<nav> impossible de mettre "border-right"

header { 
 padding-left: 10px; 
 padding-top: 35px; 
 font-family: helvetica; 
 font-size: 14px; 
 width: 200px; 
 position: fixed; 
 top: 0; 
 text-align: right; 
 margin-left: 10px; 
 border-right: 1px solid #000000; 

} 

nav { 
 padding-left: 0px; 
 padding-top: 0px; 
 font-family: Helvetica; 
 font-size: 12px; 
 text-align: right; 
 width: 200px; 
 position: fixed; 
 font-style: normal; 
 top: 49px; 
 margin-left: 10px; 
 border-right: 1px solid #000000; 
  
}

<nav>
	<ul id="photographers">
		<li>PHOTOGRAPHERS</li>		
	</ul>
		<ul id="sections_content">
			<li><a  href="bertrand_cavalier.html";</a>bertrand cavalier</li>
			<li><a  href="sara_gonzalez.html";</a>sara gonzalez</li>
			<li><a  href="lucie_dufour.html";</a>lucie dufour</li>
			<li><a  href="massao_mascaro.html";</a>massao mascaro</li>
			<li><a  href="gilles_ribero.html";</a>gilles ribero</li>	
		</ul>
		
	<ul id="collective_work">
		<li>COLLECTIVE WORK</li>
	</ul>	
		<ul id="sections_content_2">
			<li><a  href="projects.html";</a>projects</li>
			<li><a  href="books.html";</a>books</li>
		</ul>	

		
	<ul id="about">
		<li>THE COLLECTIVE</li>
	</ul>
		<ul id="sections_content_3">
			<li><a  href="the_collective.html";</a>about us</li>
			<li><a  href="contact_us.html";</a>contact</li>
		</ul>	
	
</nav>