Question

Можно ли очистить таблицу стилей css и вставить данный код

/*
- © nk-cs.ru 2010-2018
- Author: Erdem Turan (na3uTuB4uk)
- Author Email: support@nk-cs.ru
- ВКонтакте: http://vk.com/na3utub4uk
- Skype: na3uTuB4uk94
- Web Site: https://www.nk-cs.ru/
*/

/* Основные стили Teensy */
@import url('/css/bootstrap.css');
@import url('/css/animate.css');
@import url('/css/engine.css');

@import url('/css/styles.css');
@import url('/css/ssg.css');
@import url('/css/owl.theme.css');

@import url('/css/owl.transitions.css');
@import url('/css/owl.carousel.css');
@import url('/css/bootstrap.offcanvas.css');

/* Дополнительные стили Teensy */
.com-order-block {display: none;}
.uadm* {display:none!important;}
#post {width: 50% !important; float: left;}

.eTag {}
.eTag:hover {}

.custom-control input[type="checkbox"] { position: absolute; top: 0.25rem; left: 0; display: block; width: 1rem; height: 1rem; -webkit-user-select: none; -moz-user-select: none; -ms-user-select: none; user-select: none; background-color: #ddd; background-repeat: no-repeat; background-position: center center; background-size: 50% 50%; color: #fff; background-color: #007bff; opacity: 1; z-index: 99999;}

/* Statistic
------------------------------------------*/
.item {text-align: center; float: left;margin: 15px;}
.position {display: inline-block;}
.countr {display: block; float:left; margin: 5px;}
.num {border: 3px solid;border-radius: 7px;line-height: 27px;width: 35px;margin: auto;text-align: center;font-size:13pt;font-weight: bold;background-color: #f9f9fc;}
#tnum {border-color: #2e3243;color: #2e3243;}
#unum {border-color: #00cae3;color: #00cae3;}
#gnum {border-color: #8cc152;color: #8cc152;}

a.groupAdmin:link,a.groupAdmin:visited,a.groupAdmin:hover {color:red; font-weight: bold;} /* Администратор */
a.groupModer:link,a.groupModer:visited,a.groupModer:hover {color:blue; font-weight: bold;} /* Гл. Модератор */
a.groupVerify:link,a.groupVerify:visited,a.groupVerify:hover {color:ora; font-weight: bold;} /* Преверенный */
a.groupOther1:link,a.groupOther1:visited, pOther1:hover {color:green; font-weight: bold;} /* Модератор */
a.groupOther2:link,a.groupOther2:visited, pOther2:hover {color:#BDB76B; font-weight: bold;}
a.groupOther3:link,a.groupOther3:visited, pOther3:hover {color:#FF1493; font-weight: bold;} /* Важные персоны */
a.groupOther4:link,a.groupOther4:visited, pOther4:hover {color:#9932CC; font-weight: bold;}
a.groupOther5:link,a.groupOther5:visited, pOther5:hover {color:#00BFFF; font-weight: bold;}
a.groupOther6:link,a.groupOther6:visited, pOther6:hover {color:#FF7F50; font-weight: bold;}

.codeMessage { margin-top: 0; margin-bottom: 1rem; color: #212529 !important; display: block; padding: 10px; background: #f9fafa; border: 1px solid #ddd !important; overflow: auto !important; }
.bbQuoteName, .bbCodeName {display: none;}
.codeMessage,.quoteMessage,.uSpoilerText{ font-size: 12px; color: #939fae;}
.quoteMessage { padding: 1% 4% !important; margin: 1em 0 !important; border-left: 2px solid #e85319 !important; border-top: none !important; border-right: none !important; border-bottom: none !important; font-style: italic; }

.myWinCont input[type=text], .myWinCont input[type=password] {background:#fff!important;border:1px solid #ececec!important;font-size:11px!important;font-family:tahoma!important;color:#535353!important;border-radius:2px!important;padding:5px 8px!important;outline:none!important;box-shadow:none!important;} 
.myWinCont textarea {box-shadow:none!important;} 
.x-sh .xstl{padding-top:6px; background:none!important;} 
.x-sh .xsml{background:none!important;} 
.x-sh .xstr{padding-top:6px; background:none!important;} 
.x-sh .xsmr{background:none!important;} 
.x-sh .xsbl{padding-left:6px;background:none!important;} 
.x-sh .xsbc{background:none!important;} 
.x-sh .xsbr{padding-right:6px;background:none!important;} 
.xt {background:none!important; margin-left:5px!important; margin-top:1px!important; width:25px!important; height:20px!important;} 
.xt-close{background:url('/dleimages/12848835.png') no-repeat!important; margin:1px 0 0 0px!important;} 
.xt-close-over{background:url('/dleimages/12848835.png') no-repeat!important;} 
.xt-mini{background-position:0 -15px!important;} 
.xt-mini-over{background-position:-15px -15px!important;} 
.xt-maxi{background-position:0 -30px!important;} 
.xt-maxi-over{background-position:-15px -30px!important;} 
.xt-rest{background-position:0 -45px!important;} 
.xt-rest-over{background-position:-15px -45px!important;} 
.xw-tl {background:#fff!important; border-bottom:1px solid #6f9bc0!important; padding-left:5px!important; -webkit-border-radius: 2px 0px 0px 0px; -moz-border-radius: 2px 0px 0px 0px; border-radius: 2px 0px 0px 0px;} 
.xw-tc {background:none!important; padding:6px 10px 0px 10px!important;} 
.xw-tr {background:none!important; padding-right:5px!important; -webkit-border-radius: 0px 2px 0px 0px; -moz-border-radius: 0px 2px 0px 0px; border-radius: 0px 2px 0px 0px;} 
.xw-ml {background:#fff!important; padding-left:5px!important; color:#656565!important;} 
.xw-mr {background: none !important; padding-right:5px!important;} 
.xw-bl {background:#fff!important; padding-left:5px!important; -webkit-border-radius: 0px 0px 0px 2px; -moz-border-radius: 0px 0px 0px 2px; border-radius: 0px 0px 0px 2px;} 
.xw-br {background:#fff!important;padding-right:5px!important; -webkit-border-radius: 0px 0px 2px 0px; -moz-border-radius: 0px 0px 2px 0px; border-radius: 0px 0px 2px 0px;} 
.xw-bc {background:#fff!important; height:5px!important;} 
.xw-hdr-text {padding:0px!important;} 
.xw-hdr-text {font-size: 11px;font-weight: 700; font-family: tahoma!important; color:#656565!important; line-height: 15px!important; vertical-align:2px!important;} 
.xw-plain .xw-mc {border-radius:2px!important; border: none!important; padding:0!important; margin:0!important; font: 11px tahoma!important; color:#656565!important; background:#fff!important;} 
.xw-body, .myWinCont {padding:0!important; margin:0!important; color:#656565!important;} 
.xw-plain .xw-body{padding: 0!important; border: none!important;} 
.xw-plain {box-shadow:0 0 6px #cecece;} 
.xw-blank {background:#fff!important;} 
.myWinTD1 {background:none!important;}

Answer 1

Если вы все основные стили перенесли по файлам и хотите прописать ссылки на файлы через импорт, да, можно. Только сохраните перед этим свои стили которые есть в основной таблице стилей, сделайте резервную копию.