margin: -20px -20px 20px;
window.addEventListener('mousedown', function(e) {
document.body.classList.add('mouse-navigation');
document.body.classList.remove('kbd-navigation');
window.addEventListener('keydown', function(e) {
document.body.classList.add('kbd-navigation');
document.body.classList.remove('mouse-navigation');
window.addEventListener('click', function(e) {
if (e.target.tagName === 'A' && e.target.getAttribute('href') === '#') {
window.onerror = function(message, source, line, col, error) {
var text = error ? error.stack || error : message + ' (at ' + source + ':' + line + ':' + col + ')';
errors.textContent += text + '\n';
errors.style.display = '';
console.error = (function(old) {
return function error() {
errors.textContent += Array.prototype.slice.call(arguments).join(' ') + '\n';
errors.style.display = '';
old.apply(this, arguments);