* {
    padding: 0;
    margin: 0;
    font-family: sans-serif;
    list-style: none;
    text-decoration: none;
}

body {
    background-color: whitesmoke;
}

/* HEADER */

header {
    position: relative;
    width: auto;
    height: 100px;
    background-color: cadetblue;
    display: flex;
    flex-direction: row;
    justify-content: space-around;
}

    /* HEADER. logo */

.main_logo {
    position: absolute;
    border-top: 4px solid white;
    border-bottom: 4px solid white;
    left: 130px;
    top: 20px;
    color: white;
    font-family: sans-serif; 
    font-size: larger;
    font-weight: 500;
    text-align: center;
    border-radius: 4px;
    padding-bottom: 5px;
    transition: .3s;
}

.main_logo:hover {
    transform: scale(1.1);
}

.main_logo p {
    background-color: white;
    color: cadetblue;
    padding: -1px;
}

.main_logo a {
    text-decoration: none;
    color: white;
}

    /* HEADER. menu*/

header ul {
    display: flex;
    flex-direction: row;
    gap: 50px;
    align-items: center;
}

.menu li {
    position: relative;
    color: white;
    text-align: center;
}

.menu a {
    transition: all .5s;
    color: gray;
    font-weight: 600;
    display: block;
    padding-top: 10px;
    padding-bottom: 10px;
}

.menu a:hover {
    background-color: cadetblue;
    transition: .5s;
    color: aqua;
}

.menu ul {
    position: absolute;
    display: none;
    border-radius: 7px;
}

.menu li:hover ul {
    display: block;
    width: 200px;
    background-color: aquamarine;
    box-shadow: 1px 2px 2px 1px gray;
}

/* MAIN */

.parent {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    grid-template-rows: repeat(2, 1fr);
    grid-column-gap: 0px;
    grid-row-gap: 0px;

    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 50px;
    align-items: center;
    margin-top: 100px;
}

.parent span {
    
    display: flex;
    justify-content: center;

}

.row1 {
    display: flex;
    gap: 50px;
}

.row2 {
    display: flex;
    gap: 50px;
}

    /* MAIN. html*/

.div1 { 
    grid-area: 1 / 1 / 2 / 2; 
    
    border: 1px solid gray;
    border-radius: 5px;
    width: 500px;
    height: 380px;
    text-align: center;
    
}

.div1:hover {
    box-shadow: 3px 3px 4px 4px grey;
}

.div1 h1 {
    padding-top: 20px;
    padding-bottom: 20px;
}

.div1 ul {
    display: flex;
    flex-direction: column;
    align-content: center;
}

.a {
    color: cadetblue;
    font-size: 25px;
    width: 500px;
    display: block;
    height: 50px;
    display: flex;
    justify-content: center;
    align-items: center;
}

.div1 a:hover {
    background-color: aqua;
    transition: 1.2s;
}

    /* MAIN. css */

.div2 { 
    grid-area: 1 / 2 / 2 / 3;

    border: 1px solid gray;
    border-radius: 5px;
    width: 500px;
    height: 330px;
}

.div2:hover {
    box-shadow: 3px 3px 4px 4px grey;
}

.div2 h1 {
    text-align: center;
    padding-top: 20px;
    padding-bottom: 20px;
}

.div2 ul {
    display: flex;
    flex-direction: column;
    align-content: center;

}

.div2 li {
    list-style: none;
}

.div2 a {
    display: block;
    height: 50px;
    color: cadetblue;
    font-size: 23px;
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
}

.div2 a:hover {
    background-color: aqua;
    transition: 1.2s;
}

    /* MAIN. manuals*/

.div3 { 
    grid-area: 2 / 1 / 3 / 2; 

    border: 1px solid gray;
    border-radius: 5px;
    width: 500px;
    height: 380px;
    
}

.div3:hover {
    box-shadow: 3px 3px 4px 4px grey;
}

.div3 h1 {
    text-align: center;
    padding-top: 20px;
    padding-bottom: 20px;
}

.div3 a {
    display: block;
    height: 50px;
    color: cadetblue;
    font-size: 23px;
    text-align: center;
    display: flex;
    justify-content: center;
    align-items: center;
}

.div3 a:hover {
    background-color: aqua;
    transition: 1.2s;
}
 
    /* MAIN. info*/

.div4 { 
    grid-area: 2 / 2 / 3 / 3; 

    border: 1px solid gray;
    border-radius: 5px;
    width: 500px;
    height: 280px;
    
}

.div4:hover {
    box-shadow: 3px 3px 4px 4px grey;
}

.div4 h1 {
    text-align: center;
    padding-top: 20px;
    padding-bottom: 20px;
}

.div4 li {
    list-style: none;
    
}

.div4 a {
    color: cadetblue;
    display: block;
    font-size: 25px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.div4 a:hover {
    background-color: aqua;
    transition: 1.2s;
}

/* MAIN. html list */

.html_list {
    position: absolute;
    display: flex;
    flex-direction: column;
    width: 200px;
    height: 900px;
    overflow-y: scroll;
    left: 100px;
    text-align: center;
}

.html_list h1 {
    color: cadetblue; 
}

.html_list a {
    color: cadetblue;
    display: block;
    font-weight: bold;
    height: 40px;
    padding-top: 5px;
    padding-bottom: 5px;
}

.html_list a:hover {
    background-color: aqua;
    color: grey;
}

/* CSS LIST */

.css_list_box {
    display: flex;
    justify-content: flex-end;
    margin-top: -820px;
}

.css_list {
    position: absolute;
    float: left;
    display: flex;
    flex-direction: column;
    width: 200px;
    height: 900px;
    overflow-y: scroll;
    text-align: center;
    right: 100px;
}

.css_list a {
    color: cadetblue;
    display: block;
    font-weight: bold;
    height: 40px;
    padding-top: 5px;
    padding-bottom: 5px;
}

.css_list a:hover {
    background-color: aqua;
    color: grey;
}

/* FOOTER */

footer {
    background-color: cadetblue;
    height: 300px;
    margin-top: 1000px;
}

footer ol {
    list-style: none;
    display: flex;
    flex-direction: row;
    justify-content: space-around;
    padding-top: 15px;
}

footer ul {
    display: flex;
    flex-direction: column;
    gap: 10px;
    list-style: none;
}

footer a {
    color: white;
    font-weight: 600;
}

footer a:hover {
    color: aqua;
}