🔥 Finish Cart implementation

- Use Select component in CartItem to change quantity
- Visual update when removing or changing an item quantity
- API: Remove Cart item action
- API: Handle Cart item adding and updating (quantity)

src/style/organisms/_cart.scss

@@ -1,12 +1,13 @@
 .cart {
     display: flex;
     flex-direction: column;
+    overflow: hidden;
+    padding: 20px 20px 24px;
     background-color: $color-cream;
     border-radius: 8px;
-    padding: 20px 20px 24px;
 
     @include bp (sm) {
-        padding: 24px 32px;
+        padding: 24px 32px 32px;
     }
 
     // Heading
@@ -51,21 +52,10 @@
 
     // Content
     &__content {
+        position: relative;
         flex: 1;
     }
 
-    // Message
-    &__message {
-        display: flex;
-        align-items: center;
-        justify-content: center;
-        height: 100%;
-        padding: 24px;
-        background: #fff;
-        color: $color-gray;
-        border-radius: 6px;
-    }
-
     // Total
     &__total {
         margin-top: auto;
@@ -73,7 +63,7 @@
         color: $color-gray;
 
         @include bp (md) {
-            margin: 32px 0;
+            margin: 32px 0 0;
         }
 
         // Sum
@@ -138,6 +128,67 @@
         }
     }
 
+
+    // Empty content
+    &__empty {
+        display: flex;
+        flex-direction: column;
+        align-items: center;
+        justify-content: center;
+        height: 100%;
+        padding: 24px;
+        font-size: rem(20px);
+        font-weight: 200;
+        background: #fff;
+        color: $color-gray;
+        border-radius: 6px;
+
+        // Icon
+        .icon {
+            display: flex;
+            align-items: center;
+            justify-content: center;
+            width: 64px;
+            height: 64px;
+            margin-bottom: 16px;
+            color: #FF6C89;
+            background: $color-cream;
+            border-radius: 100%;
+        }
+    }
+
+    // Updating message
+    &__update {
+        position: absolute;
+        z-index: -1;
+        top: 0;
+        left: 0;
+        width: 100%;
+        height: 100%;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        font-size: rem(20px);
+        color: $color-secondary;
+        transition: opacity 0.6s var(--ease-quart), transform 0.6s var(--ease-quart);
+        opacity: 0;
+        transform: translate3d(0, -8px, 0);
+    }
+
+
+    // Updating state
+    &.is-updating {
+        .cart-item {
+            opacity: 0.1;
+            pointer-events: none;
+            user-select: none;
+        }
+        .cart__update {
+            opacity: 1;
+            transform: translate3d(0,0,0);
+        }
+    }
+
     // Overlay
     &-overlay {
         position: fixed;