body {
    font-family: Helvetica, Arial, sans-serif;
    padding: 0;
    margin: 0;
}

html {
    background:
    radial-gradient(circle at 25% 25%, rgba(109, 213, 237, 0.8) 0%, rgba(109, 213, 237, 0) 50%),
    radial-gradient(circle at 75% 80%, rgba(33, 147, 176, 0.8) 0%, rgba(33, 147, 176, 0) 60%),
    radial-gradient(circle at 80% 30%, rgba(0, 242, 254, 0.7) 0%, rgba(0, 242, 254, 0) 45%),
    radial-gradient(circle at 30% 75%, rgba(92, 219, 149, 0.6) 0%, rgba(92, 219, 149, 0) 50%),
    #051937;
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center top;
    height: 100%;
}

nav {
    margin-top: 50px;
    margin-left: 50px;
    float: left;
    width: 15%;
    line-height: 30px;
    position: fixed;
}

nav a {
    text-decoration: none;
    color: rgb(198, 242, 247);
    font-weight: bold;
    display: block;
}

nav a:hover {
    color: rgb(102, 179, 255)
}

#wrapper {
    margin-top: 50px;
    float: right;
    width: 60%;
    margin-right: 50px;
}

h1,
h2,
h3,
p,
figcaption,
footer {
    color: rgb(228, 219, 201);
}
img{
    border-radius: 8px;
}
header img {
    width: 100%;
    height: 100%;
}

header h1 {
    text-align: right;
    font-size: 25px;
    margin-bottom: 5px;
}

header h2 {
    margin-top: 0px;
    margin-bottom: 30px;
    text-align: right;
    font-size: 20px;
}

header h3 {
    margin-top: 0px;
    margin-bottom: 10px;
    text-align: left;
    font-size: 20px;
}

section {
    margin-bottom: 30px;
    text-align: justify;
}

article h3 {
    margin-bottom: 10px;
}

/* Version 1 */
/* .books {
    display: grid;
    grid-template-columns: auto auto auto;
    max-width: 100%;
    height: auto;
    gap: 16px;
} */

/* Version 2 */
/* .books {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    max-width: 100%;
    gap: 16px;
} */

/* Version 3 */
.books {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 20px;
}

.books img {
    display: block;
    width: 100%;
    height: auto;
}

.books figure {
    margin: 0;
}

article figure figcaption {
    margin-top: 5px;
    font-size: 12px;
}

footer {
    margin-top: 20px;
    min-height: 30px;
    font-weight: lighter;
    text-align: right;
}

/* TABLET Up to 900px */

@media (max-width: 900px) {
    #wrapper {
        width: 70%;
        margin-right: 30px;
    }

    nav {
        margin-left: 30px;
        width: 20%;
    }

    .books {
        grid-template-columns: repeat(2, 1 fr);
    }
}

/* MOBILE Up to 600px */

@media (max-width: 600px) {

    /* nav becomes a normal horizontal mobile bar */
    nav {
        width: 100%;
        box-sizing: border-box;
        margin: 0 0 40px 0;
        padding: 10px 5px;
        position: fixed;
        float: none;
        display: flex;
        justify-content: space-around;
        align-items: center;
        flex-wrap: wrap;
        line-height: 30px;

        background: rgba(255, 255, 255, 0.15);
        backdrop-filter: blur(16px) saturate(180%);
        -webkit-backdrop-filter: blur(16px) saturate(180%);
        border-radius: 12px;
        box-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.15),
        inset 0 1px 1px 0 rgba(255, 255, 255, 0.3);
        border-bottom: 4px solid black;

        z-index: 1000;
    }

    nav a {
        color: white;
    }

    /* Devices that actually support hover */
    @media (hover: hover) {
        nav a:hover {
            color: rgb(107, 153, 254);
        }
    }

    /* touch Interaction */

    nav a:active {
        background: rgb(102, 176, 249);
    }

    /* Main Content */

    #wrapper {
        width: 92%;
        margin: 0 auto;
        float: none;
    }

    /* Headings */

    header h1 {
        text-align: right;
        font-size: 23px;
        margin-top: 40px;
    }

    header h2 {
        text-align: right;
        font-size: 18px;
    }

    header h3 {
        font-size: 18px;
    }

    /* Booooooooks */
    .books {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }

    /* Fooooooooooooooooooooooooter */
    footer {
        margin-top: 40px;
        font-size: 12px;
    }

    /* Very Small Phones - Up to 400px */
    @media (max-width: 400px) {
        #wrapper {
            width: 94%
        }

        .books {
            gap: 12px
        }

        article figure figcaption {
            font-size: 11px;
        }
    }
}