Move styling to a brand new iced_style crate

style/src/container.rs

@@ -0,0 +1,41 @@
+//! Decorate content and apply alignment.
+use iced_core::{Background, Color};
+
+/// The appearance of a container.
+#[derive(Debug, Clone, Copy)]
+pub struct Style {
+    pub text_color: Option<Color>,
+    pub background: Option<Background>,
+    pub border_radius: u16,
+}
+
+/// A set of rules that dictate the style of a container.
+pub trait StyleSheet {
+    /// Produces the style of a container.
+    fn style(&self) -> Style {
+        Style {
+            text_color: None,
+            background: None,
+            border_radius: 0,
+        }
+    }
+}
+
+struct Default;
+
+impl StyleSheet for Default {}
+
+impl std::default::Default for Box<dyn StyleSheet> {
+    fn default() -> Self {
+        Box::new(Default)
+    }
+}
+
+impl<T> From<T> for Box<dyn StyleSheet>
+where
+    T: 'static + StyleSheet,
+{
+    fn from(style: T) -> Self {
+        Box::new(style)
+    }
+}