diff --git a/.changeset/scope-preflight-css.md b/.changeset/scope-preflight-css.md
new file mode 100644
index 00000000..65df1bbb
--- /dev/null
+++ b/.changeset/scope-preflight-css.md
@@ -0,0 +1,7 @@
+---
+'@youversion/platform-react-ui': patch
+'@youversion/platform-core': patch
+'@youversion/platform-react-hooks': patch
+---
+
+Fix Tailwind preflight CSS leaking globally into consumer apps. The unscoped `@import 'tailwindcss/preflight.css'` was resetting styles on all elements (h1–h6 font size/weight, margins, padding, list styles, etc.) across the entire page. Preflight resets are now scoped to `[data-yv-sdk]` so they only apply inside SDK components.
diff --git a/packages/ui/src/styles/global.css b/packages/ui/src/styles/global.css
index ebd5fe6b..2e4e1291 100644
--- a/packages/ui/src/styles/global.css
+++ b/packages/ui/src/styles/global.css
@@ -20,13 +20,168 @@
  * Note: CSS linter warnings on these imports are a known issue and do not
  * affect functionality.
  */
-@import 'tailwindcss/preflight.css' prefix(yv);
+/*
+ * NOTE: We intentionally do NOT import 'tailwindcss/preflight.css' globally.
+ * Instead, preflight resets are scoped to [data-yv-sdk] below so our SDK
+ * components get the reset without nuking consumer app styles.
+ */
 @import 'tailwindcss/theme.css' prefix(yv);
 @import 'tailwindcss/utilities.css' prefix(yv);
-
 @import 'tw-animate-css';
 @import './bible-reader.css';
 
+/* #region Tailwind's Reset CSS, scoped to [data-yv-sdk] */
+/*
+ * :where() is a CSS pseudo-class that drops the specificity of
+ * everything inside it to zero (0,0,0,0). The selectors still
+ * match, but they never win a specificity fight. This is desired.
+ */
+:where([data-yv-sdk]) {
+  *,
+  ::after,
+  ::before,
+  ::backdrop,
+  ::file-selector-button {
+    font: inherit;
+    font-family: var(--yv-font-sans);
+    box-sizing: border-box;
+    margin: 0;
+    padding: 0;
+    border: 0 solid;
+  }
+
+  line-height: 1.5;
+  -webkit-text-size-adjust: 100%;
+  tab-size: 4;
+  -webkit-tap-highlight-color: transparent;
+
+  hr {
+    height: 0;
+    color: inherit;
+    border-top-width: 1px;
+  }
+
+  abbr:where([title]) {
+    -webkit-text-decoration: underline dotted;
+    text-decoration: underline dotted;
+  }
+
+  h1,
+  h2,
+  h3,
+  h4,
+  h5,
+  h6 {
+    font-size: inherit;
+    font-weight: inherit;
+  }
+
+  a {
+    color: inherit;
+    -webkit-text-decoration: inherit;
+    text-decoration: inherit;
+  }
+
+  b,
+  strong {
+    font-weight: bolder;
+  }
+
+  code,
+  kbd,
+  samp,
+  pre {
+    font-family: var(--yv-font-mono);
+    font-size: 1em;
+  }
+
+  small {
+    font-size: 80%;
+  }
+
+  sub,
+  sup {
+    font-size: 75%;
+    line-height: 0;
+    position: relative;
+    vertical-align: baseline;
+  }
+
+  sub {
+    bottom: -0.25em;
+  }
+
+  sup {
+    top: -0.5em;
+  }
+
+  table {
+    text-indent: 0;
+    border-color: inherit;
+    border-collapse: collapse;
+  }
+
+  ol,
+  ul,
+  menu {
+    list-style: none;
+  }
+
+  img,
+  svg,
+  video,
+  canvas,
+  audio,
+  iframe,
+  embed,
+  object {
+    display: block;
+    vertical-align: middle;
+  }
+
+  img,
+  video {
+    max-width: 100%;
+    height: auto;
+  }
+
+  button,
+  input,
+  select,
+  optgroup,
+  textarea,
+  ::file-selector-button {
+    font: inherit;
+    font-family: var(--yv-font-sans);
+    font-feature-settings: inherit;
+    font-variation-settings: inherit;
+    letter-spacing: inherit;
+    color: inherit;
+    border-radius: 0;
+    background-color: transparent;
+    opacity: 1;
+  }
+
+  ::placeholder {
+    opacity: 1;
+  }
+
+  textarea {
+    resize: vertical;
+  }
+
+  button,
+  input:where([type='button'], [type='reset'], [type='submit']),
+  ::file-selector-button {
+    appearance: button;
+  }
+
+  [hidden]:where(:not([hidden='until-found'])) {
+    display: none !important;
+  }
+}
+/* #endregion Scoped Preflight */
+
 /* #region shadcn UI theme */
 @custom-variant dark (&:is([data-yv-sdk][data-yv-theme='dark'] *));