сделал how js для пк

assets/css/gp-style-desktop.css

@@ -490,6 +490,12 @@
 
     width: 100%;
 }
+.how-content__item-block{
+    height: 0;
+    overflow: hidden;
+
+    transition: height .3s;
+}
 .how-content__item{
     width: 100%;
 
@@ -498,11 +504,6 @@
     background-color: var(--background-grey);
 
     overflow: hidden;
-
-    display: none;
-}
-.how-content__item.active{
-    display: block;
 }
 .how-content__item .text-2{
     margin-top: 16px;

assets/js/main.js

@@ -43,3 +43,32 @@ const reviewsSwiper = new Swiper('.reviews-swiper', {
 })
 
 // gymSwiper.destroy();
+
+// how
+
+function howPc() {
+    let itemButtons = document.querySelectorAll('.how-control__item'),
+        itemBlocks = document.querySelectorAll('.how-content__item-block');
+
+    itemButtons.forEach((button, index) => {
+        let block = itemBlocks[index];
+
+        button.onclick = function () {
+            let activeContent = document.querySelector('.how__content').querySelector('.active'),
+                activeButton = document.querySelector('.how__control').querySelector('.active');
+            
+            activeContent.style.height = '0px';
+            activeContent.classList.remove('active');
+            activeButton.classList.remove('active');
+
+            setTimeout(() => {
+                let newHeight = block.querySelector('.how-content__item').offsetHeight + 'px';
+                block.style.height = newHeight;
+                block.classList.add('active');
+                button.classList.add('active');
+            }, 300);
+        }
+    })
+}
+
+howPc();