* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    text-decoration: none;
    border: none;
    outline: none;
    scroll-behavior: smooth;
    font-family: 'Poppins', sans-serif;
}

:root {
    /* Màu nền - Dark Mode (mặc định) */
    --bg-color: #0D0C22;
    --second-bg-color: #3A3546;
    
    /* Màu text */
    --text-color: #FFFFFF;
    --text-secondary: #CCD0D8;
    --text-light: #9E9EA7;
    
    /* Màu nhấn (accent) - Xanh lá nhạt */
    --main-color: #00D4AA;
    --accent-purple: #3E34D3;
    
    /* Màu bổ sung */
    --border-color: #524B63;
    --hover-color: #655C7A;
}

/* Light Mode */
body.light-mode {
    --bg-color: #F5F5F6;
    --second-bg-color: #FFFFFF;
    
    --text-color: #0D0C22;
    --text-secondary: #3A3546;
    --text-light: #524B63;
    
    --border-color: #E0E0E0;
    --hover-color: #E8E8E8;
}

html {
    font-size: 62.5%;
    overflow-x: hidden;
}

body {
    background: var(--bg-color);
    color: var(--text-color);
    overflow-x: hidden;
}

section {
    min-width: 100vh;
    padding: 10rem 9% 2rem;
    max-width: 100%;
}

.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    padding: 2rem 9%;
    background: var(--bg-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 100;
}

.header.sticky {
    border-bottom: .1rem solid var(--border-color);
}

.logo {
    font-size: 2.5rem;
    color: var(--text-color);
    font-weight: 600;
    cursor: default;
}

.navbar a {
    font-size: 1.7rem;
    color: var(--text-color);
    margin-left: 4rem;
    transition: .3s;
}

.navbar a:hover {
    color: var(--main-color);
}

.navbar a.active {
    color: var(--main-color);
}


#menu-icon {
    font-size: 3.6rem;
    color: var(--text-color);
    display: none;
}

#theme-toggle {
    font-size: 2.5rem;
    color: var(--text-color);
    background: none;
    border: none;
    cursor: pointer;
    transition: .3s;
    padding: 0.5rem;
}

#theme-toggle:hover {
    color: var(--main-color);
}

.home {
    display: flex;
    justify-content: center;
    align-items: center;
}

.home-content h3 {
    font-size: 3.2rem;
    font-weight: 700;
}

.home-content h3 :nth-of-type(2) {
    margin-bottom: 2rem;
}

span {
    color: var(--main-color);
}

.home-content h1 {
    font-size: 5.6rem;
    font-weight: 700;
    line-height: 1.3;
}

.home-img img {
    width: 30vw;
    height: 30vw;
    animation: floatImage 4s ease-in-out infinite;
    border-radius: 2rem;
    object-fit: cover;
    object-position: center 25%;
    max-width: 350px;
}

@keyframes floatImage {
    0%{
        transform: translateY(0)
    }
    50%{
        transform: translateY(-2.4rem)
    }
    100%{
        transform: translateY(0)
    }
}

.home-content p {
    font-size: 1.6rem;
    color: var(--text-secondary);
}


.social-media a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 4rem;
    height: 4rem;
    background: transparent;
    border: .2rem solid var(--main-color);
    border-radius: 50%;
    color: var(--main-color);
    margin: 3rem 1.5rem 3rem 0;
    transition: .5s ease;
}

.social-media a i {
    font-size: large;
}

.social-media a:hover {
    background: var(--main-color);
    color: var(--second-bg-color);
    box-shadow: 0 0 1rem var(--main-color);
}

.btn {
    display: inline-block;
    padding: 1rem 2.8rem;
    background: var(--main-color);
    border-radius: 4rem;
    box-shadow: 0 0 1rem var(--main-color);
    font-size: 1.6rem;
    color: #FFFFFF;
    letter-spacing: .1rem;
    font-weight: 600;
    transition: .5s ease;
    white-space: nowrap;
}

.btn:hover {
    box-shadow: none;
}

.about {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 3rem;
    background: var(--second-bg-color);
}

.about-img img {
    width: 40vw;
    max-width: 450px;
    height: auto;
}

.heading {
    text-align: center;
    font-size: 5rem;

}

.about-content h2 {
    text-align: left;
    line-height: 1.5;
}

.about-content h3 {
    font-size: 2.6rem;
}

.about-content p {
    font-size: 1.6rem;
    margin: 2rem 0 3rem;
    color: var(--text-secondary);
}


.services h2 {
    margin-bottom: 5rem;
}

.services-container {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 2rem;
}

.services-container .services-box {
    flex: 1 1 30rem;
    background: var(--second-bg-color);
    padding: 3rem 2rem 4rem;
    border-radius: 2rem;
    text-align: center;
    border: .2rem solid var(--border-color);
    transition: .5s ease;
}

.services-container .services-box:hover {
    border-color: var(--main-color);
    transform: scale(1.02);
}

.services-box i {
    font-size: 7rem;
    color: var(--main-color);
}

.services-box h3 {
    font-size: 2.6rem;
}

.services-box p {
    font-size: 1.6rem;
    margin: 1rem 0 3rem;
    color: var(--text-secondary);
}


.portfolio {
    background: var(--second-bg-color);
}

.portfolio h2 {
    margin-bottom: 4rem;
}

.portfolio-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    align-items: center;
    gap: 2.5rem;
}

.portfolio-container .portfolio-box {
    position: relative;
    border-radius: 2rem;
    box-shadow: 0 0 1rem var(--bg-color);
    overflow: hidden;
    display: flex;
}

.portfolio-box img {
    width: 100%;
    transition: .5s ease;
}

.portfolio-box:hover img {
    transform: scale(1.1);
}

.portfolio-box .portfolio-layer {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(rgba(13, 12, 34, 0.5), var(--main-color));
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
    text-align: center;
    padding: 0 4rem;
    transform: translateY(100%);
    transition: .5s ease;
}

.portfolio-box:hover .portfolio-layer {
    transform: translateY(0);
}

.portfolio-layer h4 {
    font-size: 3rem;
}

.portfolio-layer p {
    font-size: 1.6rem;
    margin: .3rem 0 1rem;
}

.portfolio-layer a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 5rem;
    height: 5rem;
    background: var(--text-color);
    border-radius: 50%;
}

.portfolio-layer a i {
    font-size: 2rem;
    color: var(--second-bg-color);
}

.contact h2 {
    margin-bottom: 3rem;
}

.contact form {
    max-width: 70rem;
    margin: 1rem auto;
    text-align: center;
    margin-bottom: 3rem;
}

.contact form .input-box {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
}

.contact form .input-box input,
.contact form textarea {
    width: 100%;
    padding: 1.5rem;
    font-size: 1.6rem;
    color: var(--text-color);
    background: var(--second-bg-color);
    border: .1rem solid var(--border-color);
    border-radius: .8rem;
    margin: .7rem 0;
    transition: .3s;
}

.contact form .input-box input:focus,
.contact form textarea:focus {
    border-color: var(--main-color);
    box-shadow: 0 0 1rem rgba(234, 76, 137, 0.3);
}

.contact form .input-box input {
    width: 49%;
}

.contact FORM textarea {
    resize: none;
}

.contact form .btn {
    margin-top: 2rem;
    cursor: pointer;
}

.contact-content {
    font-size: 15px;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    padding-bottom: 10px;
    display: flex;
    flex-direction: column;
    margin-left: 15rem;

}

.footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    padding: 2rem 9%;
    background: var(--second-bg-color);
}

.footer-text p {
    font-size: 1.6rem;
    color: var(--text-secondary);
}

.footer-iconTap a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    padding: .8rem;
    background: var(--main-color);
    border-radius: .8rem;
    transition: .5s ease;
}

.footer-iconTap a:hover {
    box-shadow: 0 0 1rem var(--main-color);
}

.footer-iconTap i {
    font-size: 2.4rem;
    color: var(--second-bg-color);
}



/* ========== RESPONSIVE DESIGN - DESKTOP (1200px and up) ========== */
@media (max-width: 1200px) {
    html {
        font-size: 55%;
    }
}

/* ========== RESPONSIVE DESIGN - LAPTOP/TABLET (992px - 1199px) ========== */
@media (max-width: 991px) {
    html {
        font-size: 56%;
    }

    .header {
        padding: 2rem 3%;
    }

    section {
        padding: 10rem 3% 2rem;
    }

    .footer {
        padding: 2rem 3%;
    }

    .services {
        padding-bottom: 7rem;
    }

    .portfolio {
        padding-bottom: 7rem;
    }

    .contact {
        min-height: auto;
    }

    .home {
        flex-direction: column;
    }

    .about {
        flex-direction: column;
        gap: 2rem;
    }

    .about-img img {
        width: 50vw;
        margin-top: 2rem;
    }

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

/* ========== RESPONSIVE DESIGN - TABLET (768px - 991px) ========== */
@media (max-width: 991px) and (min-width: 768px) {
    html {
        font-size: 54%;
    }

    section {
        padding: 8rem 5% 2rem;
    }

    .header {
        padding: 2rem 5%;
    }

    .navbar a {
        margin-left: 2rem;
        font-size: 1.5rem;
    }

    .home-content h1 {
        font-size: 4rem;
    }

    .home-content h3 {
        font-size: 2.4rem;
    }

    .home-img img {
        width: 50vw;
        margin-top: 3rem;
        object-position: center 25%;
    }

    .about-img img {
        width: 60vw;
    }

    .portfolio-container {
        grid-template-columns: repeat(2, 1fr);
        gap: 2rem;
    }
}

/* ========== RESPONSIVE DESIGN - MOBILE LANDSCAPE & SMALL TABLET (768px) ========== */
@media (max-width: 768px) {
    html {
        font-size: 52%;
    }

    #menu-icon {
        display: block;
    }

    .navbar {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        padding: 1rem 3%;
        background: var(--bg-color);
        border-top: .1rem solid rgba(0, 0, 0, .2);
        box-shadow: 0 .5rem 1rem rgba(0, 0, 0, .2);
        display: none;
        flex-direction: column;
    }

    .navbar.active {
        display: flex;
    }

    .navbar a {
        display: block;
        font-size: 1.8rem;
        margin: 2rem 0;
    }

    section {
        min-width: auto;
        padding: 8rem 4% 2rem;
    }

    .header {
        padding: 2rem 4%;
    }

    .home {
        flex-direction: column;
        gap: 2rem;
    }

    .home-content h3 {
        font-size: 2.4rem;
    }

    .home-content h1 {
        font-size: 3.6rem;
    }

    .home-content p {
        font-size: 1.4rem;
    }

    .home-img img {
        width: 65vw;
        max-width: 250px;
        margin-top: 2rem;
        object-position: center 20%;
    }

    .about {
        flex-direction: column;
        gap: 2rem;
    }

    .about-img img {
        width: 60vw;
        max-width: 300px;
        margin-top: 2rem;
    }

    .about-content h2 {
        font-size: 3rem;
    }

    .about-content h3 {
        font-size: 2rem;
    }

    .about-content p {
        font-size: 1.4rem;
    }

    .services-container {
        flex-direction: column;
    }

    .services-container .services-box {
        flex: 1 1 100%;
    }

    .services h2 {
        font-size: 3rem;
        margin-bottom: 2rem;
    }

    .services-box h3 {
        font-size: 2.2rem;
    }

    .services-box p {
        font-size: 1.4rem;
    }

    .portfolio h2 {
        font-size: 3rem;
        margin-bottom: 2rem;
    }

    .portfolio-container {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }

    .portfolio-layer h4 {
        font-size: 2rem;
    }

    .portfolio-layer p {
        font-size: 1.3rem;
    }

    .contact h2 {
        font-size: 3rem;
    }

    .contact form {
        max-width: 100%;
        padding: 0 1rem;
    }

    .contact form .input-box {
        flex-direction: column;
    }

    .contact form .input-box input,
    .contact form textarea {
        width: 100%;
        padding: 1.2rem;
        font-size: 1.4rem;
    }

    .footer {
        flex-direction: column;
        padding: 2rem 4%;
        gap: 2rem;
    }

    .footer-text p {
        font-size: 1.4rem;
        text-align: center;
    }

    .footer-iconTap {
        width: 100%;
        text-align: center;
    }
}

/* ========== RESPONSIVE DESIGN - LARGE MOBILE (481px - 767px) ========== */
@media (max-width: 767px) and (min-width: 481px) {
    html {
        font-size: 50%;
    }

    .header {
        padding: 1.8rem 4%;
    }

    .logo {
        font-size: 2rem;
    }

    section {
        padding: 7rem 4% 2rem;
    }

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

/* ========== RESPONSIVE DESIGN - MEDIUM MOBILE (376px - 480px) ========== */
@media (max-width: 480px) {
    html {
        font-size: 48%;
    }

    .header {
        padding: 1.5rem 3%;
    }

    .logo {
        font-size: 1.8rem;
    }

    #menu-icon {
        font-size: 3rem;
    }

    section {
        min-height: auto;
        padding: 7rem 3% 2rem;
    }

    .home {
        gap: 1.5rem;
    }

    .home-content h3 {
        font-size: 1.8rem;
        font-weight: 700;
    }

    .home-content h1 {
        font-size: 2.4rem;
    }

    .home-content p {
        font-size: 1.2rem;
        line-height: 1.5;
    }

    .home-img img {
        width: 80vw;
        max-width: 200px;
        margin-top: 1.5rem;
        object-position: center 15%;
    }

    .social-media a {
        width: 3.5rem;
        height: 3.5rem;
        margin: 2rem 1rem 2rem 0;
    }

    .btn {
        padding: 0.8rem 2rem;
        font-size: 1.4rem;
        margin: 0.5rem 0;
        display: block;
        text-align: center;
    }

    .about {
        gap: 1.5rem;
    }

    .about-content h2 {
        font-size: 2.4rem;
        text-align: left;
    }

    .about-content h3 {
        font-size: 1.8rem;
    }

    .about-content p {
        font-size: 1.2rem;
        line-height: 1.5;
    }

    .about-img img {
        width: 80vw;
        max-width: 220px;
    }

    .heading {
        font-size: 2.4rem;
    }

    .services h2 {
        margin-bottom: 2rem;
    }

    .services-container {
        flex-direction: column;
        gap: 1.5rem;
    }

    .services-box {
        padding: 2rem 1.5rem 3rem;
    }

    .services-box i {
        font-size: 4rem;
    }

    .services-box h3 {
        font-size: 1.8rem;
    }

    .services-box p {
        font-size: 1.2rem;
    }

    .portfolio h2 {
        margin-bottom: 2rem;
    }

    .portfolio-container {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .portfolio-layer {
        padding: 0 2rem;
    }

    .portfolio-layer h4 {
        font-size: 1.8rem;
    }

    .portfolio-layer p {
        font-size: 1.2rem;
    }

    .contact h2 {
        margin-bottom: 2rem;
    }

    .contact form {
        max-width: 100%;
        margin: 1rem auto;
    }

    .contact form .input-box {
        flex-direction: column;
    }

    .contact form .input-box input,
    .contact form textarea {
        width: 100%;
        padding: 1rem;
        font-size: 1.4rem;
        margin: 0.5rem 0;
    }

    .footer {
        flex-direction: column-reverse;
        gap: 1.5rem;
    }

    .footer-text p {
        font-size: 1.2rem;
        text-align: center;
    }

    .footer-iconTap {
        width: 100%;
        text-align: center;
    }

    .footer-iconTap a {
        margin: 0.5rem;
    }
}

/* ========== RESPONSIVE DESIGN - SMALL MOBILE (320px - 375px) ========== */
@media (max-width: 375px) {
    html {
        font-size: 46%;
    }

    .header {
        padding: 1.3rem 2.5%;
    }

    .logo {
        font-size: 1.6rem;
    }

    #menu-icon {
        font-size: 2.5rem;
    }

    section {
        padding: 6rem 2.5% 1.5rem;
    }

    .home-content h3 {
        font-size: 1.6rem;
    }

    .home-content h1 {
        font-size: 2rem;
    }

    .home-content p {
        font-size: 1.1rem;
    }

    .home-img img {
        width: 85vw;
        max-width: 180px;
        object-position: center 15%;
    }

    .social-media a {
        width: 3rem;
        height: 3rem;
        margin: 1.5rem 0.8rem 1.5rem 0;
    }

    .btn {
        padding: 0.7rem 1.5rem;
        font-size: 1.2rem;
    }

    .about-content h2 {
        font-size: 2rem;
    }

    .about-content h3 {
        font-size: 1.6rem;
    }

    .about-img img {
        width: 85vw;
        max-width: 180px;
    }

    .heading {
        font-size: 2rem;
    }

    .services-box {
        padding: 1.5rem 1rem 2.5rem;
    }

    .services-box i {
        font-size: 3rem;
    }

    .services-box h3 {
        font-size: 1.6rem;
    }

    .portfolio-layer h4 {
        font-size: 1.5rem;
    }

    .footer {
        padding: 1.5rem 2.5%;
        flex-direction: column-reverse;
    }

    .footer-text p {
        font-size: 1.1rem;
    }

    .footer-iconTap a {
        padding: 0.6rem;
    }

    .footer-iconTap i {
        font-size: 2rem;
    }
}