fixes #5216: calculate heading sizes via math rather than fixed pixel amounts

docs/assets/css/bootstrap.css

@@ -655,7 +655,7 @@ h6 {
   margin: 10px 0;
   font-family: inherit;
   font-weight: bold;
-  line-height: 1;
+  line-height: 20px;
   color: inherit;
   text-rendering: optimizelegibility;
 }
@@ -671,42 +671,42 @@ h6 small {
   color: #999999;
 }
 
-h1 {
-  font-size: 36px;
+h1,
+h2,
+h3 {
   line-height: 40px;
 }
 
+h1 {
+  font-size: 38.5px;
+}
+
 h2 {
-  font-size: 30px;
-  line-height: 40px;
+  font-size: 31.5px;
 }
 
 h3 {
-  font-size: 24px;
-  line-height: 40px;
+  font-size: 24.5px;
 }
 
 h4 {
-  font-size: 18px;
-  line-height: 20px;
+  font-size: 17.5px;
 }
 
 h5 {
   font-size: 14px;
-  line-height: 20px;
 }
 
 h6 {
-  font-size: 12px;
-  line-height: 20px;
+  font-size: 11.9px;
 }
 
 h1 small {
-  font-size: 24px;
+  font-size: 24.5px;
 }
 
 h2 small {
-  font-size: 18px;
+  font-size: 17.5px;
 }
 
 h3 small {

less/type.less

@@ -57,7 +57,7 @@ h1, h2, h3, h4, h5, h6 {
   margin: (@baseLineHeight / 2) 0;
   font-family: @headingsFontFamily;
   font-weight: @headingsFontWeight;
-  line-height: 1;
+  line-height: @baseLineHeight;
   color: @headingsColor;
   text-rendering: optimizelegibility; // Fix the character spacing for headings
   small {
@@ -66,17 +66,22 @@ h1, h2, h3, h4, h5, h6 {
     color: @grayLight;
   }
 }
-h1 { font-size: 36px; line-height: 40px; }
-h2 { font-size: 30px; line-height: 40px; }
-h3 { font-size: 24px; line-height: 40px; }
-h4 { font-size: 18px; line-height: 20px; }
-h5 { font-size: 14px; line-height: 20px; }
-h6 { font-size: 12px; line-height: 20px; }
-
-h1 small { font-size: 24px; }
-h2 small { font-size: 18px; }
-h3 small { font-size: 14px; }
-h4 small { font-size: 14px; }
+
+h1,
+h2,
+h3 { line-height: @baseLineHeight * 2; }
+
+h1 { font-size: @baseFontSize * 2.75; } // ~38px
+h2 { font-size: @baseFontSize * 2.25; } // ~32px
+h3 { font-size: @baseFontSize * 1.75; } // ~24px
+h4 { font-size: @baseFontSize * 1.25; } // ~18px
+h5 { font-size: @baseFontSize; }
+h6 { font-size: @baseFontSize * .85; } // ~12px
+
+h1 small { font-size: @baseFontSize * 1.75; } // ~24px
+h2 small { font-size: @baseFontSize * 1.25; } // ~18px
+h3 small { font-size: @baseFontSize; }
+h4 small { font-size: @baseFontSize; }
 
 
 // Page header