all: improve the web rendering based on result from webpagetest.org

Changes,

* In CSS, use "font-display:swap" [1]. This allow browser use fallback
  font first and changes to target font once the file downloaded.

* In HTML, add "lang=en"

* Load CSS asynchronously using `media="print" onload="this.media='all'"`

* Set empty alt text for decorative image

* Set width and height for image ratio

[1] https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face/font-display

1 files changed, 12 insertions, 0 deletions

diff --git a/_content/index.css b/_content/index.css
index f499c10..cfb8af6 100644
--- a/_content/index.css
+++ b/_content/index.css
@@ -1,4 +1,5 @@
 @font-face {
+  font-display: swap;
   font-family: "Go";
   src:
     local("Go Regular"),
@@ -11,6 +12,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go";
   src:
     local("Go Bold"),
@@ -23,6 +25,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go";
   src:
     local("Go Italic"),
@@ -35,6 +38,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go";
   src:
     local("Go Bold Italic"),
@@ -47,6 +51,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go";
   src:
     local("Go Medium"),
@@ -59,6 +64,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go";
   src:
     local("Go Medium Italic"),
@@ -71,6 +77,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go Mono";
   src:
     local("Go Mono"),
@@ -83,6 +90,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go Mono";
   src:
     local("Go Mono Bold Italic"),
@@ -95,6 +103,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go Mono";
   src:
     local("Go Mono Italic"),
@@ -107,6 +116,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go Mono";
   src:
     local("Go Mono Bold"),
@@ -119,6 +129,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go Smallcaps";
   src:
     local("Go Smallcaps Italic"),
@@ -131,6 +142,7 @@
 }
 
 @font-face {
+  font-display: swap;
   font-family: "Go Smallcaps";
   src:
     local("Go Smallcaps"),