CSS underline with same with as above element - html

Question

I am trying to create the following look:
As you can see on this picture even if there is some padding on the "sub" menu item the border still works.
So here is what I've attempted:
.menu-ul {
list-style-type: none;
}
.menu-li {
padding: 10px 0;
border-bottom: 1px solid rgba(50, 50, 50, 0.3);
width: 100%;
}
a {
font-family: Titillium Web;
font-style: normal;
font-weight: 600;
font-size: 16px;
line-height: 24px;
letter-spacing: 0.02em;
color: #323232;
text-decoration: none;
}
a:hover {
color: #DB091C;
}
.sub-menu-ul {
padding: 0px;
list-style-type: none;
border-top: 1px solid rgba(50, 50, 50, 0.3);
}
.sub-menu-li {
padding: 10px;
width: calc(100% - 20px);
border-top: 1px solid rgba(50, 50, 50, 0.3);
}
hr.solid {
border-top: 3px solid #bbb;
}
<link href="https://pro.fontawesome.com/releases/v5.14.0/css/all.css" rel="stylesheet"/>
<nav style="width: 300px">
<ul class="menu-ul">
<li class="menu-li">
<a href="" >Title </a>
<span style="float: right"><i class="fa fa-angle-down"></i></span>
<div style="display: block">
<ul class="sub-menu-ul">
<li class="sub-menu-li"> <a href="#">
Sub menu item2
</a>
<span style="float: right"><i class="fa fa-angle-right"></i></span>
</li>
</li>
<li class="sub-menu-li"> <a href="#">
Sub menu item2
</a>
</li>
</ul>
</div>
</li>
<li class="menu-li"><a href="" >Title 2</a>
</li>
<li class="menu-li"><a href="" >Title 2</a> </li>
</ul>
</nav>
But I can't seem to get the border right.

Answer 1

Try this, I have changed the padding for menu-li and width of sub-menu-li
.menu-li {
padding: 10px 0;
border-bottom: 1px solid rgba(50, 50, 50, 0.3);
width: 100%;
}
.sub-menu-li {
padding: 10px;
padding-right: 0;
width: calc(100% - 10px);
border-top: 1px solid rgba(50, 50, 50, 0.3);
}