style: add selection colors

static/css/base.css

@@ -84,6 +84,8 @@
     --view-selectable-colour: #1a1a1a;
     --view-selectable-hover-colour: var(--inline-accent-colour);
 
+    --selection-colour: #bfdac4;
+
     --secondary-background-colour: #eeeeee;
 
     --logo-text-colour: var(--inline-accent-colour);
@@ -95,6 +97,10 @@
     font-family: Archivo, Archivo Fallback, sans-serif;
 }
 
+::selection {
+    background-color: var(--selection-colour);
+}
+
 /* LINKS */
 a {
     color: var(--view-selectable-colour);
@@ -403,6 +409,8 @@ img.inline {
         --view-selectable-colour: #d0d0d0;
         --view-selectable-hover-colour: #44ff99;
 
+        --selection-colour: #294733;
+
         --secondary-background-colour: #33393b;
 
         --logo-text-colour: #289755; /* same as oklch(from var(--pmos-accent-colour) 60% c h) */