Generated by SassMeister.com.

SassMeister-input-HTML.html

<h1>
  hello
</h1>
<h2>2</h2>
<h3>3</h3>
<h4>4</h4>
<h5>5</h5>
<h6>6</h6>
<p>good-bye</p>

SassMeister-input.scss

// ----
// Sass (v3.3.1)
// Compass (v1.0.0.alpha.18)
// ----


$color-one: #333;
$color-two: lighten(desaturate($color-one,25%),50%);
$heading :
  (h1, 3rem, $color-one),
  (h2, 2.5rem, red ),
  (h3, 2rem, green),
  (h4, 1.5rem, yellow),
  (p, 1em, $color-two);

@each $header, $size, $color in  $heading{
  #{$header} {
    font-size: $size;
    background: $color;
    color: invert($color);
  }
}

$prefix: txt;
$sans: arial, sans-serif;
$serif: georgia, serif;

$font-list: (
  h1   $prefix    3em     100   $serif,
  h2   $prefix    2.5em   100   $sans,
  h3   $prefix    2em     300   $serif,
  h4   $prefix    1.75em  300   $sans,
  h5   $prefix    1.5em   400   $serif,
  h6   $prefix    1.25em  400   $sans,
  p    $prefix    1.25em  400   $sans

);


@each $value in $font-list {

  #{nth($value, 1)},
  .#{nth($value, 2)}-#{nth($value, 1)} {
      font-size: nth($value, 3);
      font-weight: nth($value, 4);
      font-family: nth($value, 5);
    }

}

SassMeister-output.css

h1 {
  font-size: 3rem;
  background: #333333;
  color: #cccccc;
}

h2 {
  font-size: 2.5rem;
  background: red;
  color: cyan;
}

h3 {
  font-size: 2rem;
  background: green;
  color: #ff7fff;
}

h4 {
  font-size: 1.5rem;
  background: yellow;
  color: blue;
}

p {
  font-size: 1em;
  background: #b3b3b3;
  color: #4c4c4c;
}

h1,
.txt-h1 {
  font-size: 3em;
  font-weight: 100;
  font-family: georgia, serif;
}

h2,
.txt-h2 {
  font-size: 2.5em;
  font-weight: 100;
  font-family: arial, sans-serif;
}

h3,
.txt-h3 {
  font-size: 2em;
  font-weight: 300;
  font-family: georgia, serif;
}

h4,
.txt-h4 {
  font-size: 1.75em;
  font-weight: 300;
  font-family: arial, sans-serif;
}

h5,
.txt-h5 {
  font-size: 1.5em;
  font-weight: 400;
  font-family: georgia, serif;
}

h6,
.txt-h6 {
  font-size: 1.25em;
  font-weight: 400;
  font-family: arial, sans-serif;
}

p,
.txt-p {
  font-size: 1.25em;
  font-weight: 400;
  font-family: arial, sans-serif;
}

SassMeister-rendered.html

<h1>
  hello
</h1>
<h2>2</h2>
<h3>3</h3>
<h4>4</h4>
<h5>5</h5>
<h6>6</h6>
<p>good-bye</p>