CSS and Styles

Genro Textual supports Textual’s CSS for styling, both as inline stylesheets and as direct widget attributes.

Inline CSS

Use source.css() in the main method for stylesheets:

source.css("""
    #sidebar { width: 30; background: $surface; border-left: solid $primary; }
    .title { color: green; text-style: bold; margin: 1 0; }
    .muted { color: $text-muted; }
""")

CSS variables ($surface, $primary, $text, $error, etc.) are Textual theme variables — they work only in source.css(), not in direct attribute assignment.

Direct Style Attributes

Set CSS properties directly on widgets:

source.vertical(id="panel", width=40, display="block")
source.static("Bold text", color="green", background="red")

At mount time, the compiler classifies each attribute:

Constructor parameter → passed to widget __init__
CSS property → applied to widget.styles
Reactive attribute → applied to widget via set_reactive

Bindable Styles

Direct style attributes support ^pointer binding:

source.vertical(width="^_system.panel.width")

When data["_system.panel.width"] changes, the width updates.

Note: CSS variables ($surface) cannot be used in direct attributes — only in source.css().

Supported CSS Properties

All Textual CSS properties are supported as direct attributes:

Property	Example
`width`, `height`	`width=40`, `height="1fr"`
`min_width`, `max_width`	`min_width=20`
`color`, `background`	`color="green"`
`display`	`display="block"`, `display="none"`
`dock`	`dock="right"`
`padding`, `margin`	`padding=(1, 2)`
`opacity`	`opacity=0.5`
`position`	`position="absolute"`

Classes and IDs

source.static("Text", id="my-label", classes="title highlight")

IDs and classes are used for CSS selector targeting.