/* ===== VARIABLES ===== */
:root {
    --primary-color: #2563eb;
    --primary-color-dark: #1e40af;
    --secondary-color: #6b7280;
    --text-dark: #1f2937;
    --text-light: #6b7280;
    --white: #ffffff;
    --light-bg: #f9fafb;
    --gray-bg: #f3f4f6;
    --dark-bg: #111827;
    --success: #10b981;
    --warning: #f59e0b;
    --danger: #ef4444;
    --border-color: #e5e7eb;
    --box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

/* ===== RESET & BASE STYLES ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Roboto', sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--white);
    overflow-x: hidden;
}

ul {
    list-style: none;
}

a {
    text-decoration: none;
    color: inherit;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

button, input, textarea {
    font-family: inherit;
    font-size: inherit;
    outline: none;
    border: none;
}

/* ===== CONTAINER ===== */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== SECTION ===== */
.section {
    padding: 100px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 36px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 20px;
    position: relative;
}

.underline {
    width: 80px;
    height: 4px;
    background-color: var(--primary-color);
    margin: 0 auto;
}

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

/* ===== BUTTONS ===== */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 50px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.primary-btn {
    background-color: var(--primary-color);
    color: var(--white);
    border: 2px solid var(--primary-color);
}

.primary-btn:hover {
    background-color: var(--primary-color-dark);
    border-color: var(--primary-color-dark);
}

.secondary-btn {
    background-color: transparent;
    color: var(--text-dark);
    border: 2px solid var(--primary-color);
}

.secondary-btn:hover {
    background-color: var(--primary-color);
    color: var(--white);
}

.small-btn {
    padding: 8px 15px;
    font-size: 14px;
    margin-right: 10px;
}

/* ===== HEADER & NAVIGATION ===== */
header {
    background-color: var(--dark-bg);
    color: var(--white);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
}

.logo h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 28px;
    font-weight: 700;
}

.logo span {
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    gap: 30px;
}

.nav-link {
    font-size: 16px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.nav-link:hover, .nav-link.active {
    color: var(--primary-color);
}

.hamburger {
    display: none;
    cursor: pointer;
}

.bar {
    display: block;
    width: 25px;
    height: 3px;
    margin: 5px auto;
    background-color: var(--white);
    transition: all 0.3s ease;
}

/* ===== HERO SECTION ===== */
.hero {
    flex: 1;
    display: flex;
    align-items: center;
}

.hero-content {
    max-width: 700px;
    text-align: center;
}

.hero-image {
    width: 200px;
    height: 200px;
    margin: 0 auto 30px;
    border-radius: 50%;
    overflow: hidden;
    border: 5px solid var(--primary-color);
    box-shadow: var(--box-shadow);
}

.hero-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.hero-content h1 {
    font-family: 'Poppins', sans-serif;
    font-size: 48px;
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
}

.hero-content h1 span {
    color: var(--primary-color);
}

.hero-content p {
    font-size: 24px;
    margin-bottom: 30px;
    color: var(--text-light);
}

.hero-buttons {
    margin-bottom: 30px;
}

.hero-buttons .btn {
    margin-right: 15px;
}

.social-links a {
    display: inline-flex;
    justify-content: center;
    align-items: center;
    width: 40px;
    height: 40px;
    background-color: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    margin-right: 15px;
    transition: all 0.3s ease;
}

.social-links a:hover {
    background-color: var(--primary-color);
}

/* ===== ABOUT SECTION ===== */
.about-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 50px;
    align-items: center;
}

.about-image img {
    border-radius: 10px;
    box-shadow: var(--box-shadow);
}

.about-text h3 {
    font-size: 28px;
    margin-bottom: 15px;
    font-family: 'Poppins', sans-serif;
}

.about-text p {
    color: var(--text-light);
    margin-bottom: 25px;
}

.about-details {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 30px;
}

.detail h4 {
    font-weight: 600;
    margin-bottom: 5px;
}

.detail p {
    margin-bottom: 0;
}

/* ===== SKILLS SECTION ===== */
.skills-content {
    margin-top: 50px;
}

.skill-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 40px;
}

.category h3 {
    font-size: 22px;
    margin-bottom: 25px;
    text-align: center;
    font-family: 'Poppins', sans-serif;
}

.skills-container {
    width: 100%;
}

.skill {
    margin-bottom: 25px;
}

.skill-name {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 10px;
}

.skill-bar {
    height: 10px;
    background-color: var(--border-color);
    border-radius: 10px;
    position: relative;
}

.skill-per {
    height: 10px;
    background-color: var(--primary-color);
    border-radius: 10px;
    position: relative;
    transition: width 1s ease;
}

.skill-per::after {
    content: attr(per);
    position: absolute;
    right: 0;
    top: -30px;
    font-size: 14px;
    font-weight: 500;
}

/* ===== PROJECTS SECTION ===== */
.project-filter {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 40px;
}

.filter-btn {
    padding: 8px 20px;
    background-color: var(--white);
    border-radius: 50px;
    cursor: pointer;
    font-weight: 500;
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.filter-btn:hover, .filter-btn.active {
    background-color: var(--primary-color);
    color: var(--white);
    border-color: var(--primary-color);
}

.projects-container {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
}

.project-card {
    background-color: var(--white);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: var(--box-shadow);
    transition: all 0.3s ease;
}

.project-card:hover {
    transform: translateY(-10px);
}

.project-img {
    height: 200px;
    overflow: hidden;
}

.project-img img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.project-card:hover .project-img img {
    transform: scale(1.1);
}

.project-info {
    padding: 20px;
}

.project-info h3 {
    font-size: 20px;
    margin-bottom: 10px;
    font-family: 'Poppins', sans-serif;
}

.project-info p {
    font-size: 15px;
    color: var(--text-light);
    margin-bottom: 15px;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 20px;
}

.project-tech span {
    font-size: 12px;
    padding: 5px 15px;
    background-color: var(--gray-bg);
    border-radius: 50px;
    font-weight: 500;
}

.project-links {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

/* ===== CONTACT SECTION ===== */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.contact-item {
    display: flex;
    align-items: flex-start;
    gap: 15px;
}

.contact-item .icon {
    width: 50px;
    height: 50px;
    background-color: var(--primary-color);
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    color: var(--white);
    font-size: 20px;
}

.contact-item .text h3 {
    font-size: 18px;
    margin-bottom: 5px;
    font-family: 'Poppins', sans-serif;
}

.contact-item .text p {
    color: var(--text-light);
}

.social-links-large {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-links-large a {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 50px;
    height: 50px;
    background-color: var(--white);
    color: var(--text-dark);
    border-radius: 50%;
    font-size: 20px;
    transition: all 0.3s ease;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.social-links-large a:hover {
    background-color: var(--primary-color);
    color: var(--white);
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 15px;
    background-color: var(--white);
    border: 1px solid var(--border-color);
    border-radius: 5px;
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--primary-color);
}

/* ===== TIMELINE (EXPERIENCE) SECTION ===== */
.timeline {
    position: relative;
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px 0;
}

.timeline::after {
    content: '';
    position: absolute;
    width: 4px;
    background-color: var(--primary-color);
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -2px;
    z-index: 1;
}

.timeline-item {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 50%;
    margin-bottom: 30px;
}

.timeline-item:nth-child(even) {
    left: 50%;
}

.timeline-item:nth-child(odd) {
    left: 0;
}

.timeline-dot {
    width: 20px;
    height: 20px;
    position: absolute;
    background-color: var(--white);
    border: 4px solid var(--primary-color);
    border-radius: 50%;
    z-index: 2;
    top: 15px;
}

.timeline-item:nth-child(odd) .timeline-dot {
    right: -10px;
}

.timeline-item:nth-child(even) .timeline-dot {
    left: -10px;
}

.timeline-content {
    padding: 20px 30px;
    background-color: var(--white);
    position: relative;
    border-radius: 10px;
    box-shadow: var(--box-shadow);
}

.timeline-item:nth-child(odd) .timeline-content {
    border-right: 3px solid var(--primary-color);
}

.timeline-item:nth-child(even) .timeline-content {
    border-left: 3px solid var(--primary-color);
}

.timeline-content h3 {
    font-size: 22px;
    margin-bottom: 8px;
    font-family: 'Poppins', sans-serif;
    color: var(--primary-color);
}

.timeline-company {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 5px;
}

.timeline-date {
    font-size: 16px;
    color: var(--text-light);
    margin-bottom: 15px;
}

.timeline-list {
    padding-left: 20px;
}

.timeline-list li {
    margin-bottom: 10px;
    list-style-type: disc;
    color: var(--text-light);
}

/* ===== EDUCATION SECTION ===== */
.education-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    padding: 20px 0;
}

.education-timeline::after {
    content: '';
    position: absolute;
    width: 3px;
    background-color: var(--primary-color);
    top: 0;
    bottom: 0;
    left: 40px;
    margin-left: -1.5px;
}

.education-item {
    padding-left: 70px;
    position: relative;
    margin-bottom: 30px;
}

.education-dot {
    width: 16px;
    height: 16px;
    position: absolute;
    background-color: var(--white);
    border: 3px solid var(--primary-color);
    border-radius: 50%;
    z-index: 2;
    left: 31px;
    top: 4px;
}

.education-content {
    padding: 20px 25px;
    background-color: var(--white);
    border-left: 3px solid var(--primary-color);
    border-radius: 0 10px 10px 0;
    box-shadow: var(--box-shadow);
}

.education-content h3 {
    font-size: 20px;
    margin-bottom: 10px;
    font-family: 'Poppins', sans-serif;
    color: var(--primary-color);
}

.education-degree {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 5px;
}

.education-date, .education-location {
    font-size: 14px;
    color: var(--text-light);
}

.thesis-section {
    max-width: 800px;
    margin: 50px auto 0;
    padding: 25px;
    background-color: var(--white);
    border-radius: 10px;
    box-shadow: var(--box-shadow);
}

.thesis-section h3 {
    font-size: 24px;
    margin-bottom: 20px;
    color: var(--primary-color);
    text-align: center;
    font-family: 'Poppins', sans-serif;
}

.thesis-content {
    padding: 15px;
}

.thesis-content h4 {
    font-size: 18px;
    margin-bottom: 10px;
    line-height: 1.4;
}

.thesis-content p {
    color: var(--text-light);
}

/* ===== PUBLICATIONS SECTION ===== */
.publications-list {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.publication-item {
    background-color: var(--white);
    border-radius: 10px;
    padding: 25px;
    box-shadow: var(--box-shadow);
    transition: transform 0.3s ease;
}

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

.publication-item h3 {
    font-size: 20px;
    margin-bottom: 15px;
    color: var(--primary-color);
    font-family: 'Poppins', sans-serif;
}

.publication-authors, .publication-venue, .publication-doi, .publication-status {
    margin-bottom: 8px;
    color: var(--text-light);
    font-size: 15px;
}

.publication-link {
    display: inline-block;
    color: var(--primary-color);
    font-weight: 600;
    margin-top: 10px;
    transition: all 0.3s ease;
}

.publication-link:hover {
    text-decoration: underline;
}

/* ===== AWARDS SECTION ===== */
.awards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.award-item {
    background-color: var(--white);
    border-radius: 10px;
    padding: 25px;
    box-shadow: var(--box-shadow);
    display: flex;
    align-items: flex-start;
    transition: transform 0.3s ease;
}

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

.award-icon {
    width: 60px;
    height: 60px;
    background-color: var(--primary-color);
    color: var(--white);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-right: 20px;
    flex-shrink: 0;
}

.award-content h3 {
    font-size: 20px;
    margin-bottom: 10px;
    color: var(--text-dark);
    font-family: 'Poppins', sans-serif;
}

.award-date {
    font-size: 14px;
    color: var(--primary-color);
    margin-bottom: 10px;
    font-weight: 600;
}

.activities-section {
    max-width: 800px;
    margin: 0 auto;
    padding: 25px;
    background-color: var(--white);
    border-radius: 10px;
    box-shadow: var(--box-shadow);
}

.activities-section h3 {
    font-size: 24px;
    margin-bottom: 20px;
    color: var(--primary-color);
    text-align: center;
    font-family: 'Poppins', sans-serif;
}

.activities-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.activity-item {
    padding: 15px;
    border-left: 3px solid var(--primary-color);
    background-color: var(--light-bg);
    border-radius: 0 5px 5px 0;
}

.activity-role {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 5px;
}

.activity-org {
    font-size: 16px;
    color: var(--text-dark);
    margin-bottom: 5px;
}

.activity-period {
    font-size: 14px;
    color: var(--text-light);
}

/* ===== FOOTER ===== */
footer {
    background-color: var(--dark-bg);
    color: var(--white);
    padding: 30px 0;
}

.footer-content {
    text-align: center;
}

/* ===== RESPONSIVE STYLES ===== */
@media (max-width: 992px) {
    .section {
        padding: 80px 0;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .about-image {
        max-width: 400px;
        margin: 0 auto 30px;
    }
    
    .about-details {
        max-width: 500px;
        margin-left: auto;
        margin-right: auto;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 50px;
    }
}

@media (max-width: 768px) {
    .hamburger {
        display: block;
    }
    
    .hamburger.active .bar:nth-child(2) {
        opacity: 0;
    }
    
    .hamburger.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }
    
    .hamburger.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 80px;
        gap: 0;
        flex-direction: column;
        background-color: var(--dark-bg);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 15px rgba(0, 0, 0, 0.1);
        z-index: 100;
        max-height: 85vh;
        overflow-y: auto;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-link {
        margin: 12px 0;
        display: block;
        font-size: 16px;
        padding: 5px 0;
    }

    /* Timeline Responsive */
    .timeline::after {
        left: 40px;
    }

    .timeline-item {
        width: 100%;
        padding-left: 80px;
        padding-right: 0;
    }

    .timeline-item:nth-child(even) {
        left: 0;
    }

    .timeline-item:nth-child(odd) .timeline-dot,
    .timeline-item:nth-child(even) .timeline-dot {
        left: 30px;
    }

    .timeline-item:nth-child(odd) .timeline-content,
    .timeline-item:nth-child(even) .timeline-content {
        border-right: none;
        border-left: 3px solid var(--primary-color);
    }
}
    
    .hero-content h1 {
        font-size: 36px;
    }
    
    .hero-content p {
        font-size: 20px;
    }
    
    .section-title h2 {
        font-size: 30px;
    }
    
    .projects-container {
        grid-template-columns: 1fr;
        max-width: 400px;
        margin: 0 auto;
    }
    
    .project-filter {
        gap: 10px;
    }
    
    .filter-btn {
        padding: 6px 15px;
        font-size: 14px;
    }
}

@media (max-width: 576px) {
    .hero-content h1 {
        font-size: 30px;
    }
    
    .hero-content p {
        font-size: 18px;
    }
    
    .hero-buttons .btn {
        width: 100%;
        margin-bottom: 15px;
        margin-right: 0;
    }
    
    .about-text h3 {
        font-size: 24px;
    }
    
    .about-details {
        grid-template-columns: 1fr;
    }
}