Code:
@import url(style_cs.css);

/* шрифты */
@font-face {
font-family: 'Journalism';
src: local("Journalism"), url('https://forumstatic.ru/files/0010/a0/ba/54498.eot'),
url('https://forumstatic.ru/files/0010/a0/ba/54498.woff'),
url('https://forumstatic.ru/files/0010/a0/ba/54498.ttf');
}

/* Стандартные коды containercontainercontainer майбб, которые пригодятся */

.punbb ul, .punbb dl, .punbb li, .punbb dd, .punbb dt {padding: 0; list-style: none;}
.punbb img {border:none}
.punbb .main table {table-layout: fixed; width: 100%;}
.checkfield input[type="checkbox"], .radiofield input[type="radio"] {margin: 0 0.3em;}

p[class="checkfield"] *,
div[class="checkfield"] *,
fieldset[class="radiofield"] * {
  height: 1.8em;
  vertical-align: middle
}

.punbb .post-content em {font-style: italic}
.punbb optgroup {font-weight: bold;}

#pun:after, .punbb .container:after, .punbb .post-links ul:after, .punbb .main div.inline:after, .punbb .post-box:after, .punbb .linksb:after {clear: both; content: "."; display: block; height: 0; visibility: hidden; overflow:hidden; line-height: 0.0; font-size: 0;}

.acchide, #pun-index #pun-main h1, #pun-navlinks h2, #pun-pagelinks h2, #pun-status h2, #pun-ulinks h2, .punbb .forum h2, .punbb .multipage .topic h2, .punbb dl.post-sig dt span, .punbb p.crumbs strong, .punbb .divider hr, .punbb .required label em, .punbb .formsubmit label, .punbb .submitfield label, .punbb .modmenu label, .usertable .main h2, #pun-title h1 { font-size: 0; height: 0; width: 0; line-height: 0.0; position:absolute; left: -9999px; overflow: hidden}

.punbb * {margin: 0;}

/* свои коды */
html { background-image: url(https://forumstatic.ru/files/0010/a0/ba/62581.jpg); background-repeat: no-repeat; background-attachment: fixed; background-size: 100%; min-height: 100%;}
body {margin: 0; font: 12px 'Gothic A1', sans-serif; color: #363921;}
a {transition: color 0.3s ease-in-out; color: #385737; text-decoration: none;}
a:hover {color: #385737;}

#pun {max-width: 940px; background: #e6f1e5; margin: 135px auto 20px; border: 1px solid #a2bfa0; box-shadow: 0 11px 29px #80a190; padding: 160px 20px 20px;}

.punbb {background: #e0ecdf; padding: 10px 15px 25px; border: 1px solid #a2bfa0;}

#pun-title {position: absolute; width: 100%; left: 0; top: 70px; z-index: 100;}

#pun-title table {background: url(https://forumstatic.ru/files/0010/a0/ba/99162.jpg); max-width: 1026px; height: 177px; border-radius: 40px; margin: 0 auto; box-shadow: 0 11px 29px #80a190;}

/* админка */
.punbb-admin #pun-admain h2 {background: rgba(128,160,145,0.4); border: 1px solid #80a091; color: #385737; margin-block: 5px;}
#pun-adnav .isactive ul.adsubnav a {color: #4f4b42!important;}
#pun-adnav .isactive ul.adsubnav a:hover {color: #a69579!important;}
#pun-admain fieldset .handle, #pun-admain fieldset p,  #pun-admain1 .sortable p, #pun-admain .adcontainer th {background-color: rgba(128,160,145,0.25)!important; border-color: rgba(128,160,145,0.5)!important; color: #385737!important;}
.punbb-admin #pun-admain .adcontainer #adnav-standard {background: rgba(128,160,145,0.25); border: 1px solid #80a091; color: #80a091;}
#pun-admain legend span {font-family: 'Journalism'; font-size: 20px!important; background: transparent!important;}
.punbb-admin #pun-admain a, .punbb-admin #pun-admain a:link, .punbb-admin #punbb-admain a:visited {color: #385737; text-decoration: none;}

/* меню, последний визит, верхний и нижний контейнер навигации */
#pun-navlinks {position: absolute; top: 40px; left: 0; width: 100%; text-align: center; z-index: 30; font-family: 'Journalism'; font-size: 18px;}
#pun-navlinks li, #pun-ulinks li  {display: inline; padding-right: 10px;}
#pun-navlinks .container {background: rgba(128,160,145,0.25); border: 1px solid #80a091; max-width: 940px; margin: 0 auto; padding: 6px 10px 10px;}
#pun-ulinks {position: absolute; width: 100%; text-align: center; z-index: 101; left: 0; top: 71px; text-transform: lowercase;}
#pun-ulinks .container { max-width: 910px; margin: 0 auto; padding: 6px 10px 10px;}
#pun-status {margin: auto; position: relative; z-index: 200;}
#pun-status .container {position: absolute; text-align: center; top: -205px; width: 100%;}
span.item3.status-right { position: absolute; top: 173px; text-transform: lowercase; color: #80a091; width: 100%;}
.punbb #pun-status .status-right {float: none; display: block;}
#pun-crumbs1 {position: absolute; width: 100%; z-index: 1; left: 0; top: 237px; text-transform: lowercase;}
#pun-crumbs1 p.container {max-width: 910px; margin: 0 auto; padding: 14px 10px 4px;}
#pun-crumbs1 p.container, #pun-crumbs2 {background: rgba(128,160,145,0.25); border: 1px solid #80a091; color: #80a091; text-shadow: 0px 1px 1px #484f5a;}
#pun-crumbs2 p.container {padding: 3px 10px 3px;}
#pun-crumbs2 {margin-block: 5px;}
#pun-about p.container {text-align: center;}
#pun-about a {color: #80a091;}

 /* сокрытие элементов */
#pun-announcement h2, #pun-announcement.section, #pun-main h1, #pun-index .main th.tcl, #pun-index .main .tc2, #pun-index .main .tc3, #pun-index .main th.tcr, #pun-userlist .punbb .user-avatar.no-avatar, .linksb .subscribelink, .pa-sex, #most_invitations.section, thead .pmtc24, #pun-messages legend, #pun-messages legend span {display: none;}


 /* анимации */
@keyframes neon1 {
  from {
    background: rgba(128,160,145,0.05);
  }
  to {
    background: rgba(128,160,145,0.25);
  }
}

@keyframes neon2 {
  from {
    background: rgba(223,237,213,0.25);
    border: 1px solid #d1eebc;
  }
  to {
    background: rgba(223,237,213,0.95);
    border: 1px solid #8cb370;
  }
}

/* мобила */

@media screen and (max-width: 900px) {
.usertable thead {display: none;}
#pun-main .usertable td {
display:block;
width: 100%;
text-align: left;
padding: 0;
}

.usertable .tcl .usersname a {font-family: 'Journalism'; font-size: 26px;
line-height: 40px;}
.usertable .relation:before {content:'Репутация: ';}
.usertable .num_posts:before {content:'Сообщений: ';}
.usertable .registered:before {content:'Зарегистрирован: ';}
.usertable .last_visit:before {content:'Последний визит: ';}

.usertable tr {
padding: 10px;
display: inline-block;
width: calc(50% - 24px);
}

}

@media screen and (max-width: 860px) {
#pun-stats li.item1, #pun-stats li.item2,#pun-stats li.item3,#pun-stats li.item4 {font-size: 14px;}
.punbb #pun-navlinks {font-size: 16px;}
#pun-ulinks li.item6, #pun-ulinks li.item7 {display: none;}
.topic h3 {font-size: 12px;}
#profile.messages-container #profilenav ul {display: grid; padding: 0;}
#pun-messages .container .post-author {width: 35%; margin: 5px; float: left;}
#pun-messages .post-author ul {display: grid; float: left;}
#pun-messages .pa-posts, #pun-messages  .pa-respect {width: calc(100% - 14px);}
#pun-status .container {margin-left: 25%;  display: grid; justify-content: space-evenly; justify-items: stretch; width: 70%; top: -180px;}
#pun #pun-crumbs1 p.container{width: calc(86% - 24px);}


}


@media screen and (min-device-width: 320px) and (max-width: 500px) {
html { background-image: url(https://forumstatic.ru/files/0010/a0/ba/70943.jpg); background-size: cover!important;}
@layer base { .post-author, #profile-left, #pun-index .main tr {background-image: url(https://forumstatic.ru/files/0010/a0/ba/70943.jpg); min-height: 500%!important; background-repeat: repeat!important;}
}
#pun_wrap {margin-top: 200px;}
#pun-main .usertable tr {display:block; width: calc(100% - 20px);}
.punbb #pun-stats li.item1, .punbb #pun-stats li.item2,.punbb #pun-stats li.item3, .punbb 
.punbb #pun-navlinks {font-size: 15px;}
.topic h3 {font-size: 10px;}
.punbb .post-links li {display: grid; justify-content: space-evenly; float: none;}
#pun-index .user-avatar .avatar-image {width: 40px!important; height: 40px!important;}
.container .post-author {width: 60%; min-height: 50px; }
li.pa-posts, li.pa-respect {font-size: 8px; width: fit-content; padding: 0 2px; height: 14px;}
.pa-author {font-size: 15px; left: 0;}
#pun-main .post h3 span {background: none!important;}
.post .container {width: 98%;}
#viewprofile  #profile-right li {background: #ecf3eb!important; margin-bottom: 4px!important; border-bottom: 2px solid #759273!important; border-left: none!important;}
li.pa-reg, .topic a.sharelink, #pun-stats li.item4, li.item10 a, li.item10, #statistic-other  {display: none;}
#pun-status .container {top: -240px; padding-left: 25px;  display: grid; justify-content: end; justify-items: stretch;}
.statscon li.item1 {display: none;}
#pun-stats .container, li#onlinelist.item5.onlinelist {text-align: center;}
th.tcr, td.tcr, th.tcl, td.tcl{width: calc(35% - 24px);}



}

Code:
/* оформление навигационных страниц и страницы статистики */
table, tbody, thead, tr {display: block;}
thead {text-align: center; font-family: 'Journalism'; font-size: 16px;}
.main thead tr {background: transparent; border: none; margin: 0;}
.main tr {display: flex; align-items: center; border: 1px solid #80a091; margin-bottom: 10px;}
th, td {display: inline-block;}
th {padding: 4px 10px;}
td {padding: 10px;}
th.tcl, td.tcl {width: calc(45% - 24px);}
th.tc2, th.tc3, td.tc2, td.tc3 {width: calc(15% - 24px); text-align: center;}
th.tcr, td.tcr {width: calc(25% - 24px);}
th.tc3.tc, td.tc3.tc {width: calc(35% - 24px);text-align: center;}

#pun-statistic td.tc-topic, #pun-statistic th.tc-topic {width: calc(30% - 24px);}
#pun-statistic td.tc-username, #pun-statistic th.tc-username {width: calc(30% - 24px);}
#pun-statistic td.tc-title, #pun-statistic td.tc-registered, #pun-statistic th.tc-title, #pun-statistic th.tc-registered {width: calc(25% - 24px);}
#pun-statistic td.tc3, #pun-statistic th.tc3 {width: calc(14% - 24px); text-align: center;}

.usertable th.tc3.relation, .usertable td.tc3.relation, .usertable th.tc3.registered, .usertable td.tc3.registered, .usertable th.tc3.posts, .usertable td.tc3.num_posts, .usertable th.tc3.last_visit, .usertable td.tc3.last_visit {width: calc(10% - 24px); text-align: center;}

.main tr:hover {animation: neon2 0.9s ease-in-out infinite alternate;}
.main thead tr:hover, #pun-index .main tr:hover {animation: neon2;}


/* оформление страницы sms */
th.tcl.pmtcl1, td.tcl.pmtcl1 {width: calc(45% - 24px)!important;}
#messages thead {width: 91%;}
.messages-container h3 {background: rgba(117,146,115,0.95);border-top: 1px solid #759273;color: #fff;font-family: 'Journalism';font-size: 18px;padding: 10px;}
.messages-container .post {border-bottom: 7px solid #759273;padding-inline: 10px;margin-top: -5px;}
#profile.messages-container #profilenav ul {padding: 10px 90px 0 40px; display: inline-block;}
#messages .inew {background: rgba(57, 168, 61, 0.2);}
#messages .inew .tclcon:before {
content:'New!';
color: #aa0d0d;
margin-right: 5px;
animation: blinkColor .9s linear infinite;
-moz-animation: blinkColor .9s linear infinite;
-webkit-animation: blinkColor .9s linear infinite;
}
tr.group1 {display: inline-flex; width: 100%; flex-direction: row; align-items: center;}
td.tc2.pmtc22 {display: inline-flex; flex-direction: row-reverse;  align-items: center; width: 30%!important;;}

/* оформление страницы профиля */
#profilenav {width: 100%;margin-left: 0;margin-bottom: 3px;}
#profilenav h2 {display: none}
#profilenav ul {text-align: center;font-family: 'Journalism';font-size: 18px;color: #385737;padding: 30px 0 20px 0;}
#profilenav li:hover {animation: neon2 0.9s ease-in-out infinite alternate;}
#profilenav li {display: inline;border-top: 1px solid #80a091;border-left: 1px solid #80a091;padding: 2px;background: rgba(128,160,145,0.25);}
#pun-profile .main tr {background: transparent;border: none;margin-bottom: 10px;}
#pun-profile .main tr:hover {animation: neon2;}
#profile-right { width: 68%!important; margin-left: 1%;}
#viewprofile #profile-right li strong {font-size: 16px;line-height: 1.1;padding: 0 10px 10px;}
#profile-right li strong a {color: #385737; font-size: 13px;}
#profile-right li {background: #ecf3eb;margin-bottom: 4px;border-bottom: 2px solid #759273;}
#profile-left li {text-align: center;}
#profile-left #profile-name strong, #profile-left #profile-title strong {color: #fff;font-family: 'Journalism';font-size: 18px;}
#profile-left #profile-name {background: rgba(162,191,160,0.25);border-bottom: 1px solid #759273;}
#profile-left #profile-title, #profile-left #pa-online {background: rgba(117,146,115,0.75);border-top: 1px solid #759273;}
#profile-left li img {background: #fff;margin-top: 10px;-webkit-border-radius: 6px;-moz-border-radius: 6px;border-radius: 6px;}
#profile-left li:nth-child(3) {border-top: 1px solid #3c7958;}
#profile-left li:last-child {background: rgba(162,191,160,0.25);border-bottom: 4px solid #759273;}
#viewprofile li span {display: inline-block;padding: 10px 10px 5px;margin: 0 0 10px;font-family: 'Journalism';font-size: 16px;}
#viewprofile li strong {display: block;font-weight: 400 !important;padding: 6px 1em;}
li#pa-avatar img {
  width: 100%;
  height: 100%;
  background-position: center center;
}
.submitend {text-align: center;}
#update_comments, #del_file {width: 35%;}
.select-file {text-align: center;}


/* оформление категорий/форумов на главной */
#pun-index td.tcl {width: calc(99% - 30px);}
#pun-index th.tcr, #pun-index td.tcr {width: calc(82% - 24px);}
#pun-index .main tr {border: none;}

#pun-index .category tr {
  display: grid;
  grid-template-columns: auto;
  grid-gap: 10px;
}

#pun-index .main .tcl {
  padding-inline: 20px;
  padding-top: 1px;
  background: rgba(224,236,223,0.75);
}

#pun-index .main .tcl:hover {
  animation: neon1 1.5s ease-in-out infinite alternate;
}


#pun-index .main .tcr {
   position: relative;
   text-align: right;
   margin-top: -40px;
   width: inherit;
}

#pun-index .main .tcr a.lastpost-link {
  background: rgba(128,160,145,0.25);
}

#pun-index .user-avatar .isonline {
  position: relative;
  left: 734px;
  top: -23px;
  width: 40%;
  height: 40%;
}

/* расположение аватара на главной и на странице подфорума */
.punbb  .hasicon .user-avatar {
    float: right;
    margin: auto;
    padding-left: 10px;
    width: auto;
}

#pun-index .user-avatar .avatar-image {
    position: relative;
    border-radius: 10px!important;
    height: 60px !important;
    width: 70px !important;
    box-shadow: 0 0 6px #80a091 !important;
    border: 1px solid #80a091;
}

.punbb .main h2 span, #pun-stats h2 span, #post-form.formal h2 span {
  display: block;
  text-align: center;
  color: rgba(128,160,145,0.95);
  font-family: 'Journalism';
  font-size: 28px;
  padding-top: 5px;
}

#pun-index td div.tclcon {
  padding-block: 12px;
  padding-inline: 5px;
}

#pun-index td div.tclcon h3 {
  font-family: 'Journalism';
  font-size: 28px;
}

.podfor {
  position: relative;
  width: 80%;
  left: 5%;
  border-block-start: 1px solid #80a091;
  padding: 5px;
}

/* оформление статистики */
#pun-stats .container {
  padding: 10px;
  margin-bottom: 10px;
  text-align: right;
}

.statscon li.item1, .statscon li.item2, .statscon li.item3, .statscon li.item4 {
  display: inline-block;
  font-family: 'Journalism';
  font-size: 18px;
  padding: 5px;
  margin-inline: 3px;
  margin-bottom: 10px;
  color: #385737;
}

li#onlinelist.item5.onlinelist {
  text-align: left;
  padding-block: 15px;
  position: relative;
  width: 80%;
  border-block-start: 1px solid #80a091;
}

li#onlinelist.item5.statistics a{
  background: rgba(128,160,145,0.25);
}

/* оформление страницы форума */
.post-author, #pun-viewtopic h3 {display: inline-block; padding-block-start: 10px; padding-block-end: 5px;}

.topic h3 {
    width: 39%;
    float: right;
    border-block-end: 1px solid #80a091;
}
.post-author {
  width: 60%;  
  border: 1px solid #80a091;
}

@layer base {
  .post-author, #profile-left, #pun-index .main tr {
  background-image: url(https://forumstatic.ru/files/0010/a0/ba/62581.jpg)!important;
  background-repeat: no-repeat; 
  background-attachment: fixed; 
  background-size: 100%; 
  min-height: 100%;
  }

}


.post-author ul {
  background: rgba(224,236,223,0.55);
  border: 1px solid #80a091;
  position: relative;
  display: inline-block;
  width: 92%;  
  left: 4%;
}

.topic a.sharelink, .post .permalink {display: inline-block;padding-bottom: 10px; float: none!important;padding-right: 10px;width: 50%;margin-left: 12px!important;}
.post .permalink {} 
.topic a.sharelink {font-family: 'Journalism';}
.pa-author, .post-author .pa-avatar img {display: inline-block;}

.post-author .pa-avatar {float: left;padding: 10px;}
.post-author .pa-avatar img {vertical-align: top;border: none;  width: 100%; height: 100%; background-position: center center;}

.post h3 strong {
  position: relative;
  font-size: 250% !important;
  float: right;
  color: #385737;
  padding-right: 5px;
  }

.post h3 strong:before {
  font-size: 60%;
  padding-right: 4px;
  content: "№";
}

.post-author li {margin: 3px;}
.pa-posts, .pa-respect {display: inline-block;width: 29%;line-height: 20px;text-align: center;text-transform: lowercase;background: rgba(128,160,145,0.25);border: 1px solid #80a091;color: #80a091;}

.pa-author {
  font-family: 'Journalism';
  font-size: 25px;
  color: #385737;
  left: 10px;
  position: relative;
  top: 5px;
}

.post-body {
  position: relative;
  top: 15px;
  text-align: justify;
  padding-top: 15px;
  padding-inline-start: 2%;
  border-inline-start: 1px solid #80a091;
}

.post-body:hover { animation: neon1 4.5s ease-in-out infinite alternate; }

.punbb .post-links {
  width: 100%; 
  padding-block: 20px;
}


.punbb .post-links li {
  display: inline;
  padding-inline: 10px;
  margin-inline: 5px;
  float: right;
  background: rgba(128,160,145,0.25);
  margin-top: 5px;
}

.punbb .linksb, .punbb .linkst   {
  margin-block: 10px;
  padding-inline: 10px;
  font-family: 'Journalism';
  font-size: 22px;
  color: #385737;
}

.linksb .postlink,.linkst .postlink {
  float: right;
}

.punbb .modmenu .container {
  margin-block: 15px;
  margin-inline: 10px;
  text-transform: lowercase;
}

/*форма ответа */
#form-buttons tr {background: transparent;border: none;}
#form-buttons tr:hover {animation: neon2;}

#form-buttons table, #table-area table,
.post-content table {display: table;}
#form-buttons tbody, #table-area tbody,
.post-content tbody{display: table-row-group;}
#form-buttons tr, #table-area tr,
.post-content tr {display: table-row;}
#form-buttons td, #table-area td,
.post-content td {display: table-cell;}


#main-reply {
  background: rgba(236,243,235,0.45);
  border: 1px solid #80a091;
}

/* позиционирование выпадающего меню */
.punbb .hashelp {
  position: relative;
  }

/* выпадающие меню в форме ответа */
#tags .container,
.popup_graffiti, .inner .popup_graffiti {
    padding: 15px 10px 10px 10px !important;
    border-radius: 2px;
    background-color: #dce8da;
    color: #011301;
    border: 1px solid #80a091;
}



/* ширина высота и прокрутка в выпадающем меню формы ответа */
#font-area {height: 200px;
overflow-y: auto;
padding: 5px;
text-align: left;
width: 150px}

/*перекраска подложки выпадающего меню в форме ответа*/

#tags .container {background-color: #dce8da;}

/* разное */
input#fld9, p.inputfield input#fld3, p.inputfield input#fld2 {width: 100%;}
.punbb .formal fieldset {border: 0px; padding: 10px; background: rgba(162,191,160,0.25);}

.punbb .formal fieldset legend {
  width: 99%;
  text-align: center;
}


.punbb .formal fieldset legend span {
  position: relative;
  padding: 10px;
  top: 17px;
  font-family: 'Journalism';
  font-size: 18px;
  color: #385737;  
}

.fs-box {
  padding-block: 10px;
  padding-inline: 2px;
  border-bottom: 2px solid #80a091;}
  
.fs-box .avatardemo {
  margin-left: 10px;
  padding: 10px;
  background: #80a091;
}
  
.punbb .inline .inputfield, .punbb .inline .selectfield, .punbb .inline .passfield {
position: relative;
display: inline-block;
padding: 10px;
 }
 
 p.infofield {
padding-block: 10px;
position: relative;
text-align: justify;
}
.pagelink, .postlink.long {display: inline-block;}
.postlink.long {float: right; width: 21%!important;}

.modmenu span {padding-left: 10px;}  

p.formsubmit {
  text-align: center;
  padding: 10px;}

/* кнопки отправить посмотреть */
input.button, #post fieldset .hashelp div input, .button, #pun-admain input {
    font-size: 11px!important;
    background: linear-gradient(#80a091, #e0ecdf)!important;
    border: 1px solid #80a091;
    color: #385737!important;
    padding: 5px 10px !important;
    cursor: pointer!important;
    transition: .1s all;
}

input.button:hover, #post fieldset .hashelp div input:hover, .button:hover {
    background: linear-gradient(#647f7f, #4a5f5f)!important;
    cursor: pointer!important;
    color: #e0ecdf!important
  }
  
.punbb .formsubmit input, .punbb .formsubmit a, .punbb .formsubmit span {margin: 0 5px 0 0;}  

.punbb input {border-radius: 5px;}

/* внешний вид текста при выделении */
::selection {   
    background: rgba(128,160,145,0.35);
}

/* содержимое постов */
.post-content em.bbuline {font-style: normal; text-decoration: underline;}
.punbb .post-content .scrollbox {overflow: auto; height: auto!important; padding: 5px;}


/*цитаты и выделить код*/
.punbb .post-content .quote-box,.punbb .post-content .code-box, .punbb .quote-box cite, .punbb .code-box strong.legend {
  background: rgba(128,160,145,0.25); 
  border: 1px solid #80a091; 
  padding: 10px;}

.punbb .quote-box cite, .punbb .code-box strong.legend { 
text-align: center;
    display: block;
    font-family: 'Journalism';
    letter-spacing: 5px;
    font-size: 18px;
    color: #385737;
}


/* Абзацы внутри постов*/
.punbb .post-content p {
margin: 0;
    padding: 0 0 1em 0;
    line-height: 150%;
}