/* =====================================================
   HASSAN EL-SHEIKHA - PERSONAL WEBSITE
   Apple-Style, Web3-Inspired Design
   ===================================================== */

/* =====================================================
   CSS VARIABLES
   ===================================================== */
:root {
    /* Colors - Dark Mode with Web3 Accents */
    --bg-primary: #050505;
    --bg-secondary: #0a0a0a;
    --bg-tertiary: #111111;
    --bg-elevated: #1a1a1a;
    
    /* Glass morphism */
    --glass-bg: rgba(255, 255, 255, 0.03);
    --glass-border: rgba(255, 255, 255, 0.08);
    --glass-hover: rgba(255, 255, 255, 0.06);
    
    /* Text */
    --text-primary: #ffffff;
    --text-secondary: rgba(255, 255, 255, 0.7);
    --text-tertiary: rgba(255, 255, 255, 0.5);
    --text-muted: rgba(255, 255, 255, 0.35);
    
    /* Accent Colors - Subtle, Sophisticated */
    --accent-primary: #6366f1;
    --accent-secondary: #8b5cf6;
    --accent-tertiary: #a855f7;
    --accent-glow: rgba(99, 102, 241, 0.4);
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a855f7 100%);
    --gradient-text: linear-gradient(135deg, #ffffff 0%, rgba(255, 255, 255, 0.8) 100%);
    --gradient-subtle: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.1) 100%);
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    --space-3xl: 4rem;
    --space-4xl: 6rem;
    --space-5xl: 8rem;
    
    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    --font-mono: 'JetBrains Mono', 'SF Mono', Monaco, Consolas, monospace;
    
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 2rem;
    --text-4xl: 2.5rem;
    --text-5xl: 3.5rem;
    --text-6xl: 4.5rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3), 0 4px 6px -2px rgba(0, 0, 0, 0.2);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.3), 0 10px 10px -5px rgba(0, 0, 0, 0.2);
    --shadow-glow: 0 0 60px -15px var(--accent-glow);
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slower: 500ms cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Layout */
    --container-max: 1200px;
    --nav-height: 72px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

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

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

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

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
}

ul, ol {
    list-style: none;
}

/* =====================================================
   AMBIENT BACKGROUND
   ===================================================== */
.ambient-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: -1;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.3;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 600px;
    height: 600px;
    background: var(--accent-primary);
    top: -200px;
    right: -200px;
    animation-delay: 0s;
}

.orb-2 {
    width: 500px;
    height: 500px;
    background: var(--accent-secondary);
    bottom: -150px;
    left: -150px;
    animation-delay: -7s;
}

.orb-3 {
    width: 400px;
    height: 400px;
    background: var(--accent-tertiary);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation-delay: -14s;
    opacity: 0.15;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    25% {
        transform: translate(30px, -30px) scale(1.05);
    }
    50% {
        transform: translate(-20px, 20px) scale(0.95);
    }
    75% {
        transform: translate(-30px, -20px) scale(1.02);
    }
}

/* =====================================================
   LAYOUT
   ===================================================== */
.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-xl);
}

.section {
    padding: var(--space-5xl) 0;
    position: relative;
}

/* =====================================================
   NAVIGATION
   ===================================================== */
.nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    z-index: 1000;
    transition: all var(--transition-base);
}

.nav::before {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(5, 5, 5, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    opacity: 0;
    transition: opacity var(--transition-base);
}

.nav.scrolled::before {
    opacity: 1;
}

.nav-container {
    position: relative;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--space-xl);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    font-size: var(--text-xl);
    font-weight: 700;
    letter-spacing: -0.02em;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--space-lg);
}

.nav-link {
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
    padding: var(--space-sm) var(--space-md);
}

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

.nav-link-cta {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    padding: var(--space-sm) var(--space-lg);
}

.nav-link-cta:hover {
    background: var(--glass-hover);
    border-color: var(--accent-primary);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: var(--space-sm);
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    transition: all var(--transition-fast);
}

/* Mobile Menu */
.mobile-menu {
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(5, 5, 5, 0.98);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
}

.mobile-menu.active {
    opacity: 1;
    visibility: visible;
}

.mobile-menu-links {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    gap: var(--space-xl);
}

.mobile-link {
    font-size: var(--text-2xl);
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

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

/* =====================================================
   HERO SECTION
   ===================================================== */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: var(--space-5xl) var(--space-xl);
    position: relative;
}

.hero-content {
    max-width: 900px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-lg);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    margin-bottom: var(--space-xl);
}

.hero-profile {
    margin-bottom: var(--space-xl);
}

.hero-avatar {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    object-fit: cover;
    border: 3px solid var(--glass-border);
    box-shadow: 0 0 40px var(--accent-glow);
    transition: all var(--transition-base);
}

.hero-avatar:hover {
    border-color: var(--accent-primary);
    transform: scale(1.05);
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: #22c55e;
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.5;
        transform: scale(1.2);
    }
}

.hero-title {
    margin-bottom: var(--space-lg);
}

.hero-greeting {
    display: block;
    font-size: var(--text-xl);
    font-weight: 400;
    color: var(--text-tertiary);
    margin-bottom: var(--space-sm);
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.hero-name {
    display: block;
    font-size: clamp(var(--text-4xl), 8vw, var(--text-6xl));
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: var(--text-xl);
    font-weight: 500;
    color: var(--accent-primary);
    margin-bottom: var(--space-lg);
}

.hero-description {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-2xl);
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

.highlight {
    color: var(--text-primary);
    font-weight: 500;
}

.hero-cta {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-md);
    margin-bottom: var(--space-3xl);
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    font-size: var(--text-base);
    font-weight: 500;
    border-radius: var(--radius-full);
    transition: all var(--transition-base);
}

.btn-primary {
    background: var(--gradient-primary);
    color: white;
    box-shadow: var(--shadow-glow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 80px -10px var(--accent-glow);
}

.btn-secondary {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    color: var(--text-primary);
}

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

.hero-stats {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xl);
}

.stat {
    text-align: center;
}

.stat-value {
    display: block;
    font-size: var(--text-3xl);
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    display: block;
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--glass-border);
}

.hero-scroll {
    position: absolute;
    bottom: var(--space-2xl);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-sm);
    color: var(--text-muted);
    font-size: var(--text-sm);
}

.scroll-indicator {
    width: 24px;
    height: 40px;
    border: 2px solid var(--glass-border);
    border-radius: var(--radius-full);
    display: flex;
    justify-content: center;
    padding-top: 8px;
}

.scroll-dot {
    width: 4px;
    height: 8px;
    background: var(--text-muted);
    border-radius: var(--radius-full);
    animation: scroll 2s ease-in-out infinite;
}

@keyframes scroll {
    0%, 100% {
        transform: translateY(0);
        opacity: 1;
    }
    50% {
        transform: translateY(12px);
        opacity: 0.3;
    }
}

/* =====================================================
   SECTION HEADERS
   ===================================================== */
.section-header {
    text-align: center;
    margin-bottom: var(--space-4xl);
}

.section-tag {
    display: inline-block;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    margin-bottom: var(--space-md);
}

.section-title {
    font-size: clamp(var(--text-3xl), 5vw, var(--text-4xl));
    font-weight: 700;
    letter-spacing: -0.02em;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* =====================================================
   ABOUT SECTION
   ===================================================== */
.about {
    background: var(--bg-secondary);
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4xl);
    align-items: start;
    margin-bottom: var(--space-4xl);
}

.about-lead {
    font-size: var(--text-xl);
    font-weight: 500;
    color: var(--text-primary);
    line-height: 1.7;
    margin-bottom: var(--space-lg);
}

.about-text {
    font-size: var(--text-base);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-md);
}

.about-text strong {
    color: var(--text-primary);
    font-weight: 500;
}

.education-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    display: flex;
    gap: var(--space-lg);
}

.education-icon {
    width: 64px;
    height: 64px;
    background: var(--gradient-subtle);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-primary);
    flex-shrink: 0;
}

.education-content h3 {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.education-degree {
    font-size: var(--text-base);
    color: var(--text-secondary);
    margin-bottom: var(--space-xs);
}

.education-field {
    font-size: var(--text-sm);
    color: var(--accent-primary);
    font-weight: 500;
    margin-bottom: var(--space-xs);
}

.education-date {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    margin-bottom: var(--space-md);
}

.education-gpa {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: var(--gradient-subtle);
    border-radius: var(--radius-full);
}

.gpa-label {
    font-size: var(--text-xs);
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.gpa-value {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--accent-primary);
}

.coursework-title {
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-lg);
    text-align: center;
}

.coursework-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-sm);
}

.course-tag {
    padding: var(--space-sm) var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.course-tag:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

/* Technologies Section */
.technologies {
    margin-top: var(--space-3xl);
}

.tech-categories {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-xl);
}

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

.tech-category-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-md);
}

.tech-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--space-sm);
}

.tech-item {
    padding: var(--space-xs) var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.tech-item:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

@media (max-width: 768px) {
    .tech-categories {
        grid-template-columns: 1fr;
        gap: var(--space-xl);
    }
}

/* =====================================================
   EXPERIENCE SECTION
   ===================================================== */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 2px;
    background: linear-gradient(to bottom, var(--accent-primary), var(--accent-tertiary));
    opacity: 0.3;
}

.timeline-item {
    position: relative;
    padding-left: var(--space-3xl);
    padding-bottom: var(--space-3xl);
}

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

.timeline-marker {
    position: absolute;
    left: -7px;
    top: 0;
    width: 16px;
    height: 16px;
    background: var(--bg-primary);
    border: 3px solid var(--accent-primary);
    border-radius: 50%;
    box-shadow: 0 0 20px var(--accent-glow);
}

.experience-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
    transition: all var(--transition-base);
}

.experience-card:hover {
    border-color: rgba(99, 102, 241, 0.3);
    box-shadow: var(--shadow-glow);
}

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

.company-info {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.company-logo {
    width: 56px;
    height: 56px;
    background: var(--glass-bg);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-primary);
    overflow: hidden;
    flex-shrink: 0;
}

.company-logo .logo-img {
    width: 40px;
    height: 40px;
    object-fit: contain;
}

.company-logo .logo-img.logo-invert {
    filter: invert(1) brightness(2);
}

.company-name {
    font-size: var(--text-xl);
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.role-title {
    font-size: var(--text-base);
    color: var(--accent-primary);
    font-weight: 500;
}

.experience-date {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    padding: var(--space-sm) var(--space-md);
    background: var(--glass-bg);
    border-radius: var(--radius-full);
}

.experience-list {
    margin-bottom: var(--space-lg);
}

.experience-list li {
    position: relative;
    padding-left: var(--space-lg);
    margin-bottom: var(--space-md);
    font-size: var(--text-base);
    color: var(--text-secondary);
    line-height: 1.7;
}

.experience-list li::before {
    content: '◆';
    position: absolute;
    left: 0;
    top: 0;
    color: var(--accent-primary);
    font-size: var(--text-xs);
    line-height: 1.7;
}

.experience-list li:last-child {
    margin-bottom: 0;
}

.experience-list strong {
    color: var(--text-primary);
    font-weight: 500;
}

.experience-list .inline-link {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.experience-list .inline-link:hover {
    color: var(--accent-secondary);
    text-decoration: underline;
}

.experience-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
}

.exp-tag {
    padding: var(--space-xs) var(--space-md);
    background: var(--gradient-subtle);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: 500;
    color: var(--accent-primary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* =====================================================
   RESEARCH SECTION
   ===================================================== */
.research {
    background: var(--bg-secondary);
}

.research-featured {
    margin-bottom: var(--space-4xl);
}

.research-card.featured {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: var(--space-3xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-2xl);
    padding: var(--space-3xl);
    position: relative;
    overflow: hidden;
}

.research-card.featured::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--gradient-subtle);
    opacity: 0.5;
}

.research-visual {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.varphi-logo {
    width: 100%;
    max-width: 200px;
    height: auto;
    position: relative;
    z-index: 1;
    filter: drop-shadow(0 0 30px var(--accent-glow));
}

.research-glow {
    position: absolute;
    width: 200px;
    height: 200px;
    background: var(--accent-primary);
    filter: blur(80px);
    opacity: 0.3;
    border-radius: 50%;
}

.research-content {
    position: relative;
    z-index: 1;
}

.research-meta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-md);
}

.research-tag {
    padding: var(--space-xs) var(--space-md);
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: 600;
    color: white;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.research-date {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.research-title {
    font-size: var(--text-3xl);
    font-weight: 700;
    margin-bottom: var(--space-xs);
    letter-spacing: -0.02em;
}

.research-subtitle {
    font-size: var(--text-lg);
    color: var(--accent-primary);
    margin-bottom: var(--space-lg);
    font-weight: 500;
}

.research-description {
    font-size: var(--text-base);
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--space-xl);
}

.research-highlights {
    display: flex;
    gap: var(--space-2xl);
    margin-bottom: var(--space-xl);
}

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

.highlight-value {
    display: block;
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--accent-primary);
}

.highlight-label {
    display: block;
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.research-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-sm);
    margin-bottom: var(--space-lg);
}

.tech-tag {
    padding: var(--space-xs) var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    color: var(--text-secondary);
}

.research-supervisor {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.research-supervisor strong {
    color: var(--text-secondary);
}

.research-links {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
}

.research-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.research-link:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    transform: translateY(-2px);
}

.research-link svg {
    flex-shrink: 0;
}

/* =====================================================
   PROJECTS SECTION
   ===================================================== */
.projects {
    background: var(--bg-primary);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
}

.project-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
    text-decoration: none;
}

.project-card:hover {
    border-color: rgba(99, 102, 241, 0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-glow);
}

.project-card.featured-project {
    border-color: rgba(99, 102, 241, 0.3);
    background: var(--gradient-subtle);
}

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

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

.project-icon-img {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-logo {
    width: 100%;
    height: 100%;
    object-fit: contain;
    border-radius: var(--radius-md);
}

.project-link-icon {
    color: var(--text-tertiary);
    transition: color var(--transition-fast);
}

.project-card:hover .project-link-icon {
    color: var(--accent-primary);
}

.project-links-row {
    display: flex;
    gap: var(--space-sm);
}

.project-mini-link {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    color: var(--text-tertiary);
    transition: all var(--transition-fast);
}

.project-mini-link:hover {
    background: var(--gradient-subtle);
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    transform: translateY(-2px);
}

.varphi-project {
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.1) 0%, rgba(139, 92, 246, 0.15) 100%);
}

.varphi-project .project-icon {
    font-family: var(--font-sans);
    font-weight: 700;
    color: var(--accent-primary);
}

.project-award {
    font-size: var(--text-xs);
    font-weight: 600;
    color: var(--accent-primary);
    background: var(--gradient-subtle);
    padding: var(--space-xs) var(--space-sm);
    border-radius: var(--radius-full);
    margin-bottom: var(--space-sm);
    display: inline-block;
}

.project-title {
    font-size: var(--text-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--space-sm);
}

.project-description {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    line-height: 1.6;
    margin-bottom: var(--space-md);
    flex-grow: 1;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-xs);
}

.project-tag {
    padding: var(--space-xs) var(--space-sm);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    color: var(--text-tertiary);
}

@media (max-width: 1024px) {
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .projects-grid {
        grid-template-columns: 1fr;
    }
}

.subsection-title {
    font-size: var(--text-xl);
    font-weight: 600;
    margin-bottom: var(--space-xl);
    text-align: center;
}

.contributions-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-lg);
}

.contributions-grid-2 {
    grid-template-columns: repeat(2, 1fr);
    max-width: 800px;
    margin: 0 auto;
}

.contribution-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    text-align: center;
    transition: all var(--transition-base);
}

.contribution-card:hover {
    border-color: rgba(99, 102, 241, 0.3);
    transform: translateY(-4px);
}

.contribution-icon {
    font-size: var(--text-3xl);
    margin-bottom: var(--space-md);
}

.contribution-card h4 {
    font-size: var(--text-base);
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.contribution-card p {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    line-height: 1.6;
}

/* =====================================================
   PUBLICATIONS SECTION
   ===================================================== */
.publications-grid {
    display: grid;
    gap: var(--space-3xl);
    max-width: 900px;
    margin: 0 auto;
}

.publication-category {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-2xl);
}

.category-title {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-lg);
    border-bottom: 1px solid var(--glass-border);
}

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

.publication-item {
    display: flex;
    gap: var(--space-lg);
    padding: var(--space-lg) 0;
    border-bottom: 1px solid var(--glass-border);
}

.publication-item:last-child {
    border-bottom: none;
    padding-bottom: 0;
}

.publication-number {
    width: 32px;
    height: 32px;
    background: var(--gradient-subtle);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--accent-primary);
    flex-shrink: 0;
}

.publication-authors {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    margin-bottom: var(--space-xs);
}

.publication-title {
    font-size: var(--text-base);
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: var(--space-xs);
    line-height: 1.5;
}

.publication-venue {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
    font-style: italic;
    margin-bottom: var(--space-sm);
}

.publication-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-xs);
    font-size: var(--text-sm);
    color: var(--accent-primary);
    font-weight: 500;
    transition: all var(--transition-fast);
}

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

/* =====================================================
   AWARDS SECTION
   ===================================================== */
.awards {
    background: var(--bg-secondary);
}

.awards-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-lg);
    max-width: 1000px;
    margin: 0 auto;
}

.award-card {
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    display: flex;
    gap: var(--space-lg);
    align-items: flex-start;
    transition: all var(--transition-base);
}

.award-card:hover {
    border-color: rgba(99, 102, 241, 0.3);
    transform: translateY(-2px);
}

.award-card-link {
    text-decoration: none;
    cursor: pointer;
}

.award-card-link:hover {
    border-color: var(--accent-primary);
    box-shadow: var(--shadow-glow);
}

.award-year {
    padding: var(--space-xs) var(--space-md);
    background: var(--gradient-subtle);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: 600;
    color: var(--accent-primary);
    white-space: nowrap;
}

.award-content h4 {
    font-size: var(--text-base);
    font-weight: 600;
    margin-bottom: var(--space-xs);
}

.award-content p {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

/* =====================================================
   CONTACT SECTION
   ===================================================== */
.contact-wrapper {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contact-title {
    font-size: clamp(var(--text-3xl), 5vw, var(--text-4xl));
    font-weight: 700;
    letter-spacing: -0.02em;
    margin-bottom: var(--space-md);
    background: var(--gradient-text);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.contact-description {
    font-size: var(--text-lg);
    color: var(--text-secondary);
    margin-bottom: var(--space-3xl);
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: var(--space-lg);
    margin-bottom: var(--space-2xl);
    flex-wrap: wrap;
}

.contact-card {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    padding: var(--space-lg) var(--space-xl);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    transition: all var(--transition-base);
    text-align: left;
}

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

.contact-icon {
    width: 48px;
    height: 48px;
    background: var(--gradient-subtle);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--accent-primary);
}

.contact-label {
    display: block;
    font-size: var(--text-xs);
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 2px;
}

.contact-value {
    display: block;
    font-size: var(--text-base);
    font-weight: 500;
    color: var(--text-primary);
}

.contact-location {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    color: var(--text-tertiary);
    font-size: var(--text-sm);
}

/* =====================================================
   FOOTER
   ===================================================== */
.footer {
    padding: var(--space-2xl) 0;
    border-top: 1px solid var(--glass-border);
}

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

.footer-text {
    font-size: var(--text-sm);
    color: var(--text-tertiary);
}

.footer-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: var(--text-sm);
    color: var(--text-secondary);
    padding: var(--space-sm) var(--space-md);
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    transition: all var(--transition-fast);
}

.footer-link:hover {
    border-color: var(--accent-primary);
    color: var(--text-primary);
}

/* =====================================================
   REVEAL ANIMATIONS
   ===================================================== */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.reveal.active {
    opacity: 1;
    transform: translateY(0);
}

/* =====================================================
   RESPONSIVE DESIGN
   ===================================================== */
@media (max-width: 1024px) {
    .about-grid {
        grid-template-columns: 1fr;
        gap: var(--space-2xl);
    }
    
    .research-card.featured {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .research-visual {
        order: -1;
    }
    
    .research-highlights {
        justify-content: center;
    }
    
    .research-tech {
        justify-content: center;
    }
    
    .contributions-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .contributions-grid-2 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .awards-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    :root {
        --nav-height: 64px;
    }
    
    .nav-links {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: var(--space-lg);
    }
    
    .stat-divider {
        width: 40px;
        height: 1px;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .timeline::before {
        left: 8px;
    }
    
    .timeline-marker {
        left: 1px;
    }
    
    .timeline-item {
        padding-left: var(--space-2xl);
    }
    
    .experience-header {
        flex-direction: column;
    }
    
    .contributions-grid {
        grid-template-columns: 1fr;
    }
    
    .contributions-grid-2 {
        grid-template-columns: 1fr;
    }
    
    .awards-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-links {
        flex-direction: column;
        align-items: stretch;
    }
    
    .contact-card {
        justify-content: center;
    }
    
    .footer-content {
        flex-direction: column;
        gap: var(--space-md);
        text-align: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--space-md);
    }
    
    .section {
        padding: var(--space-4xl) 0;
    }
    
    .hero {
        padding: var(--space-4xl) var(--space-md);
    }
    
    .hero-name {
        font-size: var(--text-3xl);
    }
    
    .education-card {
        flex-direction: column;
        text-align: center;
    }
    
    .education-icon {
        margin: 0 auto;
    }
    
    .company-info {
        flex-direction: column;
        text-align: center;
    }
    
    .experience-list li {
        flex-direction: column;
        gap: var(--space-sm);
    }
    
    .list-icon {
        display: none;
    }
}

/* =====================================================
   UTILITY CLASSES
   ===================================================== */
.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;
}