Changed and , sizes now calculated in em as FA also does.

less/_sizes.less

@@ -10,8 +10,8 @@
 
   .@{wi-css-prefix}-@{wi-icon-scale-name-unquoted} {
 
-    font-size: floor(@wi-font-size-base * @wi-icon-scale);
-    line-height: floor(@wi-font-size-base * @wi-icon-scale * 0.75);
+    font-size: unit(@wi-icon-scale, em);
+    line-height: unit(@wi-icon-scale * 0.75, em);
     vertical-align: -15%;
   }
 
@@ -20,15 +20,15 @@
 .createIconScales();
 
 // multiply icon size by n
-.createIconMultipliers(@iterator: 1) when(@iterator <= length(@wi-icon-scales)) {
+.createIconMultipliers(@iterator: 1) when(@iterator <= length(@wi-icon-multipliers)) {
 
-  @wi-icon-multiplier-name: extract(extract(@wi-icon-scales, @iterator), 1);
+  @wi-icon-multiplier-name: extract(extract(@wi-icon-multipliers, @iterator), 1);
   @wi-icon-multiplier-name-unquoted: ~"@{wi-icon-multiplier-name}";
-  @wi-icon-multiplier: extract(extract(@wi-icon-scales, @iterator), 2);
+  @wi-icon-multiplier: extract(extract(@wi-icon-multipliers, @iterator), 2);
 
   .@{wi-css-prefix}-@{wi-icon-multiplier-name-unquoted} {
 
-    font-size: floor(@wi-font-size-base * @wi-icon-multiplier);
+    font-size: unit(@wi-icon-multiplier, em);
   }
 
   .createIconMultipliers((@iterator + 1));

less/_variables.less

@@ -16,8 +16,8 @@
   "default" 1.000,
   "lg"      1.333,
   "sm"      0.666,
-  "xlg"     1.666,
-  "xsm"     0.333;
+  "xl"     1.666,
+  "xs"     0.333;
 
 // icon size multipliers - these scale font size
 // key value pair, creates selectors like `.w-2x`

scss/_sizes.scss

@@ -6,8 +6,8 @@
 
   .#{$wi-css-prefix}-#{$wi-icon-scale-name} {
 
-    font-size: #{fudge(unitless($wi-font-size-base) * $wi-icon-scale)}px;
-    line-height: #{fudge(unitless($wi-font-size-base) * $wi-icon-scale * 0.75)}px;
+    font-size: #{$wi-icon-scale}em;
+    line-height: #{$wi-icon-scale * 0.75}em;
     vertical-align: -15%;
   }
 }
@@ -17,6 +17,6 @@
 
   .#{$wi-css-prefix}-#{$wi-icon-multiplier-name} {
 
-    font-size: #{fudge($wi-font-size-base * $wi-icon-multiplier)}px;
+    font-size: #{$wi-icon-multiplier}em;
   }
 }

scss/_variables.scss

@@ -16,8 +16,8 @@ $wi-icon-scales: (
   "default": 1.000,
   "lg"     : 1.333,
   "sm"     : 0.666,
-  "xlg"    : 1.666,
-  "xsm"    : 0.333
+  "xl"    : 1.666,
+  "xs"    : 0.333
 ) !default;
 
 // icon size multipliers - these scale font size