Chechbox is cheched but content cant slide

this is my very first question! Is now a couple of days that I am facing a problementer code here with checkbox creating a slide up/down mobile first menu. The checkbox is working perfectly but what I am unable to do after is letting the menu slide up and done when checkbox is checked. Any hint or help for the right direction would be greately appreciated!

<!-- === MENUTOGGLE === -->
<input type="checkbox" name="checkbox" id="menuToggle" value="value">
<label for="menuToggle" class="menu-icon">&#9776;</label>
<!--  ==== HEADER ==== -->    
<header>
<div id="logo" class="brand">
   <h1><img src="images/logo.png" alt="Hello"></h1>
</div>`enter code here`
   <nav class="menu">
        <ul>
            <li><a href="#">Work</a></li>
            <li><a href="#">About</a></li>
            <li><a href="#">Blog </a></li>
            <li><a href="#">Contact</a></li>
        </ul>
    </nav>
</header>

---

* {
margin: 0;
padding: 0;
outline: none;
box-sizing: border-box;
}
body {
background: #eee;
color: #444;
-webkit-font-smoothing: antialiased;
font-family: Arial, sans-serif; 
font-weight: 400;
height: auto !important;
height: 100%;
min-height: 100%;
text-rendering: optimizeLegibility;
}
.menu {
width: 100%;
position: absolute;
top: 66px;
}
.menu-icon {
float: right;
color: blueviolet;
cursor: pointer;
padding-top: 25px;
padding-right: 30px;
}
#menuToggle {
display: none;
}
#menuToggle:checked + .menu {
position: absolute;
top: -66px;
}
#logo {
float: none;
text-align: left;
padding-top: 7px;
padding-left: 2em;
}
header {
display: block;
background-color: #FFF;
}
nav {
text-align: center;
}
nav ul {
background-color: rgba(255, 255, 255, 0.15);
float: none;
line-height: 3.5em;
margin: 0;
}
nav ul li {
display: block;
list-style-type: none;
}
nav ul li:hover {
background-color: rgba(171, 193, 242, 0.1);
}
nav ul li a {
text-decoration: none;
color: red;
}
nav ul li a:hover {
color: aqua;
}

/*------------ MEDIUM BIG SCREEN -----------------------*/

@media screen and (min-width:600px) {
#logo {
float: left;
}
.menu {
width: 100%;
height: 70px;
position: inherit;
}
.menu-icon {
display: none;
}
header {
height: 70px;
background-color: #FFF;
margin: auto;
width: 100%;
}
nav ul {
background-color: #FFF;
float: right;
padding: 0.55em 3em 0.55em 1.5em;
height: 70px;
}
nav ul li {
display: inline-block;
}
nav ul li a {
background-color: #FFF;
padding-left: 3em;
}