Limit number of lines shown in a textbox, but not limiting the user to write - html

Question

I have a case I am not sure how to figure it out.
I am trying to do a design to put a button over a textbox, to make my layout looks nice, but when users start typing information in textbox, it hides behind the button. I know I have 1 of 2 solutions, but I don't know how to do it:
1- either to find another way to do the layout.
2- limit the number of lines for the user to enter, but this way I am going to have a restriction for long data.
Below is my HTML and CSS:
body{
background: #000;
}
.nl-main{
width: 300px;
border: 1px solid white;
border-radius: 6px;
padding: 10px;
}
.header{
padding: 3px;
}
.header span{
color: white;
}
.nl-txt-main, .nl-btn-main{
display: inline-block;
}
.nl-btn-main .nl-btn{
border-radius: 5px;
background: blue;
color: white;
left: -50px;
position: relative;
}
.nl-txt-main .nl-txt {
width: 200px;
border-radius: 5px;
}
<div class="header">
<span>Search our database</span>
</div>
<div class="nl-controls">
<div class="nl-txt-main">
<input type="text" class="nl-txt"/>
</div>
<div class="nl-btn-main">
<input type="button" value="Send" class="nl-btn"/>
</div>
</div>
I want the button to be like part of the textbox itself, When you try to run the code, and write a long sentence in the textbox, it will hide under the button. How do I solve it?
Thank you.

Answer 1

Remove left:-50px; from you button
body{
background: #000;
}
.nl-main{
width: 300px;
border: 1px solid white;
border-radius: 6px;
padding: 10px;
}
.header{
padding: 3px;
}
.header span{
color: white;
}
.nl-txt-main, .nl-btn-main{
display: inline-block;
margin:0;
}
.nl-btn-main .nl-btn{
background: blue;
color: white;
left: -4px;
position: relative;
border-bottom-right-radius: 5px;
margin:0;
border-top-right-radius: 5px;
}
.nl-txt-main .nl-txt {
width: 200px;
border-bottom-left-radius: 5px;
margin:0;
border-top-left-radius: 5px;
}
<div class="header">
<span>Search our database</span>
</div>
<div class="nl-controls">
<div class="nl-txt-main">
<input type="text" class="nl-txt"/>
</div>
<div class="nl-btn-main">
<input type="button" value="Send" class="nl-btn"/>
</div>
</div>