Support dynamic dark/light themes

svelte/src/util/Chart.svelte

@@ -1,6 +1,7 @@
 <script>
 import { onMount } from "svelte";
 import { formatDataVolume, formatNumber } from "./Formatting.svelte";
+import { color_by_name } from "./Util.svelte";
 import {
 	Chart,
 	PointElement,
@@ -38,7 +39,7 @@ export const update = () => {
 	return chart_object.update()
 }
 
-Chart.defaults.color = "#"+window.style.bodyTextColor;
+Chart.defaults.color = color_by_name("body_text_color");
 Chart.defaults.font.size = 15;
 Chart.defaults.font.family = "system-ui, sans-serif";
 Chart.defaults.maintainAspectRatio = false;
@@ -91,7 +92,7 @@ onMount(() => {
 						grid: {
 							display: true,
 							drawBorder: false,
-							color: "#"+window.style.separatorColor,
+							color: color_by_name("separator"),
 						},
 					},
 					x: {