Use CSS custom properties to define named colors

Hurrah! I've only wanted this feature for decades.

Thanks to Richard for pointing out that it's now been well-supported
long enough that I can reliably use it. This will really help so that
I can change colors in one place and have the entire style follow the
scheme.

diff --git a/style.css b/style.css
index 2121937a6c87c831d66d1c8d8c1fbd656cb09cee..a3219e20821c34956fc5e0fabdbb2a1fddf6cd23 100644 (file)
--- a/style.css
+++ b/style.css
@@ -1,3 +1,28 @@
+/*\
+|*|
+|*| Properties for the page: colors, etc.
+|*|
+|*| This is intended to be the easiest section to edit
+|*| some easy custom theming, (a custom color scheme, etc.).
+|*|
+\*/
+
+:root {
+    /* Standard colors for text. */
+    --text-fg-color: #333738;
+    --text-bg-color: white;
+    --outside-page-bg-color: #333738;
+
+    /* A little color to avoid a fully monochromatic theme. */
+    --accent-color: #287789;
+    --accent-color-bright: #44c7ef;
+
+    /* Some colors intended to convey semnatics. */
+    --warning-color: #ffa92a;
+    --danger-color: #f56257;
+    --danger-color-dark: #bc2822;
+}
+
 /*\
 |*|
 |*| Core elements: Sizing and padding
@@ -31,11 +56,11 @@ h2 {
  * entire screen width for the page (so the background color of the
  * body is not visible anywhere). */
 body {
-    background-color: #333738;
+    background-color: var(--outside-page-bg-color);
 }
 
 #page {
-    background-color: white;
+    background-color: var(--text-bg-color);
 }
 
 /* For a small screen (in either width or height) change the
@@ -44,7 +69,7 @@ body {
  */
 @media screen and (max-width: 500px) and (max-height: 860px) {
     body {
-        background-color: white;
+        background-color: var(--text-bg-color);
     }
 }
 
@@ -180,18 +205,18 @@ input {
     font-size: 125%;
     padding: 0.5em;
     width: 100%;
-    border: 1px solid #287789;
+    border: 1px solid var(--accent-color);
     border-radius: 4px;
 }
 
 input:focus {
-    border: 2px solid #44c7ef;
+    border: 2px solid var(--accent-color-bright);
 }
 
 button {
     display: inline-block;
     border-radius: 4px;
-    background-color: #287789;
+    background-color: var(--accent-color);
     border: none;
     color: white;
     text-align: center;
@@ -204,7 +229,7 @@ button {
 
 button:hover {
     transform: translateY(-1px);
-    background-color: #44c7ef;
+    background-color: var(--accent-color-bright);
 }
 
 :focus {
@@ -224,7 +249,7 @@ button:hover {
 /* Default message severity is "info" but can be overriden. */
 .message {
     padding: 1em;
-    background-color: #44c7ef;
+    background-color: var(--accent-color-bright);
     color: white;
     transition: 0.3s;
     margin-bottom: 0.5em;
@@ -234,15 +259,15 @@ button:hover {
 }
 
 .success {
-    background-color: #44c7ef;
+    background-color: var(--accent-color-bright);
 }
 
 .warning {
-    background-color: #ffa92a;
+    background-color: var(--warning-color);
 }
 
 .danger {
-    background-color: #f56257
+    background-color: var(--danger-color);
 }
 
 .hide-button {
@@ -256,5 +281,5 @@ button:hover {
 }
 
 .hide-button:hover {
-    color: #bc2822;
+    color: var(--danger-color-dark);
 }