Navigation does not float correctly - html

Question

I am experimenting with a navigation bar, and I am unsure of how to float part of the list to the right, without the text becoming laterally inverted. I want the first link to be on the very left side, whilst all the rest of the links are on the right side. Also, using float: right makes the list items very compressed, and I was wondering on how to get past this? I have chosen to do it this way so that I could use a line when hovering over the links. https://codepen.io/anon/pen/xQjozy
html:
<div class="navigationbar">
<ul>
<li class="one">Link 1</li>
<li class="two rightside">Link 2</li>
<li class="three rightside">Link 3</li>
<li class="four rightside">Link 4</li>
<li class="five rightside">Link 5</li>
<li class="six rightside">Link 6</li>
<hr />
</ul>
</div>
css:
ul li {
display: inline;
text-align: center;
}
a {
display: inline-block;
width: 16%;
padding: .15rem 0;
margin: 0;
text-decoration: none;
color: #fff;
font-size: 1.5vw;
}
.two:hover ~ hr {
margin-left: 16%;
}
.three:hover ~ hr {
margin-left: 32%;
}
.four:hover ~ hr {
margin-left: 48%;
}
.five:hover ~ hr {
margin-left: 64%;
}
.six:hover ~ hr {
margin-left: 80%;
}
hr {
height: .25rem;
width: 16%;
margin: 0;
background: blue;
border: none;
transition: .3s ease-in-out;
}
.navigationbar{
background-color: green;
overflow: hidden;
}
ul{
margin:0.7vh 0vh 0.7vh 0vh;
}
/*
.rightside{
float:right
}*/
Thanks

Answer 1

I think this is closer to what you want I hope.
Also using border bottom is much better way to handle a link underline. It will always line itself up under the content perfectly. I would also suggest changing the font size from vw to px or em and use media queries to change the font as the browser width gets smaller/larger.
EDIT: This is how I would correct your code but I don't think this is the correct way to accomplish this.
ul li {
display: inline;
text-align: center;
border-bottom:3px solid transparent;
}
a {
display: inline-block;
padding: .15rem 0;
margin: 0;
text-decoration: none;
color: #fff;
font-size: 1.5vw;
padding:6px 15px; /*add more spacing to links*/
}
li:hover {
border-bottom:3px solid blue;
}
.navigationbar{
background-color: green;
overflow: hidden;
}
ul{
margin:0.7vh 0vh 0.7vh 0vh;
}
.leftside {
float:left;
}
.right_side_container{
float:right
}
<div class="navigationbar">
<ul>
<li class="one leftside">Link 1</li>
<div class="right_side_container">
<li class="two">Link 2</li>
<li class="three">Link 3</li>
<li class="four">Link 4</li>
<li class="five">Link 5</li>
<li class="six">Link 6</li>
</div>
</ul>
</div>

Answer 2

You could set a certain width to each of the links you floated to the right,that way it wont be compressed