2.x/3.x/v4-alpha/4.0(beta)のExampleを見れば外観の推移はほーんみたいなところある
https://getbootstrap.com/2.3.2/examples/hero.html
https://getbootstrap.com/docs/3.3/examples/jumbotron/
https://v4-alpha.getbootstrap.com/examples/jumbotron/
https://getbootstrap.com/docs/4.0/examples/jumbotron/ https://mstdn.maud.io/media/3pCXX5sX-W57pUZhYjw https://mstdn.maud.io/media/xBYdcMwfKWR-cU4L9dU https://mstdn.maud.io/media/HZsffq0k5vSYi8ukr7o https://mstdn.maud.io/media/qm8-CR3WY3P_r6dJHYs
