Site blocked by avast

Hi,

I am having a nightmare with my wordpress site. It is being blocked by avast antivirus so that anyone using this software cannot access my site – not good when its a very popular free antivirus.

I have had my laptop services and the webpage checked and the only error coming up is here:
https://quttera.com/detailed_report/www.pilateswithangela.com

Basically this file is being regarded as supiscious: /wp-content/themes/cannyon/media/css/icons.css?ver=06ca29fd4093b4b1dedad26f6712c1c9

Details:

/wp-content/themes/cannyon/media/css/icons.css?ver=06ca29fd4093b4b1dedad26f6712c1c9
Severity:	Potentially Suspicious
Reason:	Detected procedure that is commonly used in suspicious activity.
Details:	Too low entropy detected in string [['data:application/octet-stream;base64,AAEAAAAOAIAAAwBgT1MvMj7AUhIAAADsAAAAVmNtYXDYeRm3AAABRAAAAUpjdnQ']] of length 580645 which may point to obfuscation or shellcode.
Threat dump:	View code
Threat dump MD5:	FF0032D4F1F7385A528F02C543DDF2F4
File size[byte]:	1086111
File type:	ASCII
Page/File MD5:	E711701FA2E4BAF5BE16271527543080
Scan duration[sec]:	6.235000

Can anyone offer any advice? Can this be fixed easily or do I need to recreate my website using a new theme ?? ??

Any help greatly appreciated

Best wishes,

Angela