:root[data-theme="dark"] {
    --bg-primary: #0f1419;
    --bg-secondary: #1a1f29;
    --bg-tertiary: #252b38;
    --text-primary: #e6edf3;
    --text-secondary: #9198a1;
    --text-tertiary: #6e7681;
    --accent-primary: #58a6ff;
    --accent-secondary: #79c0ff;
    --border-color: #30363d;
    --success: #3fb950;
    --error: #f85149;
    --warning: #d29922;
    --code-bg: #161b22;
}

:root[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f6f8fa;
    --bg-tertiary: #eaeef2;
    --text-primary: #1f2328;
    --text-secondary: #656d76;
    --text-tertiary: #8c959f;
    --accent-primary: #0969da;
    --accent-secondary: #0550ae;
    --border-color: #d0d7de;
    --success: #1a7f37;
    --error: #d1242f;
    --warning: #bf8700;
    --code-bg: #f6f8fa;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

.container-narrow {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 2rem;
}

/* Navigation */
.navbar {
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: relative;
}

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

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

.nav-links {
    display: none;
}

.nav-links li {
    list-style: none;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s ease;
    padding: 0.5rem 1rem;
    border-radius: 6px;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--accent-primary);
    background: var(--bg-tertiary);
}

/* Desktop Theme Toggle - Hidden */
.theme-toggle-desktop {
    display: none;
}

[data-theme="dark"] .theme-toggle-sun {
    display: none;
}

[data-theme="light"] .theme-toggle-moon {
    display: none;
}

/* Mobile Controls - Visible on all screen sizes */
.mobile-controls {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.theme-toggle {
    background: var(--bg-tertiary);
    border: 2px solid var(--border-color);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    transition: all 0.3s ease;
}

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

/* Hamburger Menu */
.hamburger {
    background: transparent;
    border: none;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    gap: 5px;
    padding: 0;
    width: 30px;
    height: 30px;
    justify-content: center;
}

.hamburger-line {
    width: 100%;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all 0.3s ease;
}

.hamburger.active .hamburger-line:nth-child(1) {
    transform: translateY(8px) rotate(45deg);
}

.hamburger.active .hamburger-line:nth-child(2) {
    opacity: 0;
}

.hamburger.active .hamburger-line:nth-child(3) {
    transform: translateY(-8px) rotate(-45deg);
}

/* Mobile Menu Dropdown */
.mobile-menu {
    display: none;
    position: absolute;
    top: calc(100% + 1rem);
    right: 0;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-top: none;
    border-radius: 0 0 8px 8px;
    min-width: 200px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.mobile-menu.active {
    display: flex;
    flex-direction: column;
}

.mobile-menu-item {
    padding: 1rem 1.5rem;
    color: var(--text-secondary);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.2s;
    border-bottom: 1px solid var(--border-color);
}

.mobile-menu-item:last-child {
    border-bottom: none;
}

.mobile-menu-item:hover,
.mobile-menu-item.active {
    background: var(--bg-tertiary);
    color: var(--accent-primary);
}

/* Main Content */
.main-content {
    min-height: calc(100vh - 200px);
    padding: 2rem 0;
}

/* Hero Section */
.hero {
    padding: 6rem 0 4rem;
    text-align: center;
}

.hero-title {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    font-weight: 600;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto 2rem;
    line-height: 1.8;
}
.hero-consulting {
    font-size: 1rem;
    color: var(--accent-primary);
    max-width: 600px;
    margin: 0 auto 2rem;
    padding: 0.75rem 1.5rem;
    background: var(--bg-secondary);
    border-radius: 8px;
    border: 1px solid var(--border-color);
}

.hero-consulting strong {
    color: var(--text-primary);
}
.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-weight: 600;
    text-decoration: none;
    border: 2px solid transparent;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background: var(--accent-secondary);
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-small {
    padding: 0.4rem 0.8rem;
    font-size: 0.875rem;
}

.btn-danger {
    background: var(--error);
    color: white;
}

.btn-danger:hover {
    background: #d13438;
}

/* Sections */
.section {
    padding: 4rem 0;
}

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

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    text-align: center;
}

.section-description {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: 3rem;
}

/* Projects Grid */
.projects-grid {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    margin-top: 3rem;
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.project-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
}

.project-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent-primary);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.2);
}

.project-card.featured {
    border-color: var(--accent-primary);
    border-width: 2px;
}

.project-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.project-header h3 {
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1.3;
    word-wrap: break-word;
}

.project-badge {
    padding: 0.25rem 0.75rem;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
}

.project-badge {
    background: var(--success);
    color: white;
}

.project-badge.coming-soon {
    background: var(--warning);
    color: white;
}

.project-description {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    line-height: 1.7;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1.5rem;
}

.tag {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
}

.project-link {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 600;
    display: inline-block;
}

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

.project-link.disabled {
    color: var(--text-tertiary);
    cursor: not-allowed;
}

/* About Section */
.about-content {
    max-width: 800px;
    margin: 2rem auto;
    font-size: 1.125rem;
    line-height: 1.8;
    color: var(--text-secondary);
}

.about-content p {
    margin-bottom: 1.5rem;
}

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

/* Contact Page */
.page-title {
    font-size: 3rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 1rem;
}

.page-description {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: 3rem;
}

.contact-container {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 4rem;
    max-width: 900px;
    margin: 0 auto;
}

@media (max-width: 768px) {
    .contact-container {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

.contact-form {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    font-size: 1rem;
    transition: border-color 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--accent-primary);
}

.contact-info {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
}

.contact-info h3 {
    font-size: 1.5rem;
    margin-bottom: 1rem;
}

.social-links {
    list-style: none;
}

.social-links li {
    margin-bottom: 0.75rem;
}

.social-links a {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 500;
}

.social-links a:hover {
    text-decoration: underline;
}

/* Alerts */
.alert {
    padding: 1rem 1.5rem;
    border-radius: 8px;
    margin-bottom: 2rem;
    font-weight: 500;
}

.alert-success {
    background: rgba(63, 185, 80, 0.1);
    border: 1px solid var(--success);
    color: var(--success);
}

.alert-error {
    background: rgba(248, 81, 73, 0.1);
    border: 1px solid var(--error);
    color: var(--error);
}

/* Blog List */
.blog-grid {
    display: grid;
    gap: 2rem;
    margin-top: 3rem;
}

.blog-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 2rem;
    transition: all 0.3s ease;
}

.blog-card:hover {
    transform: translateY(-4px);
    border-color: var(--accent-primary);
}

.blog-card-header {
    margin-bottom: 1rem;
}

.blog-card-title a {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
}

.blog-card-title a:hover {
    color: var(--accent-primary);
}

.blog-card-date {
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

.blog-card-excerpt {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 1rem;
}

.blog-card-footer {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.blog-card-link {
    color: var(--accent-primary);
    text-decoration: none;
    font-weight: 600;
}

.blog-card-link:hover {
    text-decoration: underline;
}

.blog-card-views {
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

/* Blog Post */
.blog-post {
    padding: 4rem 0;
}

.blog-post-header {
    text-align: center;
    margin-bottom: 3rem;
}

.blog-post-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 1rem;
}

.blog-post-meta {
    color: var(--text-tertiary);
    font-size: 0.938rem;
}

.blog-post-separator {
    margin: 0 0.5rem;
}

.blog-post-footer {
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
}

/* Empty State */
.empty-state {
    text-align: center;
    color: var(--text-tertiary);
    padding: 3rem;
    font-size: 1.125rem;
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 2rem 0;
    text-align: center;
    color: var(--text-secondary);
}

.footer-links {
    margin-top: 1rem;
}

.footer-links a {
    color: var(--accent-primary);
    text-decoration: none;
    margin: 0 1rem;
}

.footer-links a:hover {
    text-decoration: underline;
}

/* Timeline Styles */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 2rem auto;
}

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

.timeline-item {
    position: relative;
    padding-left: 3rem;
    margin-bottom: 3rem;
}

.timeline-marker {
    position: absolute;
    left: -6px;
    top: 0;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--primary);
    border: 3px solid var(--bg);
}

.timeline-content {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

.timeline-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: 0.5rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.timeline-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text);
    margin: 0;
}

.timeline-date {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.timeline-company {
    font-size: 1rem;
    color: var(--primary);
    font-weight: 500;
    margin-bottom: 1rem;
}

.timeline-details {
    color: var(--text-secondary);
    line-height: 1.6;
}

.timeline-details li {
    margin-bottom: 0.5rem;
}

/* Education Styles */
.education-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.education-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    transition: transform 0.2s;
}

.education-card:hover {
    transform: translateY(-4px);
}

.education-card h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 0.75rem;
}

.education-school {
    font-size: 1.1rem;
    color: var(--primary);
    font-weight: 500;
    margin-bottom: 0.5rem;
}

.education-date {
    color: var(--text-secondary);
    margin-bottom: 1rem;
}

/* Certifications Styles */
.certifications-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
    margin-top: 2rem;
}

.cert-item {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 8px;
    border-left: 4px solid var(--primary);
    transition: all 0.2s;
}

.cert-item.award {
    border-left-color: #FFD700;
}

.cert-item:hover {
    transform: translateX(4px);
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}

.cert-item h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 0.5rem;
}

.cert-item p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    margin: 0;
}

/* Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .page-title {
        font-size: 2rem;
    }
    
    .blog-post-title {
        font-size: 2rem;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
}