diff --git a/demo/e2e/screenshot.spec.ts-snapshots/floating-action-button-fixed.png b/demo/e2e/screenshot.spec.ts-snapshots/floating-action-button-fixed.png
index 8ad4c6f..da1b773 100644
Binary files a/demo/e2e/screenshot.spec.ts-snapshots/floating-action-button-fixed.png and b/demo/e2e/screenshot.spec.ts-snapshots/floating-action-button-fixed.png differ
diff --git a/src/styles/components/ion-button.scss b/src/styles/components/ion-button.scss
index bf8857e..0dde1f3 100644
--- a/src/styles/components/ion-button.scss
+++ b/src/styles/components/ion-button.scss
@@ -6,11 +6,11 @@
  */
 
 $scaleup-small: 1.12;
-$scaleup-small-icon-only: 1.18;
+$scaleup-small-icon-only: api.$button-scaleup-small-icon-only;
 $scaleup-default: 1.25;
-$scaleup-default-icon-only: 1.32;
+$scaleup-default-icon-only: api.$button-scaleup-default-icon-only;
 $scaleup-large: 1.12;
-$scaleup-large-icon-only: 1.22;
+$scaleup-large-icon-only: api.$button-scaleup-large-icon-only;
 
 @mixin theme-buttons {
   @include api.glass-background($shadow-opacity: 0.08);
@@ -343,7 +343,11 @@ $scaleup-large-icon-only: 1.22;
       --color: rgba(var(--ion-color-base-rgb, var(--ion-text-color-rgb, 0, 0, 0)), 1);
     }
     &.ion-activated {
-      --opacity: 1; // for ion-back-button
+      &::part(native) {
+        @include api.glass-background-button-activated;
+        opacity: 1;
+        color: var(--color);
+      }
       --color: rgba(var(--ion-text-color-rgb, 0, 0, 0), 0.1);
       &.ion-color {
         --color: rgba(var(--ion-color-base-rgb, var(--ion-text-color-rgb, 0, 0, 0)), 0.1);
diff --git a/src/styles/components/ion-fab.scss b/src/styles/components/ion-fab.scss
index b328a7d..01b15dc 100644
--- a/src/styles/components/ion-fab.scss
+++ b/src/styles/components/ion-fab.scss
@@ -1,8 +1,8 @@
 @use '../utils/api';
 
-$scaleup-small-icon-only: 1.18;
-$scaleup-default-icon-only: 1.2;
-$scaleup-large-icon-only: 1.12;
+$scaleup-small-icon-only: api.$button-scaleup-small-icon-only;
+$scaleup-default-icon-only: api.$button-scaleup-default-icon-only;
+$scaleup-large-icon-only: api.$button-scaleup-large-icon-only;
 
 ion-fab.ios:not(.ios26-disabled) {
   --transform-value: 2.5px;
@@ -13,7 +13,7 @@ ion-fab.ios:not(.ios26-disabled) {
   ion-fab-button {
     --background: rgba(var(--ios26-glass-background-rgb), 0.72);
     --box-shadow:
-      inset 0 0 8px 0 rgba(var(--ios26-glass-box-shadow-color-rgb), 0.2), 0 0 10px 0 rgba(var(--ios26-glass-box-shadow-color-rgb), 0.82);
+      inset 0 0 8px 0 rgba(var(--ios26-glass-box-shadow-color-rgb), 0.2), 0 0.5px 1px 0 rgba(var(--ios26-glass-box-shadow-color-rgb), 0.08);
     --transition:
       var(--ios26-activated-transition-duration) transform cubic-bezier(0.25, 1.11, 0.78, 1.59),
       var(--ios26-activated-transition-duration) color ease;
@@ -38,6 +38,7 @@ ion-fab.ios:not(.ios26-disabled) {
     &.ion-activated {
       --color: rgba(var(--ion-text-color-rgb, 0, 0, 0), 0.1);
       &::part(native) {
+        @include api.glass-background-button-activated;
         transform: scale($scaleup-default-icon-only) translateZ(0);
         -webkit-transform: scale($scaleup-default-icon-only) translateZ(0);
       }
@@ -59,10 +60,8 @@ ion-fab.ios:not(.ios26-disabled) {
     }
 
     &::part(native) {
-      @include api.glass-background($include-background: false, $include-box-shadow: false);
-      // The previous background shorthand reset Ionic's padding-box default.
-      // There is no CSS custom property for background-clip, so preserve it via the Part.
       background-clip: border-box;
+      @include api.glass-background($include-background: false, $include-box-shadow: false);
     }
   }
 
diff --git a/src/styles/utils/api.scss b/src/styles/utils/api.scss
index af762cd..f2d843c 100644
--- a/src/styles/utils/api.scss
+++ b/src/styles/utils/api.scss
@@ -1,3 +1,7 @@
+$button-scaleup-small-icon-only: 1.18;
+$button-scaleup-default-icon-only: 1.38;
+$button-scaleup-large-icon-only: 1.22;
+
 $_glass-surface: linear-gradient(
   180deg,
   rgba(var(--ion-text-color-rgb, 0, 0, 0), 0) 4%,
@@ -80,6 +84,9 @@ $_glass-surface: linear-gradient(
 }
 
 @mixin glass-background-button-activated {
+  background-color: rgba(var(--ios26-glass-background-rgb), 0.96);
+  border-color: rgba(var(--ion-text-color-rgb, 0, 0, 0), 0.12) rgba(var(--ion-text-color-rgb, 0, 0, 0), 0.32)
+    rgba(var(--ion-text-color-rgb, 0, 0, 0), 0.16) rgba(var(--ion-text-color-rgb, 0, 0, 0), 0.28);
   box-shadow:
     inset 0 0 0 0.5px rgba(var(--ios26-glass-border-color-rgb), 0.95),
     inset 0 1px 3px 0 rgba(var(--ios26-glass-border-color-rgb), 0.85),
@@ -96,6 +103,8 @@ $_glass-surface: linear-gradient(
 ) {
   @if $include-background {
     background: rgba(var(--ios26-button-color-selected-rgb), $opacity);
+  } @else {
+    background-color: rgba(var(--ios26-button-color-selected-rgb), $opacity);
   }
   backdrop-filter: blur($blur) saturate($saturate);
   @if $include-box-shadow {
@@ -109,9 +118,6 @@ $_glass-surface: linear-gradient(
   background-clip: border-box;
   background-origin: padding-box;
 
-  // Hardware acceleration optimization for glass effects
-  transform: translateZ(0);
-  -webkit-transform: translateZ(0);
   -webkit-backface-visibility: hidden;
   backface-visibility: hidden;
 }
diff --git a/src/styles/utils/dark/ion-button.scss b/src/styles/utils/dark/ion-button.scss
index c64e704..2d2f3fd 100644
--- a/src/styles/utils/dark/ion-button.scss
+++ b/src/styles/utils/dark/ion-button.scss
@@ -37,7 +37,7 @@
       --color: rgba(var(--ion-color-base-rgb, var(--ion-text-color-rgb, 0, 0, 0)), 1);
     }
     &::part(native) {
-      @include api.glass-background-button-activated-dark($include-background: false, $include-box-shadow: $is-back-button);
+      @include api.glass-background-button-activated-dark($include-background: false);
     }
     ion-icon {
       color: rgb(255, 255, 255);
@@ -49,10 +49,10 @@
   ion-buttons.ios:not(.ios26-disabled):not(:has(ion-back-button, ion-button:not(.button-clear))) {
     @include theme-dark-buttons;
   }
-  ion-button:not(.ios26-disabled) {
+  ion-button.ios:not(.ios26-disabled) {
     @include theme-dark-button;
   }
-  ion-back-button:not(.ios26-disabled) {
+  ion-back-button.ios:not(.ios26-disabled) {
     @include theme-dark-button($is-back-button: true);
   }
 }
diff --git a/src/styles/utils/dark/ion-fab.scss b/src/styles/utils/dark/ion-fab.scss
index fc36a99..b693320 100644
--- a/src/styles/utils/dark/ion-fab.scss
+++ b/src/styles/utils/dark/ion-fab.scss
@@ -4,6 +4,9 @@
   ion-fab.ios:not(.ios26-disabled) {
     ion-fab-button {
       &.ion-activated {
+        &::part(native) {
+          @include api.glass-background-button-activated-dark($include-background: false);
+        }
         --color: rgba(var(--ion-text-color-rgb, 0, 0, 0), 1);
 
         &.ion-color {