$base-font-size: 16px;
$base-line-height: 1.5;
$__1px: (1px/$base-font-size) * 1rem;
$base-font-family: 'Roboto, Helvetica, sans-serif';
$code-font-family: 'Roboto Mono, Menlo, Consolas, monospace';
$_body-margin: 0;
$fore-color-var: '--fore-color';
$back-color-var: '--back-color';
$secondary-fore-color-var: '--secondary-fore-color';
$secondary-back-color-var: '--secondary-back-color';
$tertiary-back-color-var: '--tertiary-back-color';
$border-color-var: '--border-color';
$universal-margin-var: '--universal-margin';
$universal-padding-var: '--universal-padding';
$universal-border-radius-var: '--universal-border-radius';
$fore-color: #212121;
$secondary-fore-color: #444;
$tertiary-fore-color: #222;
$back-color: #fff;
$secondary-back-color: #f0f0f0;
$border-color: #fff;
$token-color-a-var: '--token-color-a';
$token-color-b-var: '--token-color-b';
$token-color-c-var: '--token-color-c';
$token-color-d-var: '--token-color-d';
$token-color-e-var: '--token-color-e';
$token-color-f-var: '--token-color-f';
$token-color-g-var: '--token-color-g';
$token-color-h-var: '--token-color-h';
$token-color-a: #7a8490;
$token-color-b: #666;
$token-color-c: #005cc5;
$token-color-d: #832ed2;
$token-color-e: #067e36;
$token-color-f: #d73a49;
$token-color-g: #097cab;
$token-color-h: #e90;
$universal-margin: 0.5rem;
$universal-padding: 0.5rem;
$universal-border-radius: 0.125rem;
$heading-line-height: 1.2;
$code-font-size:  0.8125em;

@font-face {
  font-family: 'Roboto';
  font-style: normal;
  font-weight: 400;
  src: local('Roboto'), local('Roboto-Regular'), url(https://fonts.gstatic.com/s/roboto/v18/KFOmCnqEu92Fr1Mu4mxK.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
  font-display: swap;
}
@font-face {
  font-family: 'Roboto';
  font-style: italic;
  font-weight: 400;
  src: local('Roboto Italic'), local('Roboto-Italic'), url(https://fonts.gstatic.com/s/roboto/v18/KFOkCnqEu92Fr1Mu51xIIzI.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
  font-display: swap;
}
@font-face {
  font-family: 'Roboto';
  font-style: normal;
  font-weight: 700;
  src: local('Roboto Bold'), local('Roboto-Bold'), url(https://fonts.gstatic.com/s/roboto/v18/KFOlCnqEu92Fr1MmWUlfBBc4.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
  font-display: swap;
}
@font-face {
  font-family: 'Roboto Mono';
  font-style: normal;
  font-weight: 400;
  src: local('Roboto Mono'), local('RobotoMono-Regular'), url(https://fonts.gstatic.com/s/robotomono/v5/L0x5DF4xlVMF-BfR8bXMIjhLq38.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
  font-display: swap;
}
@font-face {
  font-family: 'Roboto Mono';
  font-style: italic;
  font-weight: 400;
  src: local('Roboto Mono Italic'), local('RobotoMono-Italic'), url(https://fonts.gstatic.com/s/robotomono/v5/L0x7DF4xlVMF-BfR8bXMIjhOm32WWg.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
  font-display: swap;
}
@font-face {
  font-family: 'Roboto Mono';
  font-style: normal;
  font-weight: 700;
  src: local('Roboto Mono Bold'), local('RobotoMono-Bold'), url(https://fonts.gstatic.com/s/robotomono/v5/L0xkDF4xlVMF-BfR8bXMIjDwjmqxf78.woff2) format('woff2');
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
  font-display: swap;
}

:root {
  #{$fore-color-var}: $fore-color;
  #{$back-color-var}: $back-color;
  #{$border-color-var}: $border-color;
  #{$secondary-fore-color-var}: $secondary-fore-color;
  #{$tertiary-fore-color-var}: $tertiary-fore-color;
  #{$secondary-back-color-var}: $secondary-back-color;
  #{$universal-margin-var}: $universal-margin;
  #{$universal-padding-var}: $universal-padding;
  #{$universal-border-radius-var}: $universal-border-radius;
  #{$token-color-a-var}: $token-color-a;
  #{$token-color-b-var}: $token-color-b;
  #{$token-color-c-var}: $token-color-c;
  #{$token-color-d-var}: $token-color-d;
  #{$token-color-e-var}: $token-color-e;
  #{$token-color-f-var}: $token-color-f;
  #{$token-color-g-var}: $token-color-g;
  #{$token-color-h-var}: $token-color-h;
}

html {
  font-size: $base-font-size;
}

html, * {
  font-family: #{$base-font-family};
  line-height: $base-line-height;
  // Prevent adjustments of font size after orientation changes in mobile.
  -webkit-text-size-adjust: 100%;
}
* {
  font-size: 1rem;
  font-weight: 400;
}

a, b, del, em, i, ins, q, span, strong, u {
  font-size: 1em; // Fix for elements inside headings not displaying properly.
}

body {
  margin: $_body-margin;
  color: var(#{$fore-color-var});
  background: var(#{$back-color-var});
  overflow-x: hidden;
}

// Correct display for Edge & Firefox.
details {
  display: block;
}

// Correct display in all browsers.
summary {
  display: list-item;
}

// Abbreviations
abbr[title] {
  border-bottom: none;           // Remove bottom border in Firefox 39-.
  text-decoration: underline dotted;  // Opinionated style-fix for all browsers.
}

// Show overflow in Edge.
input {
  overflow: visible;
}

// Make images responsive by default.
img {
  max-width: 100%;
  height: auto;
}

h1, h2, h3, h4, h5, h6 {
  line-height: $heading-line-height;
  margin: calc(1.5 * var(#{$universal-margin-var})) var(#{$universal-margin-var});
}

h1 {
  font-size: 6rem;
}
h2 {
  font-size: 3.75rem;
}
h3 {
  font-size: 3rem;
}
h4 { 
  font-size: 2.125rem;
}
h5 {
  font-size: 1.5rem;
}
h6 {
  font-size: 1.25rem;
}

p {
  margin: var(#{$universal-margin-var});
}

ol, ul {
  margin: var(#{$universal-margin-var});
  padding-left: calc(2 * var(#{$universal-margin-var}));
}

b, strong {
  font-weight: 700;
}

hr {
  // Fixes and defaults for styling
  box-sizing: content-box;
  border: 0;
  // Actual styling using variables
  line-height: $horizontal-rule-line-height;
  margin: var(#{$universal-margin-var});
  height: $__1px;
  background: linear-gradient(to right, transparent, var(#{$border-color-var}) 20%, var(#{$border-color-var}) 80%, transparent);
}

code, kbd, pre, code *, pre *, kbd *, code[class*="language-"], pre[class*="language-"] {
  font-family: #{$code-font-family}; 
  font-size: $code-font-size;
}

sup, sub, code, kbd {
  line-height: 0;
  position: relative;
  vertical-align: baseline;
}

code {
  background: var(#{$secondary-back-color-var});
  padding: calc(var(#{$universal-padding-var}) / 4) calc(var(#{$universal-padding-var}) / 2);
  border-radius: var(#{$universal-border-radius-var});
}

kbd {
  background: var(#{$fore-color-var});
  color: var(#{$back-color-var});
  border-radius: var(#{$universal-border-radius-var});
  padding: calc(var(#{$universal-padding-var}) / 4) calc(var(#{$universal-padding-var}) / 2);
}

pre {
  overflow: auto; // Responsiveness
  background: var(#{$secondary-back-color-var});
  padding: calc(1.5 * var(#{$universal-padding-var}));
  margin: var(#{$universal-margin-var});
  border: $__1px solid var(#{$secondary-border-color-var});
  border-radius: var(#{$universal-border-radius-var});
}

code[class*="language-"],
pre[class*="language-"] {
  color: var(#{$tertiary-fore-color-var});
  text-align: left;
  white-space: pre;
  word-spacing: normal;
  word-break: normal;
  word-wrap: normal;
  line-height: 1.8;

  -moz-tab-size: 2;
  -o-tab-size: 2;
  tab-size: 2;

  -webkit-hypens: none;
  -moz-hyphens: none;
  -ms-hyphens: none;
  hyphens: none;
}

pre[class*="language-"] {
  padding: calc(2 * var(#{$universal-padding-var}));
  overflow: auto;
  margin: var(#{$universal-margin-var}) 0;
}

pre[class*="language-"]::-moz-selection, pre[class*="language-"] ::-moz-selection,
code[class*="language-"]::-moz-selection, code[class*="language-"] ::-moz-selection {
  background: #b3d4fc;
}

pre[class*="language-"]::selection, pre[class*="language-"] ::selection,
code[class*="language-"]::selection, code[class*="language-"] ::selection {
  background: #b3d4fc;
}

:not(pre) > code[class*="language-"] {
  padding: .1em;
  border-radius: .3em;
  white-space: normal;
}

.token.comment,
.token.prolog,
.token.doctype,
.token.cdata {
  color: var(#{$token-color-a});
}

.token.punctuation {
  color: var(#{$token-color-b});
}

.namespace {
  opacity: .7;
}

.token.property,
.token.tag,
.token.boolean,
.token.constant,
.token.symbol,
.token.deleted,
.token.function {
  color: var(#{$token-color-c});
}


.token.number,
.token.class-name {
  color: var(#{$token-color-d});
}

.token.selector,
.token.attr-name,
.token.string,
.token.char,
.token.builtin,
.token.inserted {
  color: var(#{$token-color-e});
}

.token.operator,
.token.entity,
.token.url,
.language-css .token.string,
.style .token.string,
.token.atrule,
.token.attr-value,
.token.keyword {
  color: var(#{$token-color-f});
}

.token.regex {
  color: var(#{$token-color-g});
}
.token.important,
.token.variable {
  color: var(#{$token-color-h});
}

.token.important,
.token.bold {
  font-weight: 700;
}
.token.italic {
  font-style: italic;
}

.token.entity {
  cursor: help;
}

/*
blockquote {}
sup {}
sub {}
figure {}
figcaption {}
*/

// ===================================================
// Layout
// ===================================================
$grid-medium-breakpoint: 768px;
$grid-large-breakpoint: 768px;
// Grid container
.container {
  display: grid;
  grid-template-columns: repeat(12, 1fr);
  grid-column-gap: calc(0.5 * var(#{$universal-margin-var}));
}
// Generic centered column
.col-centered {
  grid-column: span 12;
  @media screen and (min-width: #{$grid-medium-breakpoint}) {
    grid-column: 2/12;
  }
  @media screen and (min-width: #{$grid-large-breakpoint}) {
    grid-column: 3/11;
  }
}
// 25% width - For the 'in numbers' section
.col-quarter {
  grid-column: span 3;
}
// For the contributors section
.flex-row {
  display: flex;
  flex: 0 1 auto;
  flex-flow: row wrap;
  .flex-item {
    flex: 0 0 auto;
    max-width: 50%;
    flex-basis: 50%;
    @media screen and (min-width: #{$grid-medium-breakpoint}) {
      max-width: 25%;
      flex-basis: 25%;
    }
    @media screen and (min-width: #{$grid-large-breakpoint}) {
      max-width: 100%;
      flex-grow: 1;
      flex-basis: 0;
    }
  }
}
// TODO: Missing the menu system layout - probably all JS, effects and slide over
// TODO: Redesign cards from scratch
// TODO: Buttons and search form only
// TODO: Top bar - header
// TODO: Side bar - nav
// TODO: Bottom area - footer
// TODO: JS + CSS for side bar functionality
// TODO: New toast
// TODO: New marks
// TODO: Components for statistics