WKWebview not loading local HTML/CSS file

I am using WKWebview to load local html file. the folder resides in tmp directory. The relative path of js and css are in nested folders.(../css/font.css,../js/player.js), where as html in parent folder. The Url not loading in the wkwebview

Root folder name - HTMLFiles
Root HTML Path -  HTMLFiles/HTML/index.html
CSS path - HTMLFiles/design/CSS/font.css
JS path - HTMLFiles/JSPath/JS/player.js

> > Below I am trying to read from temp directory and loading into
>     > wkwebview urlToLoad =  [NSString
>     > stringWithFormat:@"file://%@/HTMLFiles/HTML/index.html",
>     > NSTemporaryDirectory()];; SEL sel =
>     > NSSelectorFromString(@"loadFileURL:allowingReadAccessToURL:"); if
>     > ([self.webView respondsToSelector:sel] &&
>     > self.useLoadFileURLreadAccessURL) {    NSString* directory =
>     > [self.urlToLoad stringByDeletingLastPathComponent];
>     >         ((id (*)(id, SEL, id, id))objc_msgSend)(self.webView, sel, [NSURL URLWithString:self.urlToLoad], [NSURL
>     > URLWithString:directory]);
>     >         [_webView loadFileURL:[NSURL URLWithString:self.urlToLoad] allowingReadAccessToURL:[NSURL
> URLWithString:directory]];
>     >     } else {
>     >         // load the passed in URL
>     >         [self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:self.urlToLoad]]];   }