:root {
  --nav-size: 60px;
  --nav-radius: 30px;
  --nav-bg: rgba(255, 255, 255, 0);
  --nav-border: #111;
  --nav-color: #111;
  --nav-shadow: 0 10px 25px rgba(0, 0, 0, 0.25);
  --nav-fade-timeout: 4000ms;
}

html {
  min-height: 100%;
  background: url('bits2.gif') repeat;
  background-size: 100px 100px;
}

*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: inherit;
  font-family: Arial, Helvetica, sans-serif;
}

.nav-arrows {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1.75rem;
  pointer-events: none;
  opacity: 1;
  transition: opacity 200ms ease;
}

.nav-arrows.nav-arrows--hidden {
  opacity: 0;
  pointer-events: none;
}

.nav-arrows.nav-arrows--light .nav-arrow {
  color: #fff;
  border-color: #fff;
}

.nav-arrow {
  width: var(--nav-size);
  height: var(--nav-size);
  display: grid;
  place-items: center;
  color: var(--nav-color);
  background: var(--nav-bg);
  border: 1px solid var(--nav-border);
  border-radius: var(--nav-radius);
  text-decoration: none;
  box-shadow: var(--nav-shadow);
  backdrop-filter: blur(8px);
  pointer-events: auto;
  transition: transform 150ms ease, box-shadow 150ms ease, background-color 150ms ease;
}

.nav-arrow i {
  font-size: 28px;
  line-height: 1;
}

.nav-arrow:hover,
.nav-arrow:focus-visible {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px rgba(0, 0, 0, 0.3);
  outline: 2px solid #0391f6;
  outline-offset: 0px;
}

.nav-arrow:active {
  transform: translateY(0);
}

.nav-arrow.is-disabled {
  opacity: 0.35;
  pointer-events: none;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

@media (max-width: 600px) {
  :root {
    --nav-size: 56px;
    --nav-radius: 30px;
  }

  .nav-arrows {
    padding: 1.4rem;
  }

  .nav-arrow i {
    font-size: 24px;
  }

  html,
  body {
    background-size: 100px 100px;
  }
}