pokk,
<html>
<head>
<title>Untitled</title>
<meta charset="utf-8">
<style>
html, body{
height:100%;
width:100%;
}
html *{
margin:0;
padding:0;
}
.content{
width:100%;
min-height:calc(100% - 6.7em);
display:flex;
}
.maintbl{
border:1px solid grey;
box-sizing:border-box;
background:#e4e5e6;
height: auto;
flex:1;
}
.BodyLeft{
background:#008000;
width:20%;
}
.BodyRight{
background:#F00;
width:20%;
}
.bottom {
padding-top:12px;
height:2em;
border-top: 1px solid white;
border-bottom: 6px solid #000;
width:100%;
background:#e4e5e6;
text-align:center;
}
.container{
text-align:center;
}
header {
background: #e4e5e6;
border-top: 6px solid #000;
border-bottom: 1px solid #BBBCBD;
/* height:35px; */
height:3em;
width:100%;
}
.Border1{
border-top: 1px solid white;
border-bottom: 1px solid #BBBCBD;
}
td{
height: 90px;
border: 1px solid #0000CD
}
</style>
</head>
<body>
<header>
<div class="container">
<h1>Заголовок</h1>
</div>
</header>
<div class="content">
<div class="BodyLeft Border1">22222222</div>
<div class="maintbl Border1">Тут небольшой контент хочуть сделать в виде ленты вниз, а по бокам пустой фон<table style="width: 100%; border-size: 1px; border-color: #CC0000; border-collapse: collapse">
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
<tr>
<td>table</td>
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<td>table</td>
</tr>
<tr>
<td>table</td>
<td>table</td>
<td>table</td>
</tr>
</table></div>
<div class="BodyRight Border1">3333333333</div>
</div>
<div class="bottom">7609098098</div>
</body>
</html>