Create a Fluid app for *twitter.com/* and add this user style

gistfile1.css

div#container, table#timeline, td.status-body > div{
	width: 100% !important;
}

div.wrapper{
	padding-left:  0px !important;
	padding-right: 0px !important;
}

tr.status > td{
	border-bottom-style: solid !important;
	border-bottom-color: #444 !important;
	padding: 0px !important;
}

form#doingForm{
	position: absolute !important;
	left: 0px !important;
	top:0px !important;
}

div#navigation, td.column#side_base{
	display: none !important;
}

div.tab{
	margin-top: 60px !important;
	margin-left: 0px !important;
	margin-right: 0px !important;
}

div#footer{
	display: none !important;
}

table.columns{
	margin-bottom: -16px !important;
}

td.thumb{
	padding: 0px !important;
	vertical-align: middle !important;
}

*{
	font-family: Helvetica !important;
	background-color: black !important;
	color: white !important;
}