How to make responsive this menu code ? ( one expert ) - css

Question

My problem is this menu, which I can not make responsive for all resolutions. Maybe you know how to edit it better, I can't manage this menu in order to be responsive (position, size and text size). I want to make size and position responsive in percent or other solution. Thank you very much, I'm waiting for your help.
Demo codepen
#import url(http://fonts.googleapis.com/css?family=Raleway);
#cssmenu,
#cssmenu ul,
#cssmenu ul li,
#cssmenu ul li a,
#cssmenu #menu-button {
margin: 0;
padding: 0;
border: 0;
list-style: none;
line-height: 1;
display: block;
position: relative;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
}
#cssmenu:after,
#cssmenu > ul:after {
display: block;
clear: both;
visibility: hidden;
line-height: 0;
height: 0;
}
#cssmenu #menu-button {
display: none;
}
#cssmenu {
width: auto;
font-family: Raleway, sans-serif;
line-height: 1;
}
#cssmenu > ul {
width:100%;
BACKGROUND-COLOR: RED;
}
#cssmenu > ul > li {
float: left;
-webkit-perspective: 1000%;
-moz-perspective: 1000%;
perspective: 1000%;
}
#cssmenu.align-center > ul {
font-size: 0;
text-align: center;
}
#cssmenu.align-center > ul > li {
display: inline-block;
float: none;
}
#cssmenu.align-right > ul > li {
float: right;
}
#cssmenu > ul > li > a {
padding: 16px 20px;
font-size: 14px;
color: #ffffff;
letter-spacing: 1px;
text-transform: uppercase;
text-decoration: none;
background: #c61515;
-webkit-transition: all .3s;
-moz-transition: all .3s;
-o-transition: all .3s;
transition: all .3s;
-webkit-transform-origin: 50% 0;
-moz-transform-origin: 50% 0;
transform-origin: 50% 0;
-webkit-transform-style: preserve-3d;
-moz-transform-style: preserve-3d;
transform-style: preserve-3d;
}
#cssmenu > ul > li.active > a {
font-weight: bold; color: #000000;
}
#cssmenu > ul > li:hover > a,
#cssmenu > ul > li > a:hover {
color: #dff2fa;
-webkit-transform: rotateX(90deg) translateY(-23px);
-moz-transform: rotateX(90deg) translateY(-23px);
transform: rotateX(90deg) translateY(-23px);
-ms-transform: none;
}
#cssmenu > ul > li > a::before {
position: absolute;
top: 100%;
left: 0;
z-index: -1;
-webkit-box-sizing: border-box;
-moz-box-sizing: border-box;
box-sizing: border-box;
width: 100%;
height: 100%;
padding: 16px 20px;
color: #dff2fa;
background: #19799f;
content: attr(data-title);
-webkit-transition: background 0.3s;
-moz-transition: background 0.3s;
transition: background 0.3s;
-webkit-transform: rotateX(-90deg);
-moz-transform: rotateX(-90deg);
transform: rotateX(-90deg);
-webkit-transform-origin: 50% 0;
-moz-transform-origin: 50% 0;
transform-origin: 50% 0;
-ms-transform: translateY(- -18px);
}
#cssmenu > ul > li:hover > a::before,
#cssmenu > ul > li > a:hover::before {
background: #3db2e1;
}
#cssmenu.small-screen {
width: 100%;
}
#cssmenu.small-screen > ul,
#cssmenu.small-screen.align-center > ul {
width: 100%;
text-align: left;
}
#cssmenu.small-screen > ul > li,
#cssmenu.small-screen.align-center {
float: none;
display: block;
border-top: 1px solid rgba(100, 100, 100, 0.1);
}
#cssmenu.small-screen > ul > li:hover > a,
#cssmenu.small-screen > ul > li > a:hover {
color: #dff2fa;
-webkit-transform: none;
-moz-transform: none;
transform: none;
-ms-transform: none;
}
#cssmenu.small-screen > ul > li > a::before {
display: none;
}
#cssmenu.small-screen #menu-button {
display: block;
padding: 16px 20px;
cursor: pointer;
font-size: 14px;
text-decoration: none;
color: #ffffff;
text-transform: uppercase;
letter-spacing: 1px;
background: #3db2e1;
}
#cssmenu.small-screen #menu-button:after {
content: "";
position: absolute;
right: 20px;
top: 17px;
display: block;
-webkit-box-sizing: content-box;
-moz-box-sizing: content-box;
box-sizing: content-box;
border-top: 2px solid #ffffff;
border-bottom: 2px solid #ffffff;
width: 22px;
height: 3px;
}
#cssmenu.small-screen #menu-button.menu-opened:after {
border-top: 2px solid #dff2fa;
border-bottom: 2px solid #dff2fa;
}
#cssmenu.small-screen #menu-button:before {
content: "";
position: absolute;
right: 20px;
top: 27px;
display: block;
width: 22px;
height: 2px;
background: #ffffff;
}
#cssmenu.small-screen #menu-button.menu-opened:before {
background: #dff2fa;
}

Answer 1

If you are using WordPress, it is better to use some plugin for responsive menu, but if insist not to do that, you should use #media queries. Look at this:
https://codepen.io/anon/pen/QpwRwr
I changed this codes:
<ul>
<li class='active'><a href='#'>Home</a></li>
<li><a href='#'><span>FORUM</span></a></li>
<li><a href='#'><span>SERVERE</span></a></li>
<li><a href='#'><span>ASISTENTA</span></a></li>
</ul>
and added this:
#media only screen and (max-width: 479px) {
#content ul li span {font-size: 11px}
#cssmenu ul li {width:25% }
#cssmenu ul li a {padding: 16px 10px 16px 10px}
}
This changes make it a little more responsive but the point is in using media queries, use it and build the layout you like. But in the case of WordPress, look at this plugin too.