You can use this code for when your website has a white and blue theme and you are looking for a good full screen menu for it. In this code, the menu opens with the click of a hamburger button on the left. This menu opens from the center and in a circle to take up the entire page. Menu items are all white. Menu items appear in the middle with the fade animation.


HTML
<!-- This script got from www.devanswer.com -->
<section>
    <div class="rt-container">
        <div class="col-rt-12">
            <div class="Scriptcontent">
                <!-- partial:index.partial.html -->
                <h1>Pure CSS Fullscreen Menu</h1>
                <p style="text-align: center"> A fullscreen navigation menu in pure CSS.</p>
                <div class="outer-menu">
                    <input class="checkbox-toggle" type="checkbox" />
                    <div class="hamburger">
                        <div></div>
                    </div>
                    <div class="menu">
                        <div>
                            <div>
                                <ul>
                                    <li><a href="#">About</a></li>
                                    <li><a href="#">Products</a></li>
                                    <li><a href="#">Blog</a></li>
                                    <li><a href="#">Contact</a></li>
                                </ul>
                            </div>
                        </div>
                    </div>
                </div>
                <!-- partial -->
            </div>
        </div>
    </div>
</section><div id="bcl"><a style="font-size:8pt;text-decoration:none;" href="http://www.devanswer.com">Developers Answer</a></div>
                        

CSS
@import url('https://fonts.googleapis.com/css?family=Raleway:400,500,600,700,800,900');
html {
  box-sizing: border-box;
}
*, *:before, *:after {
  box-sizing: inherit;
}
article, header, section, aside, details, figcaption, figure, footer, header, hgroup, main, nav, section, summary {
    display: block;
}
body {
    background:#f0e0e0 none repeat scroll 0 0;
    color: #222;
    font-size: 100%;
    line-height: 24px;
    margin: 0;
	padding:0;
	font-family: "Raleway",sans-serif;
}
a{
	font-family: "Raleway",sans-serif;
	text-decoration: none;
	outline: none;
}
a:hover, a:focus {
	color: #373e18;
}
section {
    float: left;
    width: 100%;
    position: relative;
	padding-bottom:3em;
}
h2 {
    color: #1a0e0e;
    font-size: 26px;
    font-weight: 700;
    margin: 0;
    line-height: normal;
	text-transform:uppercase;
}
h2 span {
    display: block;
    padding: 0;
    font-size: 18px;
    opacity: 0.7;
    margin-top: 5px;
	text-transform:uppercase;
}
#float-right{
	float:right;	
}
/* ******************************************************
	Script Top
*********************************************************/
.ScriptTop {
    background: #fff none repeat scroll 0 0;
    float: left;
    font-size: 0.69em;
    font-weight: 600;
    line-height: 2.2;
    padding: 12px 0;
    text-transform: uppercase;
    width: 100%;
}
/* To Navigation Style 1*/
.ScriptTop ul {
    margin: 24px 0;
    padding: 0;
    text-align: left;
}
.ScriptTop li{
	list-style:none;	
	display:inline-block;
}
.ScriptTop li a {
    background: #6a4aed none repeat scroll 0 0;
    color: #fff;
    display: inline-block;
    font-size: 14px;
    font-weight: 600;
    padding: 5px 18px;
    text-decoration: none;
    text-transform: capitalize;
}
.ScriptTop li a:hover{
	background:#000;
	color:#fff;
}
/* ******************************************************
	Script Header
*********************************************************/
.ScriptHeader {
    float: left;
    width: 100%;
    padding: 2em 0;
}
.rt-heading {
    margin: 0 auto;
	text-align:center;
}
.Scriptcontent{
	line-height:28px;	
}
.ScriptHeader h1{
	font-family: "brandon-grotesque", "Brandon Grotesque", "Source Sans Pro", "Segoe UI", Frutiger, "Frutiger Linotype", "Dejavu Sans", "Helvetica Neue", Arial, sans-serif;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
    color: #6a4aed;
    font-size: 26px;
    font-weight: 700;
    margin: 0;
    line-height: normal;
}
.ScriptHeader h2 {
    color: #312c8f;
    font-size: 20px;
    font-weight: 400;
    margin: 5px 0 0;
    line-height: normal;
}
.ScriptHeader h1 span {
    display: block;
    padding: 0;
    font-size: 22px;
    opacity: 0.7;
    margin-top: 5px;
}
.ScriptHeader span {
    display: block;
    padding: 0;
    font-size: 22px;
    opacity: 0.7;
    margin-top: 5px;
}
/* ******************************************************
	Responsive Grids
*********************************************************/
.rt-container {
	margin: 0 auto;
	padding-left:12px;
	padding-right:12px;
}
.rt-row:before, .rt-row:after {
  display: table;
  line-height: 0;
  content: "";
}
.rt-row:after {
  clear: both;
}
[class^="col-rt-"] {
  box-sizing: border-box;
  -webkit-box-sizing: border-box;
  -moz-box-sizing: border-box;
  -o-box-sizing: border-box;
  -ms-box-sizing: border-box;
  padding: 0 15px;
  min-height: 1px;
  position: relative;
}
@media (min-width: 768px) {
  .rt-container {
    width: 750px;
  }
  [class^="col-rt-"] {
    float: left;
    width: 49.9999999999%;
  }
  .col-rt-6, .col-rt-12 {
    width: 100%;
  }
}
@media (min-width: 1200px) {
	.rt-container {
		width: 1170px;
	}
	.col-rt-1 {
		width:16.6%;
	}
	.col-rt-2 {
		width:30.33%;
	}
	.col-rt-3 {
		width:50%;
	}
	.col-rt-4 {
		width: 67.664%;
	}
	.col-rt-5 {
		width: 83.33%;
	}
}
@media only screen and (min-width:240px) and (max-width: 768px){
	 .ScriptTop h1, .ScriptTop ul {
		text-align: center;
	}
	.ScriptTop h1{
		margin-top:0;
		margin-bottom:15px;
	}
	.ScriptTop ul{
		 margin-top:12px;		
	}
	.ScriptHeader h1,
	.ScriptHeader h2, 
	.scriptnav ul{
		text-align:center;	
	}
	.scriptnav ul{
		 margin-top:12px;		
	}
	#float-right{
		float:none;	
	}
}
@font-face {
  font-family: 'Open Sans';
  font-style: normal;
  font-weight: 300;
  src: url(https://fonts.gstatic.com/s/opensans/v18/mem5YaGs126MiZpBA-UN_r8OUuhs.ttf) format('truetype');
}
@font-face {
  font-family: 'Pacifico';
  font-style: normal;
  font-weight: 400;
  src: url(https://fonts.gstatic.com/s/pacifico/v17/FwZY7-Qmy14u9lezJ-6H6Mw.ttf) format('truetype');
}
.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}
* {
  box-sizing: border-box;
  font-family: 'Open Sans', sans-serif;
  font-weight: 300;
}
a,
a:visited,
a:hover,
a:active {
  color: inherit;
  text-decoration: none;
}
h1 {
  font-family: 'Pacifico', cursive;
  font-weight: 400;
  font-size: 3em;
  text-align: center;
}
.outer-menu {
  position: fixed;
  top: 150px;
  left: 150px;
  z-index: 1;
}
.outer-menu .checkbox-toggle {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 2;
  cursor: pointer;
  width: 60px;
  height: 60px;
  opacity: 0;
}
.outer-menu .checkbox-toggle:checked + .hamburger > div {
  transform: rotate(135deg);
}
.outer-menu .checkbox-toggle:checked + .hamburger > div:before,
.outer-menu .checkbox-toggle:checked + .hamburger > div:after {
  top: 0;
  transform: rotate(90deg);
}
.outer-menu .checkbox-toggle:checked + .hamburger > div:after {
  opacity: 0;
}
.outer-menu .checkbox-toggle:checked ~ .menu {
  pointer-events: auto;
  visibility: visible;
}
.outer-menu .checkbox-toggle:checked ~ .menu > div {
  transform: scale(1);
  transition-duration: 0.75s;
}
.outer-menu .checkbox-toggle:checked ~ .menu > div > div {
  opacity: 1;
  transition: opacity 0.4s ease 0.4s;
}
.outer-menu .checkbox-toggle:hover + .hamburger {
  box-shadow: inset 0 0 10px rgba(0, 0, 0, 0.1);
}
.outer-menu .checkbox-toggle:checked:hover + .hamburger > div {
  transform: rotate(225deg);
}
.outer-menu .hamburger {
  position: absolute;
  top: 0;
  left: 0;
  z-index: 1;
  width: 60px;
  height: 60px;
  padding: 0.5em 1em;
  background: rgba(33, 150, 243, 0.75);
  border-radius: 0 0.12em 0.12em 0;
  cursor: pointer;
  transition: box-shadow 0.4s ease;
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.outer-menu .hamburger > div {
  position: relative;
  flex: none;
  width: 100%;
  height: 2px;
  background: #FEFEFE;
  transition: all 0.4s ease;
  display: flex;
  align-items: center;
  justify-content: center;
}
.outer-menu .hamburger > div:before,
.outer-menu .hamburger > div:after {
  content: '';
  position: absolute;
  z-index: 1;
  top: -10px;
  left: 0;
  width: 100%;
  height: 2px;
  background: inherit;
  transition: all 0.4s ease;
}
.outer-menu .hamburger > div:after {
  top: 10px;
}
.outer-menu .menu {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  visibility: hidden;
  overflow: hidden;
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  outline: 1px solid transparent;
  display: flex;
  align-items: center;
  justify-content: center;
}
.outer-menu .menu > div {
  width: 200vw;
  height: 200vw;
  color: #FEFEFE;
  background: rgba(41, 98, 255, 0.85);
  border-radius: 50%;
  transition: all 0.4s ease;
  flex: none;
  transform: scale(0);
  -webkit-backface-visibility: hidden;
          backface-visibility: hidden;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}
.outer-menu .menu > div > div {
  text-align: center;
  max-width: 90vw;
  max-height: 100vh;
  opacity: 0;
  transition: opacity 0.4s ease;
  overflow-y: auto;
  flex: none;
  display: flex;
  align-items: center;
  justify-content: center;
}
.outer-menu .menu > div > div > ul {
  list-style: none;
  padding: 0 1em;
  margin: 0;
  display: block;
  max-height: 100vh;
}
.outer-menu .menu > div > div > ul > li {
  padding: 0;
  margin: 1em;
  font-size: 24px;
  display: block;
}
.outer-menu .menu > div > div > ul > li > a {
  position: relative;
  display: inline;
  cursor: pointer;
  transition: color 0.4s ease;
}
.outer-menu .menu > div > div > ul > li > a:hover {
  color: #e5e5e5;
}
.outer-menu .menu > div > div > ul > li > a:hover:after {
  width: 100%;
}
.outer-menu .menu > div > div > ul > li > a:after {
  content: '';
  position: absolute;
  z-index: 1;
  bottom: -0.15em;
  left: 0;
  width: 0;
  height: 2px;
  background: #e5e5e5;
  transition: width 0.4s ease;
}