diff --git a/elements/pfe-sass/mixins/_mixins.scss b/elements/pfe-sass/mixins/_mixins.scss
index dc420cfbc6..f2f5329744 100644
--- a/elements/pfe-sass/mixins/_mixins.scss
+++ b/elements/pfe-sass/mixins/_mixins.scss
@@ -253,7 +253,6 @@ $pfe-expand_chevron--placement:      #{$pfe-expand_button--LineHeight / 2 - $pfe
         outline: none;
         z-index: 2;
         text-decoration: underline;
-        text-decoration-color: #{pfe-color(surface--border--darker)};
     }
 
     &::-moz-focus-inner {
@@ -269,6 +268,7 @@ $pfe-expand_chevron--placement:      #{$pfe-expand_button--LineHeight / 2 - $pfe
 
 @mixin pfe-trigger-button-last($theme: light) {
   border-bottom: #{pfe-var(surface--border-width)} #{pfe-var(surface--border-style)} #{pfe-color(surface--border)};
+  border-top: 0;
   // @TODO Support differences based on theme
 }
 
@@ -305,8 +305,8 @@ $pfe-expand_chevron--placement:      #{$pfe-expand_button--LineHeight / 2 - $pfe
   @if $theme == dark {
     --pfe-#{$component-name}--main:         #{pfe-color(surface--darker)};
     --pfe-#{$component-name}--aux:          #{pfe-color(surface--darkest--text)};
-    --pfe-#{$component-name}--BorderLeft:   #{pfe-var(surface--border-width--heavy)} #{pfe-var(surface--border-style)} #{pfe-color(surface--border-darkest)};
-    --pfe-#{$component-name}--BorderRight:  #{pfe-var(surface--border-width)} #{pfe-var(surface--border-style)} #{pfe-color(surface--border-darkest)};
+    --pfe-#{$component-name}--BorderLeft:   #{pfe-var(surface--border-width--heavy)} #{pfe-var(surface--border-style)} #{pfe-color(surface--border)};
+    --pfe-#{$component-name}--BorderRight:  #{pfe-var(surface--border-width)} #{pfe-var(surface--border-style)} #{pfe-color(surface--border)};
 
     --pfe-#{$component-name}--BorderLeftColor--focus: #{pfe-color(surface--lightest)};
   }
@@ -377,11 +377,13 @@ $pfe-expand_chevron--placement:      #{$pfe-expand_button--LineHeight / 2 - $pfe
   overflow: hidden;
   will-change: height;
   border-color: transparent;
+  opacity: 0;
 }
 
 @mixin pfe-accordion-panel-expanded {
   display: block;
   position: relative;
+  opacity: 1;
 }
 
 @mixin pfe-accordion-panel-expanded-style($theme: light) {
@@ -390,8 +392,8 @@ $pfe-expand_chevron--placement:      #{$pfe-expand_button--LineHeight / 2 - $pfe
   @if $theme == dark {
     box-shadow: none;
     background-color: #{pfe-color(surface--darker)};
-    border-left-color: #{pfe-color(surface--darkest--text)};
-    border-right-color: #{pfe-color(surface--darkest--text)};
+    border-left-color: #{pfe-color(surface--border)};
+    border-right-color: #{pfe-color(surface--border)};
   }
   @else {
     box-shadow: 0 5px #{pfe-var(surface--border-width--heavy)} rgba(140, 140, 140, 0.35);
@@ -412,4 +414,4 @@ $pfe-expand_chevron--placement:      #{$pfe-expand_button--LineHeight / 2 - $pfe
   @else {
     padding: 0 #{$pfe-expand_button--padding--wide} #{$pfe-expand_button--padding} #{$pfe-expand_chevron--padding};
   }
-}
+}
\ No newline at end of file