*{  
    box-sizing: border-box;
    margin: 0px;
    padding: 0px;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}
body{
    background-color: bisque;
    height: 100vh;
}
header{
    position: relative;
    width: calc(100% - 400px);
    left: 200px;
    padding: 5px;
    background-color: rgba(220, 20, 60, 0.521);
    border: 2px solid darkslategrey;
    display: inline-block;
}
aside{
    padding: 0px;
    position: relative;
    display: block;
    top: 400px;
    width: 140px;
    height: 200px;
    background-color: rgba(220, 20, 60, 0.521);
    border: 2px solid darkslategrey;
}

li{
    position: relative;
    display: inline-block;
    list-style: none;
}

aside ul li ul{
    top: 0px;
    position: absolute;
    left: 100px;
    width: 150px;
}

header ul li ul{
    position: absolute;
    width: 150px;
}

li:hover{
    background-color: crimson;
    cursor: pointer;
}

.menupunkt_aside_1{
    width: 100%;
}


 .menu_header_1,
 .menu_header_2,
 .menu_header_3,
 .menu_header_4{
    opacity:0;
    visibility: hidden;
}
.menu_aside_1,
.menu_aside_2,
.menu_aside_3,
.menu_aside_4{
    opacity:0;
    visibility: hidden;
}

.menupunkt_header_1:hover > ul,
.menupunkt_header_2:hover > ul,
.menupunkt_header_3:hover > ul,
.menupunkt_header_4:hover > ul{
    opacity:1;
    visibility: visible;
}

.menupunkt_aside_1:hover > ul,
.menupunkt_aside_2:hover > ul,
.menupunkt_aside_3:hover > ul,
.menupunkt_aside_4:hover > ul{
    opacity:1;
    visibility: visible;
}