Use unwrap_or() instead of match block; remove unused import

src/main.rs

@@ -1,6 +1,5 @@
 use clap::Parser;
 use crossterm::terminal::size;
-use std::env;
 use unicode_width::UnicodeWidthStr;
 
 mod mikuart;
@@ -21,10 +20,7 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     let args = Args::parse();
 
     let text = args.text;
-    let style = match args.style {
-        Some(s) => s,
-        None => -1, // Default to -1 to select a random style
-    };
+    let style = args.style.unwrap_or(-1); // Default to -1 to select a random style
     draw_miku_says(&text, style)?;
 
     Ok(())