<!DOCTYPE html>
<link rel="author" title="Mats Palmgren" href="mailto:mats@mozilla.com">
<meta name="flags" content="paged">
<html>
<style>
@page {
  size: 5in 3in;
  margin: 0.5in;
}

html,body {
  color:black; background-color:white; font:20px/1 monospace; padding:0; margin:0;
  writing-mode: vertical-rl;
}
html { block-size: 40vw; }

.b {
  box-sizing: border-box;
  inline-size: 50vh;
  border: 5px solid black;
  border-block-start-color: blue;
  border-inline-start-color: lime;
  margin-inline-start: 20px;
}

.b1 {
  block-size: 100vw;
  border-block-end-style: none;
}

.b2 {
  block-size: 100vw;
  border-block-start-style: none;
  border-block-end-style: none;
}

.b3 {
  block-size: 10vw;
  border-block-start-style: none;
  margin-block-end: -20px;
}
</style>
<body>
  <div class="b b1"></div>
  <div class="b b2"></div>
  <div class="b b3"></div>
</body>
</html>