body {
    background-color: #112;
    color: white;
}
header, body > footer {
    background-color: #001;
}
h2 {
    color: #ccb;
}
#main-contents {
    width: 100%;
    max-width: none;
}
section {
    background-color: #16162b;
    padding: 15px;
    border-radius: 6px;
}
.grid-container {
    display: grid;
    gap: 20px;
}
.content {
    display: block;
}
#img2 {
    display: none;
}

@media screen and (min-width: 300px) {
    body {
        font-size: 14px;
    }
}

@media screen and (min-width: 500px) {
    .grid-container {
        grid-template-columns: 1fr;
    }
    .content {
        display: flex;
        flex-direction: column;
        align-items: center;
    }
    #img1 {
        float: left;
        margin-right: 15px;
    }
    #img2 {
        display: block;
    }
}

@media screen and (min-width: 768px) {
    body {
        font-size: 16px;
    }
    .grid-container {
        grid-template-columns: 1fr;
    }
    .content h2 {
        text-align: center;
    }
    .content p {
        margin-top: 0;
    }
}

@media screen and (min-width: 992px) {
    body {
        font-size: 18px;
    }
    .grid-container {
        grid-template-columns: repeat(3, 1fr);
    }
    .intro {
        grid-column: span 3;
    }
}