How to center a menu using CSS and changing the menu opacity

I need help centering my menu on my webpage. I have tried several different methods but none solved the problem correctly. I thought maybe if I gave the direct coding, someone could see what I needed to add to solve the problem.
Website: http://www.curlswithattitude.com

.menu-bar {
display:inline-block;
  width: 100%;
  margin: 0px 0px 0px 0px;
  padding: 6px 6px 6px 6px;
  height: 60px;
  line-height: 100%;
  border-radius: 0px;
  -webkit-border-radius: 0px;
  -moz-border-radius: 0px;
  box-shadow: 1px 1px 1px #000000;
  -webkit-box-shadow: 0px 0px 0px #000000;
  -moz-box-shadow: 0px 0px 0px #000000;
  background: #FFF;
  border: solid 1px #FFFFFF;
  text-align: center;
  z-index:999;
position: relative;
opacity: 1;
}
.menu-bar li {
  margin: 0px 0px 6px 0px;
  padding: 5px 5px 5px 5px;
  float: left;
  position: relative;
  list-style: none;
}
.menu-bar a {
  font-weight: bold;
  font-family: "Montserrat", sans-serif;
  font-style: normal;
  font-size: 13px;
  color: #000000;
  text-decoration: none;
  display: block;
  padding: 10px 20px 10px 20px;
  margin: 0;
  margin-bottom: 6px;
  border-radius: 10px;
  -webkit-border-radius: 10px;
  -moz-border-radius: 10px;
  text-shadow: 0px 0px 0px #000000;
  text-transform: uppercase;
text-align: right;
}
.menu-bar li ul li a {
  margin: 0;
}
.menu-bar :active, .menu-bar li:hover > a {
  background: #acacac;
  color: #FFFFFF
  -webkit-box-shadow: 0 1px 1px rgba(0, 0, 0, .2);
  -moz-box-shadow: 0 1px 1px rgba(0, 0, 0, .2);
  box-shadow: 0 1px 1px rgba(0, 0, 0, .2);
  text-shadow: 0px 0px 0px #000000;

}
.menu-bar ul li:hover a, .menu-bar li:hover li a {
  background:  none;
  border: none;
  color: #666;
  -box-shadow: none;
  -webkit-box-shadow: none;
  -moz-box-shadow: none;
}
.menu-bar ul a:hover {
  background: #acacac !important;
  color: #000000 !important;
  border-radius: 0px;
  -webkit-border-radius: 0;
  -moz-border-radius: 0;
  text-shadow: 0px 0px 0px #FFFFFF;
}
.menu-bar li:hover > ul {
  display: block;
}
.menu-bar ul {
  background: #FFFFFF;
  display: none;
  margin: 0;
  padding: 10px;
  width: 185px;
  position: absolute;
  top: 30px;
  left: 0;
  border: solid 1px #B4B4B4;
  border-radius: 10px;
  -webkit-border-radius: 10px;
  -moz-border-radius: 10px;
  -webkit-box-shadow: 0px 0px 0px #222222;
  -moz-box-shadow: 0px 0px 0px #222222;
  box-shadow: 0px 0px 0px #222222;
}
.menu-bar ul li {
  float: none;
  margin: 0;
  padding: 0px;
}
.menu-bar ul a {
  padding:8px 0px 8px 15px;
  color:#000000 !important;
  font-size:13px;
  font-style:normal;
  font-family:"Montserrat", sans-serif;
  font-weight: normal;
  text-align:left;
  text-shadow: 0px 0px 0px #FFFFFF;
text-transform: uppercase;
}
.menu-bar ul li:first-child > a {
  border-top-left-radius: 10px;
  -webkit-border-top-left-radius: 10px;
  -moz-border-radius-topleft: 10px;
  border-top-right-radius: 10px;
  -webkit-border-top-right-radius: 10px;
  -moz-border-radius-topright: 10px;
}
.menu-bar ul li:last-child > a {
  border-bottom-left-radius: 10px;
  -webkit-border-bottom-left-radius: 10px;
  -moz-border-radius-bottomleft: 10px;
  border-bottom-right-radius: 10px;
  -webkit-border-bottom-right-radius: 10px;
  -moz-border-radius-bottomright: 10px;
}
.menu-bar:after {
  content: ".";
  display: block;
  clear: both;
  visibility: hidden;
  line-height: 0;
  height: 0;
}
.menu-bar {
  display: inline-block;
}
  html[xmlns] .menu-bar {
  display: block;
}
* html .menu-bar {
  height: 1%;
}

And also, how can I change the opacity of the menu? I don’t want it to be completely transparent but a little see-through?

Thanks!