Div with :before and :after content not responsive - css

Question

I have a header that needs to have a greeting div inside of it. And that div has to be styled with :before and :after. I cannot add it via HTML. But when you resize the window, everything gets messed up. And I have no idea how to stop it from happening, without changing the font-size.
Can someone please take a look and tell me if there's something I can do? Thank you!
.header {
background-image: url('http://lorempixel.com/1300/800/');
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
min-height: 765px;
}
.title {
position: absolute;
top: 50%;
left: 50%;
transform: translateY(-50%) translateX(-50%);
padding: 0px 20px 7px 20px;
border: 1px solid #fff;
outline: 2px solid #000;
box-shadow: 0 0 15px 0 rgba(0, 0, 0, .375);
font-size: 3em;
font-weight: 700;
color: #fff;
line-height: 1.3;
}
.title:before {
font-family: FontAwesome;
content: "\f051";
font-size: 1.5em;
vertical-align: bottom;
}
.title:after {
content: "Hello hello";
position: absolute;
font-size: 17px;
font-weight: 400;
text-transform: uppercase;
display: block;
top: 15px;
left: 75px;
line-height: 1;
}
<div class="header">
<div class="title">
Hello
</div>
</div>

Answer 1

you may try this code, removed the absolute position :
.header {
background-image: url('http://lorempixel.com/1300/800/');
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
min-height: 765px;
text-align:center;
}
.title {
position: relative;
display:inline-block;
margin-top:15%;
padding: 0px 20px 7px 20px;
border: 1px solid #fff;
outline: 2px solid #000;
box-shadow: 0 0 15px 0 rgba(0, 0, 0, .375);
font-size: 3em;
font-weight: 700;
color: #fff;
line-height: 1.3;
}
.title:before {
font-family: FontAwesome;
content: "\f051";
font-size: 1.5em;
vertical-align: bottom;
}
.title:after {
content: "Hello hello";
position: absolute;
font-size: 17px;
font-weight: 400;
text-transform: uppercase;
display: block;
top: 15px;
left: 75px;
line-height: 1;
}
<div class="header">
<div class="title">
Hello
</div>
</div>