diff --git a/packages/lit-dev-content/site/_includes/default.html b/packages/lit-dev-content/site/_includes/default.html index fe04aacdd..9b1754b6b 100644 --- a/packages/lit-dev-content/site/_includes/default.html +++ b/packages/lit-dev-content/site/_includes/default.html @@ -14,6 +14,7 @@ {% endif %} + {% inlinejs "global/apply-saved-theme.js" %} {% inlinecss "colors.css" %} {% inlinecss "global.css" %} diff --git a/packages/lit-dev-content/src/global/apply-saved-theme.ts b/packages/lit-dev-content/src/global/apply-saved-theme.ts index a20e1f24f..3c74ff02f 100644 --- a/packages/lit-dev-content/src/global/apply-saved-theme.ts +++ b/packages/lit-dev-content/src/global/apply-saved-theme.ts @@ -4,6 +4,8 @@ * SPDX-License-Identifier: Apache-2.0 */ +import {updateMetaColor} from './theme.js'; + // Checks if there has been a theme already set from a prior visit let lastTheme = localStorage.getItem('color-mode'); @@ -15,3 +17,4 @@ if (!lastTheme) { // Applies the theme string to the document. document.body.classList.add(lastTheme); +updateMetaColor(lastTheme as 'light' | 'dark' | 'auto'); diff --git a/packages/lit-dev-content/src/global/theme.ts b/packages/lit-dev-content/src/global/theme.ts index 8630188b5..8fb19245e 100644 --- a/packages/lit-dev-content/src/global/theme.ts +++ b/packages/lit-dev-content/src/global/theme.ts @@ -37,6 +37,36 @@ function saveColorMode(mode: ColorMode) { localStorage.setItem('color-mode', mode); } +/** + * Updates the `` tag to match the current color mode. + * + * @param mode Mode from which to update the meta color. + */ +export function updateMetaColor(mode: ColorMode) { + const meta = document.head.querySelector( + 'meta[name="theme-color"]:not([media])' + ); + if (!meta) { + return; + } + + let isLight = mode === 'light'; + + if (mode === 'auto') { + const prefersDark = window.matchMedia( + '(prefers-color-scheme: dark)' + ).matches; + isLight = !prefersDark; + } + + if (isLight) { + meta?.setAttribute('content', '#fff'); + return; + } + + meta?.setAttribute('content', '#121212'); +} + /** * Applies theme-based event listeners such as changing color mode. */ @@ -46,5 +76,13 @@ export function applyColorThemeListeners() { } document.body.addEventListener('change-color-mode', (event) => { applyColorMode(event.mode); + updateMetaColor(event.mode); }); + window + .matchMedia('(prefers-color-scheme: dark)') + .addEventListener('change', (event) => { + if (getCurrentMode() === 'auto') { + updateMetaColor(event.matches ? 'dark' : 'light'); + } + }); }