CSS - Align div to bottom respective his parent div - html

Question

I'm trying to align div # alignBottom1 and # alignBottom2 down without removing the float left from the parent div and without using position absolute or margin top.
How can I do?
This is my code:
#TotContainer {
height: 900px;
}
#container {
max-height: 90%
}
.col-sm-6 {
width: 50%;
float: left;
height: 100%;
padding: 10px;
}
.col-sm-12 {
width: 100%;
float: left;
background: yellow;
}
* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
<div id="TotContainer">
<div id="container">
<div class="col-sm-6" style="background:blue;">XXXXXX</div>
<div class="col-sm-6" style="background:red;">
<div id="alignBottom1">Text to align at the bottom 1</div>
<div id="alignBottom2">Text to align at the bottom 2</div>
</div>
<div class="col-sm-12">footer</div>
</div>
</div>
Thanks for any help!

Answer 1

You can do this easily if you turn the parent container into a flexbox.
In your sample, I gave the parent a height value so that you can see the effect of using flexbox and justifying the content to the end of it's parent.
#alignBottom {
display: flex;
flex-flow: column nowrap;
justify-content: flex-end;
height: 100px; /* giving the element a height to exaggerate the effect */
}
#TotContainer {
height: 900px;
}
#container {
max-height: 90%
}
.col-sm-6 {
width: 50%;
float: left;
height: 100%;
padding: 10px;
}
.col-sm-12 {
width: 100%;
float: left;
background: yellow;
}
* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
<div id="TotContainer">
<div id="container">
<div class="col-sm-6" style="background:blue;">XXXXXX</div>
<div id="alignBottom" class="col-sm-6" style="background:red;">
<div id="alignBottom1">Text to align at the bottom 1</div>
<div id="alignBottom2">Text to align at the bottom 2</div>
</div>
<div class="col-sm-12">footer</div>
</div>
</div>

Answer 2

CSS flexbox helps aligning the content inside the container in multiple ways with few lines of code. This might work for you.
#TotContainer {
height: 900px;
}
#container {
max-height: 90%
}
.col-sm-6 {
width: 50%;
float: left;
height: 100%;
padding: 10px;
}
.col-sm-6:nth-child(2){
/* adding this */
display: flex;
flex-direction: column;
justify-content: flex-end;
/* adding some height to the container for better visibility od effect */
height: 80px;
}
.col-sm-12 {
width: 100%;
float: left;
background: yellow;
}
* {
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
<div id="TotContainer">
<div id="container">
<div class="col-sm-6" style="background:blue;">XXXXXX</div>
<div class="col-sm-6" style="background:red;">
<div id="alignBottom1">Text to align at the bottom 1</div>
<div id="alignBottom2">Text to align at the bottom 2</div>
</div>
<div class="col-sm-12">footer</div>
</div>
</div>