:root {

    --light: #FFFFFF;
    --dark: #020024;

    --primary-text-color: #020024;
    --page-background-color: #f2f5f8;

    --primary-text-accent-1: #353350;
    --primary-text-accent-2: #7D7D8F;
    --primary-text-accent-3: #ACACB7;
    --primary-text-accent-4: #BDBDC5;
    --primary-text-accent-5: #CACAD1;
    --primary-text-accent-6: #D5D5DA;
    --primary-text-accent-7: #DDDDE1;

    --footer-text: #F3FAFE;
    --footer-text-accent-1: #F9FDFE;

    --gradient-end: #ACACB7;
    --gradient-middle: #7D7D8F;
    --gradient-start: #353350;

    --button-transition-slow: background-color 0.3s ease;
    --button-transition-slower: background-color 0.5 ease;

/* ------------- Box Colors ---------------*/

    --box-color-green: #035008;
    --box-color-purple: #4B0082;
    --box-color-gray: #2C2C2D;

}

*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    font-family: 'Montserrat', 'Open Sans', Tahoma, Verdana, Arial sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--page-background-color);
    color: var(--primary-text-color);
    line-height: 1.6;
}


/* ------------------------------ Typography ---------------------------------------- */
h1,
h2,
h3,
h4,
h5,
h6 {
    margin: 0;
    padding: .25em 0;
}

h1 {
    font-size: 2.2rem;
}

h2 {
    font-size: 2.0rem;
}

h3 {
    font-size: 1.8rem;
}

h4 {
    font-size: 1.6rem;
}

h5 {
    font-size: 1.4rem;
}

h6 {
    font-size: 1.2rem;
}

img {
    max-width: 100%;
}

p {
    margin: 1em 0;
    font-size: 1.1rem;
    line-height: 1.4;
    font-weight: 300;
}

.p-spacer {
    margin: .5em 0;
}

/* ------------------------------ Section Style ------------------------------------- */

.container {
    width: 95%;
    max-width: 1100px;
    margin: 0 auto;
}

main {
    margin: 2em 0;
}

/* ------------------------------ Navigation Style ---------------------------------- */

.main_nav {
    margin: -1em 0 0 0;
    padding: 1em 0;
}

.main_nav_menu {
    display: flex;
    flex-direction: column;
    justify-content: center;
    flex-wrap: wrap;
}

.hover-underline-animation {
    display: inline-block;
    position: relative;
    transition: var(--button-transition-slow);
}

.hover-underline-animation:after {
    content: '';
    position: absolute;
    width: 100%;
    transform: scaleX(0);
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: #d5d6db;
    transform-origin: bottom right;
    transition: transform 0.25s ease-out;
}

.hover-underline-animation:hover:after {
    transform: scaleX(1);
    transform-origin: bottom left;
}

/* ------------------------------ Link Style ---------------------------------------- */

.back-link {
    padding: 2em 0;
    font-size: 1rem;
}

.back-link:hover {
    font-weight: 600;
    transition: var(--button-transition-slow);
}

.link-page-link {
    margin: 1em .75em;
    padding: .5em;
}

/* ------------------------------ Header Style -------------------------------------- */

header {
    padding: 1em 0 8em 0;
    /* https://hdwallsbox.com/aircraft-p-51-p51-mustang-wallpaper-128022/ */
    background-image: url(../images/aircraft-p-51-p51-mustang-1920x1080-73479.jpg);
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center center;
    opacity: .85;
}

.headerTitle {
    text-align: center;
    font-size: 2rem;
    padding: 1em 0 0 0;
    color: var(--primary-text-accent-7);
    text-shadow: 3px 3px 3px var(--primary-text-color);
}

.disclaimer {
    font-size: 1.4rem;
    text-align: center;
    margin: 30px 0;
}

.main_link {
    text-align: center;
    margin: 0 .5em;
    padding: .5em 1em;
    color: #ffffff;
    text-shadow: 2px 2px 2px #000000;
}

/* ------------------------------ Footer Style -------------------------------------- */

footer {
    margin-top: 3em;
    text-align: center;
    padding: 3em 0;
    background: var(--dark);
    background: linear-gradient(0deg, rgba(44, 44, 45, 1) 0%, rgba(77, 77, 79, 1) 35%, rgba(166, 171, 172, 1) 100%);
    color: var(--footer-text);
}

.footerBox {
    display: flex;
    flex-direction: column;
    flex-wrap: wrap;
}

.footerLeft {
    margin: 0 auto;
    padding: 0 1em;
}

.footerCenter {
    margin: 0 auto;
    padding: 0 1em;
}

.footerRight {
    margin: 0 auto;
    padding: 0 1em;
}

.copyright {
    padding: 3em 0;
    font-size: 0.9rem;
}

.logo {
    width: auto;
    height: 4.5em;
    margin: .8em 0;
}

/* ------------------------------ Login Style --------------------------------------- */

.loginForm {
    text-align: center;
    padding: 20px 40px;
}

.loginRequired {
    text-align: center;
    margin: 20px auto;
    padding: 20px;
}

.loginButton {
    background-color: var(--dark);
    color: var(--light);
    margin: 10px;
    padding: 10px 15px;
    cursor: pointer;
    border-radius: 4px;
    font-size: 0.9rem;
}

.loginButton:hover {
    color: var(--dark);
    background-color: var(--light);
    font-weight: 700;
    transition: var(--button-transition-slower);
    border: solid 1px var(--dark);
}
/* ------------------------------ Button Style -------------------------------------- */

.projectButton, .wp_projectButton, .classworkButton, .bookButton {
    margin: 10px;
    padding: 10px 15px;
    cursor: pointer;
    border-radius: 4px;
    font-size: 0.8rem;
}

.projectButton {
    background-color: var(--light);
    color: var(--dark);
}

.wp_projectButton {
    background-color: var(--light);
    color: var(--dark);
}

.classworkButton {
    background-color: var(--light);
    color: var(--dark);
}

.projectButton:hover, .wp_projectButton:hover, .classworkButton:hover {
    color: var(--light);
    box-shadow: rgba(0, 0, 0, 0.3) 0px 19px 38px, rgba(0, 0, 0, 0.22) 0px 15px 12px;
    font-weight: 700;
    transition: var(--button-transition-slow);
}

.projectButton:hover {
    background-color: var(--box-color-green);
}

.wp_projectButton:hover {
    background-color: var(--box-color-purple);
}

.classworkButton:hover {
    background-color: var(--box-color-gray);
    opacity: 0.9;
}

.bookButton {
    font-size: 1.4rem;
    background: rgb(2,0,36);
    background: linear-gradient(90deg, rgba(2,0,36,0.7) 0%, rgba(2,0,36,0.6) 35%, rgba(2,0,36,0.5) 100%);
}

.bookButton:hover {
    background-color: rgba(2,0,36,0.45);
    text-transform: capitalize;
    font-weight: 100;
    transition: var(--button-transition-slower);
}

/* ------------------------------ Box Style ----------------------------------------- */

.projectBox, .wp_projectBox, .classworkBox, .bookBox {
    margin: 0;
    padding: .75em;
    color: var(--light);
    box-shadow: rgba(0, 0, 0, 0.3) 0px 19px 38px, rgba(0, 0, 0, 0.22) 0px 15px 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
}

.projectBox {
    background: var(--box-color-green);
    background: linear-gradient(90deg, rgba(3, 80, 8, 1) 0%, rgba(3, 80, 8, .9) 65%, rgba(3, 80, 8, .8) 100%);
}

.wp_projectBox {
    background: var(--box-color-purple);
    background: linear-gradient(90deg, rgba(75, 0, 130, 1.0) 0%, rgba(102, 45, 145, 1) 14%, rgba(102, 45, 145, .8) 100%);
}

.classworkBox {
    background-color: var(--box-color-gray);
    opacity: 0.9;
}

.bookBox {
    background: rgb(2,0,36);
    background: linear-gradient(90deg, rgba(2,0,36,0.7) 0%, rgba(2,0,36,0.6) 35%, rgba(2,0,36,0.5) 100%); 
}

/* ------------------------------ Book Style ---------------------------------------- */

.book_select_options {
    display: grid;
    grid-template-columns: 1fr;
    grid-gap: 2em;
    justify-content: center;
    margin: 1em 0;
}

.book_options_display {
    margin: 1em 0;
}

.book-number-list {
    list-style: decimal;
    margin: 0 1em;
    padding: 0 1em;
}

.book-link-description {
    font-size: 1rem;
}

.link-hover:hover {
    font-weight: 600;
}

.book_link {
    display: block;
    margin: 0 auto;
    padding: .75em 1.8em;
    cursor: pointer;
    border-radius: 4px;
    font-size: 1rem;
    text-align: center;
    background-color: var(--dark);
    color: var(--light);
    max-width: 250px;
}

.book_link:hover {
    font-weight: 500;
    color: var(--primary-text-accent-1);
    background-color: #ffffff;
    box-shadow: rgba(0, 0, 0, 0.3) 0px 9px 18px, rgba(0, 0, 0, 0.22) 0px 7px 6px;
    transition: var(--button-transition-slower);
}

/*  Book page styles */
.book_grid {
    display: grid;
    grid-template-columns: auto;
    grid-column-gap: 20px;
    grid-row-gap: 20px;
}

.book_grid_item {
    margin: 1em 0;
    padding: 10px;
    border-radius: 10px;
    color: var(--primary-text-color);
}

.book_grid_item {
    box-shadow: rgba(149, 157, 165, 0.2) 0px 8px 24px;
}

.books{
    margin: 0 auto;
}

.books_top10 {
    margin: 0;
    padding: 0 0 10px 10px;
    box-shadow: rgba(149, 157, 165, 0.2) 0px 8px 24px;
}

.books_goodreads {
    margin: 0;
    padding: 0 0 10px 10px;
    box-shadow: rgba(149, 157, 165, 0.2) 0px 8px 24px;
}

.book_title {
    font-size: 1.35rem;
    font-weight: 400;
}

.book_subtitle {
    font-size: 1.15rem;
}

.book_author {
    font-style: italic;
    font-weight: 300;
}

.featured_book_title {
    font-size: 1.85rem;
    padding-right: 5px;
}

.featured_book_subtitle {
    font-size: 1.55rem;
    padding-right: 5px;
}

.book_description {
    margin: .75em 0;
    font-weight: 300;
}

.book_list {
    list-style-type: decimal;
    margin: 0 30px;
    padding: 0 0 0 10px;
}

/* ------------------------------ List Style ---------------------------------------- */

.list_link {
    display: block;
    margin: 0.25em 2em;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 4px;
    font-size: 1.35rem;
    text-align: center;
    color: var(--dark);
}

.link-page-link:hover {
    color: var(--dark);
    font-weight: 700;
    transition: var(--button-transition-slow);
}

/* ------------------------------ Form Style ---------------------------------------- */

.form_container {
    margin: 2em auto;
    padding: 1em;
    max-width: 400px;
    color: var(--primary-text-color);
    border-radius: 4px;
    box-shadow: rgba(0, 0, 0, 0.3) 0px 19px 38px, rgba(0, 0, 0, 0.22) 0px 15px 12px;
}

.form_item_container {
    padding: .75em;
}

input[type=text] {
    margin: .25em 0;
    padding: .75em 1.75em;
    border: 1px solid black;
    border-radius: 4px;
    width: 100%;
}

input[type=password] {
    margin: .25em 0;
    padding: .75em 1.75em;
    border: 1px solid black;
    border-radius: 4px;
    width: 100%;
}

input[type=text]:hover {
    background-color: var(--primary-text-accent-7);
    font-weight: 400;
    transition: var(--button-transition-slow);
}

input[type=password]:hover {
    background-color: var(--primary-text-accent-7);
    font-weight: 400;
    transition: var(--button-transition-slow);
}

input[type=submit] {
    margin: .25em 0;
    padding: .75em 1.75em;
    border: 1px solid black;
    border-radius: 4px;
    box-shadow: rgba(0, 0, 0, 0.07) 0px 1px 2px, rgba(0, 0, 0, 0.07) 0px 2px 4px, rgba(0, 0, 0, 0.07) 0px 4px 8px, rgba(0, 0, 0, 0.07) 0px 8px 16px, rgba(0, 0, 0, 0.07) 0px 16px 32px, rgba(0, 0, 0, 0.07) 0px 32px 64px;
    font-weight: 400;
}

input[type=submit]:hover {
    font-weight: 700;
    transition: var(--button-transition-slow);
}

.form-label {
    font-weight: 500;
}

.form_input {
    font-weight: 100;
    font-style: italic;
}

/* ------------------------------ Grid Styles  -------------------------------------- */

.grid-main-aside-col {
    display: grid;
    grid-template-columns: 1fr;
    column-gap: .75em;
}

/*  2 col grid for main page */

.main-2-col {
    display: grid;
    grid-column-gap: 10px;
    grid-row-gap: 50px;
}

.main_grid_item {
    justify-content: center;
    align-content: center;
}

.link-page-grid {
    display: grid;
    /*   grid-template-columns: repeat(auto-fit, minmax(min(27rem, 100%), 1fr));
    grid-template-columns: repeat(auto-fit, minmax(275px, 1fr));   */
    grid-template-columns: repeat(auto-fit, minmax(min(20rem, 100%), 1fr));
    gap: 2em;
}

/* ------------------------------ Image Style --------------------------------------- */

.mainImage {
    border-radius: 20px;
    box-shadow: rgba(0, 0, 0, 0.56) 0px 22px 70px 4px;
}

/* ------------------------------ Pagination Styles  -------------------------------- */

.pagination-page-numbers {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(35px, 45px));
    justify-content: left;
    align-items: center;
}

.pagination-flex {
    display: flex;
    flex-direction: row;
    justify-content: flex-start;
    align-items: center;
    padding-left: 2em;
}

.pagination-title {
    font-size: 1rem;
    font-weight: 700;
    margin-top: 1em;
}

.pagination-link {
    font-size: .95rem;
    margin: 1em 0;
    padding: .5em .75em;
    text-align: center;
}

p.pagination-link > a:hover {
    font-weight: 700;
    text-decoration: underline;
    transition: var(--button-transition-slow);
}

.selected {
    font-weight: 600;
    background-color: var(--primary-text-accent-7);
    color: var(--primary-text-accent-1);
    border-radius: 4px;
}

@media (min-width: 800px) {

    .main_nav {
        background: rgb(0, 0, 0);
        background: linear-gradient(180deg, rgba(0, 0, 0, 0.1) 0%, rgba(147, 147, 149, 0.1) 35%, rgba(230, 230, 233, 0.1) 100%);
    }

    .main_nav_menu {
        flex-direction: row;
        justify-content: flex-end;
    }

    .headerTitle {
        text-align: right;
        font-size: 4rem;
    }

    .grid-3-col {
        display: grid;
        grid-template-columns: repeat(3, 1fr);
        grid-column-gap: 100px;
        grid-row-gap: 50px;
        padding: 10px;
    }

    .book-select-options {
        display: flex;
        flex-direction: column;
        font-size: 1.1rem;
    }

    .grid-main-aside-col {
        display: grid;
        grid-template-columns: 1fr;
        column-gap: .75em;
    }

    .footerBox {
        flex-direction: row;
    }

    .footerLeft {
        max-width: 30%;
    }

    .footerCenter {
        max-width: 30%;
    }

    .footerRight {
        max-width: 30%;
    }

    .book_grid {
        grid-template-columns: repeat(4, 1fr);
    }

    .main-2-col {
        grid-template-columns: repeat(2, 1fr);
        padding: 0 200px;
    }

    .mainImage {
        margin: 0;
    }

    .list-grid {
        margin: 2em 0;
        gap: 1em;
    }

    .grid-main-aside-col {
        grid-template-columns: 8fr 2fr;
        column-gap: 2em;
    }

}