fix postcss 8 error

For some reason, postcss 8 does not allow multiplication by -1

Author: andymark-by

src/components/navigation/navigation.scss

@@ -12,7 +12,7 @@
   top: 50%;
   width: calc(var(--swiper-navigation-size) / 44 * 27);
   height: var(--swiper-navigation-size);
-  margin-top: calc(-1 * var(--swiper-navigation-size) / 2);
+  margin-top: calc(0 - (var(--swiper-navigation-size) / 2));
   z-index: 10;
   cursor: pointer;
   display: flex;