cotech-blue: #2DA9D7;
}

* {
  max-inline-size: var(--measure);
}

html,
body,
div,
header,
nav,
main,
footer {
  max-inline-size: none;
}

p, li, a {
  font-family: "open_sansregular", "Helvetica Neue", Helvetica, Roboto, Arial, sans-serif;
  color: var(--cotech-white);
  font-weight: 400;
}

h1, h2, h3, h4, h5, h6 {
  font-family: "source_serif_regular", Palatino, Palladio, "URW Palladio L", "Book Antiqua", Baskerville, "Bookman Old Style", "Bitstream Charter", "Nimbus Roman No9 L", Garamond, "Apple Garamond", "ITC Garamond Narrow", "New Century Schoolbook", "Century Schoolbook", "Century Schoolbook L", Georgia, serif;
  color: var(--cotech-white);
  font-weight: 400;
}

h1, h2 {
  border-left: 4px solid var(--cotech-blue);
  padding-left: var(--space-xs);
}

h3.title {
  font-family: "open_sansregular", "Helvetica Neue", Helvetica, Roboto, Arial, sans-serif;
  color: var(--cotech-white);
  font-weight: 700;
}


@media (min-width: 48em) {
  h1 {
    font-size: calc(2.625rem + ((1vw - 0.48rem) * 2.8646));
    line-height: calc(1.2 + ((1vw - 0.48) * -0.2083));
    min-height: 0vw;
  }

  h2 {
    font-size: calc(2rem + ((1vw - 0.48rem) * 1.7361));
    line-height: calc(1.2 + ((1vw - 0.48) * -0.1389));
    min-height: 0vw;
  }

  h3 {
    font-size: calc(1.625rem + ((1vw - 0.48rem) * 1.2153));
    line-height: calc(1.2 + ((1vw - 0.48) * -0.1389));
    min-height: 0vw;
  }

  h3.title {
    font-size: calc(1.25rem + ((1vw - 0.48rem) * 0.3472));
    min-height: 0vw;
  }

  p.large {
    font-size: calc(1.375rem + ((1vw - 0.48rem) * 0.6944));
    min-height: 0vw;
    line-height: 1.4;
  }

  p.intro {
    font-size: calc(1.125rem + ((1vw - 0.48rem) * 0.1736));
    min-height: 0vw;
    line-height: 1.4;
  }

  p, li, a {
    font-size: calc(0.875rem + ((1vw - 0.48rem) * 0.1736));
    min-height: 0vw;
    line-height: 1.4;
  }
}

@media (min-width: 120em) {
  h1 {
    font-size: 4.6875rem;
    line-height: 1.05;
  }

  h2 {
    font-size: 3.25rem;
    line-height: 1.1;
  }

  h3 {
    font-size: 2.5rem;
    line-height: 1.1;
  }

  h3.title {
    font-size: 1.5rem;
  }

  p.large {
    font-size: 1.875rem;
    line-height: 1.4;
  }

  p.intro {
    font-size: 1.25rem;
    line-height: 1.4;
  }

  p, li, a {
    font-size: 1rem;
    line-height: 1.4;
  }
}

body {
  background-color: var(--cotech-black);
}

img.greyscale {
  filter: grayscale(100);
}

section {
  padding: var(--space-sm);
}

.box {
  background: linear-gradient(180deg, rgba(45, 169, 215, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
  border: 1px solid var(--cotech-dark-grey);
  border-radius: var(--space-sm);
  padding: var(--space-sm);
}

.stack {
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
}

.stack > * {
  margin-block: 0;
}

.stack > * + * {
  margin-block-start: var(--space, 1.4rem);
}

.btn {
  padding: var(--space-sm) var(--space-lg);
  background: var(--cotech-white);
  color: var(--cotech-black);
  text-decoration: none;
  font-family: "open_sansbold", "Helvetica Neue", Helvetica, Roboto, Arial, sans-serif;
  border-radius: var(--space-sm);
  width: fit-content;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.btn::after {
  content: " →";
}

.btn:hover {
  background: var(--cotech-black);
  color: var(--cotech-white);
}

.header {
  display: flex;
  padding: var(--space-lg) var(--space-md);
  align-items: center;
  justify-content: space-between;
}

.header a {
  text-decoration: none;
}

.header a:hover {
  text-decoration: underline;
}

.header_logo-link {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.header_menu-list {
  font-family: 'open_sansbold';
  list-style-type: none;
  display: flex;
  gap: var(--space-md);
  font-size: 1rem;
  letter-spacing: 0.05em;
}

.header_menu-list a {
  font-family: 'open_sansbold';
}

.header_burger-btn {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-xs);
  color: var(--cotech-white);
}

.header_close-icon {
  display: none;
}

@media screen and (width < 480px) {
  .header {
    position: relative;
  }

  .header_burger-btn {
    display: block;
  }

  .header_menu-list {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background-color: var(--cotech-black);
    flex-direction: column;
    justify-content: center;
    align-items: center;
    gap: var(--space-lg);
    font-size: 1.5rem;
    z-index: 1000;
    transform: translateX(-100%);
  }

  .header_menu-list.active {
    transform: translateX(0);
  }

  .header_burger-btn.active .header_burger-icon {
    display: none;
  }

  .header_burger-btn.active .header_close-icon {
    display: block;
  }

  .header_burger-btn {
    position: relative;
    z-index: 1001;
  }
}
