@function sam-typography-level(
  $font-size,
  $line-height: $font-size,
  $font-weight: 400,
  $font-family: null,
  $letter-spacing: null) {

  @return (
    font-size:        $font-size,
    line-height:      $line-height,
    font-weight:      $font-weight,
    font-family:      $font-family,
    letter-spacing:   $letter-spacing
  );
}

// Defaults come from https://designsystem.digital.gov/components/typography/
@function sam-typography-config(
  $font-family:   '"Source Sans Pro", "Helvetica Neue", "Helvetica", sans-serif',
  $heading-1:     sam-typography-level(38px, 42px, 700, null, -1px),
  $heading-2:     sam-typography-level(32px, 41px, 700, null, -.8px),
  $heading-3:     sam-typography-level(24px, 31px, 600),
  $heading-4:     sam-typography-level(18px, 25px, 700),
  $lead:          sam-typography-level(20px, 26px, 300, null, 0),
  $body:          sam-typography-level(16px, 24px, 400),
  $body-strong:   sam-typography-level(16px, 24px, 600),
  $small:         sam-typography-level(15px, 22px, 400),
  $button:        sam-typography-level(14px, 14px, 600),
  $input:         sam-typography-level(inherit, 1.125, 400)
) {

  // Declare an initial map with all of the levels.
  $config: (
    heading-1:     $heading-1,
    heading-2:     $heading-2,
    heading-3:     $heading-3,
    heading-4:     $heading-4,
    lead:          $lead,
    body:          $body,
    body-strong:   $body-strong,
    small:         $small,
    button:        $button,
    input:         $input
  );

  // Loop through the levels and set the `font-family` of the ones that don't have one to the base.
  // Note that Sass can't modify maps in place, which means that we need to merge and re-assign.
  @each $key, $level in $config {
    @if map-get($level, font-family) == null {
      $new-level: map-merge($level, (font-family: $font-family));
      $config: map-merge($config, ($key: $new-level));
    }
  }

  // Add the base font family to the config.
  @return map-merge($config, (font-family: $font-family));
}

// Adds the base typography styles, based on a config.
@mixin sam-base-typography($config, $selector: '.sam-typography') {
  h1.sam.heading, .sam.h1, #{$selector} h1 {
    @include sam-typography-level-to-styles($config, heading-1);
    padding: 25px 0 20px;
    margin: 0;
    .intro{
      @include sam-typography-level-to-styles($config, body);
      letter-spacing: 0;
      text-transform: uppercase;
      display: block;
      margin-bottom: 5px;
    }
  }

  h2.sam.heading, .sam.h2, #{$selector} h2 {
    @include sam-typography-level-to-styles($config, heading-2);
    padding: 20px 0 15px;
    margin: 0;
  }

  h3.sam.heading, .sam.h3, #{$selector} h3 {
    @include sam-typography-level-to-styles($config, heading-3);
    padding: 15px 0 10px;
    margin: 0;
  }

  h4.sam.heading, .sam.h4, #{$selector} h4 {
    @include sam-typography-level-to-styles($config, heading-4);
    padding: 10px 0 5px;
    margin: 0;
  }

  .sam.lead{
    @include sam-typography-level-to-styles($config, lead);
    padding-bottom: 30px !important;
    margin: 0;
  }

  html {
    font-family: "Source Sans Pro";
  }

  body{
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
  }

  p{
    @include sam-typography-level-to-styles($config, body);
    padding-bottom: 15px !important;
    margin: 0;
  }

  b,strong {
    font-weight: 600;
  }

  a{
    font-weight: 400;
    text-decoration: none;
    cursor: pointer;
  }

  a:hover{
    text-decoration: underline;
  }

  .sam.body, #{$selector} {
    @include sam-typography-level-to-styles($config, body);

    p {
      margin: 0 0 12px;
    }
  }

  .sam.small {
    @include sam-typography-level-to-styles($config, small);
  }
}