@font-face{font-family:BTComputerModern;src:url('bt-tree-assets/cm-regular.woff') format('woff');font-display:swap}
canvas{transform-origin:0 0}
*{box-sizing:border-box}html,body{margin:0;width:100%;height:100%;overflow:hidden;background:#fff;color:#222;font-family:BTComputerModern,Georgia,serif}canvas{display:block;touch-action:none;cursor:grab;outline:none}canvas.dragging{cursor:grabbing}canvas:focus-visible{outline:1px dotted #777;outline-offset:-3px}.bt-nav{position:fixed;z-index:20;bottom:max(18px,env(safe-area-inset-bottom));left:50%;transform:translateX(-50%);display:flex;align-items:center;gap:19px;padding:11px 17px;background:rgba(255,255,255,.96);border:1px solid #ddd;box-shadow:0 1px 6px #00000008;white-space:nowrap;font-size:16px}.bt-nav a{color:inherit;text-decoration:none}.bt-nav a:hover{text-decoration:underline}.bt-nav button{font:inherit;border:0;background:none;color:#777;cursor:pointer;padding:0}.bt-help{position:fixed;z-index:25;left:50%;bottom:82px;transform:translateX(-50%);width:min(530px,calc(100% - 30px));padding:20px 25px;background:#fffffff5;border:1px solid #ddd;box-shadow:0 8px 35px #0002;line-height:1.5}.bt-help h2{margin:0 0 10px;font-size:21px}.bt-help p{margin:8px 0}.bt-help button{padding:7px 10px;margin:3px;border:1px solid #ccc;background:white;font:inherit;cursor:pointer}#bt-error{color:#a13325}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}[hidden]{display:none!important}