Check out example codes for "html position div inside div". It will help you in understanding the concepts better.

Code Example 1

.textblock-container {
width: 500px;
height: 500px;
border: 1px solid red;
position: relative;
}

div.textblock {
width: 100px;
height: 100px;
line-height: 100px;
border: 1px solid black;
position: absolute;
text-align: center;             
background: rgb(0, 150, 0);
background: rgba(0, 150, 0, .5);
}

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