Fixing wrong dark mode color on button

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hibas123/theme",
-  "version": "1.2.0",
+  "version": "1.2.2",
   "description": "",
   "main": " ",
   "files": [

src/base/_btn.scss

@@ -1,6 +1,5 @@
-.btn-flat {
+@mixin btn-flat() {
     position: relative;
-    color: black;
     border: 0;
     margin: .3rem;
     padding: .5rem;
@@ -9,8 +8,12 @@
     transition: .05s background-color linear;
 }
 
+.btn-flat {
+    @include btn-flat();
+}
+
 .btn {
-    @extend .btn-flat;
+    @include btn-flat();
 }
 
 .btn-primary {

src/theme/_btn.scss

@@ -1,4 +1,4 @@
-.btn-flat {
+@mixin btn-flat {
     background: $button-color;
 
     &:hover {
@@ -10,9 +10,13 @@
     }
 }
 
+.btn-flat {
+    @include btn-flat();
+}
+
 .btn {
     @include Elevation(1);
-    @extend .btn-flat;
+    @include btn-flat();
 }
 
 .fab {