RFS (Responsive font size) implementation

scss/_badge.scss

@@ -6,7 +6,7 @@
 .badge {
   display: inline-block;
   padding: $badge-padding-y $badge-padding-x;
-  font-size: $badge-font-size;
+  @include font-size($badge-font-size);
   font-weight: $badge-font-weight;
   line-height: 1;
   text-align: center;

scss/_close.scss

@@ -1,6 +1,6 @@
 .close {
   float: right;
-  font-size: $close-font-size;
+  @include font-size($close-font-size);
   font-weight: $close-font-weight;
   line-height: 1;
   color: $close-color;

scss/_code.scss

@@ -1,6 +1,6 @@
 // Inline code
 code {
-  font-size: $code-font-size;
+  @include font-size($code-font-size);
   color: $code-color;
   word-break: break-word;
 
@@ -13,15 +13,15 @@ code {
 // User input typically entered via keyboard
 kbd {
   padding: $kbd-padding-y $kbd-padding-x;
-  font-size: $kbd-font-size;
+  @include font-size($kbd-font-size);
   color: $kbd-color;
   background-color: $kbd-bg;
   @include border-radius($border-radius-sm);
   @include box-shadow($kbd-box-shadow);
 
   kbd {
     padding: 0;
-    font-size: 100%;
+    @include font-size(100%);
     font-weight: $nested-kbd-font-weight;
     @include box-shadow(none);
   }
@@ -30,12 +30,12 @@ kbd {
 // Blocks of code
 pre {
   display: block;
-  font-size: $code-font-size;
+  @include font-size($code-font-size);
   color: $pre-color;
 
   // Account for some code outputs that place code tags in pre tags
   code {
-    font-size: inherit;
+    @include font-size(inherit);
     color: inherit;
     word-break: normal;
   }

scss/_custom-forms.scss

@@ -215,7 +215,7 @@
   height: $custom-select-height;
   padding: $custom-select-padding-y ($custom-select-padding-x + $custom-select-indicator-padding) $custom-select-padding-y $custom-select-padding-x;
   font-family: $custom-select-font-family;
-  font-size: $custom-select-font-size;
+  @include font-size($custom-select-font-size);
   font-weight: $custom-select-font-weight;
   line-height: $custom-select-line-height;
   color: $custom-select-color;
@@ -270,15 +270,15 @@
   padding-top: $custom-select-padding-y-sm;
   padding-bottom: $custom-select-padding-y-sm;
   padding-left: $custom-select-padding-x-sm;
-  font-size: $custom-select-font-size-sm;
+  @include font-size($custom-select-font-size-sm);
 }
 
 .custom-select-lg {
   height: $custom-select-height-lg;
   padding-top: $custom-select-padding-y-lg;
   padding-bottom: $custom-select-padding-y-lg;
   padding-left: $custom-select-padding-x-lg;
-  font-size: $custom-select-font-size-lg;
+  @include font-size($custom-select-font-size-lg);
 }
 
 

scss/_dropdown.scss

@@ -24,7 +24,7 @@
   min-width: $dropdown-min-width;
   padding: $dropdown-padding-y 0;
   margin: $dropdown-spacer 0 0; // override default ul
-  font-size: $dropdown-font-size;
+  @include font-size($dropdown-font-size);
   color: $dropdown-color;
   text-align: left; // Ensures proper alignment if parent has it changed (e.g., modal footer)
   list-style: none;
@@ -178,7 +178,7 @@
   display: block;
   padding: $dropdown-padding-y $dropdown-item-padding-x;
   margin-bottom: 0; // for use with heading elements
-  font-size: $font-size-sm;
+  @include font-size($font-size-sm);
   color: $dropdown-header-color;
   white-space: nowrap; // as with > li > a
 }

scss/_forms.scss

@@ -10,7 +10,7 @@
   height: $input-height;
   padding: $input-padding-y $input-padding-x;
   font-family: $input-font-family;
-  font-size: $input-font-size;
+  @include font-size($input-font-size);
   font-weight: $input-font-weight;
   line-height: $input-line-height;
   color: $input-color;
@@ -83,21 +83,21 @@ select.form-control {
   padding-top: calc(#{$input-padding-y} + #{$input-border-width});
   padding-bottom: calc(#{$input-padding-y} + #{$input-border-width});
   margin-bottom: 0; // Override the `<label>/<legend>` default
-  font-size: inherit; // Override the `<legend>` default
+  @include font-size(inherit); // Override the `<legend>` default
   line-height: $input-line-height;
 }
 
 .col-form-label-lg {
   padding-top: calc(#{$input-padding-y-lg} + #{$input-border-width});
   padding-bottom: calc(#{$input-padding-y-lg} + #{$input-border-width});
-  font-size: $input-font-size-lg;
+  @include font-size($input-font-size-lg);
   line-height: $input-line-height-lg;
 }
 
 .col-form-label-sm {
   padding-top: calc(#{$input-padding-y-sm} + #{$input-border-width});
   padding-bottom: calc(#{$input-padding-y-sm} + #{$input-border-width});
-  font-size: $input-font-size-sm;
+  @include font-size($input-font-size-sm);
   line-height: $input-line-height-sm;
 }
 
@@ -137,15 +137,15 @@ select.form-control {
 .form-control-sm {
   height: $input-height-sm;
   padding: $input-padding-y-sm $input-padding-x-sm;
-  font-size: $input-font-size-sm;
+  @include font-size($input-font-size-sm);
   line-height: $input-line-height-sm;
   @include border-radius($input-border-radius-sm);
 }
 
 .form-control-lg {
   height: $input-height-lg;
   padding: $input-padding-y-lg $input-padding-x-lg;
-  font-size: $input-font-size-lg;
+  @include font-size($input-font-size-lg);
   line-height: $input-line-height-lg;
   @include border-radius($input-border-radius-lg);
 }

scss/_images.scss

@@ -37,6 +37,6 @@
 }
 
 .figure-caption {
-  font-size: $figure-caption-font-size;
+  @include font-size($figure-caption-font-size);
   color: $figure-caption-color;
 }

scss/_input-group.scss

@@ -104,7 +104,7 @@
   align-items: center;
   padding: $input-padding-y $input-padding-x;
   margin-bottom: 0; // Allow use of <label> elements by overriding our default margin-bottom
-  font-size: $input-font-size; // Match inputs
+  @include font-size($input-font-size); // Match inputs
   font-weight: $font-weight-normal;
   line-height: $input-line-height;
   color: $input-group-addon-color;
@@ -139,7 +139,7 @@
 .input-group-lg > .input-group-prepend > .btn,
 .input-group-lg > .input-group-append > .btn {
   padding: $input-padding-y-lg $input-padding-x-lg;
-  font-size: $input-font-size-lg;
+  @include font-size($input-font-size-lg);
   line-height: $input-line-height-lg;
   @include border-radius($input-border-radius-lg);
 }
@@ -156,7 +156,7 @@
 .input-group-sm > .input-group-prepend > .btn,
 .input-group-sm > .input-group-append > .btn {
   padding: $input-padding-y-sm $input-padding-x-sm;
-  font-size: $input-font-size-sm;
+  @include font-size($input-font-size-sm);
   line-height: $input-line-height-sm;
   @include border-radius($input-border-radius-sm);
 }

scss/_mixins.scss

@@ -2,6 +2,9 @@
 //
 // Used in conjunction with global variables to enable certain theme features.
 
+// Vendor
+@import "vendor/rfs";
+
 // Deprecate
 @import "mixins/deprecate";
 

scss/_navbar.scss

@@ -44,7 +44,7 @@
   padding-top: $navbar-brand-padding-y;
   padding-bottom: $navbar-brand-padding-y;
   margin-right: $navbar-padding-x;
-  font-size: $navbar-brand-font-size;
+  @include font-size($navbar-brand-font-size);
   line-height: inherit;
   white-space: nowrap;
 
@@ -107,7 +107,7 @@
 // Button for toggling the navbar when in its collapsed state
 .navbar-toggler {
   padding: $navbar-toggler-padding-y $navbar-toggler-padding-x;
-  font-size: $navbar-toggler-font-size;
+  @include font-size($navbar-toggler-font-size);
   line-height: 1;
   background-color: transparent; // remove default button style
   border: $border-width solid transparent; // remove default button style

scss/_popover.scss

@@ -8,7 +8,7 @@
   // Our parent element can be arbitrary since tooltips are by default inserted as a sibling of their target element.
   // So reset our font and text properties to avoid inheriting weird values.
   @include reset-text();
-  font-size: $popover-font-size;
+  @include font-size($popover-font-size);
   // Allow breaking very long words so they don't overflow the popover's bounds
   word-wrap: break-word;
   background-color: $popover-bg;
@@ -153,7 +153,7 @@
 .popover-header {
   padding: $popover-header-padding-y $popover-header-padding-x;
   margin-bottom: 0; // Reset the default from Reboot
-  font-size: $font-size-base;
+  @include font-size($font-size-base);
   color: $popover-header-color;
   background-color: $popover-header-bg;
   border-bottom: $popover-border-width solid darken($popover-header-bg, 5%);

scss/_progress.scss

@@ -10,7 +10,7 @@
   display: flex;
   height: $progress-height;
   overflow: hidden; // force rounded corners by cropping it
-  font-size: $progress-font-size;
+  @include font-size($progress-font-size);
   background-color: $progress-bg;
   @include border-radius($progress-border-radius);
   @include box-shadow($progress-box-shadow);

scss/_reboot.scss

@@ -46,7 +46,7 @@ article, aside, figcaption, figure, footer, header, hgroup, main, nav, section {
 body {
   margin: 0; // 1
   font-family: $font-family-base;
-  font-size: $font-size-base;
+  @include font-size($font-size-base);
   font-weight: $font-weight-base;
   line-height: $line-height-base;
   color: $body-color;
@@ -155,7 +155,7 @@ strong {
 }
 
 small {
-  font-size: 80%; // Add the correct font size in all browsers
+  @include font-size(80%); // Add the correct font size in all browsers
 }
 
 //
@@ -166,7 +166,7 @@ small {
 sub,
 sup {
   position: relative;
-  font-size: 75%;
+  @include font-size(75%);
   line-height: 0;
   vertical-align: baseline;
 }
@@ -220,7 +220,7 @@ code,
 kbd,
 samp {
   font-family: $font-family-monospace;
-  font-size: 1em; // Correct the odd `em` font sizing in all browsers.
+  @include font-size(1em); // Correct the odd `em` font sizing in all browsers.
 }
 
 pre {
@@ -317,7 +317,7 @@ optgroup,
 textarea {
   margin: 0; // Remove the margin in Firefox and Safari
   font-family: inherit;
-  font-size: inherit;
+  @include font-size(inherit);
   line-height: inherit;
 }
 
@@ -416,7 +416,7 @@ legend {
   max-width: 100%; // 1
   padding: 0;
   margin-bottom: .5rem;
-  font-size: 1.5rem;
+  @include font-size(1.5rem);
   line-height: inherit;
   color: inherit; // 2
   white-space: normal; // 1

scss/_toasts.scss

@@ -1,7 +1,7 @@
 .toast {
   max-width: $toast-max-width;
   overflow: hidden; // cheap rounded corners on nested items
-  font-size: $toast-font-size; // knock it down to 14px
+  @include font-size($toast-font-size);
   color: $toast-color;
   background-color: $toast-background-color;
   background-clip: padding-box;

scss/_tooltip.scss

@@ -7,7 +7,7 @@
   // Our parent element can be arbitrary since tooltips are by default inserted as a sibling of their target element.
   // So reset our font and text properties to avoid inheriting weird values.
   @include reset-text();
-  font-size: $tooltip-font-size;
+  @include font-size($tooltip-font-size);
   // Allow breaking very long words so they don't overflow the tooltip's bounds
   word-wrap: break-word;
   opacity: 0;

scss/_type.scss

@@ -13,36 +13,36 @@ h1, h2, h3, h4, h5, h6,
   color: $headings-color;
 }
 
-h1, .h1 { font-size: $h1-font-size; }
-h2, .h2 { font-size: $h2-font-size; }
-h3, .h3 { font-size: $h3-font-size; }
-h4, .h4 { font-size: $h4-font-size; }
-h5, .h5 { font-size: $h5-font-size; }
-h6, .h6 { font-size: $h6-font-size; }
+h1, .h1 { @include font-size($h1-font-size); }
+h2, .h2 { @include font-size($h2-font-size); }
+h3, .h3 { @include font-size($h3-font-size); }
+h4, .h4 { @include font-size($h4-font-size); }
+h5, .h5 { @include font-size($h5-font-size); }
+h6, .h6 { @include font-size($h6-font-size); }
 
 .lead {
-  font-size: $lead-font-size;
+  @include font-size($lead-font-size);
   font-weight: $lead-font-weight;
 }
 
 // Type display classes
 .display-1 {
-  font-size: $display1-size;
+  @include font-size($display1-size);
   font-weight: $display1-weight;
   line-height: $display-line-height;
 }
 .display-2 {
-  font-size: $display2-size;
+  @include font-size($display2-size);
   font-weight: $display2-weight;
   line-height: $display-line-height;
 }
 .display-3 {
-  font-size: $display3-size;
+  @include font-size($display3-size);
   font-weight: $display3-weight;
   line-height: $display-line-height;
 }
 .display-4 {
-  font-size: $display4-size;
+  @include font-size($display4-size);
   font-weight: $display4-weight;
   line-height: $display-line-height;
 }
@@ -66,7 +66,7 @@ hr {
 
 small,
 .small {
-  font-size: $small-font-size;
+  @include font-size($small-font-size);
   font-weight: $font-weight-normal;
 }
 
@@ -104,19 +104,19 @@ mark,
 
 // Builds on `abbr`
 .initialism {
-  font-size: 90%;
+  @include font-size(90%);
   text-transform: uppercase;
 }
 
 // Blockquotes
 .blockquote {
   margin-bottom: $spacer;
-  font-size: $blockquote-font-size;
+  @include font-size($blockquote-font-size);
 }
 
 .blockquote-footer {
   display: block;
-  font-size: $blockquote-small-font-size;
+  @include font-size($blockquote-small-font-size);
   color: $blockquote-small-color;
 
   &::before {