Что значит каждая строка ? * { box-sizing: border-box; } html, body, div, span, h1, h2, h3, h4, h5, h6, p, a, ul, li{ margin: 0; padding: 0; border: 0; font-size: 100%; vertical-align: baseline; } body { font-family: Verdana, Arial, sans-serif; background-color: #f7f7f7; } #header{ background-color: #f4f4f4; } #header h1 { font-size: 24px; text-transform: uppercase; font-weight: bold; padding: 30px 30px 30px 10px; clear: both; } #nav { background-color: #eee; border-top: 1px solid #ccc; border-bottom: 1px solid #ccc; } #nav li { float: left; list-style: none; } #nav a { display: block; color: black; padding: 10px 25px; text-decoration: none; border-right: 1px solid #ccc; } #nav li:last-child a { border-right: none; } #nav a:hover { font-weight: bold; } #nav:after { content: " "; display: table; clear: both; } .wrapper{ background-color: #f7f7f7; } .aside h2 { font-size: 0.95em; margin-top: 15px; } .aside h3 { font-size: 0.85em; margin-top: 10px; } .aside p, .aside li { font-size: .75em; margin-top: 10px; } .aside li{ list-style-type: none; } #sidebar1 { float: left; width: 20%; padding: 0 10px 0 20px; } #sidebar2 { float: right; width: 20%; padding: 0 20px 0 10px; } #article{ background-color: #fafafa; border-left: 1px solid #ccc; border-right: 1px solid #ccc; margin-left: 20%; margin-right: 20%; padding: 15px; width: 60%; } #article:after{ clear:both; display:table; content:''; } #article h2{ font-size: 1.3em; margin-bottom:15px; } #article p{ line-height: 150%; margin-bottom: 15px; } #footer{ border-top: 1px solid #ccc; font-size: .8em; text-align: center; padding: 10px 10px 30px 10px; } #nav ul, #header h1, .wrapper, #footer p { max-width: 1200px; margin: 0 auto; } .wrapper, #nav, #header, #footer{ min-width: 768px; }