/* Main Styles */
body {
    margin: 0px 10px 0px 10px;
    font-family: Arial, sans-serif;
    background-color: #111;
    color: #fff;
    font-family: 'Times New Roman', Times, serif;

}
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: rgba(22, 21, 21, 0.95);
    padding: 15px 34px;
    z-index: 2;
    /* position: fixed; */
    width: 100%;
    top: 0;
    box-shadow: 0 2px 15px 0px rgba(139, 132, 132, 0.9);
    backdrop-filter: blur(10px);
   margin-left: -20px;
}
.navbar .logo {
    display: flex;
    align-items: center;
}
.navbar .logo span {
    font-size: 24px;
    color: #fff;
    letter-spacing: 10px;
}
/* .navbar .logo span:nth-child(2) {
    margin-left: 5px;
} */
.navbar ul {
    list-style: none;
    display: flex;
    margin: 0;
    padding: 0;
    padding-right: 20px;
}
.navbar ul li {
    margin-left: 20px;
}
.navbar ul li a {
    text-decoration: none;
    color: #fff;
    font-size: 14px;
    padding: 5px 7px;
    transition: all 0.3s ease;
    position: relative;
}
.navbar ul li a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: #f39c12;
    transition: width 0.3s ease;
}
.navbar ul li a:hover::after {
    width: 100%;
}
.navbar ul li a:hover {
    color: #f39c12;
}
.navbar ul li a.active {
    color: #f39c12;
}

.main-content {
    display: flex;
    flex-direction: column;
    align-items: baseline;
    justify-content: center;
    height: 100vh;
    background-color: #111;
    color: #fff;
    text-align: left;
    position: relative;
    padding-left: 100px;
    padding-top: 0px;
    z-index: 1;
    margin-top: 20px;
    margin-left: -20px;
    overflow: hidden;
    box-sizing: border-box;
}
.main-content h1 {
    font-size: 36px;
    margin: 0;
    line-height: 1.2;
}
.main-content h2 {
    font-size: 72px;
    margin: 0;
    line-height: 1.2;
    font-weight: bold;
    text-align: right;
    padding-left: 15%;
    padding-top: 5%;
}
.main-content img {
    position: absolute;
    right: 0;
    width: 50%;
    height: 80%;
    object-fit: cover;
    z-index: -1;
}
.orange-line {
    width: 51%;
    height: 3px;
    background-color: #f39c12;
    margin: 20px 0;
}
.main-contain-part-2 {
    display: flex;
    flex-direction: column;
    align-items: baseline;
    justify-content: center;
    height: auto;
    background-color: #111;
    color: #fff;
    text-align: left;
    padding-left: 100px;
    position: relative;
}
.main-contain-part-2 p {
    font-size: 27px;
    max-width: 800px;
    margin: 20px 0 0;
}

.biography-section {
    display: flex;
    flex-direction: column;
    padding: 0px 0px;
    background-color: aliceblue;
    color: #030303;
    height: auto;
}

.biography-section span {
    text-align: center;
    font-size: 2.5em;
    color: #ff660a;
    font-weight: bold;
    padding: 20px;
}

.biography-section > div {
    display: flex;
    flex-direction: row;
    /* height: 100%; */
}

/* .biography-section img {
    width: 50%;
    height: 172.3vh;
    object-fit: cover;
} */

.biography-text-container {
    padding-left: 0px;
    max-width: 50%;
    /* height: 100%; */
    background-color: aliceblue;
}

.biography-orange-line{
    width: 100%;
    height: 3px;
    background-color: #f39c12;
    margin:  0;
    margin-top: -10px;
    }
.biography-section img {
    width: 50%;
    /* height: 100%; */
    object-fit: cover;
}
.biography-text-container {
    padding-left: 0px;
    max-width: 50%;
    height:100%;
    background-color: aliceblue;
}
.biography-text {
    line-height: 1.3;
    font-size: 19px;
    padding: 0px 10px;
    text-align: justify;
  }

.biography-text h3 {
    color: #f39c12;
    margin-top: -4px;
}
.button-about-me {
    display: inline-block;
    padding: 10px 20px;
    margin: 10px 0;
    background-color: #f39c12;
    color: #111;
    text-decoration: none;
    border-radius: 10px;
    transition: background-color 0.3s;
    position: right;
}
.button-about-me:hover {
    background-color: #e67e22;
}


.education-section {
    display: flex;
    flex-direction: column;
    padding: 50px 0px;
    background-color: #353333;
    color: #030303;
    height: auto;
    margin-top: 40px;
    overflow: auto;
    height: auto;

}

.education-section span {
    text-align: center;
    font-size: 2.5em;
    color:#ff660a;
    margin-bottom: 40px;
    font-weight: bold;
}

.education-content {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    padding: 0 20px;
    height: auto;
}

.education-item {
    width: 31%;
    padding: 14px;
    background-color:#222;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.education-item h3 {
    color: #f39c12;
    font-size: 25px;
    margin-bottom: 15px;
}

.education-orange-line {
    width: 100%;
    height: 3px;
    background-color: #f39c12;
    margin-top: -10px;
    margin-bottom: 20px;
}

.education-item p {
    line-height: 1.6;
    font-size: 20px;
    color: #fff9f9;
    margin-bottom: 15px;
}

.education-year {
    font-weight: bold;
    color: #f39c12;
    font-size: 18px;
}

@media (max-width: 768px) {
    .education-content {
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .education-item {
        width: 90%;
    }
}

/* <publications Section */
.theorem-section {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background-color: #333;
    padding: 20px;
    color: #fff;
    margin-top: -58px;
}

    .equation {
        flex: 1;
    }

    .equation img {
        width: 100%;
        max-width: 400px;
        height: auto;
    }

    .theorem-text {
        flex: 1;
        padding: 20px;
        background-color: #222;
    }

    .theorem-text h2 {
        margin: 0 0 10px;
        font-size: 24px;
        color: #fff;
    }

    .theorem-orange-line {
         width: 100%;
         height: 3px;
         background-color: #f39c12;
         margin:  0;
    }

    .theorem-text p {
        font-size: 16px;
        line-height: 1.5;
        color: #ccc;
    }

    .theorem-text a {
        color: #fff;
        text-decoration: none;
    }

    .theorem-text a:hover {
        color: #fff;
        text-decoration: none;
        font-size: 18px;
    }

    .button {
        display: inline-block;
        padding: 10px 20px;
        margin: 20px 0 0;
        background-color: #f39c12;
        color: #111;
        text-decoration: none;
        border-radius: 5px;
        transition: background-color 0.3s;
        display: none;
    }

    .button:hover {
        background-color: #e67e22;
    }

    .projects{
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        height: 30vh;
        background-color: #ec1717;
        color: #ffff;
        padding: 20px;
        margin-top: 20px;
    }
    .projects h2 {
        color: #000000;
    }       
    



/* image Section */
.container-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    
}

.section {
    display: block;
    margin-bottom: 20px; 
    text-align: center; 
    position: relative;
    
    overflow: hidden;
    /* padding: 20px; */
}


.section img {
    width: 100%;
    height: 380px; 
    object-fit: cover;
    display: block; 
    margin-bottom: 4px;
    
}

.section-content {
    position: relative;
    z-index: 1;
    max-width: 80%;
    margin-top: 10px;
    text-align: left;
}
.section-content h2 {
    margin: 0;
    color: orange;
    display: inline-block;
    text-align: left;
}
.section-content .orange-line-section {
    width: 124%;
    height: 3px;
    background-color: orange;
    margin: 20px 0;
}
.section-content p {
    margin: 15px 0 0;
    text-align: justify; 
    width: 124%;
    height: 80px;
}
.button {
    margin-top: 15px;
    padding: 10px 20px;
    background-color: orange;
    color: #fff;
    text-decoration: none;
    border-radius: 10px;
    display: inline-block;
    border-radius: 10px;
}
.full-width {
    grid-column: span 2;
    margin: 20px 0px 0px 0px; 
}



.section-end {
    position: relative;
    height: 62vh;
    background-image: url('../../images/nanjing cover pic.jpg'); 
    background-size: cover;
    background-position: center;
    display: flex;
    justify-content: center;
    align-items: center;
    text-align: center;
    color: white;
}
.section-end::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.4); /* Dark overlay */
}
.content-section-end {
    position: relative;
    z-index: 1;
}
.content-section-end h1 {
    font-size: 4rem;
    margin: 0;
    margin-bottom: 20px;
    font-weight: bold;
}
.button-section-end {
    margin-top: 20px;
    padding: 15px 30px;
    background-color: rgb(255, 102, 0);
    color: #fff;
    text-decoration: none;
    font-size: 1.2rem;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}
.button-section-end:hover {
    background-color: rgb(244, 83, 5);
}


/* Section Contact  */
.contact {
    padding: 20px 20px;
    background-color: #111;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
}

/* Toast Notification */
.toast {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 15px;
    background: #fff;
    border-radius: 4px;
    box-shadow: 0 5px 10px rgba(0,0,0,0.1);
    border-left: 6px solid;
    overflow: hidden;
    transform: translateX(calc(100% + 30px));
    transition: all 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.35);
    z-index: 9999;
}

.toast.success {
    border-color: #28a745;
}

.toast.error {
    border-color: #dc3545;
}

.toast.active {
    transform: translateX(0);
}

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

.toast .toast-content i {
    font-size: 20px;
    margin-right: 10px;
}

.toast.success i {
    color: #28a745;
}

.toast.error i {
    color: #dc3545;
}

.toast .message {
    display: flex;
    flex-direction: column;
}

.toast .message .text {
    font-size: 14px;
    font-weight: 400;
}

.toast .message .text.text-1 {
    font-weight: 600;
    color: #333;
}

.toast .progress {
    position: absolute;
    bottom: 0;
    left: 0;
    height: 3px;
    width: 100%;
}

.toast .progress:before {
    content: '';
    position: absolute;
    bottom: 0;
    right: 0;
    height: 100%;
    width: 100%;
    background-color: #28a745;
}

.toast.error .progress:before {
    background-color: #dc3545;
}

.toast.active .progress:before {
    animation: progress 5s linear forwards;
}

@keyframes progress {
    100% {
        right: 100%;
    }
}

/* Footer */

footer {
    text-align: center;
    padding: 2rem;
    background: #0b0c0c;
    color: white;
}


.section-title {
    color: #f37712;
    font-size: 2.5rem;
    margin-bottom: 50px;
    text-align: center;
}

.contact-content {
    display: flex;
    justify-content: space-between;
    max-width: 1200px;
    width: 100%;
    margin: 0 auto;
    gap: 50px;
}

.contact-info {
    flex: 1;
    padding: 20px;
}

.contact-item {
    display: flex;
    align-items: center;
    margin-bottom: 30px;
    padding: 20px;
    background-color: #222;
    border-radius: 10px;
    transition: transform 0.3s ease;
}

.contact-item:hover {
    transform: translateY(-5px);
}

.contact-item i {
    font-size: 24px;
    color: #f39c12;
    margin-right: 15px;
}

.contact-item p {
    color: #fff;
    font-size: 1.1rem;
}

.contact-form {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 20px;
    padding: 30px;
    background-color: #222;
    border-radius: 10px;
}

.contact-form input,
.contact-form textarea {
    padding: 15px;
    border: none;
    border-radius: 5px;
    background-color: #333;
    color: #fff;
    font-size: 1rem;
}

.contact-form textarea {
    height: 150px;
    resize: vertical;
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: 2px solid #f39c12;
}

.btn.primary {
    padding: 15px 30px;
    background-color: #f39c12;
    color: #fff;
    border: none;
    border-radius: 5px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.btn.primary:hover {
    background-color: #e67e22;
}

/* Responsive design for contact page */
@media (max-width: 768px) {
    .contact-content {
        flex-direction: column;
    }
    
    .contact-info,
    .contact-form {
        width: 100%;
    }
}



/* Buttons */
.button {
    display: inline-block;
    padding: 12px 30px;
    background: #ff6b00;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: background 0.3s ease;
    margin-top: 20px;
    display: none;
}

.button:hover {
    background: #e65100;
}

/* Animation for orange line */
@keyframes width {
    from {
        width: 0;
    }
    to {
        width: 100px;
    }
}

[data-aos="width"] {
    width: 0;
}

[data-aos="width"].aos-animate {
    width: 100px;
    transition: width 1s ease;
}


/*  */


#myskills {
    /* padding: 5rem 10%; */
    color: #fff;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    /* color: var(--text-color); */
}

/* About Section */
.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    align-items: center;
}

.about-image img {
    width: 100%;
    border-radius: 10px;
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.skill-category {
    background: #222;
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    height: 130px;
}

.skill-items {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-top: 1rem;
}

.skill-items span {
    background: #0f1214;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.9rem;
}

/* Project Section */
.projects-section {
    display: flex;
    flex-direction: column;
    padding: 50px 0px;
    background-color: #353333;
    color: #030303;
    height: auto;
    margin-top: 20px;
    height: auto;
}


.projects-section span {
    text-align: center;
    font-size: 2.5em;
    color:#ff660a;
    margin-bottom: 40px;
    font-weight: bold;
}

.projects-content {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    padding: 0 20px;
    height: calc(100% - 100px);
}

.projects-item {
    width: 31%;
    padding: 14px;
    background-color:#222;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    color: white;
}

.projects-item h3 {
    color: #f39c12;
    font-size: 25px;
    margin-bottom: 15px;
}

.projects-orange-line {
    width: 100%;
    height: 3px;
    background-color: #f39c12;
    margin-top: -10px;
    margin-bottom: 20px;
}

.projects-item p {
    line-height: 1.6;
    font-size: 20px;
    color: #fff9f9;
    margin-bottom: 15px;
}

.projects-year {
    font-weight: bold;
    color: #f39c12;
    font-size: 18px;
}

@media (max-width: 768px) {
    .projects-content {
        flex-direction: column;
        align-items: center;
        gap: 20px;
    }

    .projects-item {
        width: 90%;
    }
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        padding: 10px;
    }
    .main-content {
        padding-left: 5%;
        padding-right: 5%;
    }
}