--- title: Automatic Dark Mode in Avalonia From a Single Theme description: I built automatic dark mode directly into my Avalonia theme engine — one theme definition that handles light and dark for you. No duplicate styles, no manual... canonical: https://daily.dev/posts/automatic-dark-mode-in-avalonia-from-a-single-theme-j0imgwoyd twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Automatic Dark Mode in Avalonia From a Single Theme | daily.dev og:description: I built automatic dark mode directly into my Avalonia theme engine — one theme definition that handles light and dark for you. No duplicate styles, no manual... og:url: https://daily.dev/posts/automatic-dark-mode-in-avalonia-from-a-single-theme-j0imgwoyd og:image: https://api.daily.dev/og/posts/j0IMGwoyD.png og:image:alt: Automatic Dark Mode in Avalonia From a Single Theme og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Automatic Dark Mode in Avalonia From a Single Theme **[AngelSix](https://daily.dev/sources/angelsix)** · 10 min read · 0 upvotes · 0 comments ## Summary I built automatic dark mode directly into my Avalonia theme engine — one theme definition that handles light and dark for you. No duplicate styles, no manual dark one / light seven on every control. Define your colors once, and source generators + color maps automatically convert contrasts, states, and ramps between modes. And when you don't like what it picks, you can override it per-brush. This is part of a complete series on building a fully custom Avalonia UI theme from scratch, hand-coded with zero AI assistance. ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 📌 WHAT YOU'LL LEARN ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ • How automatic dark mode works from a single theme definition • How source generators bake light-to-dark conversion into the engine • How to override auto colors per-brush - red in light, blue in dark • Why fixed colors like dark one / light seven were replaced with tokens • The new token system for theme defaults - surface, text, hover, background • How changing one token value retints every button and label instantly • How to scope dark mode to just one region of your UI ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ⏱ TIMESTAMPS ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ [0:00] – Automatic dark mode from a single theme [0:35] – Fully customizable - you're not locked in [0:44] – How it's baked into the theme engine with source generators [1:16] – Demo - red accent in light becomes blue in dark [2:16] – Coming next - opt-out flag for static colors [3:07] – Open source update + what changed [3:20] – Goodbye dark one / light seven - moving to tokens [3:54] – New token system - surface, text, hover, background defaults [5:30] – Demo - retint every button and label from one value [6:32] – Fixing label inheritance in partial dark regions [7:40] – Partial dark mode - theming just one region [9:14] – Wrap + next up - remaking the date/calendar control ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 🔗 LINKS & RESOURCES ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ ▶ Full Avalonia Themes Playlist: https://www.youtube.com/playlist?list=PLrW43fNmjaQVE2vDBeWD8QYIm06w6bKyO ▶ Source Code (AvaloniaThemeLab): https://github.com/angelsix/youtube/tree/develop/AvaloniaThemeLab ▶ GitHub: https://github.com/angelsix ▶ Website: https://www.angelsix.com ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 📚 SERIES — Avalonia UI Theming – Hand Coded From Scratch ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 01 — Setup — https://www.youtube.com/watch?v=rUKlQnjU0tc 02 — Buttons | Hand Coded From Scratch — https://www.youtube.com/watch?v=oKjk6pyyARI 03 — Button Spinner | Anatomy & Internals — https://www.youtube.com/watch?v=WMaTbXkvm9g 04 — Designing a Theme System From Scratch — https://www.youtube.com/watch?v=I5halHoNfH0 05 — Checkbox Control Deep Dive — https://www.youtube.com/watch?v=uIimnwjITT0 06 — Checkbox Styling — https://www.youtube.com/watch?v=uv1bNrfCjtY 07 — Theme Engine From Scratch — https://www.youtube.com/watch?v=NXz8hwITg5U 08 — Building a Design Token System — https://www.youtube.com/watch?v=QMVdxRZqaU8 09 — One Token System for the Entire Theme — https://www.youtube.com/watch?v=JEcD1XXIiA8 10 — Avalonia Styles Not Working? You're Breaking This Rule — https://www.youtube.com/watch?v=OhJN8Ssp2hA 11 — Avalonia Just Got a Full Icon System — https://www.youtube.com/watch?v=N5HPe5GYCPo 12 — Breaking Every Avalonia Control On Purpose — https://www.youtube.com/watch?v=OmVFU-iowqI 13 — Avalonia Tool That Finds Bugs My Compiler Can't See — https://www.youtube.com/watch?v=WQB5kFJWRmc 14 — The Avalonia Accent System That Generates Its Own Shades — https://www.youtube.com/watch?v=YFQEVLaYk94 15 — The Color Ramp That Themes Your Whole App — https://www.youtube.com/watch?v=xhnUQOOrShs 16 — Theme Token Reduction (One File, Every Control) — https://www.youtube.com/watch?v=tg2gSQRJtmY 17 — This Video — Automatic Dark Mode From a Single Theme #avalonia #avaloniaui #xaml #csharp #dotnet #uiux #desktopapp #softwaretutorial #coding ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: --- Tags: [#avalonia](https://daily.dev/tags/avalonia) [View this post on daily.dev](https://daily.dev/posts/automatic-dark-mode-in-avalonia-from-a-single-theme-j0imgwoyd) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Automatic Dark Mode in Avalonia From a Single Theme","url":"https://daily.dev/posts/automatic-dark-mode-in-avalonia-from-a-single-theme-j0imgwoyd","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/automatic-dark-mode-in-avalonia-from-a-single-theme-j0imgwoyd"},"datePublished":"2026-10-04T13:04:32.113Z","dateModified":"2026-10-04T21:57:11.216Z","description":"I built automatic dark mode directly into my Avalonia theme engine — one theme definition that handles light and dark for you.\n\nNo duplicate styles, no manual...","image":"https://i.ytimg.com/vi/m2WjfZAOUyM/sddefault.jpg","thumbnailUrl":"https://i.ytimg.com/vi/m2WjfZAOUyM/sddefault.jpg","isAccessibleForFree":true,"articleSection":"AngelSix","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"AngelSix","logo":"https://media.daily.dev/image/upload/s--h1ikmN_u--/f_auto,q_auto/v1791119063/logos/angelsix?_a=BAMAMicg0","url":"https://daily.dev/sources/angelsix"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/automatic-dark-mode-in-avalonia-from-a-single-theme-j0imgwoyd","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"avalonia","timeRequired":"PT10M","video":{"@type":"VideoObject","name":"Automatic Dark Mode in Avalonia From a Single Theme","description":"I built automatic dark mode directly into my Avalonia theme engine — one theme definition that handles light and dark for you.\n\nNo duplicate styles, no manual...","thumbnailUrl":"https://i.ytimg.com/vi/m2WjfZAOUyM/sddefault.jpg","uploadDate":"2026-10-04T13:04:32.113Z","duration":"PT10M","url":"https://api.daily.dev/r/j0IMGwoyD","embedUrl":"https://www.youtube.com/embed/m2WjfZAOUyM"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"AngelSix","item":"https://daily.dev/sources/angelsix"},{"@type":"ListItem","position":3,"name":"Automatic Dark Mode in Avalonia From a Single Theme"}]} ```