styles.css

:root {
    --titleFont: 'Petit Formal Script', cursive;
    --textFont: 'Roboto', sans-serif;
    --titleColor: rgb(66, 122, 93);
    --subTitleColor:  rgb(190, 137, 25);
    --lightBgColor:rgba(230, 210, 199, 0.9);
    --darkBgColor:rgb(53, 95, 58);
    --hoverColor: rgb(190, 137, 25);
    --textColor: rgba(0, 0, 0, 0.623);
}

* {
    margin: 0;
    padding: 0;
    font-size: 20px;
    font-family: var(--textFont);
    color: var(--textColor);
}

a {
    text-decoration: none;
}

a:hover {
    font-weight: bolder;
    color: var(--hoverColor)
}

h1, h2 {
    font-family: var(--titleFont);
    color: var(--titleColor)
}

h2 {
    font-size: 1.8rem;
    padding: 0.5rem 1rem;
    margin: 2rem auto;
    border-bottom: 1px solid;
}

h3 {
    font-size: 1.1rem;
}

p {
    text-align: justify;
    line-height: 1.35rem;
}

section {
    margin: 0 20%;
}

section:nth-of-type(odd) h2 {
    color: var(--subTitleColor)
}

nav {
    height: 4rem;
}

nav ul {
    width: 60%;
    height: 100%;
    margin: 0 auto;
    list-style-type: none;

    display: flex;
    justify-content: space-between;
    align-items: center;
}

nav ul>li {
    width: 25%;
    height: 50%;
    text-align: center;
    border-right: 1px solid var(--textColor);
    font-weight: normal;
}

nav ul li:last-of-type {
    border-right: none;
}

nav a {
    width: 100%;
    height: 100%;
    font-size: 1.2rem;

    display: flex;
    align-items: center;
    justify-content: center;
}

header {
    position: relative;
    height: calc(100vh - 4rem);
    max-height: 60vw;
    width: 70%;
    margin: 0 auto;
    display: flex;
    justify-content: flex-end;
    align-items: center;
}

header img {
    width: 75%;
    opacity: 0.9;
}

header div {
    position: absolute;
    bottom: 30%;
    left: 0;
    background-color: var(--lightBgColor);
    padding: 1rem 3.5rem;
    z-index: 10;
    text-align: right;
}

header h1 {
    font-size: 5rem;
    text-align: center;
    color: var(--titleColor);
}

header h2 {
    font-family: var(--textFont);
    color: var(--textColor);
    font-size: 2rem;
    font-weight: lighter;
    margin: 1rem 0;
    padding: 0;
    border: none;
}

button, input, textarea {
    border: 1px solid var(--textColor);
    font-size: 0.8rem;
    outline: none;
    background-color: transparent;
    border-radius: 2rem;
    padding: 0.8rem;
}

textarea {
    border-radius: 1.3rem;
}

button, input[type="submit"] {
    transition: background-color 0.5s ease-in-out;
    width: 8.5rem;
    text-transform: uppercase;
    color:#FAFAFA;
    border: 1px solid var(--titleColor);
    font-weight: bold;
    background-color: var(--titleColor);
    opacity: 0.9;
    cursor: pointer;
}

button:hover, input[type="submit"]:hover {
    opacity: 0.75
}

input, textarea, label {
    width: 80%;
    margin: 0.3rem auto;
}

input, textarea {
    box-sizing: border-box;
}

input[type="submit"] {
    width: max-content;
    margin: 1rem auto;
}

label {
    font-weight: bolder;
}

form {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    width: 100%;
}

form > label {
    text-align: left;
}

footer {
    background-color: var(--darkBgColor);
    padding: 3rem 20%;
    display: flex;
    justify-content: space-between;
}

footer p {
    color: #FAFAFA;
}

footer section {
    margin: 0
}

footer section:first-child a {
    font-style: italic;
}

footer section:last-child {
    flex: 1;
    display: flex;
    justify-content: flex-end;
    align-items: center;
}

footer section:last-child i {
    font-size: 2rem;
    padding: 0.5rem 0 0.5rem 1rem;
}

footer section:last-child i:hover {
    color: var(--hoverColor)
}

footer a {
    font-weight: bold;
    color: #FAFAFA;
}

footer a>i {
    color: #FAFAFA;
}

#menu {
    display: none;
}

#about {
    display: flex;
    justify-content: space-between;
}

#about div {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50%;
}

#about img:first-child, #about img:last-child {
    width: 75%;
    opacity: 0.9;
    position: relative;
}

#about img:last-child {
    display: none;
}

#about div::after {
    content: "";
    position: absolute;
    width: 80%;
    height: 90%;
    background-color: var(--darkBgColor);
    left: 1rem;
    z-index: -1;
}

#about article {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    width: 50%;
}

#about h2 {
    width: 100%;
    margin: 0 auto 2rem auto;
    box-sizing: border-box;
}

#about h3 {
    padding: 2rem 0 1rem 1rem;
}

#about p, #about ul {
    padding: 0 1rem;
}

#about ul {
    list-style-position: inside;
    list-style-type: circle;
    display: inline;
}

#about ul>li {
    padding: 0.2rem 0;
}

#technologies div {
    display: flex;
    justify-content: space-between;
    padding: 0 1rem;
}

#technologies div div {
    display: flex;
    flex-direction: column;
    justify-content: center;
    text-align: center;
}

#technologies div div>i {
    font-size: 6rem;
    padding-bottom: 1rem;
}

#technologies div div:hover {
    opacity: 0.8;
}

#technologies div div:hover .fa-html5 {
    color: hsl(12, 78%, 52%);
}

#technologies div div:hover .fa-css3-alt {
    color: hsl(228, 73%, 51%);
}

#technologies div div:hover .fa-js {
    color: hsl(53, 87%, 53%);
}

#technologies div div:hover .fa-react {
    color: hsl(195, 89%, 72%);
}

#technologies div div:hover .fa-sass {
    color: hsl(332, 61%, 59%);
}

#projectsGallery {
    margin: 0;
    display: grid;
    grid-template-columns: 45% calc(10% - 2rem) 45%;
    grid-template-rows: repeat(2, 22rem);
    grid-gap: 1rem;
    grid-auto-flow: dense;
}

#projectsGallery div:nth-of-type(even) {
    grid-column: span 2;
}

#projectsGallery div:nth-of-type(3) {
    grid-area: 2/3/3/4
}

#contact {
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
    margin-top: 2rem;
}

#contact div {
    width: 70%;
    align-self: center;
    background-color: var(--lightBgColor);
    margin: 3rem auto;
    padding: 2rem;
    box-sizing: border-box;
    border-radius: 4rem;
}

#contact div h2 {
    text-align: center;
}

#contactImg {
    position: absolute;
    width: 100%;
    height: 100%;
    opacity: 0.8;
    z-index: -1
}

#project1 {
    background-image: url('./assets/images/nick-morrison-FHnnjk1Yj7Y-unsplash-1200w.jpg');
}

#project2 {
    background-image: url('./assets/images/tran-mau-tri-tam-vGsf7HSWOU8-unsplash-1200w.jpg');
}

.textBox {
    position: relative;
    width: 222%;
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    z-index: 10;
    cursor: pointer;
}

.textBoxRight.textBox {
    text-align: right;
    justify-self: right;
    flex-direction: row-reverse;
}

/*arrow */

.textBox::after {
    content: "";
    position: absolute;
    border-top: 11rem solid transparent;
	border-bottom: 11rem solid transparent;
    border-left: 3.5rem solid var(--lightBgColor);
    bottom: 0;
    left: 45%;
    transition: left 0.5s ease-in-out, opacity .5s ease-in-out;
}

.textBox:hover.textBox::after {
    left: 100%;
    opacity: 0
}

.textBoxRight::after {
    border-right: 3.5rem solid var(--lightBgColor);
    border-left: 0;
    left: calc(55% - 3.5rem)
}

.textBoxRight:hover.textBoxRight::after{
    left: -3.5rem
}

/*box */
.textBox::before {
    content: "";
    position: absolute;
    width: 0;
    height: 100%;
    left: 45%;
    transition: width 0.5s ease-in-out;
    background-color: var(--lightBgColor);
}

.textBox:hover.textBox::before {
    width: 55.2%;
}

.textBoxRight::before {
    left: auto;
    right: 45%; 
}

/* button box */

.textBox:hover > .buttonBox {
    flex: 1;
    animation: changeVisibility 0.6s;
    animation-delay: 0.5s;
    animation-fill-mode: forwards;
}

.buttonBox {
    visibility: hidden;
    display: flex;
    justify-content: space-around;
    flex: 1;
    position: relative;
}

.description {
    padding: 0 2rem;
    display: flex;
    flex-direction: column;
    width: 45%;
    height: 100%;
    justify-content: center;
    box-sizing: border-box;
    background-color: var(--lightBgColor);
}

.projectClipping {
    background-size: cover;
    filter: opacity(0.9);
}

@keyframes changeVisibility {
    0% {
        visibility: visible;
        opacity: 0;
    }
    50% {
        opacity: 0.5;
    }
    100% {
        visibility: visible;
        opacity: 1;
    }
}

@media (max-width: 1500px) {

    * {
        font-size: 18px;
    }
    header {
        width: 80%;
    }
}

@media (max-width: 1100px) {

    section {
        margin: 0 5%;
    }

    header {
        width: 90%;
    }

    header h1 {
        font-size: 4rem;
    }

    header h2 {
        font-size: 1.5rem;
    }

    footer {
        padding: 3rem 5%;
    }

    #project1 {
        background-image: url('./assets/images/nick-morrison-FHnnjk1Yj7Y-unsplash-800w.jpg');
    }
    
    #project2 {
        background-image: url('./assets/images/tran-mau-tri-tam-vGsf7HSWOU8-unsplash-800w.jpg');
    }

    #contact div {
        width: 70%;
    }

    .textBox {
        width: 100%;
        flex-direction: column;
        cursor: pointer;
        padding: 1rem 1.5rem;
        box-sizing: border-box;
        background-color: var(--lightBgColor);
    }   

    .textBoxRight.textBox {
        text-align: right;
        justify-self: right;
        flex-direction: column;
    }
    
    /*arrow */

    .textBox::after {
        left: 100%;
        transition: none;
    }

    .textBox:hover.textBox::after {
        left: 100%;
        opacity: 1
    }

    .textBoxRight::after {
        border-right: 3.5rem solid var(--lightBgColor);
        border-left: 0;
        left: auto;
        right: 100%;
    }

    .textBoxRight:hover.textBoxRight::after{
        left: auto
    }

    /*box */
    .textBox::before {
        height: 0;
        left: 45%;
        transition: none;
        background-color: transparent;
    }

    .textBox:hover.textBox::before {
        width: 0
    }

    .textBoxRight::before {
        left: auto;
        right: 45%; 
    }

    /* button box */

    .textBox:hover > .buttonBox {
        flex: 1;
        animation: changeVisibility 0.6s;
        animation-delay: 0.5s;
        animation-fill-mode: forwards;
    }

    .buttonBox {
        visibility: visible;
        justify-content: space-between;
        align-items: center;
        height: auto;
        width: 100%;
    }

    .description {
        width: 100%;
        height: 70%;
        padding: 0;
        background-color: transparent;
    }

}

@media (max-width: 800px) {

    * {
        font-size: 16px;
    }

    h2 {
        padding-left: 2rem;
    }

   nav {
        display: flex;
        flex-direction: column;
        align-items: flex-end;
        justify-content: center;
        position: relative
    }

    nav ul {
        display: none;
    }

    nav:hover ul{
        display: block;
        position: absolute;
        flex-direction: column;
        justify-content: flex-start;
        top: 100%;
        background-color: #fff;
        z-index: 100;
        height: 100vh;
    } 

    nav:hover #menu i{
        color: var(--hoverColor);
    }
    
    nav ul > li {
        border: none;
        height: max-content;
        width: 100%;
        cursor: pointer;
    }

    nav a {
        height: max-content;
        padding: 1rem 0;
        box-sizing: border-box;
    }

    section {
        margin: 0;
    }
    
    header {
        margin: 0;
        width: 100%;
        max-height: calc(100vh - 4rem);
        height: max-content;
        flex-direction: column;
        justify-content: flex-start;
        align-items: stretch;
    }

    header img {
        margin: 0 0;
        width: 100%;
    }

    header div {
       position: static;
       flex: 1;
       order: 2;
       display: flex;
       flex-direction: column;
       justify-content: center;
       align-items: center;
       padding: 3rem 1rem;
    }

    button {
        width: 8rem;
        max-width: 11rem;
        padding: 0.8rem;
    }

    footer {
        flex-direction: column;
        padding: 1.5rem 2rem;
    }

    footer section:first-child {
        display: flex;
        align-items: center;
        flex-direction: column;
    }

    footer section:last-child {
        order: -1;
        justify-content: center;
        padding: 0.5rem 0;
    }

    #menu {
        display: inline;
        padding: 0 2rem;
    }

    #menu i {
        font-size: 1.5rem;
    }

    #technologies div{
        display: grid;
        grid-template-rows: repeat(2, max-content);
        grid-template-columns: repeat(6, 1fr);
        grid-gap: 1rem;
        padding: 0;
    }

    #technologies div>div {
        grid-column: span 2;
    }

    #technologies div div:nth-child(4) {
        grid-area: 2/2/3/4;
    }

    #technologies div div>i {
        font-size: 5rem;
        padding-bottom: 0;
    }

    #projectsGallery {
        grid-template-columns: 100%;
        grid-template-rows: max-content 20rem max-content 20rem;
        grid-auto-flow: unset;
        grid-gap: 0;
    }

    #projectsGallery div:nth-of-type(even) {
        grid-column: span 1;
    }
    
    #projectsGallery div:nth-of-type(3) {
        grid-area: auto
    }

    #contact {
        margin-top: 0;
    }
    
    #contact div {
        width: 100%;
        background-color: transparent;
        margin: 0 auto 2rem auto;
        padding: 0;
    }

    #contactImg {
        display: none;
    }

    #about {
        flex-direction: column;
    }
    
    #about div {
        margin-top: 2rem;
        width: 100%;
    }

    #about img:first-child {
        display: none;
    }
    
    #about img:last-child {
        display: block;
        width: 80%;
    }
    
    #about div::after {
        width: 100%;
        height: 80%;
        left: 0;
    }
    
    #about article {
        order: -1;
        width: 100%;
    }

    #about article>p, #about article>ul, #about article>h3 {
        padding-right: 2rem;
        padding-left: 2rem;
    }
    
    #about h2 {
        margin-top: 2rem;
    }

    /*arrow */

    .textBox::after {
        border-top: 2rem solid var(--lightBgColor);
        border-left: 8rem solid transparent;
        border-right: 8rem solid transparent;
        top: 100%;
        right: auto;
        left: auto;
        transition: none;
    }

    .textBoxRight::after {
        right: auto;
        left: auto;
    }

    .textBox:hover.textBox::after {
        opacity: 1;
        left: auto
    }

    .textBoxRight:hover.textBoxRight::after {
        left: auto;
    }

    .description, .buttonBox {
        padding: 1rem 0;
    }
}