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

:root {
    /* Dark Theme Colors */
    --primary-blue: #3b82f6;           /* Bright blue for accents */
    --dark-blue: #1e3a5f;              /* Dark blue for headers */
    --darker-blue: #0f1c2e;            /* Darker blue for navbar */
    --bg-dark: #0a1628;                /* Main background - very dark blue */
    --bg-card: #152238;                /* Card background - dark blue-gray */
    --bg-hover: #1a2a42;               /* Hover state - lighter blue-gray */
    
    /* Text Colors */
    --text-primary: #e2e8f0;           /* Main text - light gray */
    --text-secondary: #94a3b8;         /* Secondary text - muted gray */
    --text-muted: #64748b;             /* Muted text */
    
    /* Accent Colors */
    --accent-light: #60a5fa;           /* Light blue accent */
    --accent-glow: #3b82f6;            /* Glow effect blue */
    
    /* Borders & Dividers */
    --border-color: #1e293b;
    --border-light: #334155;
    
    /* White for contrast */
    --white: #ffffff;
    
    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.5);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.6);
    --shadow-blue: 0 0 20px rgba(59, 130, 246, 0.3);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-dark);
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

/* Navigation */
.navbar {
    background-color: var(--darker-blue);
    box-shadow: var(--shadow-md);
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-light);
}

.nav-container {
    max-width: 1128px;
    margin: 0 auto;
    padding: 0.75rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-brand {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-blue);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 0;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    padding: 1rem 1.25rem;
    display: block;
    transition: color 0.2s ease;
    border-bottom: 3px solid transparent;
    position: relative;
}

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

.nav-link.active {
    color: var(--primary-blue);
    border-bottom-color: var(--primary-blue);
}

/* Main Content */
.main-content {
    margin-top: 60px;
    padding: 1.5rem;
    flex: 1;
}

.page {
    display: none;
    max-width: 1128px;
    margin: 0 auto;
}

.page.active {
    display: block;
}

.content-wrapper {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

/* Profile Header */
.profile-header {
    background: var(--bg-card);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    margin-bottom: 1rem;
    border: 1px solid var(--border-light);
}

.profile-banner {
    height: 200px;
    background: url('images/banner.svg') center/cover no-repeat, linear-gradient(135deg, #1e3a5f 0%, #3b82f6 50%, #1e40af 100%);
    position: relative;
}

.banner-image {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.9;
}

.profile-container {
    padding: 0 1.5rem 1.5rem;
}

.profile-main {
    display: flex;
    gap: 1.5rem;
    margin-top: -4rem;
    position: relative;
}

.profile-picture-wrapper {
    flex-shrink: 0;
    position: relative;
}

.profile-picture,
.profile-picture-placeholder {
    width: 152px;
    height: 152px;
    border-radius: 50%;
    border: 4px solid var(--white);
    background: var(--bg-dark);
    object-fit: cover;
    box-shadow: var(--shadow-md);
}

.profile-picture-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--dark-blue) 0%, var(--primary-blue) 100%);
    color: var(--text-primary);
}

.profile-picture-placeholder svg {
    width: 80px;
    height: 80px;
}

.profile-picture {
    display: none;
}

.profile-picture[src$=".jpg"],
.profile-picture[src$=".jpeg"],
.profile-picture[src$=".png"],
.profile-picture[src$=".gif"],
.profile-picture[src$=".webp"] {
    display: block;
}

.profile-picture[src$=".jpg"] + .profile-picture-placeholder,
.profile-picture[src$=".jpeg"] + .profile-picture-placeholder,
.profile-picture[src$=".png"] + .profile-picture-placeholder,
.profile-picture[src$=".gif"] + .profile-picture-placeholder,
.profile-picture[src$=".webp"] + .profile-picture-placeholder {
    display: none;
}

.profile-info {
    padding-top: 1rem;
}

.profile-name {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.profile-headline {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    line-height: 1.5;
}

.profile-location {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.profile-stats {
    font-size: 0.875rem;
    color: var(--primary-blue);
    font-weight: 600;
}

.stat-item {
    margin-right: 1rem;
}

.profile-actions {
    display: flex;
    gap: 0.75rem;
    margin-top: 1rem;
}

/* Buttons */
.btn {
    padding: 0.625rem 1.75rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    font-size: 0.95rem;
    transition: all 0.3s ease;
    display: inline-block;
    border: 2px solid;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.1);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.btn:hover::before {
    width: 300px;
    height: 300px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-blue) 0%, #2563eb 100%);
    color: var(--white);
    border-color: var(--primary-blue);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.4);
}

.btn-primary:hover {
    box-shadow: 0 6px 20px rgba(59, 130, 246, 0.6);
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    background-color: rgba(59, 130, 246, 0.1);
    box-shadow: 0 4px 12px rgba(59, 130, 246, 0.3);
}

/* Content Cards */
.content-card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 1.75rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    margin-bottom: 1rem;
    border: 1px solid var(--border-color);
    transition: border-color 0.2s ease;
}

.content-card:hover {
    border-color: var(--primary-blue);
}

.card-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    padding-left: 0.875rem;
    border-bottom: 1px solid var(--border-color);
    border-left: 3px solid var(--primary-blue);
}

.card-content {
    color: var(--text-primary);
    line-height: 1.8;
}

.card-content p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

.subsection-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--accent-light);
    margin-top: 1.5rem;
    margin-bottom: 1rem;
}

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

.skill-item {
    display: flex;
    gap: 1rem;
    padding: 1.25rem;
    background: var(--bg-dark);
    border: 1px solid var(--border-light);
    border-radius: 10px;
    transition: all 0.3s ease;
}

.skill-item:hover {
    border-color: var(--primary-blue);
    background: var(--bg-hover);
}

.skill-icon {
    font-size: 2.5rem;
    line-height: 1;
}

.skill-info h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.skill-info p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

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

.competency-item {
    background: var(--bg-dark);
    padding: 1.5rem;
    border-radius: 10px;
    border: 1px solid var(--border-light);
    transition: all 0.3s ease;
}

.competency-item:hover {
    border-color: var(--primary-blue);
}

.competency-item h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--accent-light);
    margin-bottom: 1rem;
}

.competency-item ul {
    list-style: none;
    padding-left: 0;
}

.competency-item li {
    padding: 0.625rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-bottom: 1px solid var(--border-color);
}

.competency-item li:last-child {
    border-bottom: none;
}

.competency-item li:before {
    content: "▹";
    position: absolute;
    left: 0;
    color: var(--primary-blue);
    font-weight: bold;
    font-size: 1.2rem;
}

/* Certifications */
.certifications-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.cert-item {
    display: flex;
    gap: 1rem;
    padding: 1.25rem;
    background: var(--bg-dark);
    border: 1px solid var(--border-light);
    border-radius: 10px;
    transition: all 0.3s ease;
}

.cert-item:hover {
    border-color: var(--primary-blue);
}

.cert-icon {
    font-size: 2.5rem;
    line-height: 1;
}

.cert-info h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.cert-info p {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Timeline (Experience) */
.timeline {
    position: relative;
    padding-left: 2.5rem;
}

.timeline:before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(180deg, var(--primary-blue) 0%, var(--dark-blue) 100%);
}

.timeline-item {
    position: relative;
    padding-bottom: 2.5rem;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-marker {
    position: absolute;
    left: -2.75rem;
    top: 0.25rem;
    width: 14px;
    height: 14px;
    border-radius: 50%;
    background: var(--primary-blue);
    border: 3px solid var(--bg-card);
    z-index: 1;
}

.timeline-content {
    background: var(--bg-dark);
    padding: 1.5rem;
    border-radius: 10px;
    border: 1px solid var(--border-light);
    transition: all 0.3s ease;
}

.timeline-content:hover {
    border-color: var(--primary-blue);
}

.experience-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.experience-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.25rem;
}

.company-name {
    font-size: 0.95rem;
    color: var(--accent-light);
    font-weight: 500;
}

.experience-date {
    font-size: 0.875rem;
    color: var(--text-muted);
    white-space: nowrap;
    background: var(--bg-card);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    border: 1px solid var(--border-light);
}

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

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

.experience-achievements li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.experience-achievements li:before {
    content: "▹";
    position: absolute;
    left: 0;
    color: var(--primary-blue);
    font-size: 1.3rem;
}

/* Education */
.education-item {
    background: var(--bg-dark);
    padding: 1.5rem;
    border-radius: 10px;
    border: 1px solid var(--border-light);
}

.education-item h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.university-name {
    font-size: 1rem;
    color: var(--accent-light);
    margin-bottom: 0.25rem;
    font-weight: 500;
}

.education-date {
    font-size: 0.875rem;
    color: var(--text-muted);
}

/* Articles Grid */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1.25rem;
}

.article-card {
    border: 1px solid var(--border-light);
    border-radius: 12px;
    overflow: hidden;
    transition: all 0.3s ease;
    background: var(--bg-dark);
}

.article-card:hover {
    border-color: var(--primary-blue);
    transform: translateY(-3px);
}

.article-image-placeholder {
    height: 180px;
    background: linear-gradient(135deg, var(--dark-blue) 0%, var(--primary-blue) 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
}

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

.placeholder-content {
    font-size: 3.5rem;
    color: var(--text-primary);
    opacity: 0.5;
}

.article-content {
    padding: 1.5rem;
}

.article-content h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.article-meta {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

.article-content p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Contact Grid */
.contact-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.25rem;
}

.contact-card {
    padding: 2rem;
    background: var(--bg-dark);
    border: 1px solid var(--border-light);
    border-radius: 12px;
    text-align: center;
    transition: all 0.3s ease;
}

.contact-card:hover {
    border-color: var(--primary-blue);
    transform: translateY(-3px);
}

.contact-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.contact-card h3 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.75rem;
}

.contact-card p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.contact-card a {
    color: var(--primary-blue);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
}

.contact-card a:hover {
    color: var(--accent-light);
}

/* Footer */
.footer {
    background-color: var(--darker-blue);
    border-top: 1px solid var(--border-light);
    padding: 2rem 1.5rem;
    margin-top: 2rem;
    box-shadow: 0 -4px 6px rgba(0, 0, 0, 0.3);
}

.footer-content {
    max-width: 1128px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-content p {
    color: var(--text-muted);
    font-size: 0.875rem;
}

.footer-links {
    display: flex;
    gap: 2rem;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    transition: all 0.3s ease;
}

.footer-links a:hover {
    color: var(--primary-blue);
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-content {
        padding: 1rem;
    }

    .nav-menu {
        gap: 0;
    }

    .nav-link {
        padding: 1rem 0.75rem;
        font-size: 0.8rem;
    }

    .profile-main {
        flex-direction: column;
        margin-top: 0;
        align-items: center;
        text-align: center;
    }

    .profile-picture-wrapper {
        margin-top: -4rem;
    }

    .profile-info {
        padding-top: 0;
    }

    .profile-actions {
        justify-content: center;
    }

    .experience-header {
        flex-direction: column;
    }

    .competencies-grid,
    .skills-container,
    .articles-grid,
    .contact-grid {
        grid-template-columns: 1fr;
    }

    .timeline {
        padding-left: 2rem;
    }

    .timeline-marker {
        left: -2.25rem;
    }

    .profile-name {
        font-size: 1.5rem;
    }

    .profile-headline {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .nav-container {
        padding: 0.5rem 1rem;
    }

    .nav-brand {
        font-size: 1.25rem;
    }

    .nav-link {
        padding: 0.75rem 0.5rem;
        font-size: 0.75rem;
    }

    .profile-picture,
    .profile-picture-placeholder {
        width: 120px;
        height: 120px;
    }

    .profile-name {
        font-size: 1.25rem;
    }

    .profile-headline {
        font-size: 0.95rem;
    }

    .content-card {
        padding: 1.25rem;
    }

    .card-title {
        font-size: 1.25rem;
    }
}

/* Page Transition Animation */
.page {
    animation: fadeIn 0.4s ease-in;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(15px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
    background: var(--dark-blue);
    border-radius: 5px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-blue);
}