diff --git a/src/fonts.ts b/src/fonts.ts
--- a/src/fonts.ts
+++ b/src/fonts.ts
@@ -6,6 +6,7 @@
   displayName: string;
   fontFamily: string;
   fallback: string[];
+  baseSize?: number; // base font size in px for document content
 } & (
   | {
       // Self-hosted fonts with local files
@@ -33,6 +34,7 @@
     id: "quattro",
     displayName: "iA Writer Quattro",
     fontFamily: "iA Writer Quattro V",
+    baseSize: 16,
     type: "local",
     files: [
       {
@@ -52,6 +54,7 @@
     id: "lora",
     displayName: "Lora",
     fontFamily: "Lora",
+    baseSize: 17,
     type: "local",
     files: [
       {
@@ -67,119 +70,45 @@
     ],
     fallback: ["Georgia", "serif"],
   },
-  "source-sans": {
-    id: "source-sans",
-    displayName: "Source Sans",
-    fontFamily: "Source Sans 3",
-    type: "local",
-    files: [
-      {
-        path: "/fonts/SourceSans3-Variable.woff2",
-        style: "normal",
-        weight: "200 900",
-      },
-      {
-        path: "/fonts/SourceSans3-Italic-Variable.woff2",
-        style: "italic",
-        weight: "200 900",
-      },
-    ],
-    fallback: ["system-ui", "sans-serif"],
-  },
   "atkinson-hyperlegible": {
     id: "atkinson-hyperlegible",
     displayName: "Atkinson Hyperlegible",
     fontFamily: "Atkinson Hyperlegible Next",
+    baseSize: 18,
     type: "google",
     googleFontsFamily:
       "Atkinson+Hyperlegible+Next:ital,wght@0,200..800;1,200..800",
     fallback: ["system-ui", "sans-serif"],
   },
-  "space-mono": {
-    id: "space-mono",
-    displayName: "Space Mono",
-    fontFamily: "Space Mono",
-    type: "google",
-    googleFontsFamily: "Space+Mono:ital,wght@0,400;0,700;1,400;1,700",
-    fallback: ["monospace"],
-  },
-
   // Additional Google Fonts - Mono
   "sometype-mono": {
     id: "sometype-mono",
     displayName: "Sometype Mono",
     fontFamily: "Sometype Mono",
+    baseSize: 17,
     type: "google",
     googleFontsFamily: "Sometype+Mono:ital,wght@0,400;0,700;1,400;1,700",
     fallback: ["monospace"],
   },
 
   // Additional Google Fonts - Sans
-  "pt-sans": {
-    id: "pt-sans",
-    displayName: "PT Sans",
-    fontFamily: "PT Sans",
-    type: "google",
-    googleFontsFamily: "PT+Sans:ital,wght@0,400;0,700;1,400;1,700",
-    fallback: ["system-ui", "sans-serif"],
-  },
   montserrat: {
     id: "montserrat",
     displayName: "Montserrat",
     fontFamily: "Montserrat",
+    baseSize: 17,
     type: "google",
     googleFontsFamily: "Montserrat:ital,wght@0,400;0,700;1,400;1,700",
     fallback: ["system-ui", "sans-serif"],
   },
-  "alegreya-sans": {
-    id: "alegreya-sans",
-    displayName: "Alegreya Sans",
-    fontFamily: "Alegreya Sans",
+  "source-sans": {
+    id: "source-sans",
+    displayName: "Source Sans 3",
+    fontFamily: "Source Sans 3",
+    baseSize: 18,
     type: "google",
-    googleFontsFamily: "Alegreya+Sans:ital,wght@0,400;0,700;1,400;1,700",
+    googleFontsFamily: "Source+Sans+3:ital,wght@0,400;0,700;1,400;1,700",
     fallback: ["system-ui", "sans-serif"],
-  },
-
-  // Additional Google Fonts - Serif
-  "pt-serif": {
-    id: "pt-serif",
-    displayName: "PT Serif",
-    fontFamily: "PT Serif",
-    type: "google",
-    googleFontsFamily: "PT+Serif:ital,wght@0,400;0,700;1,400;1,700",
-    fallback: ["Georgia", "serif"],
-  },
-  "crimson-text": {
-    id: "crimson-text",
-    displayName: "Crimson Text",
-    fontFamily: "Crimson Text",
-    type: "google",
-    googleFontsFamily: "Crimson+Text:ital,wght@0,400;0,700;1,400;1,700",
-    fallback: ["Georgia", "serif"],
-  },
-  cardo: {
-    id: "cardo",
-    displayName: "Cardo",
-    fontFamily: "Cardo",
-    type: "google",
-    googleFontsFamily: "Cardo:ital,wght@0,400;0,700;1,400",
-    fallback: ["Georgia", "serif"],
-  },
-  "ibm-plex-serif": {
-    id: "ibm-plex-serif",
-    displayName: "IBM Plex Serif",
-    fontFamily: "IBM Plex Serif",
-    type: "google",
-    googleFontsFamily: "IBM+Plex+Serif:ital,wght@0,400;0,700;1,400;1,700",
-    fallback: ["Georgia", "serif"],
-  },
-  "source-serif": {
-    id: "source-serif",
-    displayName: "Source Serif 4",
-    fontFamily: "Source Serif 4",
-    type: "google",
-    googleFontsFamily: "Source+Serif+4:ital,wght@0,400;0,700;1,400;1,700",
-    fallback: ["Georgia", "serif"],
   },
 };
 
diff --git a/src/utils/blockTextSize.ts b/src/utils/blockTextSize.ts
new file mode 100644
--- /dev/null
+++ b/src/utils/blockTextSize.ts
@@ -0,0 +1,7 @@
+export const blockTextSize = {
+  p: "1em",
+  h1: "2em",
+  h2: "1.5em",
+  h3: "1.25em",
+  h4: "1.125em",
+} as const;
diff --git a/components/Blocks/TextBlock/index.tsx b/components/Blocks/TextBlock/index.tsx
--- a/components/Blocks/TextBlock/index.tsx
+++ b/components/Blocks/TextBlock/index.tsx
@@ -25,14 +25,21 @@
 import { DotLoader } from "components/utils/DotLoader";
 import { useMountProsemirror } from "./mountProsemirror";
 import { schema } from "./schema";
+import { blockTextSize } from "src/utils/blockTextSize";
 
 import { Mention, MentionAutocomplete } from "components/Mention";
 import { addMentionToEditor } from "app/[leaflet_id]/publish/BskyPostEditorProsemirror";
 
 const HeadingStyle = {
-  1: "text-xl font-bold [font-family:var(--theme-heading-font)]",
-  2: "text-lg font-bold [font-family:var(--theme-heading-font)]",
-  3: "text-base font-bold text-secondary [font-family:var(--theme-heading-font)]",
+  1: "font-bold [font-family:var(--theme-heading-font)]",
+  2: "font-bold [font-family:var(--theme-heading-font)]",
+  3: "font-bold text-secondary [font-family:var(--theme-heading-font)]",
+} as { [level: number]: string };
+
+const headingFontSize = {
+  1: blockTextSize.h1,
+  2: blockTextSize.h2,
+  3: blockTextSize.h3,
 } as { [level: number]: string };
 
 export function TextBlock(
@@ -162,7 +169,10 @@
   }
   return (
     <div
-      style={{ wordBreak: "break-word" }} // better than tailwind break-all!
+      style={{
+        wordBreak: "break-word",
+        ...(props.type === "heading" ? { fontSize: headingFontSize[headingLevel?.data.value || 1] } : {}),
+      }}
       className={`
         ${alignmentClass}
         ${props.type === "blockquote" ? (props.previousBlock?.type === "blockquote" ? `blockquote pt-3 ` : "blockquote") : ""}
@@ -266,7 +276,11 @@
           // unless we break *only* on urls, this is better than tailwind 'break-all'
           // b/c break-all can cause breaks in the middle of words, but break-word still
           // forces break if a single text string (e.g. a url) spans more than a full line
-          style={{ wordBreak: "break-word", fontFamily: props.type === "heading" ? "var(--theme-heading-font)" : "var(--theme-font)" }}
+          style={{
+            wordBreak: "break-word",
+            fontFamily: props.type === "heading" ? "var(--theme-heading-font)" : "var(--theme-font)",
+            ...(props.type === "heading" ? { fontSize: headingFontSize[headingLevel?.data.value || 1] } : {}),
+          }}
           className={`
             ${alignmentClass}
           grow resize-none align-top whitespace-pre-wrap bg-transparent
@@ -290,6 +304,7 @@
         props.nextBlock === null ? (
           // if this is the only block on the page and is empty or is a canvas, show placeholder
           <div
+            style={props.type === "heading" ? { fontSize: headingFontSize[headingLevel?.data.value || 1] } : undefined}
             className={`${props.className} ${alignmentClass} w-full pointer-events-none absolute top-0 left-0  italic text-tertiary flex flex-col
               ${props.type === "heading" ? HeadingStyle[headingLevel?.data.value || 1] : textStyle}
               `}
diff --git a/app/lish/[did]/[publication]/[rkey]/PostContent.tsx b/app/lish/[did]/[publication]/[rkey]/PostContent.tsx
--- a/app/lish/[did]/[publication]/[rkey]/PostContent.tsx
+++ b/app/lish/[did]/[publication]/[rkey]/PostContent.tsx
@@ -34,6 +34,7 @@
 import { PublishedPollBlock } from "./Blocks/PublishedPollBlock";
 import { PollData } from "./fetchPollData";
 import { ButtonPrimary } from "components/Buttons";
+import { blockTextSize } from "src/utils/blockTextSize";
 
 export function PostContent({
   blocks,
@@ -346,6 +347,7 @@
     case PubLeafletBlocksText.isMain(b.block):
       return (
         <p
+          style={{ fontSize: blockTextSize.p }}
           className={`textBlock ${className} ${b.block.textSize === "small" ? "text-sm text-secondary" : b.block.textSize === "large" ? "text-lg" : ""}`}
           {...blockProps}
         >
@@ -362,7 +364,7 @@
     case PubLeafletBlocksHeader.isMain(b.block): {
       if (b.block.level === 1)
         return (
-          <h2 className={`h1Block ${className}`} {...blockProps}>
+          <h2 style={{ fontSize: blockTextSize.h1 }} className={`h1Block ${className}`} {...blockProps}>
             <TextBlock
               {...b.block}
               index={index}
@@ -373,7 +375,7 @@
         );
       if (b.block.level === 2)
         return (
-          <h3 className={`h2Block ${className}`} {...blockProps}>
+          <h3 style={{ fontSize: blockTextSize.h2 }} className={`h2Block ${className}`} {...blockProps}>
             <TextBlock
               {...b.block}
               index={index}
@@ -384,7 +386,7 @@
         );
       if (b.block.level === 3)
         return (
-          <h4 className={`h3Block ${className}`} {...blockProps}>
+          <h4 style={{ fontSize: blockTextSize.h3 }} className={`h3Block ${className}`} {...blockProps}>
             <TextBlock
               {...b.block}
               index={index}
@@ -396,7 +398,7 @@
       // if (b.block.level === 4) return <h4>{b.block.plaintext}</h4>;
       // if (b.block.level === 5) return <h5>{b.block.plaintext}</h5>;
       return (
-        <h6 className={`h6Block ${className}`} {...blockProps}>
+        <h6 style={{ fontSize: blockTextSize.h4 }} className={`h6Block ${className}`} {...blockProps}>
           <TextBlock
             {...b.block}
             index={index}
diff --git a/app/lish/[did]/[publication]/[rkey]/StaticPostContent.tsx b/app/lish/[did]/[publication]/[rkey]/StaticPostContent.tsx
--- a/app/lish/[did]/[publication]/[rkey]/StaticPostContent.tsx
+++ b/app/lish/[did]/[publication]/[rkey]/StaticPostContent.tsx
@@ -12,6 +12,7 @@
   PubLeafletPagesLinearDocument,
 } from "lexicons/api";
 import { blobRefToSrc } from "src/utils/blobRefToSrc";
+import { blockTextSize } from "src/utils/blockTextSize";
 import { TextBlockCore, TextBlockCoreProps } from "./Blocks/TextBlockCore";
 import { StaticMathBlock } from "./Blocks/StaticMathBlock";
 import { codeToHtml, bundledLanguagesInfo, bundledThemesInfo } from "shiki";
@@ -119,7 +120,7 @@
     }
     case PubLeafletBlocksText.isMain(b.block):
       return (
-        <p>
+        <p style={{ fontSize: blockTextSize.p }}>
           <StaticBaseTextBlock
             facets={b.block.facets}
             plaintext={b.block.plaintext}
@@ -130,26 +131,26 @@
     case PubLeafletBlocksHeader.isMain(b.block): {
       if (b.block.level === 1)
         return (
-          <h1>
+          <h1 style={{ fontSize: blockTextSize.h1 }}>
             <StaticBaseTextBlock {...b.block} index={[]} />
           </h1>
         );
       if (b.block.level === 2)
         return (
-          <h2>
+          <h2 style={{ fontSize: blockTextSize.h2 }}>
             <StaticBaseTextBlock {...b.block} index={[]} />
           </h2>
         );
       if (b.block.level === 3)
         return (
-          <h3>
+          <h3 style={{ fontSize: blockTextSize.h3 }}>
             <StaticBaseTextBlock {...b.block} index={[]} />
           </h3>
         );
       // if (b.block.level === 4) return <h4>{b.block.plaintext}</h4>;
       // if (b.block.level === 5) return <h5>{b.block.plaintext}</h5>;
       return (
-        <h6>
+        <h6 style={{ fontSize: blockTextSize.h4 }}>
           <StaticBaseTextBlock {...b.block} index={[]} />
         </h6>
       );