/* CSS Variables for Light and Dark Themes */
:root {
    /* Light Theme Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-dark: #2c3e50;
    --text-primary: #333333;
    --text-secondary: #666666;
    --text-light: rgba(255, 255, 255, 0.8);
    --accent-primary: #3498db;
    --accent-secondary: #9b59b6;
    --card-bg: #ffffff;
    --card-shadow: rgba(0, 0, 0, 0.1);
    --border-color: rgba(0, 0, 0, 0.1);
    --navbar-bg: rgba(255, 255, 255, 0.95);
    --navbar-scrolled: rgba(255, 255, 255, 0.98);
}

[data-theme="dark"] {
    /* Dark Theme Colors */
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-dark: #21262d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-light: rgba(230, 237, 243, 0.8);
    --accent-primary: #58a6ff;
    --accent-secondary: #bc8cff;
    --card-bg: #21262d;
    --card-shadow: rgba(0, 0, 0, 0.3);
    --border-color: #30363d;
    --navbar-bg: rgba(13, 17, 23, 0.95);
    --navbar-scrolled: rgba(13, 17, 23, 0.98);
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background: var(--navbar-bg);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background: var(--navbar-scrolled);
    box-shadow: 0 2px 20px var(--card-shadow);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    transition: color 0.3s ease;
}

.nav-logo a:hover {
    color: var(--accent-primary);
}

.nav-menu {
    display: flex;
    gap: 25px;
}

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: 8px 12px;
    border-radius: 8px;
}

.nav-link i {
    font-size: 1.1rem;
}

.nav-text {
    font-size: 0.8rem;
    opacity: 0.8;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-primary);
    background-color: var(--bg-secondary);
    transform: translateY(-2px);
}

.nav-link:hover .nav-text,
.nav-link.active .nav-text {
    opacity: 1;
}

/* Navigation Actions */
.nav-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.theme-toggle {
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 1.2rem;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
}

.theme-toggle:hover {
    background-color: var(--bg-secondary);
    color: var(--accent-primary);
    transform: scale(1.1);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-primary);
    margin: 3px 0;
    transition: 0.3s;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    position: relative;
    overflow: hidden;
    padding-top: 70px;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="1"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 2;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: 60px;
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    line-height: 1.2;
}

.typing-text {
    display: inline-block;
    border-right: 3px solid #fff;
    animation: blink 1s infinite;
}

@keyframes blink {
    0%, 50% { border-color: #fff; }
    51%, 100% { border-color: transparent; }
}

.hero-subtitle {
    font-size: 1.5rem;
    font-weight: 400;
    margin-bottom: 20px;
    opacity: 0.9;
}

.hero-description {
    font-size: 1.1rem;
    margin-bottom: 40px;
    opacity: 0.8;
    line-height: 1.6;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    margin-bottom: 40px;
}

.btn {
    padding: 12px 30px;
    border: none;
    border-radius: 50px;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
    cursor: pointer;
    text-align: center;
}

.btn-primary {
    background: #3498db;
    color: white;
}

.btn-primary:hover {
    background: #2980b9;
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(52, 152, 219, 0.3);
}

.btn-secondary {
    background: transparent;
    color: white;
    border: 2px solid white;
}

.btn-secondary:hover {
    background: white;
    color: #333;
    transform: translateY(-2px);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-link {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    color: white;
    font-size: 1.2rem;
    text-decoration: none;
    transition: all 0.3s ease;
}

.social-link:hover {
    background: white;
    color: #333;
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

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

.image-container {
    position: relative;
    width: 350px;
    height: 350px;
}

.profile-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    border-radius: 50%;
    border: 5px solid rgba(255, 255, 255, 0.2);
    transition: all 0.3s ease;
}

.image-overlay {
    position: absolute;
    top: -10px;
    left: -10px;
    right: -10px;
    bottom: -10px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    animation: rotate 20s linear infinite;
}

@keyframes rotate {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.scroll-indicator {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 10px;
    opacity: 0.7;
    animation: bounce 2s infinite;
}

.scroll-arrow {
    width: 20px;
    height: 20px;
    border-right: 2px solid white;
    border-bottom: 2px solid white;
    transform: rotate(45deg);
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% { transform: translateY(0) translateX(-50%); }
    40% { transform: translateY(-10px) translateX(-50%); }
    60% { transform: translateY(-5px) translateX(-50%); }
}

/* Sections */
.section {
    padding: 100px 0;
    scroll-margin-top: 70px;
}

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

.bg-dark {
    background-color: var(--bg-dark);
    color: var(--text-light);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 60px;
    position: relative;
    color: var(--text-primary);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -15px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary));
    border-radius: 2px;
}

/* About Section */
.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-text {
    font-size: 1.1rem;
    line-height: 1.8;
}

.about-stats {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.stat-item {
    text-align: center;
    padding: 30px;
    background: var(--card-bg);
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--card-shadow);
    transition: transform 0.3s ease;
}

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

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--accent-primary);
    margin-bottom: 10px;
}

.stat-label {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 500;
}

/* Research Section */
.research-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.research-item {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--card-shadow);
    transition: all 0.3s ease;
    text-align: center;
}

.research-item:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.research-icon {
    font-size: 3rem;
    color: var(--accent-primary);
    margin-bottom: 20px;
}

.research-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.research-description {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Projects Section */
.projects-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
    position: relative;
}

.projects-header .section-title {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    margin-bottom: 0;
}

.projects-navigation {
    display: flex;
    gap: 10px;
}

.scroll-btn {
    background: var(--card-bg);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    color: var(--text-primary);
}

.scroll-btn:hover {
    background: var(--accent-primary);
    color: white;
    border-color: var(--accent-primary);
    transform: scale(1.1);
}

.scroll-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.projects-grid {
    display: flex;
    gap: 30px;
    overflow-x: auto;
    padding: 20px 0;
    scroll-behavior: smooth;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
    scrollbar-color: var(--accent-primary) var(--bg-secondary);
}

.projects-grid::-webkit-scrollbar {
    height: 8px;
}

.projects-grid::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: 4px;
}

.projects-grid::-webkit-scrollbar-thumb {
    background: var(--accent-primary);
    border-radius: 4px;
}

.projects-grid::-webkit-scrollbar-thumb:hover {
    background: var(--accent-secondary);
}

.project-card {
    background: var(--card-bg);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 30px var(--card-shadow);
    transition: all 0.3s ease;
    flex: 0 0 350px;
    min-width: 350px;
}

.project-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.project-image {
    height: 200px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    overflow: hidden;
    position: relative;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-image i {
    font-size: 2rem;
    color: white;
}

.project-content {
    padding: 30px;
}

.project-title {
    font-size: 1.3rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.project-description {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 20px;
}

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

.project-tag {
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.project-links {
    display: flex;
    gap: 15px;
}

.project-links a {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.project-links a:hover {
    color: var(--accent-secondary);
}

/* Publications Section */
.publications-list {
    max-width: 800px;
    margin: 0 auto;
}

.publication-item {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 5px 20px var(--card-shadow);
    margin-bottom: 30px;
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.publication-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px var(--card-shadow);
}

.publication-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.publication-authors {
    color: var(--text-secondary);
    margin-bottom: 10px;
}

.publication-venue {
    color: var(--accent-primary);
    font-weight: 500;
    margin-bottom: 15px;
}

.publication-links {
    display: flex;
    gap: 15px;
}

.publication-links a {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.publication-links a:hover {
    color: var(--accent-secondary);
}

/* Education Timeline */
.education-timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

/* Work Experience Timeline */
.experience-timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.experience-timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--accent-primary);
    transform: translateX(-50%);
}

.experience-item {
    display: flex;
    align-items: center;
    margin-bottom: 50px;
    position: relative;
}

.experience-item:nth-child(even) {
    flex-direction: row-reverse;
}

.experience-content {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--card-shadow);
    width: calc(50% - 30px);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.experience-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px var(--card-shadow);
}

.experience-period {
    background: var(--accent-primary);
    color: white;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    display: inline-block;
    margin-bottom: 15px;
}

.experience-position {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.experience-company {
    font-size: 1.1rem;
    font-weight: 500;
    color: var(--accent-primary);
    margin-bottom: 10px;
}

.experience-location {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.experience-description {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 15px;
}

.experience-achievements {
    list-style: none;
    padding: 0;
}

.experience-achievements li {
    color: var(--text-secondary);
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
}

.experience-achievements li:before {
    content: '•';
    color: var(--accent-primary);
    font-weight: bold;
    position: absolute;
    left: 0;
}

.experience-technologies {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 15px;
}

.experience-tech {
    background: var(--bg-secondary);
    color: var(--text-primary);
    padding: 4px 10px;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--border-color);
}

.experience-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    background: var(--accent-primary);
    border: 4px solid var(--bg-primary);
    border-radius: 50%;
    box-shadow: 0 0 0 4px var(--accent-primary);
}

.education-timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--accent-primary);
    transform: translateX(-50%);
}

.education-item {
    display: flex;
    align-items: center;
    margin-bottom: 50px;
    position: relative;
}

.education-item:nth-child(even) {
    flex-direction: row-reverse;
}

.education-content {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--card-shadow);
    width: calc(50% - 30px);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.education-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px var(--card-shadow);
}

.education-period {
    background: var(--accent-primary);
    color: white;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    display: inline-block;
    margin-bottom: 15px;
}

.education-degree {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.education-institution {
    font-size: 1rem;
    font-weight: 500;
    color: var(--accent-primary);
    margin-bottom: 10px;
}

.education-location {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

.education-description {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 15px;
}

.education-achievements {
    list-style: none;
    padding: 0;
}

.education-achievements li {
    color: var(--text-secondary);
    margin-bottom: 8px;
    padding-left: 20px;
    position: relative;
}

.education-achievements li:before {
    content: '•';
    color: var(--accent-primary);
    font-weight: bold;
    position: absolute;
    left: 0;
}

.education-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    background: var(--accent-primary);
    border: 4px solid var(--bg-primary);
    border-radius: 50%;
    box-shadow: 0 0 0 4px var(--accent-primary);
}

/* Achievements Timeline */
.achievements-timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
}

.achievements-timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--accent-primary);
    transform: translateX(-50%);
}

.achievement-item {
    display: flex;
    align-items: center;
    margin-bottom: 50px;
    position: relative;
}

.achievement-item:nth-child(even) {
    flex-direction: row-reverse;
}

.achievement-content {
    background: var(--card-bg);
    padding: 30px;
    border-radius: 15px;
    box-shadow: 0 10px 30px var(--card-shadow);
    width: calc(50% - 30px);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.achievement-content:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px var(--card-shadow);
}

.achievement-date {
    background: var(--accent-primary);
    color: white;
    padding: 5px 15px;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
    display: inline-block;
    margin-bottom: 15px;
}

.achievement-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.achievement-description {
    color: var(--text-secondary);
    line-height: 1.6;
}

.achievement-marker {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 20px;
    height: 20px;
    background: var(--accent-primary);
    border: 4px solid var(--bg-primary);
    border-radius: 50%;
    box-shadow: 0 0 0 4px var(--accent-primary);
}

/* News Section */
.news-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.news-item {
    background: var(--card-bg);
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 30px var(--card-shadow);
    transition: all 0.3s ease;
    border: 1px solid var(--border-color);
}

.news-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 35px var(--card-shadow);
}

.news-content {
    padding: 30px;
}

.news-date {
    color: var(--accent-primary);
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 15px;
}

.news-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 15px;
}

.news-description {
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Blog Section */
.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 30px;
}

.blog-card {
    background: white;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
}

.blog-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
}

.blog-image {
    height: 200px;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
}

.blog-content {
    padding: 30px;
}

.blog-date {
    color: #3498db;
    font-size: 0.9rem;
    font-weight: 500;
    margin-bottom: 15px;
}

.blog-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: #2c3e50;
    margin-bottom: 15px;
}

.blog-excerpt {
    color: #666;
    line-height: 1.6;
    margin-bottom: 20px;
}

.blog-link {
    color: #3498db;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
}

.blog-link:hover {
    color: #2980b9;
}

/* Contact Section */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 60px;
    max-width: 1000px;
    margin: 0 auto;
}

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

.contact-item {
    display: flex;
    align-items: center;
    gap: 20px;
    font-size: 1.1rem;
}

.contact-item i {
    font-size: 1.5rem;
    color: #3498db;
    width: 30px;
    text-align: center;
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group input,
.form-group textarea {
    padding: 15px;
    border: 2px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.1);
    color: white;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #3498db;
    background: rgba(255, 255, 255, 0.15);
}

/* Footer */
.footer {
    background: #2c3e50;
    color: white;
    padding: 40px 0;
    text-align: center;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.footer-social {
    display: flex;
    gap: 15px;
}

.footer-social a {
    color: white;
    font-size: 1.2rem;
    transition: color 0.3s ease;
}

.footer-social a:hover {
    color: #3498db;
}

/* Loading Spinner */
.loading-spinner {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.9);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.loading-spinner.active {
    opacity: 1;
    visibility: visible;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 5px solid #ecf0f1;
    border-top: 5px solid #3498db;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* Desktop - hide text on smaller screens */
@media (max-width: 1200px) {
    .nav-text {
        display: none;
    }
    
    .nav-link {
        padding: 10px;
        gap: 0;
    }
    
    .nav-menu {
        gap: 20px;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: var(--navbar-bg);
        backdrop-filter: blur(10px);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: 0 10px 27px var(--card-shadow);
        padding: 20px 0;
        gap: 20px;
        border-top: 1px solid var(--border-color);
    }
    
    .nav-text {
        display: block;
        font-size: 0.9rem;
    }
    
    .nav-link {
        padding: 15px 20px;
        width: 100%;
        gap: 8px;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .hero {
        padding-top: 90px;
        min-height: calc(100vh - 20px);
    }

    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .hero-buttons {
        justify-content: center;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .about-stats {
        flex-direction: row;
        gap: 20px;
    }

    .contact-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .footer-content {
        flex-direction: column;
        gap: 20px;
    }

    .education-timeline::before {
        left: 20px;
    }

    .education-item {
        flex-direction: row !important;
        padding-left: 50px;
    }

    .education-content {
        width: 100%;
    }

    .education-marker {
        left: 20px;
    }

    .experience-timeline::before {
        left: 20px;
    }

    .experience-item {
        flex-direction: row !important;
        padding-left: 50px;
    }

    .experience-content {
        width: 100%;
    }

    .experience-marker {
        left: 20px;
    }

    .achievements-timeline::before {
        left: 20px;
    }

    .achievement-item {
        flex-direction: row !important;
        padding-left: 50px;
    }

    .achievement-content {
        width: 100%;
    }

    .achievement-marker {
        left: 20px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }

    .hero-title {
        font-size: 2rem;
    }

    .section-title {
        font-size: 2rem;
    }

    .projects-header {
        flex-direction: column;
        gap: 20px;
        align-items: center;
    }
    
    .projects-header .section-title {
        position: static;
        transform: none;
        margin-bottom: 20px;
    }
    
    .project-card {
        flex: 0 0 280px;
        min-width: 280px;
    }
    
    .news-grid,
    .research-grid {
        grid-template-columns: 1fr;
    }

    .btn {
        padding: 10px 20px;
        font-size: 0.9rem;
    }

    .hero-buttons {
        flex-direction: column;
        gap: 15px;
    }

    .about-stats {
        flex-direction: column;
        gap: 20px;
    }
}

/* Animations */
.fade-in {
    opacity: 1;
    transform: translateY(0);
    transition: all 0.6s ease;
}

.fade-in:not(.visible) {
    opacity: 0;
    transform: translateY(30px);
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.slide-in-left {
    opacity: 1;
    transform: translateX(0);
    transition: all 0.6s ease;
}

.slide-in-left:not(.visible) {
    opacity: 0;
    transform: translateX(-50px);
}

.slide-in-left.visible {
    opacity: 1;
    transform: translateX(0);
}

.slide-in-right {
    opacity: 1;
    transform: translateX(0);
    transition: all 0.6s ease;
}

.slide-in-right:not(.visible) {
    opacity: 0;
    transform: translateX(50px);
}

.slide-in-right.visible {
    opacity: 1;
    transform: translateX(0);
}

/* Utility Classes */
.text-center {
    text-align: center;
}

.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 10px; }
.mb-2 { margin-bottom: 20px; }
.mb-3 { margin-bottom: 30px; }

.mt-0 { margin-top: 0; }
.mt-1 { margin-top: 10px; }
.mt-2 { margin-top: 20px; }
.mt-3 { margin-top: 30px; }