style1.css

* {
	box-sizing: border-box;
	font-family: fantasy, sans-serif;
	padding: 0;
	margin: 0;
}

.wrapper {
	margin: 0 auto;
	width: 100%;
}

.nav-link {
	color: black;
	text-decoration: none;
}

.main-menu {
	list-style: none;
}
.main-menu__item {
	background: #30f2c5;
	display: block;
	outline: none;
	text-decoration: none;
}
.main-menu__item:link,
.main-menu__item:visited {
	color:black;
}
.main-menu__item:hover {
	color: blueviolet;
	text-decoration: underline;
}
.main-menu__item:active {
	text-shadow: 0 0 3px black;
}

.portfolio-container {
	font-size: 0;
	list-style: none;
}

.portfolio__item {
	display: block;
	float: left;
	height: auto;
	margin: 0.5% 0.5%;
	width: 20%;
}

.portfolio-container::after {
	content: "";
	display: table;
	clear: both;
}

@media screen and (max-width: 988px) {
	.portfolio__item{
		margin: 0.3% 0.6%;
		width: 32%;
	}
}

@media screen and (max-width: 400px) {
	
	.wrapper {
		width: 90%;
	}
	
	.logo {
		text-align: center;
	}
	
	.main-menu__item {
		margin: 0 auto;
		text-align: center;
	}
	
	.portfolio__item {
		float: none;
		margin: 10px auto;
		width: 100%;
	}
	
	footer {
		text-align: center;
	}
}