Bootstrap button text not visible
<p>I have a simple <code>input-group</code> which contains a input-field and button.</p>

<p>The strange thing is, it doesn't show up. The color isn't the same as background-color, checked in inspect element.</p>

<p>I've created a JSfiddle, but that doesn't do anything, cause it shows perfectly there...</p>

<p><a href="https://jsfiddle.net/u691aw17/" rel="nofollow noreferrer">https://jsfiddle.net/u691aw17/</a> </p>

<p>Maybe you guys have an idea?</p>

<pre><code>&lt;!-- language: lang-css --&gt;

/* CSS */

div.input-group {
   width: 350px;
   margin-left: auto;
   margin-right: auto;   
   font-size: 14px;
     input[type="text"]{
        width:300px;
        height:50px;
        font-size: 14px;
     }
     input[type="text"]::-webkit-input-placeholder{
        text-transform: uppercase;
        font-size: 14px;
     }
     input[type="text"]:-moz-placeholder /* Firefox 18- */
          {
        text-transform: uppercase;
        font-size: 14px;
    } 
    input[type="text"]::-moz-placeholder /* Firefox 19+ */
          {
        text-transform: uppercase;
        font-size: 14px;
    }
    input[type="text"]:-ms-input-placeholder{
        text-transform: uppercase;
        font-size: 14px;
    }
    span.input-group-btn button.btn {
        width:150px;
        height:50px;
        line-height: 1em;
        padding: 0px;
    }
}
.btn {
   background-color: green;
   color:#ffffff;
}

&lt;!-- language: lang-html --&gt;

    &lt;div class="input-group"&gt;
        &lt;input type="text" class="form-control" placeholder="Email"&gt;
        &lt;span class="input-group-btn"&gt;
            &lt;button class="btn" type="button" &gt;Sign up&lt;/button&gt;
        &lt;/span&gt;
    &lt;/div&gt;


&lt;!-- end snippet --&gt;
</code></pre>

<p><a href="https://i.stack.imgur.com/DDW6G.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/DDW6G.png" alt="Problem"></a></p>

<p><a href="https://i.stack.imgur.com/FEEBI.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FEEBI.png" alt="Element inspect"></a></p>