Code HTML <div id='editor' class='editor' contenteditable="true"> 吾輩は猫である。... </div> <button class='btn' id='btn-show'>表<br />示</button> CSS .editor { width: 100%; height: 100%; padding: 2rem; -webkit-writing-mode: vertical-rl; -moz-writing-mode: vertical-rl; writing-mode: vertical-rl; background-color: white; } .btn { position: fixed; left: 15px; bottom: 15px; } JavaScript window.onload = functio
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