Substack Design and Branding: How Far the Theme Settings Actually Go

Substack gives you real but bounded design control. You can change colours, pick a font style, upload a logo, choose a homepage layout, and edit your navigation. You cannot write custom CSS or restructure the post template. This guide covers exactly what is adjustable, where the ceiling is, and what to do about the parts you cannot change.

#What You Can Change Inside Substack

#Colours

Substack's theme settings let you set an accent colour along with colours for your welcome page, homepage and post pages. The accent colour is the highest-leverage single change — it carries through buttons and links, so it is what a reader's eye picks up first.

Pick one accent colour and use it everywhere else too: your site, your social headers, your post thumbnails. Recognition comes from repetition, not from range.

#Fonts

The theme settings offer a selection of font styles rather than arbitrary font uploads. You are choosing from a set, not specifying a typeface.

This is worth understanding before you plan a brand around a specific font. If your identity depends on a particular typeface, you will be able to use it on your own website and in embedded forms, but not inside the Substack publication itself.

#Homepage Layout

Substack offers a choice between homepage layouts, and more recently a Use custom body layout option on the Home page tab, which unlocks additional control over how the body of your homepage is arranged.

Layout does more work than colour for how "considered" a publication feels. If you have a strong archive, a layout that surfaces more of it gives new readers evidence before they are asked to subscribe.

#Logo

You can upload a custom logo. Keep it legible at small sizes — it renders in navigation and in email, both of which are small contexts. A wordmark or a single letterform usually survives that better than a detailed illustration.

#Navigation and Sidebar Links

You can edit your navigation bar and add sidebar links on your homepage. These are underused. Default navigation tells a reader nothing; labels like "Start here", "Archive by topic", or "About the author" route people toward the things that actually convert them.

#Your URL

You can change your subdomain, or connect a custom domain so your publication runs on a URL you own.

#Where Substack Stops

This is the part most branding guides skip, and it is the part that determines what is worth your time.

No custom CSS. Substack's theme editor does not expose custom CSS on standard publications. You work with the provided options.

A shared post template. The reading experience — how a post is structured, where elements sit — is broadly consistent across Substack. Colour and font choices change the feel; they do not change the frame.

A fixed font set. Covered above, but worth restating as a limit rather than a feature.

Limited control over the subscribe experience. Substack's own embeddable form comes with its styling largely fixed, which is why an embedded Substack form on an otherwise designed website usually looks borrowed.

None of this makes Substack a bad choice. It is the standard trade-off of a hosted platform: you give up presentation control and get publishing, payments, delivery and a discovery network in return. But it does mean there is a ceiling, and effort spent pushing against it is wasted.

#A Branding Checklist That Works Within the Limits

Work through these in order. Each is adjustable, and consistency across them does more for recognition than any single dramatic change.

1. Logo — legible at 32px, works in one colour
2. Accent colour — one, used everywhere, not a palette of five
3. Page colours — welcome, homepage and post, consistent with each other
4. Font style — chosen once, then matched on every other surface you control
5. Homepage layout — chosen for what your archive actually looks like
6. Navigation labels — descriptive, not default
7. Post thumbnails — a repeatable template, same typeface and palette every time
8. Custom domain — if you are past the experimenting stage

#The Part You Fully Control

Everything above is bounded by what Substack exposes. The parts of your presence you own outright are your own website, your landing pages, and any subscribe forms you place on them — and those have no ceiling.

This is where a reader forms their first impression, and where the mismatch usually shows: a carefully designed site with a default Substack form dropped into it.

Supascribe exists for that gap. It does not change your Substack publication's theme — nothing outside Substack can. What it changes is the surface you own:

• Colours — set primary, accent, background and border colours to match your site exactly
• Font — the form inherits your site's body font by default, or override it with a web-safe or Google Font, including the brand typeface you could not use inside Substack
• Layout — single-line for headers and constrained spaces, or stacked for narrow columns; both responsive
• Copy — headline, description, button label, placeholder and success message, all yours
• Where they land — redirect new subscribers to a thank-you page, a lead magnet, or your best archive piece instead of a generic confirmation

Subscribers still sync directly to your Substack list. The feed widget applies the same treatment to your post previews, so visitors can see your writing before deciding.

#What Actually Moves the Needle

If you do three things, do these:

Pick one accent colour and one font style, and apply them to every surface — Substack, your website, your thumbnails, your embedded forms. Consistency across surfaces beats sophistication on any one of them.

Build a reusable thumbnail template. It is the highest-frequency brand asset you own.

Fix the seam between your website and your Substack. A reader who moves from a designed site to a default form notices, even if they could not tell you what they noticed. Closing that gap is usually the largest perceived-quality gain available, because it is the one place where the ceiling does not apply.

Design work inside Substack has a real ceiling. Recognising where it sits means you stop spending effort there and start spending it where the returns are uncapped.