fix(spinner): loading animation not playing unless forced to

fix(methanium-theme): missing light mode values for border and card
fix(secret-theme): contrast issues
feat(secret-theme): use lighter colors in light mode
feat(themes): make markdown code box backgrounds fit better to each theme
feat(qol): add flag to auto-reset themes if they're not customised

src/markdown/code-block.tsx

@@ -71,7 +71,7 @@ function CodeBlock({
       data-slot="code-block"
       data-line-numbers={showLineNumbers || undefined}
       data-language={language || undefined}
-      className="group/code-block overflow-hidden rounded-lg border-[length:var(--ui-border-width)] border-border bg-[var(--markdown-code-background)] my-2!"
+      className="group/code-block overflow-hidden rounded-lg border-[length:var(--ui-border-width)] border-border bg-[var(--markdown-code-background,var(--markdown-code-background-default))] my-2!"
     >
       <figcaption
         data-slot="code-block-header"