Use Obsidian font stack

Author: marcusolsson

src/css/custom.css

@@ -1,5 +1,10 @@
+@import url("https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap");
+
 :root {
   --ifm-color-primary: #7f6df2;
+  --ifm-font-family-base: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
+    Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji",
+    "Segoe UI Symbol", "Microsoft YaHei Light", sans-serif;
 }
 
 .docusaurus-highlight-code-line {