main.css

        * {
            box-sizing: border-box;
            margin: 0;
            padding: 0;
        }

        body>header {
            background-color: #2f3640;
            padding: 16px 0;
            color: #f5f6fa
        }

        header .container {
            display: flex;
            align-items: center;
            justify-content: space-between
        }

        header li {
            display: inline;
            font-family: Arial, Helvetica, sans-serif;
            font-weight: bold;
            margin-left: 16px;
        }

        header li a {
            color: #f5f6fa;
            text-decoration: none;
        }

        .container {
            width: 1366px;
            margin: 0 auto;
        }

        .articles {
            display: flex;
            flex-wrap: wrap;
            justify-content: space-between;
        }

        .articles article img {
            height: 180px;
            width: 100%;
        }

        .articles article {
            width: 30%;
        }

        section {
            padding: 16px 0;
        }

        section h2,
        .articles article {
            margin-bottom: 16px;
        }

        .articles article h3 {
            margin-top: 8px;
            margin-bottom: 8px;
        }

        .articles article a {
            background-color: blue;
            color: white;
            padding: 8px;
            display: inline-block;
            text-decoration: none;
            font-weight: bold;
            margin-top: 8px;
        }

        .articles article a:hover {
            text-decoration: underline;
        }

        .articles article p,
        .articles article a {
            font-family: Arial, Helvetica, sans-serif;
        }

        .articles article h3 {
            font-size: 24px;
        }

        section h2 {
            font: size 32px;
        }

        #sports {
            background-color: rgba(0, 255, 0, 0.1)
        }

        #sports .articles article a {
            background-color: #009432;
        }

        #economy {
            background-color: #f8f59f;
        }

        #technology .articles article a {
            background-color: #6541b9;
        }

        #technology {
            background-color: hsl(259, 56%, 74%);
        }

        #technology .articles article a {
            background-color: #641a3f;
        }

        #entertainment .articles article a {
            background-color: #dd90e6;
        }

        #entertainment {
            background-color: hsl(184, 45%, 86%);
        }

        #entertainment .articles article a {
            background-color: #ecbdd5;
        }