titan-iac/services/jenkins/scripts/theme.groovy

import jenkins.model.Jenkins
import org.codefirst.SimpleThemeDecorator

def instance = Jenkins.get()
def decorators = instance.getExtensionList(SimpleThemeDecorator.class)

if (decorators?.size() > 0) {
  def theme = decorators[0]
  theme.setCssUrl("https://cdn.jsdelivr.net/gh/Jorg3Lucas/jenkins-modern-themes@main/dist/modern-blue-grey.css")
  theme.setCssRules("""
:root {
  --atlas-bg: #0f1216;
  --atlas-surface: #171b21;
  --atlas-surface-alt: #1f252d;
  --atlas-border: #2b313b;
  --atlas-text: #e6e9ef;
  --atlas-text-muted: #b3bac6;
  --atlas-link: #8fb7ff;
}

body,
#page-body,
#page-header,
#header,
#main-panel,
#main-panel-content,
#side-panel,
.top-sticker-inner,
.bottom-sticker-inner,
#breadcrumbBar,
#breadcrumbs {
  background-color: var(--atlas-bg) !important;
  color: var(--atlas-text) !important;
}

#side-panel .task-link,
#breadcrumbs a,
#breadcrumbs,
#projectstatus th a,
#projectstatus td,
#projectstatus th {
  color: var(--atlas-text-muted) !important;
}

a,
a:visited,
a:link {
  color: var(--atlas-link) !important;
}

a:hover {
  opacity: 0.85;
}

#main-panel,
#main-panel-content,
#description,
.pane,
table.pane {
  background-color: var(--atlas-surface) !important;
  color: var(--atlas-text) !important;
}

table.pane tr:nth-child(odd) td {
  background-color: var(--atlas-surface) !important;
}

table.pane tr:nth-child(even) td,
#projectstatus tr:hover td {
  background-color: var(--atlas-surface-alt) !important;
}

input,
select,
textarea,
#search-box {
  background-color: var(--atlas-surface-alt) !important;
  color: var(--atlas-text) !important;
  border-color: var(--atlas-border) !important;
}

#header,
#page-header {
  background-color: #202734 !important;
}

#header .login,
#page-header .login {
  color: var(--atlas-text) !important;
}

#side-panel .task-link,
#side-panel .task-link:visited,
#side-panel .task-link:hover {
  color: var(--atlas-text) !important;
}

#footer {
  background-color: var(--atlas-bg) !important;
  color: var(--atlas-text-muted) !important;
}

.jenkins_ver:after {
  content: "atlas dark";
}
""".stripIndent().trim())
  theme.setJsUrl("")
  instance.save()
  println("Applied simple-theme-plugin dark theme")
} else {
  println("simple-theme-plugin not installed; skipping theme configuration")
}