The compress option has been deprecated. We recommend you use a dedicated css minifier, for instance see less-plugin-clean-css.
*,*:after,*:before{box-sizing:border-box;-moz-box-sizing:border-box;-webkit-box-sizing:border-box}a{color:#4a5963;text-decoration:underline}a:hover{text-decoration:none}h1{font:400 63px/1.1em 'mullerextrabold',sans-serif;color:#4a5963;margin:0 0 15px 0}h2{font:400 36px/1.3em 'mullerextrabold',sans-serif;color:#4a5963;margin:0 0 10px 0}h3{font:400 24px/1.3em 'mullerextrabold',sans-serif;color:#4a5963;margin:0 0 10px 0}@font-face{font-family:'mullerextrabold';src:url('https://soilwater.eu/font/muller-extrabold-webfont.eot');src:url('https://soilwater.eu/font/muller-extrabold-webfont.eot?#iefix') format('embedded-opentype'),url('https://soilwater.eu/font/muller-extrabold-webfont.woff2') format('woff2'),url('https://soilwater.eu/font/muller-extrabold-webfont.woff') format('woff'),url('https://soilwater.eu/font/muller-extrabold-webfont.ttf') format('truetype');font-weight:normal;font-style:normal}h1{color:#4a5963;font-size:50px}h3 span{font-size:80%;font-weight:bold}body{font-family:'Open Sans',sans-serif;font-size:15px;line-height:1.5em;color:#4a5963;background:#fff;min-width:500px;margin:0;width:100%;padding:0;position:relative}.header{margin:0 auto;padding:0;background:#f25e3b}.c-return{background:#43515b;color:#fff;margin:0;padding:0;height:40px;vertical-align:middle;width:100%;line-height:40px}.c-return a{color:#fff;padding-left:1em}p{line-height:160%}.c-main{background:#f4f1ee;padding:1em;min-height:30em}.main{margin:0 auto;padding:1em}.button{text-decoration:none;padding:.6em .7em;background:#f25e3b;color:#fff;font-weight:bold}.button:hover{background-color:#ea3910}.footer{text-align:center;margin-top:4em;padding-bottom:2em}.lab-list{display:flex;flex-wrap:wrap;text-align:left;margin:0 auto}.lab{width:25%;padding:1em;margin:.4em;background:#fff;border-left:4px solid #f25e3b;transition:ease-in 100ms;box-shadow:1px 5px 5px rgba(0,0,0,0.2)}.lab:hover{transform:scale(1.1);border-color:#ea3910}@media screen and (max-width:800px){.lab{width:45%;padding:.5em;margin:.1em}}@media screen and (max-width:400px){.lab{width:100%}}