add login/sign-up page with dark/light mode

node_modules/es-abstract/2020/InLeapYear.js

@@ -0,0 +1,19 @@
+'use strict';
+
+var $EvalError = require('es-errors/eval');
+
+var DaysInYear = require('./DaysInYear');
+var YearFromTime = require('./YearFromTime');
+
+// https://262.ecma-international.org/5.1/#sec-15.9.1.3
+
+module.exports = function InLeapYear(t) {
+	var days = DaysInYear(YearFromTime(t));
+	if (days === 365) {
+		return 0;
+	}
+	if (days === 366) {
+		return 1;
+	}
+	throw new $EvalError('Assertion failed: there are not 365 or 366 days in a year, got: ' + days);
+};