doing the math for ink - responsive mail framework by zurb

ink.css.scss

/**
 * GRID Settings
 */

$GRID_WIDTH: 580; // original: 580 - can be changed within this single line
$HUMAN_NUMBERS: one, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve;

$UNIT_COUNT: length($HUMAN_NUMBERS);
$GRID_GUTTER: 20;
$GRID_WIDTH_TOTAL: $GRID_WIDTH + $GRID_GUTTER;
$UNIT_WIDTH: $GRID_WIDTH_TOTAL / $UNIT_COUNT;

/**********************************************
* Ink v1.0.5 - Copyright 2013 ZURB Inc        *
**********************************************/

/* Client-specific Styles & Reset */

#outlook a {
  padding:0;
}

body{
  width:100% !important;
  min-width: 100%;
  -webkit-text-size-adjust:100%;
  -ms-text-size-adjust:100%;
  margin:0;
  padding:0;
}

.ExternalClass {
  width:100%;
}

.ExternalClass,
.ExternalClass p,
.ExternalClass span,
.ExternalClass font,
.ExternalClass td,
.ExternalClass div {
  line-height: 100%;
}

#backgroundTable {
  margin:0;
  padding:0;
  width:100% !important;
  line-height: 100% !important;
}

img {
  outline:none;
  text-decoration:none;
  -ms-interpolation-mode: bicubic;
  width: auto;
  max-width: 100%;
  float: left;
  clear: both;
  display: block;
}

center {
  width: 100%;
  min-width: #{$GRID_WIDTH}px;
}

a img {
  border: none;
}

p {
  margin: 0 0 0 #{$GRID_GUTTER/2}px;
}

table {
  border-spacing: 0;
  border-collapse: collapse;
}

td {
  word-break: break-word;
  -webkit-hyphens: auto;
  -moz-hyphens: auto;
  hyphens: auto;
  border-collapse: collapse !important;
}

table, tr, td {
  padding: 0;
  vertical-align: top;
  text-align: left;
}

hr {
  color: #d9d9d9;
  background-color: #d9d9d9;
  height: 1px;
  border: none;
}

/* Responsive Grid */

table.body {
  height: 100%;
  width: 100%;
}

table.container {
  width: #{$GRID_WIDTH}px;
  margin: 0 auto;
  text-align: inherit;
}

table.row {
  padding: 0px;
  width: 100%;
  position: relative;
}

table.container table.row {
  display: block;
}

td.wrapper {
  padding: #{$GRID_GUTTER/2}px #{$GRID_GUTTER}px 0px 0px;
  position: relative;
}

table.columns,
table.column {
  margin: 0 auto;
}

table.columns td,
table.column td {
  padding: 0px 0px #{$GRID_GUTTER/2}px;
}

table.columns td.sub-columns,
table.column td.sub-columns,
table.columns td.sub-column,
table.column td.sub-column {
  padding-right: #{$GRID_GUTTER/2}px;
}

td.sub-column, td.sub-columns {
  min-width: 0px;
}

table.row td.last,
table.container td.last {
  padding-right: 0px;
}

/**
  // ORIGINAL (@ $GRID_WIDTH: 580):
    table.one { width: 30px; }
    table.two { width: 80px; }
    table.three { width: 130px; }
    table.four { width: 180px; }
    table.five { width: 230px; }
    table.six { width: 280px; }
    table.seven { width: 330px; }
    table.eight { width: 380px; }
    table.nine { width: 430px; }
    table.ten { width: 480px; }
    table.eleven { width: 530px; }
    table.twelve { width: 580px; }

 */
@for $i from 1 through length($HUMAN_NUMBERS) {
  table.#{nth($HUMAN_NUMBERS, $i)} {
    width: #{ ( $UNIT_WIDTH * $i - $GRID_GUTTER) }px;
    center {
      /* see #1 */
      min-width: #{ ( $UNIT_WIDTH * $i - $GRID_GUTTER) }px;
    }
    .panel center {
      /* see #2 */
      min-width: #{ ( $UNIT_WIDTH * $i - $GRID_GUTTER * 2) }px;
    }
  }
  /* see #3 */
  .body .columns td.#{nth($HUMAN_NUMBERS, $i)},
  .body .column td.#{nth($HUMAN_NUMBERS, $i)} {
    width: percentage($UNIT_WIDTH * $i / $GRID_WIDTH_TOTAL);
  }
  /* see #4 */
  td.offset-by-#{nth($HUMAN_NUMBERS, $i)} {
    padding-left: #{$UNIT_WIDTH * $i}px;
  }
}

/**
  // ORIGINAL #1:
    table.one center { min-width: 30px; }
    table.two center { min-width: 80px; }
    table.three center { min-width: 130px; }
    table.four center { min-width: 180px; }
    table.five center { min-width: 230px; }
    table.six center { min-width: 280px; }
    table.seven center { min-width: 330px; }
    table.eight center { min-width: 380px; }
    table.nine center { min-width: 430px; }
    table.ten center { min-width: 480px; }
    table.eleven center { min-width: 530px; }
    table.twelve center { min-width: 580px; }

  // ORIGINAL #2:
    table.one .panel center { min-width: 10px; }
    table.two .panel center { min-width: 60px; }
    table.three .panel center { min-width: 110px; }
    table.four .panel center { min-width: 160px; }
    table.five .panel center { min-width: 210px; }
    table.six .panel center { min-width: 260px; }
    table.seven .panel center { min-width: 310px; }
    table.eight .panel center { min-width: 360px; }
    table.nine .panel center { min-width: 410px; }
    table.ten .panel center { min-width: 460px; }
    table.eleven .panel center { min-width: 510px; }
    table.twelve .panel center { min-width: 560px; }

// ORIGINAL #3:
  .body .columns td.one,
  .body .column td.one { width: 8.333333%; }
  .body .columns td.two,
  .body .column td.two { width: 16.666666%; }
  .body .columns td.three,
  .body .column td.three { width: 25%; }
  .body .columns td.four,
  .body .column td.four { width: 33.333333%; }
  .body .columns td.five,
  .body .column td.five { width: 41.666666%; }
  .body .columns td.six,
  .body .column td.six { width: 50%; }
  .body .columns td.seven,
  .body .column td.seven { width: 58.333333%; }
  .body .columns td.eight,
  .body .column td.eight { width: 66.666666%; }
  .body .columns td.nine,
  .body .column td.nine { width: 75%; }
  .body .columns td.ten,
  .body .column td.ten { width: 83.333333%; }
  .body .columns td.eleven,
  .body .column td.eleven { width: 91.666666%; }
  .body .columns td.twelve,
  .body .column td.twelve { width: 100%; }

// ORIGINAL #4:
  td.offset-by-one { padding-left: 50px; }
  td.offset-by-two { padding-left: 100px; }
  td.offset-by-three { padding-left: 150px; }
  td.offset-by-four { padding-left: 200px; }
  td.offset-by-five { padding-left: 250px; }
  td.offset-by-six { padding-left: 300px; }
  td.offset-by-seven { padding-left: 350px; }
  td.offset-by-eight { padding-left: 400px; }
  td.offset-by-nine { padding-left: 450px; }
  td.offset-by-ten { padding-left: 500px; }
  td.offset-by-eleven { padding-left: 550px; }
*/
td.expander {
  visibility: hidden;
  width: 0px;
  padding: 0 !important;
}

table.columns .text-pad,
table.column .text-pad {
  padding-left: #{$GRID_GUTTER/2}px;
  padding-right: #{$GRID_GUTTER/2}px;
}

table.columns .left-text-pad,
table.columns .text-pad-left,
table.column .left-text-pad,
table.column .text-pad-left {
  padding-left: #{$GRID_GUTTER/2}px;
}

table.columns .right-text-pad,
table.columns .text-pad-right,
table.column .right-text-pad,
table.column .text-pad-right {
  padding-right: #{$GRID_GUTTER/2}px;
}

/* Block Grid */

.block-grid {
  width: 100%;
  max-width: #{$GRID_WIDTH}px;
}

.block-grid td {
  display: inline-block;
  padding: #{$GRID_GUTTER/2}px;
}

// see #5
@for $i from 2 through 8 {
  .#{nth($HUMAN_NUMBERS, $i)}-up td {
    width: #{ floor($GRID_WIDTH / $i) - $GRID_GUTTER}px;
  }
}
/*
// ORIGINAL

  .two-up td {
    width: 270px;
  }

  .three-up td {
    width:173px;
  }

  .four-up td {
    width:125px;
  }

  .five-up td {
    width:96px;
  }

  .six-up td {
    width:76px;
  }

  .seven-up td {
    width:62px;
  }

  .eight-up td {
    width:52px;
  }
 */
/* Alignment & Visibility Classes */

table.center, td.center {
  text-align: center;
}

h1.center,
h2.center,
h3.center,
h4.center,
h5.center,
h6.center {
  text-align: center;
}

span.center {
  display: block;
  width: 100%;
  text-align: center;
}

img.center {
  margin: 0 auto;
  float: none;
}

.show-for-small,
.hide-for-desktop {
  display: none;
}

/* Typography */

body, table.body, h1, h2, h3, h4, h5, h6, p, td {
  color: #222222;
  font-family: "Helvetica", "Arial", sans-serif;
  font-weight: normal;
  padding:0;
  margin: 0;
  text-align: left;
  line-height: 1.3;
}

h1, h2, h3, h4, h5, h6 {
  word-break: normal;
}

h1 {font-size: 40px;}
h2 {font-size: 36px;}
h3 {font-size: 32px;}
h4 {font-size: 28px;}
h5 {font-size: 24px;}
h6 {font-size: 20px;}
body, table.body, p, td {font-size: 14px;line-height:19px;}

p.lead, p.lede, p.leed {
  font-size: 18px;
  line-height:21px;
}

p {
  margin-bottom: #{$GRID_GUTTER/2}px;
}

small {
  font-size: 10px;
}

a {
  color: #2ba6cb;
  text-decoration: none;
}

a:hover {
  color: #2795b6 !important;
}

a:active {
  color: #2795b6 !important;
}

a:visited {
  color: #2ba6cb !important;
}

h1 a,
h2 a,
h3 a,
h4 a,
h5 a,
h6 a {
  color: #2ba6cb;
}

h1 a:active,
h2 a:active,
h3 a:active,
h4 a:active,
h5 a:active,
h6 a:active {
  color: #2ba6cb !important;
}

h1 a:visited,
h2 a:visited,
h3 a:visited,
h4 a:visited,
h5 a:visited,
h6 a:visited {
  color: #2ba6cb !important;
}

/* Panels */

.panel {
  background: #f2f2f2;
  border: 1px solid #d9d9d9;
  padding: #{$GRID_GUTTER/2}px !important;
}

.sub-grid table {
  width: 100%;
}

.sub-grid td.sub-columns {
  padding-bottom: 0;
}

/* Buttons */

table.button,
table.tiny-button,
table.small-button,
table.medium-button,
table.large-button {
  width: 100%;
  overflow: hidden;
}

table.button td,
table.tiny-button td,
table.small-button td,
table.medium-button td,
table.large-button td {
  display: block;
  width: auto !important;
  text-align: center;
  background: #2ba6cb;
  border: 1px solid #2284a1;
  color: #ffffff;
  padding: 8px 0;
}

table.tiny-button td {
  padding: 5px 0 4px;
}

table.small-button td {
  padding: 8px 0 7px;
}

table.medium-button td {
  padding: 12px 0 10px;
}

table.large-button td {
  padding: 21px 0 18px;
}

table.button td a,
table.tiny-button td a,
table.small-button td a,
table.medium-button td a,
table.large-button td a {
  font-weight: bold;
  text-decoration: none;
  font-family: Helvetica, Arial, sans-serif;
  color: #ffffff;
  font-size: 16px;
}

table.tiny-button td a {
  font-size: 12px;
  font-weight: normal;
}

table.small-button td a {
  font-size: 16px;
}

table.medium-button td a {
  font-size: 20px;
}

table.large-button td a {
  font-size: 24px;
}

table.button:hover td,
table.button:visited td,
table.button:active td {
  background: #2795b6 !important;
}

table.button:hover td a,
table.button:visited td a,
table.button:active td a {
  color: #fff !important;
}

table.button:hover td,
table.tiny-button:hover td,
table.small-button:hover td,
table.medium-button:hover td,
table.large-button:hover td {
  background: #2795b6 !important;
}

table.button:hover td a,
table.button:active td a,
table.button td a:visited,
table.tiny-button:hover td a,
table.tiny-button:active td a,
table.tiny-button td a:visited,
table.small-button:hover td a,
table.small-button:active td a,
table.small-button td a:visited,
table.medium-button:hover td a,
table.medium-button:active td a,
table.medium-button td a:visited,
table.large-button:hover td a,
table.large-button:active td a,
table.large-button td a:visited {
  color: #ffffff !important;
}

table.secondary td {
  background: #e9e9e9;
  border-color: #d0d0d0;
  color: #555;
}

table.secondary td a {
  color: #555;
}

table.secondary:hover td {
  background: #d0d0d0 !important;
  color: #555;
}

table.secondary:hover td a,
table.secondary td a:visited,
table.secondary:active td a {
  color: #555 !important;
}

table.success td {
  background: #5da423;
  border-color: #457a1a;
}

table.success:hover td {
  background: #457a1a !important;
}

table.alert td {
  background: #c60f13;
  border-color: #970b0e;
}

table.alert:hover td {
  background: #970b0e !important;
}

table.radius td {
  -webkit-border-radius: 3px;
  -moz-border-radius: 3px;
  border-radius: 3px;
}

table.round td {
  -webkit-border-radius: 500px;
  -moz-border-radius: 500px;
  border-radius: 500px;
}

/* Outlook First */

body.outlook p {
  display: inline !important;
}

/*  Media Queries */

@media only screen and (max-width: 600px) {

  table[class="body"] img {
    width: auto !important;
    height: auto !important;
  }

  table[class="body"] center {
    min-width: 0 !important;
  }

  table[class="body"] .container {
    width: 95% !important;
  }

  table[class="body"] .row {
    width: 100% !important;
    display: block !important;
  }

  table[class="body"] .wrapper {
    display: block !important;
    padding-right: 0 !important;
  }

  table[class="body"] .columns,
  table[class="body"] .column {
    table-layout: fixed !important;
    float: none !important;
    width: 100% !important;
    padding-right: 0px !important;
    padding-left: 0px !important;
    display: block !important;
  }

  table[class="body"] .wrapper.first .columns,
  table[class="body"] .wrapper.first .column {
    display: table !important;
  }

  table[class="body"] table.columns td,
  table[class="body"] table.column td {
    width: 100% !important;
  }

@for $i from 1 through length($HUMAN_NUMBERS) {
  /* see #6 */
  table[class="body"] .columns td.#{nth($HUMAN_NUMBERS, $i)},
  table[class="body"] .column td.#{nth($HUMAN_NUMBERS, $i)} {
    width: percentage($UNIT_WIDTH * $i / $GRID_WIDTH_TOTAL) !important;
  }
}

// ORIGINAL #6
/*
  table[class="body"] .columns td.one,
  table[class="body"] .column td.one { width: 8.333333% !important; }
  table[class="body"] .columns td.two,
  table[class="body"] .column td.two { width: 16.666666% !important; }
  table[class="body"] .columns td.three,
  table[class="body"] .column td.three { width: 25% !important; }
  table[class="body"] .columns td.four,
  table[class="body"] .column td.four { width: 33.333333% !important; }
  table[class="body"] .columns td.five,
  table[class="body"] .column td.five { width: 41.666666% !important; }
  table[class="body"] .columns td.six,
  table[class="body"] .column td.six { width: 50% !important; }
  table[class="body"] .columns td.seven,
  table[class="body"] .column td.seven { width: 58.333333% !important; }
  table[class="body"] .columns td.eight,
  table[class="body"] .column td.eight { width: 66.666666% !important; }
  table[class="body"] .columns td.nine,
  table[class="body"] .column td.nine { width: 75% !important; }
  table[class="body"] .columns td.ten,
  table[class="body"] .column td.ten { width: 83.333333% !important; }
  table[class="body"] .columns td.eleven,
  table[class="body"] .column td.eleven { width: 91.666666% !important; }
  table[class="body"] .columns td.twelve,
  table[class="body"] .column td.twelve { width: 100% !important; }
*/

  table[class="body"] td.offset-by-one,
  table[class="body"] td.offset-by-two,
  table[class="body"] td.offset-by-three,
  table[class="body"] td.offset-by-four,
  table[class="body"] td.offset-by-five,
  table[class="body"] td.offset-by-six,
  table[class="body"] td.offset-by-seven,
  table[class="body"] td.offset-by-eight,
  table[class="body"] td.offset-by-nine,
  table[class="body"] td.offset-by-ten,
  table[class="body"] td.offset-by-eleven {
    padding-left: 0 !important;
  }

  table[class="body"] table.columns td.expander {
    width: 1px !important;
  }

  table[class="body"] .right-text-pad,
  table[class="body"] .text-pad-right {
    padding-left: #{$GRID_GUTTER/2}px !important;
  }

  table[class="body"] .left-text-pad,
  table[class="body"] .text-pad-left {
    padding-right: #{$GRID_GUTTER/2}px !important;
  }

  table[class="body"] .hide-for-small,
  table[class="body"] .show-for-desktop {
    display: none !important;
  }

  table[class="body"] .show-for-small,
  table[class="body"] .hide-for-desktop {
    display: inherit !important;
  }
}