remove darkmode concept viz

Author: zsimjee

docs/concepts/guard.md

@@ -6,7 +6,6 @@ The guard object is the main interface for Guardrails. It can be used without co
 ## How it works
 
 ![Guardrails Logo](../img/guardrails_arch_white_vertical.png#only-light)
-![Guardrails Logo](../img/guardrails_arch_dark_vertical.png#only-dark)
 
 
 ## Two main flows
@@ -87,4 +86,4 @@ print(guard.history.last.reasks) # A list of reasks
 
 ## Error Handling and Retries
 
-Guardrails is designed to account for different types of errors that can occur when calling the LLM, and it is also designed to emit helpful errors when validations fail. Read more about error handling and retries [here](./error_remediation).
+Guardrails is designed to account for different types of errors that can occur when calling the LLM, and it is also designed to emit helpful errors when validations fail. Read more about error handling and retries [here](./error_remediation).