I am using a template for my website, namely

https://github.com/mkenworthy/mkenworthy.github.io.

I like this template very much; however, on a wide screen, the navigation bar cannot be seen completely (the rightmost parts cannot be seen on a wide screen; when making the browser window narrower everything is fine), as shown in the attached screenshot:

incomplete navigation bar

Do you see a way to fix that?

Here is the CSS-file which probably is relevant (called tufte_navbar.css):

`.anch {
    /* places the contents of the element 100px from the top of the view-port */
    padding-top: 80px;
    margin-top: -80px;
}


/* header */

.header {
  background-color: #fff;
  box-shadow: 1px 1px 4px 0 rgba(0,0,0,.1);
  position: fixed;
  width: 87.5%;
  z-index: 3;
  position-left: 0;
}

.header ul {
  margin: 0;
  padding: 0;
  list-style: none;
  overflow: hidden;
  background-color: #fff;
  margin: 0;
}

.header li a {
  display: block;
  padding: 10px 10px;
  border-right: 1px solid #f4f4f4;
  text-decoration: none;
  background-repeat: no-repeat; 
}

.header li a:hover,
.header .menu-btn:hover {
  background-color: #f4f4f4;
}

.header .logo {
  display: block;
  float: left;
  font-size: 1.6em;
  padding: 10px 10px;
  text-decoration: none;
  background-repeat: no-repeat; 
}

/* menu */

.header .menu {
  clear: both;
  max-height: 0;
  transition: max-height .2s ease-out;
}

/* menu icon */

.header .menu-icon {
  cursor: pointer;
  display: inline-block;
  float: right;
  padding: 28px 20px;
  position: relative;
  user-select: none;
}

.header .menu-icon .navicon {
  background: #333;
  display: block;
  height: 2px;
  position: relative;
  transition: background .2s ease-out;
  width: 18px;
}

.header .menu-icon .navicon:before,
.header .menu-icon .navicon:after {
  background: #333;
  content: '';
  display: block;
  height: 100%;
  position: absolute;
  transition: all .2s ease-out;
  width: 100%;
}

.header .menu-icon .navicon:before {
  top: 5px;
}

.header .menu-icon .navicon:after {
  top: -5px;
}

/* menu btn */

.header .menu-btn {
  display: none;
}

.header .menu-btn:checked ~ .menu {
  max-height: 300px; /* modded so that all menu selections are visible */
}

.header .menu-btn:checked ~ .menu-icon .navicon {
  background: transparent;
}

.header .menu-btn:checked ~ .menu-icon .navicon:before {
  transform: rotate(-45deg);
}

.header .menu-btn:checked ~ .menu-icon .navicon:after {
  transform: rotate(45deg);
}

.header .menu-btn:checked ~ .menu-icon:not(.steps) .navicon:before,
.header .menu-btn:checked ~ .menu-icon:not(.steps) .navicon:after {
  top: 0;
}

/* 48em = 768px */

/* @media (min-width: 48em) { */
  @media (min-width: 970px) { /* changes when menu folds down to a hamburger icon */
  .header li {
    float: left;
    margin: 0;
  }
  .header li a {
    padding: 10px 15px;
  }
  .header .menu {
    clear: none;
    float: right;
    max-height: none;
  }
  .header .menu-icon {
    display: none;
  }
}`

I tried to modify this file but I was not successfull since I do not have enough experience with css.