:root {
    /* Modern Color Palette */
    --color-background: #0a0a0a;
    --color-surface: #1a1a1a;
    --color-surface-variant: #2a2a2a;
    --color-primary: #667eea;
    --color-primary-hover: #764ba2;
    --color-accent: #f093fb;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-text-primary: #ffffff;
    --color-text-secondary: #a0a0a0;
    --color-text-muted: #808080;
    --color-border: #333333;
    --color-shadow: rgba(0, 0, 0, 0.5);
    
    /* Spacing System */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Typography */
    --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 2rem;
    --font-size-4xl: 2.5rem;
    
    /* Border Radius */
    --border-radius-sm: 0.5rem;
    --border-radius-md: 0.75rem;
    --border-radius-lg: 1rem;
    --border-radius-xl: 1.5rem;
    --border-radius-full: 50%;
    
    /* Animations */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
    --transition-slow: 500ms ease-in-out;
    
    /* Z-index */
    --z-negative: -1;
    --z-normal: 1;
    --z-elevated: 10;
    --z-sticky: 100;
    --z-modal: 1000;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-glow: 0 0 20px rgba(102, 126, 234, 0.3);
}

/* Google Fonts Import */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

/* CSS Reset & Base */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-family-primary);
    background: var(--color-background);
    color: var(--color-text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Screen Reader Only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Video Background */
.video-background {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: var(--z-negative);
    overflow: hidden;
    pointer-events: none;
}

.video-background video {
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0.3;
    will-change: transform;
    transform: translateZ(0);
    backface-visibility: hidden;
    transition: opacity var(--transition-slow);
}

.video-background video[data-lazy="true"] {
    opacity: 0;
}

.video-background video[data-lazy="false"] {
    opacity: 0.3;
}

/* Fallback background for slow connections */
.video-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, 
        var(--color-background) 0%, 
        #1a1a2e 50%, 
        var(--color-background) 100%);
    z-index: -1;
}

.video-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, 
        rgba(10, 10, 10, 0.8) 0%, 
        rgba(26, 26, 46, 0.9) 50%, 
        rgba(10, 10, 10, 0.8) 100%);
}

/* Header */
.header {
    background: rgba(26, 26, 26, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    padding: var(--spacing-sm) 0;
}

.header-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
}

.logo-link {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
    text-decoration: none;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    transition: all var(--transition-normal);
}

.logo-link:hover {
    transform: scale(1.05);
}

.navbar {
    display: flex;
    gap: var(--spacing-sm);
}

.nav-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--border-radius-md);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    transition: all var(--transition-normal);
    font-size: var(--font-size-sm);
}

.nav-link:hover,
.nav-link:focus {
    color: var(--color-text-primary);
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    border-color: var(--color-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* Main Content Layout */
.main-content {
    display: grid;
    grid-template-columns: 1fr;
    grid-template-areas: 
        "content"
        "about"
        "stats"
        "quote";
    gap: var(--spacing-xl);
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-md);
    min-height: calc(100vh - 140px);
}

/* Content Section */
.content-section {
    grid-area: content;
    order: 1;
}

/* About Section */
.about-section {
    grid-area: about;
    order: 2;
}

.about-card {
    background: rgba(26, 26, 26, 0.9);
    backdrop-filter: blur(10px);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-xl);
    text-align: center;
    animation: slideInUp 0.8s ease-out;
}

.profile-photo {
    width: 150px;
    height: 150px;
    border-radius: var(--border-radius-full);
    object-fit: cover;
    border: 4px solid var(--color-primary);
    box-shadow: var(--shadow-glow);
    margin-bottom: var(--spacing-md);
    transition: transform var(--transition-normal);
}

.profile-photo:hover {
    transform: scale(1.05) rotate(2deg);
}

.about-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    margin-bottom: var(--spacing-xs);
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.about-subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
}

.emoji {
    font-style: normal;
}

.about-text {
    font-size: var(--font-size-base);
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* Statistics Section */
.stats-section {
    grid-area: stats;
    order: 3;
}

.stats-container {
    display: grid;
    gap: var(--spacing-md);
    animation: slideInUp 0.8s ease-out 0.2s both;
}

.stat-card {
    background: rgba(26, 26, 26, 0.9);
    backdrop-filter: blur(10px);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
    text-align: center;
    transition: all var(--transition-normal);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border-color: var(--color-primary);
}

.stat-card h3 {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--color-primary);
    margin-bottom: var(--spacing-xs);
}

.stat-card p {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    text-transform: capitalize;
}

/* Tab Container */
.tab-container {
    background: rgba(26, 26, 26, 0.9);
    backdrop-filter: blur(10px);
    border-radius: var(--border-radius-xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    animation: slideInUp 0.8s ease-out 0.4s both;
}

.tab-header {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
}

.tab-button {
    background: none;
    border: none;
    color: var(--color-text-secondary);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-normal);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    font-family: inherit;
    font-size: var(--font-size-sm);
    position: relative;
}

.tab-button::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 3px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    transition: width var(--transition-normal);
}

.tab-button.active::before,
.tab-button:hover::before {
    width: 100%;
}

.tab-button.active {
    color: var(--color-text-primary);
    background: rgba(102, 126, 234, 0.1);
}

.tab-button:hover {
    color: var(--color-text-primary);
    background: rgba(102, 126, 234, 0.05);
}

.tab-icon {
    font-size: var(--font-size-xl);
}

.tab-text {
    font-size: var(--font-size-sm);
}

.tab-count {
    background: var(--color-primary);
    color: white;
    font-size: var(--font-size-xs);
    padding: 2px 8px;
    border-radius: var(--border-radius-full);
    font-weight: 700;
}

/* Tab Content */
.tab-content {
    display: none;
    padding: var(--spacing-xl);
    animation: fadeIn 0.5s ease-out;
}

.tab-content.active {
    display: block;
}

.content-grid {
    display: grid;
    gap: var(--spacing-lg);
}

/* Item Cards */
.item {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--spacing-lg);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.item::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.03), transparent);
    transition: left var(--transition-slow);
}

.item:hover::before {
    left: 100%;
}

.item:hover {
    transform: translateY(-4px);
    border-color: var(--color-primary);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.item-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

.item-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text-primary);
    line-height: 1.3;
    flex: 1;
}

.item-badge {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: white;
    font-size: var(--font-size-xs);
    font-weight: 600;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-full);
    white-space: nowrap;
}

.item-description {
    color: var(--color-text-secondary);
    line-height: 1.6;
    margin-bottom: var(--spacing-md);
}

.item-technologies {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-md);
}

.tech-tag {
    background: var(--color-surface-variant);
    color: var(--color-text-secondary);
    font-size: var(--font-size-xs);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--color-border);
}

.item-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.item-links {
    display: flex;
    gap: var(--spacing-sm);
}

.item-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--color-primary);
    text-decoration: none;
    font-size: var(--font-size-sm);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 1px solid var(--color-primary);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-normal);
}

.item-link:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
}

.item-link svg {
    width: 14px;
    height: 14px;
}

/* Quote Widget */
.quote-widget {
    grid-area: quote;
    order: 4;
    animation: slideInUp 0.8s ease-out 0.6s both;
}

.quote-content {
    background: rgba(26, 26, 26, 0.9);
    backdrop-filter: blur(10px);
    padding: var(--spacing-lg);
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-lg);
    position: relative;
}

#quote {
    font-style: italic;
    font-size: var(--font-size-sm);
    line-height: 1.6;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-md);
}

.quote-refresh {
    background: var(--color-primary);
    color: white;
    border: none;
    border-radius: var(--border-radius-full);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition-normal);
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
}

.quote-refresh:hover {
    background: var(--color-primary-hover);
    transform: rotate(180deg);
}

/* Footer */
.footer {
    background: rgba(26, 26, 26, 0.9);
    backdrop-filter: blur(10px);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-lg);
    text-align: center;
    margin-top: auto;
}

.footer-content p {
    margin: 0;
    color: var(--color-text-muted);
    font-size: var(--font-size-sm);
}

.footer-note {
    margin-top: var(--spacing-xs) !important;
    font-size: var(--font-size-xs) !important;
    opacity: 0.7;
}

/* Animations */
@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

/* Focus States for Accessibility */
.tab-button:focus,
.nav-link:focus,
.item-link:focus,
.quote-refresh:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* Responsive Design */
@media (min-width: 640px) {
    .tab-button {
        flex-direction: row;
        gap: var(--spacing-sm);
    }
    
    .tab-text {
        font-size: var(--font-size-base);
    }
    
    .content-grid {
        grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    }
    
    .stats-container {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

@media (min-width: 768px) {
    .main-content {
        grid-template-columns: 300px 1fr 250px;
        grid-template-areas: 
            "about content stats"
            "quote content stats";
        gap: var(--spacing-2xl);
        padding: var(--spacing-2xl);
    }
    
    .about-section {
        order: unset;
    }
    
    .stats-section {
        order: unset;
    }
    
    .quote-widget {
        order: unset;
    }
    
    .stats-container {
        grid-template-columns: 1fr;
    }
    
    .profile-photo {
        width: 200px;
        height: 200px;
    }
    
    .navbar {
        gap: var(--spacing-md);
    }
    
    .nav-link {
        font-size: var(--font-size-base);
        padding: var(--spacing-sm) var(--spacing-lg);
    }
}

@media (min-width: 1024px) {
    .main-content {
        grid-template-columns: 350px 1fr 280px;
    }
    
    .content-grid {
        grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
        gap: var(--spacing-xl);
    }
    
    .tab-content {
        padding: var(--spacing-2xl);
    }
}

@media (min-width: 1200px) {
    .main-content {
        grid-template-columns: 400px 1fr 320px;
    }
}

/* Reduced motion preferences */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    
    html {
        scroll-behavior: auto;
    }
    
    .video-background video {
        animation: none;
    }
}

/* High contrast mode */
@media (prefers-contrast: high) {
    :root {
        --color-border: #666666;
        --color-text-secondary: #cccccc;
    }
}

/* GitHub Projects Specific Styles */
.project-category {
    margin-bottom: var(--spacing-2xl);
}

.category-header {
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--color-border);
}

.category-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.category-icon {
    font-size: var(--font-size-2xl);
}

.category-count {
    background: var(--color-primary);
    color: white;
    font-size: var(--font-size-xs);
    padding: 2px 8px;
    border-radius: var(--border-radius-full);
    font-weight: 500;
}

.category-description {
    color: var(--color-text-secondary);
    font-size: var(--font-size-sm);
    margin: 0;
}

.category-projects {
    display: grid;
    gap: var(--spacing-lg);
}

.project-card {
    position: relative;
    overflow: hidden;
}

.project-card.highlighted {
    border-color: var(--color-primary);
    background: linear-gradient(135deg, 
        var(--color-surface) 0%, 
        rgba(102, 126, 234, 0.05) 100%);
}

.project-card.highlighted::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 4px;
    height: 100%;
    background: linear-gradient(to bottom, var(--color-primary), var(--color-accent));
}

.project-badges {
    display: flex;
    gap: var(--spacing-xs);
    align-items: center;
}

.language-badge {
    background: var(--color-surface-variant);
    color: var(--color-text-secondary);
    font-size: var(--font-size-xs);
    font-weight: 500;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--border-radius-sm);
    border: 1px solid var(--color-border);
}

.highlight-badge {
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: white;
    font-size: var(--font-size-xs);
    width: 24px;
    height: 24px;
    border-radius: var(--border-radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}

.project-stats {
    display: flex;
    gap: var(--spacing-md);
    margin: var(--spacing-md) 0;
    padding: var(--spacing-sm) 0;
    border-top: 1px solid var(--color-border);
}

.stat {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
    color: var(--color-text-muted);
}

.stat-icon {
    font-size: var(--font-size-base);
}

.stat-value {
    font-weight: 500;
}

/* Loading animation for dynamic content */
.projects-loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: var(--spacing-2xl);
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
}

.projects-loading::after {
    content: '';
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-border);
    border-top: 2px solid var(--color-primary);
    border-radius: var(--border-radius-full);
    animation: spin 1s linear infinite;
    margin-left: var(--spacing-sm);
}

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

/* Responsive adjustments for projects */
@media (min-width: 640px) {
    .category-projects {
        grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    }
    
    .project-stats {
        gap: var(--spacing-lg);
    }
}

@media (min-width: 1024px) {
    .category-projects {
        grid-template-columns: repeat(auto-fit, minmax(450px, 1fr));
    }
}

/* Print styles */
@media print {
    .video-background,
    .quote-widget,
    .stats-section {
        display: none;
    }
    
    .main-content {
        grid-template-columns: 1fr;
        grid-template-areas: 
            "about"
            "content";
    }
    
    body {
        background: white;
        color: black;
    }
    
    .project-card {
        break-inside: avoid;
        margin-bottom: var(--spacing-md);
    }
}