OMIProjectBranding/Template/project/branding_styles.php

<?php if (isset($branding["enabled"]) && $branding["enabled"] == 1 && !empty($branding["accent_color"])): ?>
<style>
  .app-main .sidebar a.active, .btn-blue, .project-main .views-switcher a.active {
    color: <?= $branding["accent_color"] ?> !important;
  }
  .btn-blue {
    background-color: <?= $branding["accent_color"] ?> !important;
    border-color: <?= $branding["accent_color"] ?> !important;
  }
  .project-header .views-switcher a.active::after, .view-project-header .views-switcher a.active::after {
    background-color: <?= $branding["accent_color"] ?> !important;
  }
</style>
<?php endif ?>