Bootstrap children element height 100% - html

Question

I want a Button, with 2 elements in it, to slide the Background.
But I want both elements to center vertical and get height 100% even when the other element is bigger.
Here is the HTML
<button class="btn-cstm-slide">
<div class="btn-cstm-slide-logo"><span>Test Test 14343</span></div>
<div class="btn-cstm-slide-text">
<span>Just a Testtest</span>
<br/>
<span>Let's see</span>
</div>
</button>
And here the CSS
.btn-cstm-slide {
height: 100%;
padding: 0px;
display: flex;
position: relative;
text-decoration: none;
overflow: hidden;
background: #333C42;
border: none;
box-shadow: 0px 1px 1px rgba(0,0,0,.1);
}
.btn-cstm-slide-logo {
height:100%;
min-height:100%;
margin: 0;
padding: 10px;
position: relative;
text-decoration: none;
background: #474f54;
color: #fff;
}
.btn-cstm-slide-text {
padding: 10px;
position: relative;
text-decoration: none;
background: #333C42;
color: #fff;
-webkit-transition: all 0.5s ease;
-moz-transition: all 0.5s ease;
-o-transition: all 0.5s ease;
transition: all 0.5s ease;
}
.btn-cstm-slide-text * {
position:relative;
}
.btn-cstm-slide-text:before {
content: "";
position: absolute;
height: 100%;
width: 0;
bottom: 0;
left:0;
background-color: #474f54;
-webkit-transition: all 0.4s ease-in-out 0s;
transition: all 0.4s ease-in-out 0s;
}
.btn-cstm-slide-text:hover:before {
width: 100%;
}
Demo
FIDDLE
Can you help me? :(

Answer 1

Is this what you had in mind?
https://jsfiddle.net/e07uc4kj/9/
.btn-cstm-slide {
height: 100%;
padding: 0px;
display: flex;
position: relative;
text-decoration: none;
overflow: hidden;
background: #333C42;
border: none;
box-shadow: 0px 1px 1px rgba(0,0,0,.1);
}
.btn-cstm-slide-logo {
padding: 10px;
min-width: 80px;
position: absolute;
top: 0px;
bottom: 0px;
text-decoration: none;
background: #474f54;
color: #fff;
vertical-align: middle;
}
.btn-cstm-slide-text {
margin-left: 100px;
padding: 10px;
position: relative;
text-decoration: none;
background: #333C42;
color: #fff;
-webkit-transition: all 0.5s ease;
-moz-transition: all 0.5s ease;
-o-transition: all 0.5s ease;
transition: all 0.5s ease;
}
.btn-cstm-slide-text:before {
content: "";
position: absolute;
height: 100%;
width: 0;
bottom: 0;
left:0;
background-color: #474f54;
-webkit-transition: all 0.4s ease-in-out 0s;
transition: all 0.4s ease-in-out 0s;
}
.btn-cstm-slide-text:hover:before {
width: 100%;
}