@charset "utf-8";
@import url("https://fonts.googleapis.com/css?family=Orbitron&display=swap");

* {
	margin: 0px;
	padding: 0px;
}
ul,
ol,
li {
	list-style: none;
}
a {
	text-decoration: none;
}

body {
	background: #efefef;
}

header {
	width: 400px;
	height: 100%;
	background: linear-gradient(45deg, aqua, royalblue);
	/* main 영역에서 스크롤해도 header 영역은 브라우저 왼쪽에 고정되도록 함 */
	position: fixed;
	top: 0px;
	left: 0px;
}
header h1 {
	font: bold 50px/1 "orbitron";
	color: #fff;
	letter-spacing: 1px;
	position: absolute;
	left: 50px;
	top: 50%;
	transform: translateY(-150%);
}
header h1::before {
	/* 로고 아래 설명 글 */
	content: "UI/UX DEVELOPMENT";
	display: block;
	font: 14px/1 "orbitron";
	color: #fff;
	letter-spacing: 2px;
	position: absolute;
	left: 0px;
	top: 140px;
	opacity: 0.8;
}
header h1::after {
	/* 로고 아래 가로 막대 */
	content: "";
	display: block;
	width: 150px;
	height: 2px;
	background: #fff;
	margin-top: 20px;
}

header ul {
	position: absolute;
	left: 40px;
	bottom: 100px;
}
header ul li {
	float: left; /* li 요소는 좌우 배치 */
	margin-right: 10px;
}
header ul li a {
	font-size: 20px;
	color: #fff;
}
header ul li a span {
	display: inline-block;
	font-weight: bold;
	opacity: 0.7;
	transform: scale(0.7) translateX(-10px);
}

main {
	/* main 영역에 너비값을 적용하지 않은 상태에서
	    margin-left로 여백을 설정하면 브라우저가 나머지 너비값으로 자동 계산해줌 */
	margin-left: 400px;
	box-sizing: border-box;
	padding: 20px;
}
main section {
	width: 100%;
}
main section::after {
	content: "";
	display: block;
	clear: both;
}
main section article {
	width: 20%; /* main 영역에서 article이 가로로 5개가 배치되도록 함 */
	float: left;
	box-sizing: border-box;
	padding: 12px;
}
main section article div {
	width: 100%;
	height: 100%;
	background: #fff;
	border-radius: 4px;
	box-shadow: 5px 5px 10px rgba(0, 0, 0, 0.1);
	box-sizing: border-box;
	padding: 14px;
}
main section article div img {
	width: 100%;
}
main section article div h2 {
	margin-top: 15px;
	font: bold 11px/1 "orbitron";
	letter-spacing: 1px;
	color: #444;
	margin-bottom: 5px;
}
main section article div p {
	font: 10px/1.2 "arial";
	color: #777;
	margin-bottom: 15px;
}

main ul {
	width: 100%;
	margin-bottom: 10px;
	margin-right: 20px;
}
main ul::after {
	content: "";
	display: block;
	clear: both;
}
main ul li {
	float: right;
	margin-right: 20px;
	width: 100px;
	height: 26px;
}
main ul li a {
	display: block;
	width: 100%;
	height: 100%;
	font: bold 7px/26px "orbitron";
	color: #aaa;
	letter-spacing: 1px;
	text-align: center;
	border-radius: 5px;
	box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.05);
	background: #fff;
}
main ul li.on a {
	background: linear-gradient(45deg, #67faf3, #58abf8);
	box-shadow: 0px 5px 20px rgba(0, 255, 255, 0.527);
	color: #fff;
}

@media screen and (max-width: 1599px) {
	header {
		width: 350px;
	}
	main {
		margin-left: 350px;
	}
	main section article {
		width: 25%;
	}
}

@media screen and (max-width: 1199px) {
	header {
		width: 100%;
		height: 80px;
		position: relative;
	}
	header h1 {
		font: bold 24px/1 "orbitron";
		transform: translateY(-50%);
	}
	header h1::before,
	#header h1::after {
		display: none;
	}
	header ul {
		left: 83%;
		bottom: 25px;
	}
	header ul li {
		margin-right: 20px;
	}
	header ul li a {
		font-size: 20px;
	}
	header ul li a span {
		display: none;
	}
	main {
		width: 100%;
		margin-left: 0px;
	}
	main section article {
		width: 25%;
	}
}

@media screen and (max-width: 899px) {
	header ul {
		left: 80%;
	}
	main section article {
		width: 33.333%;
	}
}

@media screen and (max-width: 679px) {
	header ul {
		left: 70%;
	}
	main section article {
		width: 50%;
	}
}

@media screen and (max-width: 539px) {
	header ul {
		display: none;
	}
	main ul {
		margin-right: 0px;
		box-sizing: border-box;
		padding: 0px 13px;
	}
	main ul li {
		margin-right: 2%;
		width: 32%;
	}
	main ul li:nth-of-type(1) {
		margin-right: 0%;
	}
	main section article {
		width: 100%;
	}
}