how to make my font size responsive?

Question

I'm trying to make some big title responsive. I tried a few things such as: this Link. But it didn't work.

CSS

body {
    margin-top: 50px; /* Required margin for .navbar-fixed-top. Remove if using .navbar-static-top. Change if height of navigationchanges. */  
}


#page-wrap {

  width: 760px;
  margin: 0 auto;
}

.title {
    font-family: Brush Script MT,cursive;
    font-size: 10vw;
    font-style: normal;
    font-variant: normal;
    font-weight: 500;

}

#welcome {
    @extend .title;   
}

#to {
    @extend .title;
    text-align: center;
    font-size: 50px;   
}

#mp{
    @extend .title;
    text-align: right;

}


.full { 
   background-image: url('../img/beach-bg1920-1080.jpg');
   background-repeat: no-repeat;
   background-attachment: fixed;
   background-position: center; 
   -webkit-background-size: cover;
   -moz-background-size: cover;
   background-size: cover;
   -o-background-size: cover;

}



/*******navbar elements *********/
.navbar-inner {
    background:transparent;
    border: solid#ffffff 2px;
}

.nav > li > a:focus, .nav > li > a:hover {
    text-decoration: none;
    background-color: $hover-color;
}
.navbar-nav > li > a {
    padding-top: 15px;
    padding-bottom: 15px;
    color: white;
}

.navbar > .container .navbar-brand, .navbar > .container-fluid .navbar-brand {
    margin-left: -15px;
    color: #ffffff;
}
.navbar-brand:focus, .navbar-brand:hover {
    text-decoration: none;
}

/*******navbar elements End *********/

HTML

    <div id="page-wrap">           
        <h1 id="welcome">Welcome!</h1>
        <h2 id="to">to</h2>
        <h1 id="mp">My Portfolio!</h1>
    </div>  

You can't see the word "My portfolio". i am trying to move everything to the left. in other words, I just want to make sure that this is going to look alright on mobile devices.

Solution

Check this code.

#welcome{
  font-size:10vw;
}
#to{
  font-size:6vw;
}
#mp{
  font-size:12vw;
}

<div id="page-wrap">           
  <h1 id="welcome">Welcome!</h1>
  <h2 id="to">to</h2>
  <h1 id="mp">My Portfolio!</h1>
</div>

We can make font size responsive by giving responsive unit to font. px unit is not responsive, whereas percent (%), vh/vw, em, rem units are responsive.

In given example link (css tricks) they've used viewport unit to make font responsive. viewport unit is nothing but vh,vw. vh is: viewport height and vw is viewport width.

If you give vw unit to font, it'll change/ get responsive according to your screen width.