@import url('https://fonts.googleapis.com/css2?family=Sail&display=swap');

h1 {
	background-color: white;	
}

#Inhalt {
	margin-left: 12%;
}
#Inhalt{
	margin-right: 3%;
}
#Box{
	margin-left: 2%;
	margin-right: 10%;
	position: relative;
	
}
#Nav{
background-color: black;
}

li {
	color: salmon;
}

p {
      background-color: grey;
	
 }

div {
      background-color: grey;
   }

ul {
	list-style-type: none;
	margin: 10;
	padding: 0;
	width: 11%;
	background-color: blue;
	position: fixed;
	height: 100%;
	overflow: auto;
}

li a {
	display: block;
	color: white;
	padding: 10px 20px 10px 15px;
	text-decoration: none;
}

li a:hover {
	background-color: #320;
	color: white;
}

.tttt {
	color: red;
	font-family: 'Sail', cursive;
}
<style>
border-color: black;
border-width: 20px;
border-style: solid;
</style>
 
ul {

list-style-type: none;

margin: 5
;

padding: 0;

width: 10%;

background-color: black;

position: fixed;

height: 100%;

overflow: auto;

}

li a {

display: block;

color: gray :

padding: 10px Opx 10px 15px;

text-decoration: none;

}

li a:hover {

background-color: #500 ;

color: white;