feat: arrow_down icon

assets/arrow_down.svg

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<svg xmlns="http://www.w3.org/2000/svg" height="48" viewBox="0 -960 960 960" width="48">
+  <path fill="#ffffff" d="M457.308-779.999v513.692L212.001-511.999l-32 31.999L480-180.001 779.999-480l-32-31.999-245.307 245.692v-513.692h-45.384Z"/>
+</svg>

assets/resources.json

@@ -1,10 +1,13 @@
 {
   "icon": "icon/icon_48.png",
   "close": "close.png",
+
   "delete": "delete.svg",
   "error": "error.svg",
   "lyrics": "lyrics.svg",
   "spinner": "spinner.svg",
+  "arrow_down": "arrow_down.svg",
+
   "github": "external/github.png",
   "greasyfork": "external/greasyfork.png"
 }