Kiso

Rails component library built on ERB partials + Tailwind CSS + class_variants + tailwind_merge. Inspired by shadcn/ui and Nuxt UI, adapted for Rails + Hotwire.

Installation

# Gemfile
gem "kiso"

bundle install
bin/rails generate kiso:install

Rendering Components

Use the kui() helper to render components:

<%= kui(:badge, color: :success, variant: :soft) { "Active" } %>

<%= kui(:card) do %>
  <%= kui(:card, :header) do %>
    <%= kui(:card, :title, text: "Members") %>
  <% end %>
  <%= kui(:card, :content) do %>
    ...
  <% end %>
<% end %>

Colors

7 semantic colors configurable via theme CSS variables:

Variants

Components that accept both color and variant use compound variants (Nuxt UI pattern):

Theming

Components use semantic Tailwind utilities (bg-primary, text-foreground, bg-muted) that resolve to CSS variables. Dark mode flips automatically — components never use dark: prefixes.

Override brand colors in your app's CSS:

@theme inline {
  --color-primary: var(--color-orange-600);
  --color-primary-foreground: white;
}

Customizing Components

Global overrides

Override all instances of a component via Kiso.configure in an initializer:

# config/initializers/kiso.rb
Kiso.configure do |config|
  config.theme[:button] = { base: "rounded-full", defaults: { variant: :outline } }
  config.theme[:card_header] = { base: "p-8 sm:p-10" }
end

Override hashes accept base:, variants:, compound_variants:, defaults:. Applied once at boot — zero per-render cost.

Per-instance overrides

Pass css_classes: to override styles on a specific instance. Conflicting classes are resolved automatically via tailwind_merge:

<%= kui(:badge, color: :primary, css_classes: "rounded-full px-4") { "Custom" } %>

Layer order: theme default < global config < per-instance css_classes:.

Icons

Kiso uses kiso-icons for server-side inline SVG rendering. Lucide (~1500 icons) is bundled and works out of the box:

<%= kiso_icon("check") %>
<%= kiso_icon("settings", size: :md) %>
<%= kiso_icon("heroicons:check-circle") %>  <%# from a pinned set %>

Add more icon libraries:

bin/kiso-icons pin heroicons mdi tabler

Override component default icons globally:

Kiso.configure do |config|
  config.icons[:chevron_right] = "heroicons:chevron-right"
  config.icons[:menu] = "heroicons:bars-3"
end

Additional references

Load based on your task — do not load all at once:

• references/components.md — all components with props and usage
• references/theming.md — CSS variables, tokens, brand customization
• references/icons.md — icon rendering, pinning sets, component icon overrides