feat: choose FOUT over FOIT (#71)

Use font-display swap

Author: Kocal

styles/font.styl

@@ -3,6 +3,7 @@
   font-family: 'PT Serif';
   font-style: normal;
   font-weight: 400;
+  font-display: swap;
   src: local('PT Serif'), local('PTSerif-Regular'), url('~fonts/EJRVQgYoZZY2vCFuvAFbzr-_dSb_nco.woff2') format('woff2');
   unicode-range: U+0460-052F, U+1C80-1C88, U+20B4, U+2DE0-2DFF, U+A640-A69F, U+FE2E-FE2F;
 }
@@ -11,6 +12,7 @@
   font-family: 'PT Serif';
   font-style: normal;
   font-weight: 400;
+  font-display: swap;
   src: local('PT Serif'), local('PTSerif-Regular'), url('~fonts/EJRVQgYoZZY2vCFuvAFSzr-_dSb_nco.woff2') format('woff2');
   unicode-range: U+0400-045F, U+0490-0491, U+04B0-04B1, U+2116;
 }
@@ -19,6 +21,7 @@
   font-family: 'PT Serif';
   font-style: normal;
   font-weight: 400;
+  font-display: swap;
   src: local('PT Serif'), local('PTSerif-Regular'), url('~fonts/EJRVQgYoZZY2vCFuvAFYzr-_dSb_nco.woff2') format('woff2');
   unicode-range: U+0100-024F, U+0259, U+1E00-1EFF, U+2020, U+20A0-20AB, U+20AD-20CF, U+2113, U+2C60-2C7F, U+A720-A7FF;
 }
@@ -27,6 +30,7 @@
   font-family: 'PT Serif';
   font-style: normal;
   font-weight: 400;
+  font-display: swap;
   src: local('PT Serif'), local('PTSerif-Regular'), url('~fonts/EJRVQgYoZZY2vCFuvAFWzr-_dSb_.woff2') format('woff2');
   unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+2000-206F, U+2074, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
 }

styles/index.styl

@@ -73,7 +73,7 @@ strong
 h1, h2, h3, h4, h5, h6
   font-weight 600
   line-height 1.25
-  font-family PT Serif
+  font-family PT Serif, Serif
 
   {$contentClass}:not(.custom) > &
     margin-top 'calc(0.5rem - %s)' % ($headerHeight)