diff --git a/.changeset/long-geckos-clap.md b/.changeset/long-geckos-clap.md
new file mode 100644
index 0000000000..b6553e284c
--- /dev/null
+++ b/.changeset/long-geckos-clap.md
@@ -0,0 +1,8 @@
+---
+'@swisspost/design-system-styles': patch
+---
+
+- Reduced horizontal padding of tertiary buttons.
+- Updated font-size progression according to button size.
+- Changed transparent color to full-tone colors.
+- Updated slightly the font and border color of secondary and tertiary buttons.
diff --git a/packages/styles/src/components/button.scss b/packages/styles/src/components/button.scss
index c65911365b..d6b0361bb0 100644
--- a/packages/styles/src/components/button.scss
+++ b/packages/styles/src/components/button.scss
@@ -33,7 +33,7 @@
   border-radius: button.$btn-border-radius;
   background-color: transparent;
   box-shadow: none;
-  color: var(--post-contrast-color);
+  color: var(--post-gray-80);
   font-family: inherit;
   font-weight: button.$btn-font-weight;
   text-decoration: none !important; // For <a> tags, !important for hover
@@ -43,7 +43,7 @@
 // Primary
 .btn-primary {
   border-color: transparent;
-  background-color: rgba(var(--post-contrast-color-rgb), 0.8);
+  background-color: var(--post-gray-80);
   color: var(--post-contrast-color-inverted);
 
   @include utilities.not-disabled-focus-hover() {
@@ -53,9 +53,14 @@
 
   @include color-mx.on-dark-background {
     background-color: var(--post-contrast-color);
+    color: var(--post-gray-10); // Apply same color as secondary/tertiary button on dark theme
 
     @include utilities.not-disabled-focus-hover() {
-      background-color: rgba(var(--post-contrast-color-rgb), 0.8);
+      background-color: var(--post-gray-80);
+    }
+
+    &:disabled {
+      color: var(--post-gray-80);
     }
   }
 
@@ -83,7 +88,7 @@
   }
 
   &:disabled {
-    background-color: rgba(var(--post-contrast-color-rgb), 0.4);
+    background-color: var(--post-gray-40);
   }
 
   .pi {
@@ -96,28 +101,18 @@
 .btn-default,
 .btn-secondary {
   @extend %btn-default;
-
-  // Invert icon on dark backgrounds
-  @include color-mx.on-dark-background() {
-    .pi {
-      filter: invert(1);
-    }
-  }
+  @extend %btn-transparent-background;
 }
 
 // Tertiary
 .btn-link,
 .btn-tertiary {
+  @extend %btn-transparent-background;
   border: 0;
-  padding-right: 0.375rem;
-  padding-left: 0.375rem;
-
-  @include utilities.not-disabled-focus-hover() {
-    color: rgba(var(--post-contrast-color-rgb), 0.8);
-  }
+  padding-inline: spacing.$size-micro;
 
   &:disabled {
-    color: rgba(var(--post-contrast-color-rgb), 0.6);
+    color: var(--post-gray-60);
   }
 
   // Styles  to improve accessibility in high contrast mode
diff --git a/packages/styles/src/mixins/_button.scss b/packages/styles/src/mixins/_button.scss
index 2c69a4fdfa..ee8dae85b0 100644
--- a/packages/styles/src/mixins/_button.scss
+++ b/packages/styles/src/mixins/_button.scss
@@ -20,10 +20,13 @@
 
 @mixin button-size($size: md) {
   min-height: map.get(button.$btn-height-map, $size);
-  padding: 0 map.get(button.$btn-padding-x-map, $size);
   font-size: map.get(button.$btn-font-size-map, $size);
   gap: map.get(button.$btn-padding-x-map, $size) * 0.5;
 
+  &:where(:not(.btn-link, .btn-tertiary)) {
+    padding: 0 map.get(button.$btn-padding-x-map, $size);
+  }
+
   > .pi {
     width: map.get(button.$btn-icon-size-map, $size);
     height: map.get(button.$btn-icon-size-map, $size);
diff --git a/packages/styles/src/placeholders/_button.scss b/packages/styles/src/placeholders/_button.scss
index ffbebff732..1b3a93c77a 100644
--- a/packages/styles/src/placeholders/_button.scss
+++ b/packages/styles/src/placeholders/_button.scss
@@ -3,23 +3,35 @@
 @use './../variables/components/button';
 
 %btn-default {
-  border: button.$btn-border-width solid rgba(var(--post-contrast-color-rgb), 0.2);
+  border: button.$btn-border-width solid var(--post-gray-60);
 
   @include utilities.not-disabled-focus-hover() {
     border-color: var(--post-contrast-color);
-    color: var(--post-contrast-color); // Override <a> color
   }
 
   @include color-mx.on-dark-background() {
     border-color: var(--post-contrast-color);
 
     @include utilities.not-disabled-focus-hover() {
-      border-color: rgba(var(--post-contrast-color-rgb), 0.4);
+      border-color: var(--post-gray-40);
     }
   }
 
   &:disabled {
-    border-color: rgba(var(--post-contrast-color-rgb), 0.4);
-    color: rgba(var(--post-contrast-color-rgb), 0.6);
+    border-color: var(--post-gray-40);
+    color: var(--post-gray-60);
+  }
+}
+
+%btn-transparent-background {
+  @include utilities.not-disabled-focus-hover() {
+    color: var(--post-contrast-color);
+  }
+
+  // Invert icon on dark backgrounds
+  @include color-mx.on-dark-background() {
+    .pi {
+      filter: invert(1);
+    }
   }
 }
diff --git a/packages/styles/src/variables/_type.scss b/packages/styles/src/variables/_type.scss
index 8c7f103e89..69842b1254 100644
--- a/packages/styles/src/variables/_type.scss
+++ b/packages/styles/src/variables/_type.scss
@@ -29,6 +29,7 @@ $font-size-small-huge: sizing.px-to-rem(48px);
 $font-size-huge: sizing.px-to-rem(56px);
 
 // New
+$font-size-12: sizing.px-to-rem(12px);
 $font-size-14: sizing.px-to-rem(14px);
 $font-size-16: sizing.px-to-rem(16px);
 $font-size-18: sizing.px-to-rem(18px);
diff --git a/packages/styles/src/variables/components/_button.scss b/packages/styles/src/variables/components/_button.scss
index a59065bc42..53bfc16950 100644
--- a/packages/styles/src/variables/components/_button.scss
+++ b/packages/styles/src/variables/components/_button.scss
@@ -43,7 +43,7 @@ $btn-padding-x-sm: spacing.$size-regular !default;
 $btn-animation-distance-sm: spacing.$size-mini !default;
 // Design System only
 $btn-height-sm: 2rem;
-$btn-font-size-sm: type.$font-size-tiny !default;
+$btn-font-size-sm: type.$font-size-12 !default;
 $btn-icon-size-sm: spacing.$size-regular !default;
 
 // rg
@@ -52,7 +52,7 @@ $btn-padding-x-rg: spacing.$size-large !default;
 $btn-animation-distance-rg: 0.625rem !default;
 // Design System only
 $btn-height-rg: 2.5rem;
-$btn-font-size-rg: type.$font-size-regular !default;
+$btn-font-size-rg: type.$font-size-14 !default;
 $btn-icon-size-rg: 1.125rem !default;
 
 // md
@@ -61,7 +61,7 @@ $btn-padding-x-md: spacing.$size-big !default;
 $btn-animation-distance-md: spacing.$size-small-regular !default;
 // Design System only
 $btn-height-md: 3rem;
-$btn-font-size-md: type.$font-size-regular !default;
+$btn-font-size-md: type.$font-size-16 !default;
 $btn-icon-size-md: spacing.$size-small-large !default;
 
 // lg
@@ -70,7 +70,7 @@ $btn-padding-x-lg: spacing.$size-bigger-big !default;
 $btn-animation-distance-lg: spacing.$size-regular !default;
 // Design System only
 $btn-height-lg: 3.5rem;
-$btn-font-size-lg: type.$font-size-bigger-regular !default;
+$btn-font-size-lg: type.$font-size-18 !default;
 $btn-icon-size-lg: spacing.$size-large !default;
 
 // Available button sizes except the default, which is md