style.css

body {margin:0; padding:0; font-family: Verdana, "Bitstream Vera Sans", "Lucida Grande", sans-serif;}
header {margin:0; padding:0;background-color: #121212;min-height: 80px;}
h1 {color: white;font-size: 3.1em;font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;font-weight: 900;text-align: center;margin: 0;}
.body {
	width: 100%;
	max-width: 1200px;
	order:2;
}

.sidebar {
	width: 30%;
	max-width: 450px;
}

.flex-container{
    margin: 0 auto;
    display: flex;
}


.CodeMirror {
	font-size: 16px;
}

.table td {
	text-align: left;
}

.regExMatch0 {
	background-color: #ADC4CC;
}

.regExMatch1 {
	background-color: #9B539C;
}

.explanation {
	overflow-x: scroll;
	align: center;
	text-align: center;
}

.collapsible {
	background-color: #eee;
	color: black;
	cursor: pointer;
	padding: 11px;
	width: 100%;
	box-sizing: border-box;
	border: none;
	text-align: left;
	outline: none;
	font-size: 15px;
}

.collapsible:after {
	content: '\002B';
	color: black;
	font-weight: bold;
	float: right;
	margin-left: 5px;
}

.collapsible-active,
.collapsible:hover {
	background-color: rgb(105, 105, 105);
}

.collapsible-content {
	padding: 0 10px;
	display: none;
	overflow: hidden;
	background-color: #f1f1f1;
}

.editor-container-regexp {
	display: inline-block;
	border: 2px solid #bbbbbb;
	padding: 0px;
	margin-top: 8px;
	width: 85.5%;
	vertical-align: top;
}

.editor-container {
    border: 2px solid #bbbbbb;
    padding: 0px;
    margin-top: 8px;
}


.flag {
	text-align: center;
	display: inline-block;
	border: 2px solid #bbbbbb;
	border-width: 2px 2px 2px 0;
	display: inline-block;
	width: 13%;
	margin-top: 8px;
	vertical-align: top;
	margin-left:-6px;
}

.flag:hover {
	color: white;
}

.flag:hover::after {
	color: white;
}

.regex-quick-section {
	background-color: #4DAF52;
	margin: 8px auto 0px auto;
	color: white;
	font-weight: bold;
	text-align: center;
	width: 90%;
	border-radius: 2px 2px 0px 0px;
}

.regex-quick-section:hover {
	background-color: #4DAF52;
}

.regex-quick-section:after {
	color: white;
}

.regex-quick-section:hover::after {
	color: white;
}

.regex-quick-content {
	width: 90%;
	margin: auto;
}

.regex-quick-impair {
	background-color: #4DAF52;
}

.table {
	width: 100%;
}

.regex-quick-first {
	width: 20%;
	font-weight: bold;
}

.regex-quick-second {
	width: 80%;
}

#engine {
	padding: 10px;
	font-size: 1em;
	margin-left: 8%;
}

.editor-msg {
	min-height: 34px;
}

#engine label {
	font-size: 18px;
	font-weight: bold;
}

.radio {
	margin: 0.5rem;
}

.radio input[type="radio"] {
	position: absolute;
	opacity: 0;
}

.radio input[type="radio"]+.radio-label:before {
	content: "";
	background: #f4f4f4;
	border-radius: 100%;
	border: 1px solid #4DAF52;
	display: inline-block;
	width: 1.4em;
	height: 1.4em;
	position: relative;
	top: -0.2em;
	margin-right: 1em;
	vertical-align: top;
	cursor: pointer;
	text-align: center;
	-webkit-transition: all 250ms ease;
	transition: all 250ms ease;
}

.radio input[type="radio"]:checked+.radio-label:before {
	background-color: #4DAF52;
	box-shadow: inset 0 0 0 4px #f4f4f4;
}

.radio input[type="radio"]:focus+.radio-label:before {
	outline: none;
	border-color: #4DAF52;
}

.radio input[type="radio"]:disabled+.radio-label:before {
	box-shadow: inset 0 0 0 4px #f4f4f4;
	border-color: #4DAF52;
	background: #4DAF52;
}

.radio input[type="radio"]+.radio-label:empty:before {
	margin-right: 0;
}

.regex-generate-string {
	float: right;
	margin-right: 3px;
	font-weight: bold;
}

.regex-space-top {
	margin-top: 3px;
}

.regex-pointer {
	cursor: pointer;
}

.nolist {
	list-style-type: none;
}

	.tab-sub-menu {
		color: #616161!important;
		user-select: none;
		border: none;
		display: inline-block;
		padding: 8px 11px;
		vertical-align: middle;
		overflow: hidden;
		text-decoration: none;
		text-align: center;
		cursor: pointer;
		white-space: nowrap;
	}
	.tab-sub-menu:hover {
		border-bottom-width: 3px;
		border-bottom-style: solid;
		border-bottom-color: #bbbbbb;
	}
	.tab-sub-menu-select {
		border-bottom-width: 3px;
		border-bottom-style: solid;
	}

	.editor-error {
    color: red;
    padding: 8px;
    background-color: #F6CECE;
    margin: 10px 0px;
}

.editor-valid {
    color: green;
    padding: 8px;
    background-color: #D0F5A9;
    margin: 10px 0px;
}

@media (max-width:860px) {
	.body {
		width: 100%;
	}
	.sidebar {
		width: 100%;
	}

}