Fix style and responsive issues

src/style/atoms/_button-cart.scss

@@ -1,7 +1,6 @@
-// Cart
 .button-cart {
-    display: none;
     position: relative;
+    pointer-events: auto;
 
     @include bp (sm) {
         display: flex;
@@ -14,11 +13,11 @@
 
     // Icon
     svg {
-        color: #fff;
         display: block;
-        width: 27px;
-        height: 27px;
+        width: min(65%, 27px);
+        height: min(65%, 27px);
         margin-top: -3px;
+        color: #fff;
     }
 
     // Quantity label
@@ -31,13 +30,19 @@
         display: flex;
         align-items: center;
         justify-content: center;
-        width: 22px;
-        height: 22px;
-        font-size: rem(12px);
+        width: 18px;
+        height: 18px;
+        font-size: rem(11px);
         font-weight: 600;
         color: #fff;
         background-color: $color-secondary;
         border-radius: 100%;
         opacity: 1;
+
+        @include bp (md) {
+            width: 22px;
+            height: 22px;
+            font-size: rem(12px);
+        }
     }
 }