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

:root {
    /* Colors */
    --primary-navy: #0f172a;
    --secondary-navy: #1e293b;
    --accent-blue: #3b82f6;
    --accent-blue-light: #60a5fa;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-light: #64748b;
    --background-white: #ffffff;
    --background-light: #f8fafc;
    --background-gray: #f1f5f9;
    --border-color: #e2e8f0;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 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: 1.875rem;
    --font-size-4xl: 2.25rem;
    --font-size-5xl: 3rem;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* 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);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

section {
    scroll-margin-top: 80px;
}

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    color: var(--primary-navy);
}

h1 {
    font-size: var(--font-size-5xl);
    margin-bottom: var(--spacing-md);
}

h2 {
    font-size: var(--font-size-4xl);
    margin-bottom: var(--spacing-lg);
}

h3 {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-sm);
}

h4 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
}

p {
    margin-bottom: var(--spacing-md);
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-base);
}

strong {
    font-weight: 600;
    color: var(--accent-blue);
}

/* ===================================
   Container & Layout
   =================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.section {
    padding: var(--spacing-2xl) 0;
}

.section-dark {
    background: linear-gradient(135deg, var(--primary-navy) 0%, var(--secondary-navy) 100%);
    color: #ffffff;
}

.section-dark h2,
.section-dark h3,
.section-dark h4,
.section-dark p {
    color: #ffffff;
}

.section-light {
    background-color: var(--background-white);
}

.section-title {
    text-align: center;
    position: relative;
    padding-bottom: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--accent-blue), var(--accent-blue-light));
    border-radius: 2px;
}

/* ===================================
   Navigation
   =================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

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

.nav-brand a {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--primary-navy);
    transition: color var(--transition-base);
}

.nav-brand a:hover {
    color: var(--accent-blue);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    font-weight: 500;
    color: var(--text-secondary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: 6px;
    transition: all var(--transition-base);
}

.nav-link:hover {
    color: var(--accent-blue);
    background-color: var(--background-gray);
}

.nav-cta {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-blue-light));
    color: white !important;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: 8px;
    font-weight: 600;
}

.nav-cta:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.mobile-menu-btn span {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--primary-navy);
    border-radius: 2px;
    transition: all var(--transition-base);
}

/* ===================================
   Hero Section
   =================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, var(--primary-navy) 0%, var(--secondary-navy) 100%);
    color: white;
    padding-top: 80px;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.hero-greeting {
    font-size: var(--font-size-lg);
    color: var(--accent-blue-light);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.hero-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    color: white;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, #ffffff, var(--accent-blue-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: var(--font-size-2xl);
    color: var(--accent-blue-light);
    margin-bottom: var(--spacing-lg);
    font-weight: 600;
}

.hero-description {
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.85);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

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

.hero-info {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-lg);
    justify-content: center;
    padding-top: var(--spacing-lg);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.info-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: rgba(255, 255, 255, 0.9);
}

.info-item .icon {
    width: 20px;
    height: 20px;
    color: var(--accent-blue-light);
}

.info-item a {
    color: rgba(255, 255, 255, 0.9);
    transition: color var(--transition-base);
}

.info-item a:hover {
    color: var(--accent-blue-light);
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-block;
    padding: var(--spacing-sm) var(--spacing-lg);
    border-radius: 8px;
    font-weight: 600;
    text-align: center;
    transition: all var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-blue-light));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(59, 130, 246, 0.4);
}

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

.btn-secondary:hover {
    background-color: white;
    color: var(--accent-blue);
}

.btn-large {
    padding: var(--spacing-md) var(--spacing-xl);
    font-size: var(--font-size-lg);
}

/* ===================================
   About Section
   =================================== */
.about-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
}

.about-content {
    padding-right: var(--spacing-lg);
}

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

.education-highlight {
    margin-top: var(--spacing-xl);
    padding: var(--spacing-lg);
    background-color: var(--background-gray);
    border-radius: 12px;
}

.subsection-title {
    font-size: var(--font-size-2xl);
    color: var(--primary-navy);
    margin-bottom: var(--spacing-md);
}

.education-item {
    margin-bottom: var(--spacing-lg);
}

.education-item:last-child {
    margin-bottom: 0;
}

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

.edu-header h4 {
    font-size: var(--font-size-lg);
    color: var(--primary-navy);
    margin-bottom: 0;
}

.edu-year {
    font-size: var(--font-size-sm);
    color: var(--accent-blue);
    font-weight: 600;
}

.edu-institution {
    font-size: var(--font-size-base);
    color: var(--text-secondary);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.edu-details {
    font-size: var(--font-size-base);
    color: var(--text-secondary);
    line-height: 1.7;
}

.edu-details li {
    margin-left: var(--spacing-md);
    margin-bottom: var(--spacing-xs);
}

.about-stats {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.stat-card {
    background-color: white;
    padding: var(--spacing-lg);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.stat-icon {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-blue-light));
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
}

.stat-icon svg {
    width: 24px;
    height: 24px;
    color: white;
}

.stat-card h4 {
    font-size: var(--font-size-base);
    color: var(--primary-navy);
    margin-bottom: var(--spacing-xs);
}

.stat-card p {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* ===================================
   Featured Project Section
   =================================== */
.project-featured {
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 16px;
    padding: var(--spacing-xl);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.project-header {
    margin-bottom: var(--spacing-xl);
}

.project-badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    background-color: var(--accent-blue);
    color: white;
    border-radius: 20px;
    font-size: var(--font-size-sm);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
}

.project-title {
    font-size: var(--font-size-3xl);
    color: white;
    margin-bottom: var(--spacing-sm);
}

.project-subtitle {
    font-size: var(--font-size-lg);
    color: var(--accent-blue-light);
    margin-bottom: var(--spacing-xs);
}

.project-period {
    font-size: var(--font-size-base);
    color: rgba(255, 255, 255, 0.7);
}

.project-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
}

.project-description h4 {
    color: white;
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-md);
}

.project-description p {
    color: rgba(255, 255, 255, 0.9);
    font-size: var(--font-size-base);
    line-height: 1.8;
}

.project-highlights {
    margin-top: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.highlight-item {
    display: flex;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    border-left: 4px solid var(--accent-blue);
}

.highlight-icon {
    width: 28px;
    height: 28px;
    color: var(--accent-blue-light);
    flex-shrink: 0;
}

.highlight-item h5 {
    color: white;
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
}

.highlight-item p {
    color: rgba(255, 255, 255, 0.85);
    font-size: var(--font-size-sm);
    line-height: 1.6;
    margin-bottom: 0;
}

.project-sidebar {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.project-tech,
.project-metrics {
    background-color: rgba(255, 255, 255, 0.05);
    padding: var(--spacing-lg);
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.project-tech h4,
.project-metrics h4 {
    color: white;
    font-size: var(--font-size-lg);
    margin-bottom: var(--spacing-md);
}

.tech-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.tech-tag {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--accent-blue);
    color: white;
    border-radius: 6px;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

.metric-item {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

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

.metric-value {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    color: var(--accent-blue-light);
}

.metric-label {
    font-size: var(--font-size-sm);
    color: rgba(255, 255, 255, 0.8);
}

/* ===================================
   Skills Section
   =================================== */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-lg);
}

.skill-category {
    background-color: white;
    padding: var(--spacing-lg);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.skill-category:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.skill-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--background-gray);
}

.skill-icon {
    width: 40px;
    height: 40px;
    color: var(--accent-blue);
}

.skill-header h3 {
    font-size: var(--font-size-xl);
    color: var(--primary-navy);
    margin-bottom: 0;
}

.skill-list {
    list-style: none;
}

.skill-list li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid var(--background-gray);
}

.skill-list li:last-child {
    border-bottom: none;
}

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

.skill-level {
    font-size: var(--font-size-sm);
    color: var(--accent-blue);
    font-weight: 600;
}

.skill-note {
    padding: var(--spacing-sm) 0;
    font-size: var(--font-size-sm);
    color: var(--text-light);
    font-style: italic;
    border-bottom: none !important;
}

/* ===================================
   Experience Section
   =================================== */
.experience-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

.experience-card {
    background-color: var(--background-light);
    padding: var(--spacing-lg);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: all var(--transition-base);
    border: 1px solid var(--border-color);
}

.experience-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--accent-blue);
}

.experience-icon {
    width: 50px;
    height: 50px;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-blue-light));
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: var(--spacing-md);
}

.experience-icon svg {
    width: 28px;
    height: 28px;
    color: white;
}

.experience-card h3 {
    font-size: var(--font-size-lg);
    color: var(--primary-navy);
    margin-bottom: var(--spacing-md);
}

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

.experience-skills {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
}

.exp-skill {
    padding: var(--spacing-xs) var(--spacing-sm);
    background-color: var(--background-gray);
    color: var(--accent-blue);
    border-radius: 6px;
    font-size: var(--font-size-xs);
    font-weight: 600;
}

/* ===================================
   Contact Section
   =================================== */
.contact-content {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: var(--spacing-xl);
}

.contact-intro {
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.8;
    margin-bottom: var(--spacing-xl);
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.contact-method {
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background-color: rgba(255, 255, 255, 0.05);
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    transition: all var(--transition-base);
}

.contact-method:hover {
    background-color: rgba(255, 255, 255, 0.1);
    transform: translateX(4px);
}

.contact-icon {
    width: 28px;
    height: 28px;
    color: var(--accent-blue-light);
    flex-shrink: 0;
}

.contact-method h4 {
    color: var(--accent-blue-light);
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-xs);
}

.contact-method p {
    color: rgba(255, 255, 255, 0.9);
    font-size: var(--font-size-base);
    margin-bottom: 0;
}

.contact-cta {
    background-color: rgba(255, 255, 255, 0.05);
    padding: var(--spacing-xl);
    border-radius: 12px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.contact-cta h3 {
    color: white;
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-md);
}

.contact-cta p {
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: var(--spacing-md);
}

.opportunity-list {
    list-style: none;
    margin-bottom: var(--spacing-xl);
}

.opportunity-list li {
    padding: var(--spacing-sm) 0;
    color: rgba(255, 255, 255, 0.9);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    padding-left: var(--spacing-md);
    position: relative;
}

.opportunity-list li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent-blue-light);
    font-weight: 700;
}

.opportunity-list li:last-child {
    border-bottom: none;
}

/* ===================================
   Footer
   =================================== */
.footer {
    background-color: var(--primary-navy);
    color: rgba(255, 255, 255, 0.8);
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.footer-content {
    max-width: 600px;
    margin: 0 auto;
}

.footer-content p {
    margin-bottom: var(--spacing-sm);
}

.footer-tagline {
    color: var(--accent-blue-light);
    font-style: italic;
}

/* ===================================
   Animations
   =================================== */
.fade-in {
    animation: fadeIn 0.8s ease-out forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 992px) {
    .about-grid,
    .project-content,
    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .about-content {
        padding-right: 0;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .hero-info {
        flex-direction: column;
        align-items: center;
    }
}

@media (max-width: 768px) {
    :root {
        --font-size-5xl: 2.5rem;
        --font-size-4xl: 2rem;
        --font-size-3xl: 1.75rem;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        flex-direction: column;
        background-color: white;
        width: 100%;
        padding: var(--spacing-lg);
        box-shadow: var(--shadow-lg);
        transition: left var(--transition-base);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .mobile-menu-btn {
        display: flex;
    }
    
    .hero {
        min-height: auto;
        padding: calc(80px + var(--spacing-xl)) 0 var(--spacing-xl);
    }
    
    .section {
        padding: var(--spacing-xl) 0;
    }
    
    .skills-grid,
    .experience-grid {
        grid-template-columns: 1fr;
    }
    
    h1 {
        font-size: var(--font-size-4xl);
    }
    
    h2 {
        font-size: var(--font-size-3xl);
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .btn {
        width: 100%;
    }
    
    .hero-cta {
        width: 100%;
    }
    
    .edu-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* ===================================
   Accessibility
   =================================== */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
a:focus,
button:focus {
    outline: 2px solid var(--accent-blue);
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .navbar,
    .hero-cta,
    .contact-cta {
        display: none;
    }
    
    .section {
        page-break-inside: avoid;
    }
}