add class to modal

[kandrelczyk]

Hi, added class to the modal component. Without it I couldn't make it responsive and fit nicely on mobile.
I tested the component but I'm getting errors when I try to build the demo page:

error[E0282]: type annotations needed for `Box<_>`
  --> /opt/cargo/registry/src/index.crates.io-6f17d22bba15001f/time-0.3.30/src/format_description/parse/mod.rs:83:9
   |
83 |     let items = format_items
   |         ^^^^^
...
86 |     Ok(items.into())
   |              ---- type must be known at this point
   |
help: consider giving `items` an explicit type, where the placeholders `_` are specified
   |
83 |     let items: Box<_> = format_items
   |              ++++++++

Hope the markdown is ok.
Any idea what is causing the error? I'm on rust 1.80.0-nightly.

[kandrelczyk]

Also added closable param.

[luoxiaozero]

Any idea what is causing the error? I'm on rust 1.80.0-nightly.

Run cargo update to solve the problem. See time-rs/time#681.