High-contrast accessibility fixes

Author: albinazs

tbx/static_src/sass/components/_button-link.scss

@@ -11,6 +11,8 @@
     transition: background-color $transition-quick;
     // TODO: add default bg color for themed pages var(--color--accent) once color themes BE is ready
 
+    @include high-contrast-text-decoration();
+
     @include reduced-motion() {
         transition: none;
     }

tbx/static_src/sass/components/_division-signpost.scss

@@ -32,6 +32,10 @@
             flex-basis: calc(33.33% - ($spacer-mini-plus * 2 / 3));
         }
 
+        @include high-contrast-mode() {
+            border: 1px solid var(--color--text);
+        }
+
         &--theme-coral {
             background-color: var(--color--coral-charity);
 

tbx/static_src/sass/config/_mixins.scss

@@ -385,6 +385,10 @@
         @include focus-style();
     }
 
+    @include high-contrast-text-decoration();
+}
+
+@mixin high-contrast-text-decoration() {
     @include high-contrast-mode() {
         text-decoration: underline;
         text-decoration-thickness: $link-underline-thickness;