Vintage envelope themed border via border-image
{"view":"split","fontsize":"100","seethrough":"","prefixfree":"1","page":"css"}
// alert('Hello world!');
<div>Bacon ipsum dolor amet eu adipisicing elit tongue ground round ex fatback proident kielbasa ham hock. Sausage beef beef ribs aliquip t-bone mollit. Quis beef tri-tip sunt, cupim ut magna salami t-bone. Ut laboris bresaola ribeye biltong landjaeger. Chuck pork belly sed sausage.</div>
/**
* Vintage envelope themed border via border-image
*/
div {
padding: 1em;
border: 16px solid transparent;
border-image: 16 repeating-linear-gradient(-45deg, red 0, red 1em, transparent 0, transparent 2em,
#58a 0, #58a 3em, transparent 0, transparent 4em);
max-width: 20em;
font: 100%/1.6 Baskerville, Palatino, serif;
}