AdminLTE/src/scss/_root.scss

:root,
[data-bs-theme="light"] {
  // Content Wrapper
  --#{$lte-prefix}main-color: #{$lte-main-color};
  --#{$lte-prefix}main-bg: #{$lte-main-bg};

  // Sidebar
  --#{$lte-prefix}sidebar-width: #{$lte-sidebar-width};
}

@if $enable-dark-mode {
  @include color-mode(dark, true) {
    color-scheme: dark;
    // Body Color
    --#{$lte-prefix}main-color: #{$lte-main-color-dark};
    --#{$lte-prefix}main-bg: #{$lte-main-bg-dark};
  }
}