refine button

Author: zheng-wang

index.md

@@ -31,7 +31,7 @@ API Test Base is a free tool for integration testing a variety of APIs. It is su
 
 Supported API types: HTTP, SOAP, Relational databases (Oracle, SQL Server, PostgreSQL, H2, etc.), JMS (ActiveMQ, Solace), FTP(S), SFTP, AMQP, MQTT, IBM MQ, IBM App Connect Enterprise (ACE; formerly IIB).
 
-<div style="text-align:center"><a class="button button--outline-success button--pill" href="/docs/en/quick-start">Quick Start</a></div>
+<div style="text-align:center"><a class="button button--outline-primary button--pill" href="/docs/en/quick-start">Quick Start</a></div>
 
 The tool
 * has GUI, saving user programming skills. Users have better experience using GUIed tool, as writing, reading and maintaining code are more brain power draining.