diff --git a/theme/boost/scss/moodle/buttons.scss b/theme/boost/scss/moodle/buttons.scss
index a19c088a274..8b1317e8912 100644
--- a/theme/boost/scss/moodle/buttons.scss
+++ b/theme/boost/scss/moodle/buttons.scss
@@ -49,8 +49,10 @@ p.arrow_button {
 .btn.btn-icon {
     @extend .btn-link;
 
-    height: $icon-width;
-    width: $icon-width;
+    height: ($icon-width + 20px);
+    width: ($icon-width + 20px);
+    font-size: $icon-width;
+    line-height: $icon-width;
     padding: 0;
     border-radius: 50%;
     flex-shrink: 0;
@@ -63,6 +65,8 @@ p.arrow_button {
         &.icon-size-#{$size} {
             height: ($length + 20px) !important; /* stylelint-disable-line declaration-no-important */
             width: ($length + 20px) !important; /* stylelint-disable-line declaration-no-important */
+            font-size: $length !important; /* stylelint-disable-line declaration-no-important */
+            line-height: $length !important; /* stylelint-disable-line declaration-no-important */
         }
     }
 }
diff --git a/theme/boost/scss/moodle/core.scss b/theme/boost/scss/moodle/core.scss
index 3e75cb14dfd..27306ceaefc 100644
--- a/theme/boost/scss/moodle/core.scss
+++ b/theme/boost/scss/moodle/core.scss
@@ -2258,6 +2258,10 @@ $switch-transition: .2s all !default;
     text-decoration: none !important; /* stylelint-disable-line declaration-no-important */
 }
 
+.colour-inherit {
+    color: inherit !important; /* stylelint-disable-line declaration-no-important */
+}
+
 .position-right {
     right: 0 !important; /* stylelint-disable-line declaration-no-important */
 }
diff --git a/theme/boost/style/moodle.css b/theme/boost/style/moodle.css
index d026e5e16d8..e2f38f12c7a 100644
--- a/theme/boost/style/moodle.css
+++ b/theme/boost/style/moodle.css
@@ -11453,6 +11453,10 @@ div.editor_atto_toolbar button .icon {
   text-decoration: none !important;
   /* stylelint-disable-line declaration-no-important */ }
 
+.colour-inherit {
+  color: inherit !important;
+  /* stylelint-disable-line declaration-no-important */ }
+
 .position-right {
   right: 0 !important;
   /* stylelint-disable-line declaration-no-important */ }
@@ -16924,8 +16928,10 @@ p.arrow_button {
   margin: 0 0 10px 5px; }
 
 .btn.btn-icon, #page-grade-grading-manage .actions .btn-icon.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon, #rubric-rubric.gradingform_rubric .btn-icon.addcriterion {
-  height: 16px;
-  width: 16px;
+  height: 36px;
+  width: 36px;
+  font-size: 16px;
+  line-height: 16px;
   padding: 0;
   border-radius: 50%;
   flex-shrink: 0; }
@@ -16935,31 +16941,55 @@ p.arrow_button {
     height: 20px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 20px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 0 !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 0 !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-1, #page-grade-grading-manage .actions .btn-icon.icon-size-1.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-1, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-1.addcriterion {
     height: 24px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 24px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 4px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 4px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-2, #page-grade-grading-manage .actions .btn-icon.icon-size-2.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-2, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-2.addcriterion {
     height: 28px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 28px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 8px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 8px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-3, #page-grade-grading-manage .actions .btn-icon.icon-size-3.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-3, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-3.addcriterion {
     height: 36px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 36px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 16px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 16px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-4, #page-grade-grading-manage .actions .btn-icon.icon-size-4.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-4, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-4.addcriterion {
     height: 44px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 44px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 24px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 24px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-5, #page-grade-grading-manage .actions .btn-icon.icon-size-5.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-5, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-5.addcriterion {
     height: 68px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 68px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 48px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 48px !important;
     /* stylelint-disable-line declaration-no-important */ }
 
 .gradetreebox h4 {
diff --git a/theme/classic/style/moodle.css b/theme/classic/style/moodle.css
index de2838b0ae1..6a648ada33e 100644
--- a/theme/classic/style/moodle.css
+++ b/theme/classic/style/moodle.css
@@ -11708,6 +11708,10 @@ div.editor_atto_toolbar button .icon {
   text-decoration: none !important;
   /* stylelint-disable-line declaration-no-important */ }
 
+.colour-inherit {
+  color: inherit !important;
+  /* stylelint-disable-line declaration-no-important */ }
+
 .position-right {
   right: 0 !important;
   /* stylelint-disable-line declaration-no-important */ }
@@ -17200,8 +17204,10 @@ p.arrow_button {
   margin: 0 0 10px 5px; }
 
 .btn.btn-icon, #page-grade-grading-manage .actions .btn-icon.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon, #rubric-rubric.gradingform_rubric .btn-icon.addcriterion {
-  height: 16px;
-  width: 16px;
+  height: 36px;
+  width: 36px;
+  font-size: 16px;
+  line-height: 16px;
   padding: 0;
   border-radius: 50%;
   flex-shrink: 0; }
@@ -17211,31 +17217,55 @@ p.arrow_button {
     height: 20px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 20px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 0 !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 0 !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-1, #page-grade-grading-manage .actions .btn-icon.icon-size-1.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-1, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-1.addcriterion {
     height: 24px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 24px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 4px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 4px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-2, #page-grade-grading-manage .actions .btn-icon.icon-size-2.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-2, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-2.addcriterion {
     height: 28px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 28px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 8px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 8px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-3, #page-grade-grading-manage .actions .btn-icon.icon-size-3.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-3, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-3.addcriterion {
     height: 36px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 36px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 16px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 16px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-4, #page-grade-grading-manage .actions .btn-icon.icon-size-4.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-4, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-4.addcriterion {
     height: 44px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 44px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 24px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 24px !important;
     /* stylelint-disable-line declaration-no-important */ }
   .btn.btn-icon.icon-size-5, #page-grade-grading-manage .actions .btn-icon.icon-size-5.action, #rubric-rubric.gradingform_rubric #rubric-criteria .criterion .addlevel input.btn-icon.icon-size-5, #rubric-rubric.gradingform_rubric .btn-icon.icon-size-5.addcriterion {
     height: 68px !important;
     /* stylelint-disable-line declaration-no-important */
     width: 68px !important;
+    /* stylelint-disable-line declaration-no-important */
+    font-size: 48px !important;
+    /* stylelint-disable-line declaration-no-important */
+    line-height: 48px !important;
     /* stylelint-disable-line declaration-no-important */ }
 
 .gradetreebox h4 {