blog/chacha8rand: give perf graphs a white background

They have black text and black on very dark gray doesn't
look that great in dark mode (although it does seem in keeping
with the gestalt of dark mode).

Also fix coloring of links containing <code> text, by removing
color override for <code>. Otherwise only the non-code parts
of the links shows up blue, which is very confusing, like in

<a><code>math/rand</code>'s <code>Read</code></a>

where only the 's shows up blue.

Change-Id: I345fd1ffaaa7e20804b31adcdab8d3d3d4acb924
Reviewed-on: https://go-review.googlesource.com/c/website/+/583835
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>
diff --git a/_content/blog/chacha8rand.md b/_content/blog/chacha8rand.md
index 44d7c8e..656db91 100644
--- a/_content/blog/chacha8rand.md
+++ b/_content/blog/chacha8rand.md
@@ -437,6 +437,7 @@
 the primitive operation “Uint64,” which returns the next `uint64` in the random stream,
 and the higher-level operation “N(1000),” which returns a random value in the range [0, 1000).
 
+<div style="background-color: white;">
 <img src="chacha8rand/amd.svg">
 <img src="chacha8rand/intel.svg">
 <img src="chacha8rand/amd32.svg">
@@ -444,6 +445,7 @@
 <img src="chacha8rand/m1.svg">
 <img src="chacha8rand/m3.svg">
 <img src="chacha8rand/taut2a.svg">
+</div>
 
 The “running 32-bit code” graphs show modern 64-bit x86 chips
 executing code built with `GOARCH=386`, meaning they are
diff --git a/_content/css/styles.css b/_content/css/styles.css
index 377d3b1..11dfb5d 100644
--- a/_content/css/styles.css
+++ b/_content/css/styles.css
@@ -858,8 +858,7 @@
   overflow-x: auto;
   padding: 1.5rem;
 }
-.Article pre,
-.Article code {
+.Article pre {
   color: var(--color-text);
 }
 .Article pre {