Refine header search styling

index.html

@@ -193,12 +193,10 @@
               class="header-search__filter"
               aria-label="Open search filters"
             >
-              <img
-                src="assets/svg/filter.svg"
-                alt=""
+              <span
                 aria-hidden="true"
-                class="header-search__icon"
-              />
+                class="header-search__icon header-search__icon--filter"
+              ></span>
             </button>
             <label for="headerSearchInput" class="sr-only">Search videos</label>
             <input
@@ -211,12 +209,10 @@
             />
             <button type="submit" class="header-search__submit">
               <span class="sr-only">Submit search</span>
-              <img
-                src="assets/svg/search.svg"
-                alt=""
+              <span
                 aria-hidden="true"
-                class="header-search__icon"
-              />
+                class="header-search__icon header-search__icon--submit"
+              ></span>
             </button>
           </form>
         </div>