Installing Solo takes one Composer command; configuring it takes about twenty minutes, and the order matters more than any individual setting. Solo hides the settings for a region until that region has a block in it, so a site builder who opens the settings page first sees a fraction of what is actually there, concludes the theme is limited, and configures the wrong things. Place blocks first. Everything else follows.
This is the sequence, with the exact admin paths and the two decisions that are painful to reverse later.
Before you start: sub-theme or not?
Decide this first, because moving settings afterwards is tedious. Use Solo directly if everything you need is a setting in the admin. Create a sub-theme if you will write your own CSS, override a Twig template, add JavaScript, or write a preprocess function — and Solo ships an empty starter, solo_subtheme, inside the theme folder so this costs you a copy and a rename rather than a build.
Copy that folder out of the Solo directory into themes/custom/ before you install anything, so it survives a Composer update of the parent. Its .info.yml already declares base theme: solo and carries the same region list, so there is nothing to wire up.
Step 1: require the theme
composer require drupal/solo
drush theme:enable solo
drush config:set system.theme default solo -y
drush crIf you prefer the interface, the same three actions are Appearance → Install and set as default, then Configuration → Development → Performance → Clear all caches. Solo declares core_version_requirement: ^10.1 || ^11 || ^12 and php: ^8.1, so Composer will refuse the install rather than break your site if either is unmet — which is the behaviour you want.
Step 2: place your blocks, before you touch any settings
Go to Structure → Block layout. Solo gives you 24 placeable regions plus a hidden region for blocks you want configured but not rendered. Place at least one block into every region you intend to use, even a placeholder.
This is the step that changes everything downstream. Solo builds its settings form by loading the block entities assigned to each region of the active theme and only emitting the settings group for regions that came back non-empty. An empty region has no colour tab, no layout selector, no padding controls — not hidden behind a toggle, simply not rendered. Place a block, save, reload the settings page, and the whole group appears.
The containers work the same way. The Top Containers settings group only exists once one of top_first, top_second or top_third has content; the same is true of the bottom and footer groups. There is a walkthrough of the top containers if you want to see the grouping behaviour before you commit to a block layout.
Step 3: set the global width and breakpoints
At Appearance → Settings → Solo, open Global & Misc. Two settings here shape every page:
- Website width — eight presets from 800px / 50rem up to 2560px / 160rem, plus 100% for edge-to-edge layouts.
- Website's breakpoint — five values (576, 768, 992, 1200 and 1400px) that decide where the multi-column layout collapses to a single column. The menu has its own separate breakpoint selector with the same five values, so navigation can switch to its mobile mode at a different width from the page body.
Set these before you spend time on colour. Changing the width later changes how every colour block reads.
Step 4: choose a starting palette, then adjust
Solo ships 50 predefined colour schemes organised into 12 categories — midnight and twilight, ocean and deep sea, berry and fruit tones, urban and modern hues, and so on. Applying one from Predefined Color Schemes gets you a coherent starting point in a single select, which is far faster than picking 15 colours per region from scratch.
Then adjust. Each configurable area exposes the same 15 inputs: region background and text, headings, link and link-hover, borders, form field background, menu link text and background with their hover states, and button text and background with theirs. Solo writes your choices out as CSS custom properties on the region wrapper, which means you can inspect any region in DevTools and read exactly which value came from which setting.
Step 5: layout per region, and per content type
Under the Main Containers group you get a two-column ratio selector with seven options (50/50, 67/33, 75/25, 80/20 and the three mirrored versions) and a three-column selector with three (33/33/33, 25/50/25, 20/60/20). Which one applies depends on how many of sidebar_first, content and sidebar_second actually contain blocks.
Below those is a checkbox for per-content-type layouts. Tick it and Solo adds a collapsible group per content type with its own two- and three-column overrides, so an article can be narrow and a landing page wide without a second theme or a Layout Builder deployment.
Step 6: navigation
Solo has a primary menu region and a separate primary sidebar menu region, and the mega-menu selector offers fifteen arrangements from a single 100% column through to four-column layouts with asymmetric ratios. Add your links at Structure → Menus, place the menu block into Primary Menu or Primary Sidebar Menu, then configure appearance under the theme settings.
Step 7: check it, then check it logged out
Resize the browser through each of your chosen breakpoints, then open the site in a private window. Anonymous pages come from a different cache layer and are what your visitors and search engines actually get. A layout that only looks right while you are logged in is a layout you have not tested.
Common questions
Why can I not find the settings for a region?
Because that region has no blocks in it. This is by far the most common Solo support question and the answer is always the same: place a block, save the block layout, reload the theme settings page.
Do I have to re-do this on my sub-theme?
Yes. Theme settings are stored per theme, so switching the default theme from Solo to your sub-theme starts you from defaults. Decide on the sub-theme before you configure, not after.
Can I move a configured site to a different width later?
Yes, the width is one select. But re-check your images and any hard-coded pixel values in custom CSS afterwards, because those do not move with it.
What if I need per-node widths rather than per-content-type?
That needs the companion module. Solo Utilities adds a width select to the node form and applies a strict node-beats-content-type-beats-global precedence.
Where to go from here
Work through the seven steps in order and you will have a configured, responsive site without writing CSS. When you hit something the admin cannot express — and you eventually will — the sub-theme CSS diagnostic order is the next thing to read, because it will save you the afternoon most people lose on their first custom stylesheet.
If you would rather have the whole configuration done once, correctly, and handed over documented, that is what Drupal services covers. Send me the design and I will tell you what Solo can do from the admin and what will need code.