style.css

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    scroll-behavior: smooth
}
body {
    background-color: #333;
    font-family:Arial, Helvetica, sans-serif;
    color: white;
    text-align: center;
    width: 100vw;
    overflow-x: hidden;
}
#showcase {
    width: 100vw;
    height: 50vh;
    overflow: hidden;
}
#showcase .bg-img {
    background: #333 url('https://images.pexels.com/photos/270348/pexels-photo-270348.jpeg?auto=compress&cs=tinysrgb&h=650&w=940');
    background-position: center;
    background-size: cover;
    background-repeat: no-repeat;
    width: 100%;
    height: 50vh;
    position: absolute;
    z-index: -1;
    opacity: 0.4;
}
#showcase .content-wrap {
    height: 50vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 0 3em;
}
.content-wrap h1 {
    padding: 0.5em 0;

}
.content-wrap .btn {
    margin: 1em 0;
    text-decoration: none;
    color: white;
    border: 0.025em solid white;
    padding: 0.5em 1em;
    cursor: pointer;
}
.btn:hover {
    background-color: #fff;
    color: #333;
}
#section-a {
    background-color: #fff;
    color: #333;
    padding: 2em;
}
h2, h3 {
    padding-bottom: 1em;
}
#section-b {
    padding: 2em;
}
#section-b img {
    display: block;
    width: 100%;
    height: auto;
}
#section-b ul {
    list-style-type: none;
}
#section-b .content-wrap {
    padding: 2em;
}
#section-b li {
    background-color: #fff;
    color: #333;
    margin-bottom: 1em;
}
#section-b li:nth-child(3) {
    margin-bottom: 0;
}
#section-c {
    padding: 2em;
    background: #fff;
    color: #333;
}
#section-d .box {
    padding: 2em;
}
#section-d .box:first-child {
    background: #2690d4;
}
footer {
    padding: 2em;
    background: #000;
    color: #fff;
    text-align: center;
}
footer a {
    text-decoration: none;
    color: #2690d4;
}

@media (min-width: 700px) {
    .grid {
        display: grid;
        grid-template-columns: 1fr repeat(2, minmax(auto, 25em)) 1fr;
    }
    #section-a .content-text {
        columns: 2;
    }
    .content-wrap, #section-b ul {
        grid-column: 2/4;
    }
    .box, #footer-section div {
        grid-column: span 2;
    }
    #section-b ul {
        display: flex;
        gap: 1em;
    }
    #section-b li {
        margin-bottom: 0;
    }
}