CSS の代わりに xpath を使用する必要があると思います。xpath は非常に強力で、DOM をナビゲートしてデータを取得するのがはるかに簡単になります。
例として、指定された URL で衣類のすべての名前を取得し、配列を出力するには:
doc.xpath("//ul[@id = 'productsCatalog']//li//a//span[@class='itm-title']").children.map{|x| x.text.gsub("\r\n ","").strip}
=> ["Ruffle Sleeves Self Pattern Green Top", "Cap Sleeve Solid Red Top", "3/4Th Sleeve Embroidered Blue Tunic", "Ruffle Sleeves Embroidered Beige Tunic", "3/4Th Sleeve Stripe Blue Tunic", "Ruffle Sleeves Printed Beige/Pink Tunic", "Short Sleeve Embroidered Black Tunic", "Sleeve Less Solid Black Top", "Short Sleeve Solid Black Top", "Puffed Sleeve Embroidered Black Top", "Sleeve Less Printed Cream Top", "Sleeve Less Solid Yellow Top", "3/4Th Sleeve Embroidered Black Top", "Sleeve Less Solid Off White Top", "Sleeve Less Solid Fuschia Top", "Mega Sleeves Embroidered Green T-Shirt", "Sleeve Less Solid Orange Tunic", "Puffed Sleeve Embroidered Black Top", "Mega Sleeves Printed Beige Top", "Mega Sleeves Printed Beige T-Shirt", "Puffed Sleeve Stripe Red Dress", "Puffed Sleeve Stripe Blue Top", "Puffed Sleeve Printed Yellow Top", "Cap Sleeves Printed Multi Dress", "Short Sleeve Solid Mustard Yellow Tunic", "Mega Sleeves Embroidered Red Tunic", "Short Sleeve Stripe Red Dress", "Puffed Sleeve Embroidered Beige Top", "Short Sleeve Solid Black Top", "Butterfly Sleeve Check Beige Top", "Short Sleeve Solid Black tunic", "Sleeve Less Embroidered Green Top", "Mega Sleeves Printed Cream Tunic", "Mega Sleeves Embroidered Black Tunic", "Ruffle Sleeves Printed Orange Tunic", "Mega Sleeves Solid Pink Top", "Ruffle Sleeves Solid Rust Dress", "Sleeve Less Solid Navy Blue Dress", "Sleeve Less Self Pattern White Top", "Puffed Sleeve Stripe Red Top", "Mega Sleeves Solid Pink Tunic", "Roll Up Sleeve Solid Off White Tunic", "Sleeve Less Pintucks White Top", "Puffed Sleeve Embroidered Off White Top", "Puffed Sleeve Printed Pink Top", "Raglan Sleeve Solid Black Top", "Mega Sleeves Printed Beige Tunic", "Sleeve Less Solid Yellow Top", "Puffed Sleeve Self Pattern Beige Top", "Cap Sleeve Printed Yellow Dress", "Sleeve Less Solid Pink Dress"]