$font-size: 18px;
$heading-font-size: $font-size + 1;
$code-block-font-size: $font-size - 1;
$line-height: 1.5;

$page-item-prefix-max-chars: 3ch;
$page-item-prefix-pad: 2ch;
$page-item-prefix-width: $page-item-prefix-max-chars + $page-item-prefix-pad;

$subcontent-indent: 4ch;

$breakpoint-sm: 700px;

@function px-to-em($s, $b: $font-size) {
  @return 1 / ($b / 1px) * ($s / 1px) * 1em;
}

@function str-repeat($s, $n) {
  $r: "";
  @while $n > 0 {
    $r: $r + $s;
    $n: $n - 1;
  }
  @return $r;
}

@font-face {
  font-family: "Iosevka Term SS09";
  font-style: normal;
  font-weight: normal;
  src: url("/iosevka-term-ss09-regular.woff2") format("woff2");
}

@font-face {
  font-family: "Iosevka Term SS09";
  font-style: normal;
  font-weight: bold;
  src: url("/iosevka-term-ss09-bold.woff2") format("woff2");
}

:root {
  --gray1: hsl(270, 0%, 9.7%);
  --gray2: hsl(270, 1%, 29%);
  --gray3: hsl(270, 2%, 54%);
  --gray4: hsl(270, 2%, 73%);
  --gray5: hsl(270, 2%, 83%);
  --gray6: hsl(270, 2%, 100%);

  --bg: var(--gray1);
  --bg-plus: var(--gray2);
  --fg-minus: var(--gray3);
  --fg: var(--gray4);
  --fg-plus: var(--gray6);

  --select-bg: hsla(270, 2%, 100%, 0.996);
  --select-fg: var(--gray1);

  --code-fg: var(--fg-minus);
  --code-block-fg: var(--fg-minus);

  --page-item-prefix-fg: var(--fg-minus);

  --link-idle-fg: var(--gray6); //#90acf2; //var(--gray6);
  --link-visited-fg: var(--gray5); //#bc9df2; //var(--gray5);
  --link-hover-bg: var(--gray6);
  --link-hover-fg: var(--gray1);

  --heading: var(--fg-plus);
}

::selection {
  color: var(--select-fg);
  background-color: var(--select-bg);
}

html,
pre,
code {
  font-family: "Iosevka Term SS09", "Lucida Console", "Courier New", Courier,
    monospace;
  font-feature-settings: "calt" 0, "dlig" 1;
}

html {
  font-size: px-to-em($font-size, 16px);
  line-height: $line-height;
  background-color: var(--bg);
  color: var(--fg);
}

body {
  margin: 2em;
  padding: 0;

  @media (max-width: $breakpoint-sm) {
    margin: 1em;
  }
}

main {
  max-width: 70ch;
  margin: 0 auto;
}

code {
  color: var(--code-fg);
}

pre {
  margin: 0;
  color: var(--code-block-fg);
  font-size: $code-block-font-size;
  line-height: 1.4;

  strong {
    font-weight: normal;
  }
}

strong {
  color: var(--fg-plus);
  font-weight: bold;
}

ul,
ol {
  margin: ($line-height * 1rem) 0 0;
  padding: 0;
  list-style: none;

  > li {
    position: relative;
    padding-left: $subcontent-indent;

    &::before {
      position: absolute;
      display: inline-block;
      width: $subcontent-indent;
      margin-left: -1 * $subcontent-indent;
      color: var(--fg-minus);
    }
  }
}

ul {
  > li::before {
    content: "-";
  }

  &.refs > li {
    padding-left: 0;

    &::before {
      display: none;
    }
  }
}

ol {
  counter-reset: cnt;

  > li {
    counter-increment: cnt;

    &::before {
      content: counter(cnt) ".";
    }
  }
}

h1,
h2,
h3 {
  margin: ($line-height * 2rem) 0 0;

  + h1,
  + h2,
  + h3 {
    margin-top: $line-height * 1rem;
  }
}

h1 {
  text-transform: uppercase;
  font-size: px-to-em($heading-font-size);
  color: var(--heading);
}

h2 {
  font-size: 1em;
  color: var(--heading);
}

h3 {
  font-size: 1em;
}

p {
  margin: ($line-height * 1em) 0 0;
}

a {
  position: relative;
  z-index: 1000;
  padding: 0.1em 0.3em;
  margin: 0 -0.3em;
  color: var(--link-idle-fg);

  &:visited {
    color: var(--link-visited-fg);
  }

  &:hover {
    background-color: var(--link-hover-bg);
    color: var(--link-hover-fg);
    text-decoration: none;
  }
}

hr {
  height: 1px;
  margin: ($line-height * 2rem) 0 ($line-height * 2rem);
  background-color: var(--bg-plus);
  border: 0;

  @media (max-width: $breakpoint-sm) {
    margin-left: 0;
  }
}

blockquote {
  position: relative;
  margin: ($line-height * 1rem) 0 0;
  padding-left: calc(#{$subcontent-indent} - 2px);
  border-left: 2px solid var(--bg-plus);
}

.c-page-header {
  margin-bottom: $line-height * 2rem;
  overflow: hidden;

  &::after {
    position: relative;
    z-index: -10;
    content: str-repeat("░", 120);
    display: block;
    height: $line-height;
    margin-top: px-to-em(2px);
    padding-top: px-to-em(2px);
    color: var(--fg-minus);
    border-top: 1px solid var(--fg-minus);
  }

  &--sm {
    display: none;
  }

  @media (max-width: $breakpoint-sm) {
    display: none;

    &--sm,
    &--nohide {
      display: block;
    }
  }
}

.s-page {
  padding-left: $page-item-prefix-width;

  h1,
  h2,
  h3,
  ul.refs > li,
  pre {
    position: relative;
    margin-left: -1 * $page-item-prefix-width;
    padding-left: $page-item-prefix-width;

    &::before {
      position: absolute;
      box-sizing: border-box;
      display: inline-block;
      margin-left: -1 * $page-item-prefix-width;
      padding-right: $page-item-prefix-pad;
      width: $page-item-prefix-width;
      color: var(--page-item-prefix-fg);
      font-size: 1rem;
      font-weight: normal;
      text-align: right;
    }

    @media (max-width: $breakpoint-sm) {
      margin-left: 0;
      padding-left: 0;

      &::before {
        display: none;
      }
    }
  }

  h1::before {
    content: "#";
  }

  h2::before {
    content: "##";
  }

  h3::before {
    content: "###";
  }

  ul.refs > li::before {
    content: "|>";
  }

  pre::before {
    content: str-repeat("``\A", 40);
    height: 100%;
    color: var(--page-item-prefix-fg);
    overflow: hidden;
    line-height: 1.4 * ($code-block-font-size / $font-size)
  }

  hr {
    margin-left: -1 * $page-item-prefix-width;
  }

  .c-page-header {
    margin-left: -1 * $page-item-prefix-width;
    padding-left: $page-item-prefix-width;

    &::after {
      margin-left: -1 * $page-item-prefix-width;
    }

    @media (max-width: $breakpoint-sm) {
      margin-left: 0;
      padding-left: 0;

      &::after {
        margin-left: 0;
      }
    }
  }

  @media (max-width: $breakpoint-sm) {
    padding-left: 0;
  }
}