Laravel app.js and app.css why need to use ? Can we removed those?
<p>I am new learner on Laravel.</p>

<p>I am using <strong>Laravel</strong> <strong>5.3</strong>.But I want Use <strong>Bootstrap</strong> <strong>css</strong> and <strong>Js</strong>.
But Laravel have default <code>app.css</code> and <code>app.js</code>. 
Hare  <code>app.css</code> actually <strong>Bootstrap</strong> <strong>CSS</strong> and also <code>app.js</code> work like Bootstarp <strong>js</strong>.
But can i delete <code>app.js</code> and <code>app.css</code> and can i use custom version Bootstrap <strong>CSS</strong> &amp; <strong>JS</strong> ?</p>

<p>So I need to know why we will be use this two files ?</p>