div {
  width: 160px;
  height: 80px;
  padding: 20px;
  border: none solid #FFF;
  background: yellow;
  margin: none;
}

header {
  width: auto;
  height: 80px;
  padding: 0px;
  border: none solid #FFF;
  background: #CF6;  
  margin: 0px;

}

main {
  width: 600px;
  height: 200px;
  padding: 20px;
  border: none solid #FFF;
  background: #F9C;
  margin: 0px;
  float: none;
  clear: both;
}

aside {
  width: 160px;
  height: 80px;
  padding: 20px;
  border: none solid #FFF;
  background: #9F3;
  margin: 0px;

}

nav {
  width: auto;
  height: auto;
  padding: 4px;
  border: 1px solid red;
  border-style: solid none;
  background: #CCC;
  text-align: center;

}

footer {
  width: auto;
  height: auto;
  padding: 4px;
  border: 1px solid red;
  border-style: solid none;
  background: #CCC;
  margin: 0px;
  text-align: center;``
}

p {
 box-sizing: border-box;
   padding: 0px;

}

.width-img{ 
  vertical-align: top;
}

.content-boxf { 
  box-sizing: content-box;
  float: left;
}
.content-boxc { 
  box-sizing: content-box;
  clear: both;
}
  /* CONTENT-BOX final size includes box plus all
     Total width: 160px + (2 * 20px) + (2 * 8px) = 216px
     Total height: 80px + (2 * 20px) + (2 * 8px) = 136px
     for:
     Content box width: 160px
     Content box height: 80px */


.border-box {
 box-sizing: border-box;
}
  /* BORDER-BOX final size includes box plus margin
     Total width: 160px
     Total height: 80px
     for:
     Content box width: 160px - (2 * 20px) - (2 * 8px) = 104px
     Content box height: 80px - (2 * 20px) - (2 * 8px) = 24px */