diff --git a/app/assets/stylesheets/responsive.css b/app/assets/stylesheets/responsive.css
index 703110186..5ae0185f3 100644
--- a/app/assets/stylesheets/responsive.css
+++ b/app/assets/stylesheets/responsive.css
@@ -131,15 +131,14 @@
   #project-jump.drdn {
     position: absolute;
     top: 0px;
-    left: 0;
+    inset-inline-start: 0;
 
     width: 100%;
     max-width: 100%;
     height: 2em;
     height: 64px;
-    padding: 5px;
-    padding-right: 72px;
-    padding-left: 20px;
+    padding-block: 5px;
+    padding-inline: 20px 72px;
   }
   #project-jump .drdn-trigger {
     font-size:1.5em;
@@ -147,7 +146,7 @@
     display:block;
     width:100%;
     color:var(--oc-white);
-    padding-left:24px;
+    padding-inline-start: 24px;
     background:transparent;
     height:50px;
     line-height:40px;
@@ -159,13 +158,14 @@
     font-size: 1.5em;
 
     position: absolute;
-    left: 0;
-    padding: 0 8px;
+    inset-inline-start: 0;
+    padding-block: 0;
+    padding-inline: 8px;
     /* achieve dropdwon arrow by scaling a caret character */
     content: '^';
     -webkit-transform: scale(1,-.8);
             transform: scale(1,-.8);
-    text-align: right;
+    text-align: end;
     pointer-events: none;
 
     opacity: .6;
@@ -173,13 +173,13 @@
   #project-jump.expanded .drdn-trigger:before {
     -webkit-transform: scale(1,.8);
             transform: scale(1,.8);
-    padding-top:8px;
+    padding-block-start: 8px;
   }
 
   #project-jump .drdn-content {
     position:absolute;
-    left:0px;
-    top:64px;
+    inset-inline-start:0;
+    inset-block-start:64px;
     width:100%;
     font-size:0.9375rem;
     font-weight:normal;
@@ -191,7 +191,7 @@
   #project-jump .drdn-content .autocomplete {
     height:40px;
     font-size:1.25rem;
-    padding-left: 28px !important;
+    padding-inline-start: 28px !important;
   }
   #project-jump .drdn-content a {
     padding:8px;
@@ -206,7 +206,8 @@
   \*----------------------------------------*/
 
   #main {
-    padding: 64px 0 0; /* padding-top equals header height */
+    padding-block: 64px 0; /* padding-top equals header height */
+    padding-inline: 0;
   }
 
   #main.nosidebar #content,
@@ -225,8 +226,7 @@
   .splitcontentleft, .splitcontentright, .splitcontenttop {
     width: 100%;
     flex: auto;
-    margin-right: 0;
-    margin-left: 0;
+    margin-inline: 0;
   }
 
   /*----------------------------------------*\
@@ -241,15 +241,15 @@
     z-index: 10;
 
     display: block; /* remove display: none; of non-mobile version */
-    float: right;
+    float: inline-end;
 
     width: 60px;
     height: 64px;
-    margin-top: 0;
+    margin-block-start: 0;
 
     text-align: center;
 
-    border-left: 1px solid var(--oc-gray-3);
+    border-inline-start: 1px solid var(--oc-gray-3);
   }
 
   .mobile-toggle-button:hover,
@@ -260,21 +260,21 @@
   .mobile-toggle-button:after {
     font-family: var(--fonts-main);
     display: block;
-    margin-top: -3px;
+    margin-block-start: -3px;
     content: '\2261';
   }
 
   .search-magnifier--flyout {
     position: absolute;
     z-index: 1;
-    left: 12px;
+    inset-inline-start: 12px;
   }
 
   /* Flyout Menu */
 
   .flyout-menu {
     position: absolute;
-    right: -250px;
+    inset-inline-end: -250px;
 
     display: block; /* remove display: none; of non-mobile version */
     overflow-x: hidden;
@@ -305,8 +305,7 @@
     text-transform: uppercase;
 
     color: white;
-    border-top: 1px solid #506a83;
-    border-bottom: 1px solid #506a83;
+    border-block: 1px solid #506a83;
     background-color: #628db6;
   }
 
@@ -326,12 +325,12 @@
   .flyout-menu__sidebar > form,
   .flyout-menu > div,
   .flyout-menu > form {
-    padding-left: 8px;
+    padding-inline-start: 8px;
   }
 
   .flyout-menu .flyout-menu__avatar {
-    margin-top: -1px; /* move avatar up 1px */
-    padding-left: 0;
+    margin-block-start: -1px; /* move avatar up 1px */
+    padding-inline-start: 0;
   }
 
   .flyout-menu__sidebar > form {
@@ -339,12 +338,13 @@
   }
 
   .flyout-menu__sidebar > form h3 {
-    margin-left: -8px;
+    margin-inline-start: -8px;
   }
 
   .flyout-menu__sidebar > form label {
     display: inline-block;
-    margin: 8px 0;
+    margin-block: 8px;
+    margin-inline: 0;
   }
 
   .flyout-menu__sidebar > form br  br {
@@ -353,19 +353,19 @@
 
   /* Targets list containing checkboxes (e.g. activities sidebar) in flyout menu */
   .flyout-menu__sidebar form > ul {
-    margin-left: -8px;
-    padding-left: 0;
+    margin-inline-start: -8px;
+    padding-inline-start: 0;
   }
 
   .flyout-menu__sidebar form > ul li {
     line-height: 39px;
     display: block;
-    padding-left: 8px;
-    border-top: 1px solid rgba(255,255,255,.1);
+    padding-inline-start: 8px;
+    border-block-start: 1px solid rgba(255,255,255,.1);
   }
 
   .flyout-menu__sidebar form > ul li:first-child {
-    border-top: none;
+    border-block-start: none;
   }
 
   .flyout-menu__sidebar form > ul li label {
@@ -375,7 +375,7 @@
   .flyout-menu__sidebar form > ul li label a {
     line-height: 1;
     display: inline;
-    padding-left: 0;
+    padding-inline-start: 0;
     border: none;
   }
 
@@ -403,7 +403,7 @@
   }
 
   #sidebar-wrapper {
-    margin-left: -8px;
+    margin-inline-start: -8px;
   }
 
   .flyout-menu #watchers ul li, .flyout-menu ul.queries li {
@@ -418,16 +418,16 @@
     -webkit-align-items: center;
     -webkit-box-align: center;
     align-items: center;
-    border-top: 1px solid rgba(255,255,255,.1);
+    border-block-start: 1px solid rgba(255,255,255,.1);
   }
 
   .flyout-menu #watchers ul li a, .flyout-menu ul.queries li a {
-    border-top: none;
+    border-block-start: none;
   }
 
   .flyout-menu ul.queries li a.icon-clear-query {
     flex-shrink: 0;
-    padding-right: 8px;
+    padding-inline-end: 8px;
   }
 
   .flyout-menu ul li a {
@@ -437,13 +437,13 @@
     height: 40px;
     white-space: nowrap;
     text-overflow: ellipsis;
-    border-top: 1px solid rgba(255,255,255,.1);
+    border-block-start: 1px solid rgba(255,255,255,.1);
   }
 
   .flyout-menu ul li:first-child a {
     line-height: 39px;
     height: 39px;
-    border-top: none;
+    border-block-start: none;
   }
 
   .flyout-menu a {
@@ -467,8 +467,8 @@
   .flyout-menu__search {
     line-height: 54px;
     height: 64px;
-    padding-top: 3px;
-    padding-right: 8px;
+    padding-block-start: 3px;
+    padding-inline-end: 8px;
   }
 
   .flyout-menu__search input[type='text'] {
@@ -476,7 +476,7 @@
 
     width: 100%;
     height: 38px;
-    padding-left: 27px;
+    padding-inline-start: 27px;
 
     vertical-align: middle;
 
@@ -491,7 +491,7 @@
     display: -webkit-flex;
     display: flex;
     width: 100%;
-    border-top: 1px solid rgba(255,255,255,.1);
+    border-block-start: 1px solid rgba(255,255,255,.1);
   }
 
   .flyout-menu__avatar img.gravatar {
@@ -518,8 +518,7 @@
   }
 
   .flyout-menu__avatar .user {
-    padding-left: 15px;
-    padding-right: 15px;
+    padding-inline: 15px;
     text-overflow: ellipsis;
     overflow: hidden;
     white-space: nowrap;
@@ -530,7 +529,7 @@
   /* user link when no avatar is present */
   .flyout-menu__avatar--no-avatar a.user {
     line-height: 40px;
-    padding-left: 8px;
+    padding-inline-start: 8px;
   }
 
   .flyout-is-active body {
@@ -542,7 +541,7 @@
   }
 
   .flyout-is-active #wrapper, .flyout-is-active #header {
-    right: 250px; /* when left flyout is active, move body and header to the right (same amount like flyout-menu's width) */
+    inset-inline-end: 250px; /* when left flyout is active, move body and header to the right (same amount like flyout-menu's width) */
   }
 
   .flyout-is-active #wrapper {
@@ -563,11 +562,11 @@
   }
 
   #admin-menu {
-    padding-left: 0;
+    padding-inline-start: 0;
   }
 
   #admin-menu li {
-    padding-bottom: 0;
+    padding-block-end: 0;
   }
 
   #admin-menu a,
@@ -587,8 +586,8 @@
 
   #content>.contextual {
     width: 100%;
-    margin-bottom: .5em;
-    padding-left: 0; /* reset left padding in order to use whole space */
+    margin-block-end: .5em;
+    padding-inline-start: 0; /* reset left padding in order to use whole space */
     white-space: normal;
   }
 
@@ -600,7 +599,7 @@
     display: inline-flex;
 
     margin: 5px 0;
-    margin-right: 2px;
+    margin-inline-end: 2px;
     padding: 9px 9px 9px 9px;
 
     border: 1px solid var(--oc-gray-4);
@@ -613,8 +612,7 @@
 	top:40px;
   }
   #content>.contextual .drdn .drdn-content a {
-    padding-top: 9px;
-    padding-bottom: 9px;
+    padding-block: 9px;
   }
 
   .flyout-menu .contextual {
@@ -624,7 +622,7 @@
   /* loading indicator */
   #ajax-indicator {
     width: 60%;
-    left: 20%;
+    inset-inline-start: 20%;
   }
 
   /* jquery ui dialogs */
@@ -634,12 +632,11 @@
   }
 
   .ui-dialog .ui-dialog-content {
-    padding-left: 0;
-    padding-right: 0;
+    padding-block: 0;
   }
 
   #filters-table {width:100%; float:none;}
-  .add-filter {width:100%; float:none; text-align: left; margin-top: 8px;}
+  .add-filter {width:100%; float:none; text-align: start; margin-block-start: 8px;}
 
   /*----------------------------------------*\
     F) PAGE SPECIFIC STYLES
@@ -650,23 +647,23 @@
     margin: 0;
   }
 
-  div#activity dl, #search-results {margin-left: 0;}
+  div#activity dl, #search-results {margin-inline-start: 0;}
 
   .version-overview table.progress {width:75%;}
-  div#version-summary {float:none; width:100%; margin-left:0;}
+  div#version-summary {float:none; width:100%; margin-inline-start:0;}
   body.controller-versions.action-show div#roadmap .related-issues {width:100%;}
 
   /* History and Changeset */
   div#issue-changesets {
     float: none;
     width: auto;
-    margin-left: 0;
-    padding-left: 0;
-    margin-bottom: 2em;
+    margin-inline-start: 0;
+    padding-inline-start: 0;
+    margin-block-end: 2em;
   }
 
   div#issue-changesets div.changeset {
-    padding-top: 1em;
+    padding-block-start: 1em;
   }
 
   /* Gantt charts */
@@ -687,13 +684,13 @@
 
   .gantt_subjects_column .gantt_hdr {
     width: 100% !important;
-    right: 0 !important; /* [2] */
-    border-right: solid 1px var(--oc-gray-4);
+    inset-inline-end: 0 !important; /* [2] */
+    border-inline-end: solid 1px var(--oc-gray-4);
   }
 
   #gantt_area {
-    left: -2px; /* [3] */
-    margin-right: -2px; /* [4] */
+    inset-inline-start: -2px; /* [3] */
+    margin-inline-end: -2px; /* [4] */
   }
 
   /*----------------------------------------*\
@@ -706,14 +703,14 @@
 
   /* tabular forms resets for mobile */
   .tabular p, .tabular.settings p {
-    padding-left: 0;
+    padding-inline-start: 0;
   }
 
   .tabular label, .tabular.settings label {
     display: block;
     width: 100%;
-    margin-left: 0;
-    text-align: left;
+    margin-inline-start: 0;
+    text-align: start;
   }
 
   .tabular input, .tabular select, .tabular textarea {
@@ -750,8 +747,8 @@
 
   /* issues page */
   body.controller-issues p.query-totals {
-    margin-top: 0px;
-    text-align: left;
+    margin-block-start: 0;
+    text-align: start;
   }
 
   /* subtasks and related issues list on issue show (without headers) */
@@ -764,9 +761,9 @@
   #issue_tree:not(.with-related-issues-table-headers) .issue > td:not(.checkbox),
   #relations:not(.with-related-issues-table-headers) .issue > td:not(.checkbox) {
     display: block;
-    float: left;
-    text-align: left;
-    padding-right: 5px;
+    float: inline-start;
+    text-align: start;
+    padding-inline-end: 5px;
   }
 
   #issue_tree:not(.with-related-issues-table-headers) .issue > td.subject,
@@ -776,7 +773,7 @@
 
   #issue_tree:not(.with-related-issues-table-headers) .issue:has(.buttons a) > td.subject,
   #relations:not(.with-related-issues-table-headers) .issue:has(.buttons a) > td.subject {
-    padding-right: 40px;
+    padding-inline-end: 40px;
   }
 
   #issue_tree:not(.with-related-issues-table-headers) .issue > td:not(.subject),
@@ -792,11 +789,11 @@
   /* positioniong of unline button */
   #issue_tree:not(.with-related-issues-table-headers) .issue > td.buttons,
   #relations:not(.with-related-issues-table-headers) .issue > td.buttons {
-    text-align: right;
+    text-align: end;
     position: absolute;
-    right: 0;
+    inset-inline-end: 0;
     margin: 0;
-    padding-right: 0;
+    padding-inline-end: 0;
   }
 
   #issue_tree:not(.with-related-issues-table-headers) .issue .buttons a,
@@ -819,17 +816,17 @@
   .attachments_fields span {
     position: relative;
     clear: both;
-    margin-bottom: 1em;
+    margin-block-end: 1em;
     white-space: normal;
   }
   .attachments_fields span a.remove-upload {
     position: absolute;
     top: 0;
-    right: 0;
+    inset-inline-end: 0;
   }
 
   .attachments_fields input.description {
-    margin-left: 0;
+    margin-inline-start: 0;
     width: 100%;
   }
 
@@ -851,7 +848,7 @@
 
   .cal .week-number {
     border: 1px solid var(--oc-gray-4);
-    text-align: left;
+    text-align: start;
     font-weight: bold;
     background-color: var(--oc-blue-0);
   }
@@ -862,7 +859,7 @@
 
   .cal .calbody p.day-num {
     font-size: 1.1em;
-    text-align: left;
+    text-align: start;
   }
 
   /* Sticky issue header */
@@ -887,7 +884,7 @@
   .pagination ul.pages li.previous,
   .pagination ul.pages li.next {display:inline-block; width:32%; overflow:hidden;}
 
-  #login-form {width:100%; margin-top:2em;}
+  #login-form {width:100%; margin-block-start:2em;}
 
   #filters-table .filter .field, #list-definition > div .field { width: 100%; }
   #filters-table .values { width: auto; max-width: 100%; }