:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-secondary: #64748b;
    --color-accent: #f8fafc;
    --color-text-primary: #0f172a;
    --color-text-secondary: #475569;
    --color-border: #e2e8f0;
    --color-background: #ffffff;
    --color-surface: #f8fafc;
    
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    --spacing-3xl: 4rem;
    
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    
    --transition: all 0.2s ease-in-out;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-weight: var(--font-weight-normal);
    color: var(--color-text-primary);
    background-color: var(--color-background);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--color-border);
}

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

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

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-xl);
}

.nav-link {
    text-decoration: none;
    color: var(--color-text-secondary);
    font-weight: var(--font-weight-medium);
    transition: var(--transition);
    position: relative;
}

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-primary);
    transition: var(--transition);
}

.nav-link:hover::after {
    width: 100%;
}

.hero {
    padding: calc(80px + var(--spacing-3xl)) var(--spacing-lg) var(--spacing-3xl);
    min-height: 100vh;
    display: flex;
    align-items: center;
}

.hero-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: 1fr 400px;
    gap: var(--spacing-3xl);
    align-items: center;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: var(--font-weight-bold);
    margin-bottom: var(--spacing-md);
    background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
    font-weight: var(--font-weight-medium);
}

.hero-description {
    font-size: 1.1rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
}

.btn {
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.btn-secondary {
    background-color: transparent;
    color: var(--color-text-primary);
    border: 2px solid var(--color-border);
}

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

.hero-image {
    display: flex;
    justify-content: center;
}

.profile-img {
    width: 350px;
    height: 350px;
    border-radius: 50%;
    object-fit: cover;
    box-shadow: var(--shadow-lg);
    border: 8px solid white;
}

.section-title {
    font-size: 2.5rem;
    font-weight: var(--font-weight-bold);
    text-align: center;
    margin-bottom: var(--spacing-3xl);
    color: var(--color-text-primary);
}

.about {
    padding: var(--spacing-3xl) 0;
    background-color: var(--color-surface);
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-3xl);
    align-items: center;
}

.about-text p {
    font-size: 1.1rem;
    line-height: 1.8;
    color: var(--color-text-secondary);
}

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

.stat {
    text-align: center;
    padding: var(--spacing-lg);
    background: white;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
}

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

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

.experience {
    padding: var(--spacing-3xl) 0;
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 30px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--color-border);
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-3xl);
    padding-left: 80px;
}

.timeline-marker {
    position: absolute;
    left: 22px;
    top: 8px;
    width: 16px;
    height: 16px;
    background: var(--color-primary);
    border-radius: 50%;
    border: 4px solid white;
    box-shadow: var(--shadow-md);
}

.timeline-content {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.timeline-content h3 {
    font-size: 1.25rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.timeline-content h4 {
    font-size: 1.1rem;
    color: var(--color-primary);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--spacing-sm);
}

.timeline-date {
    font-size: 0.9rem;
    color: var(--color-text-secondary);
    font-weight: var(--font-weight-medium);
    margin-bottom: var(--spacing-md);
    display: block;
}

.timeline-content ul {
    list-style: none;
    padding: 0;
}

.timeline-content li {
    position: relative;
    padding-left: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.timeline-content li::before {
    content: '•';
    position: absolute;
    left: 0;
    color: var(--color-primary);
    font-weight: var(--font-weight-bold);
}

.skills {
    padding: var(--spacing-3xl) 0;
    background-color: var(--color-surface);
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.skill-category {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.skill-category h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.1rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-md);
}

.skill-category i {
    color: var(--color-primary);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.skill-tag {
    background: var(--color-accent);
    color: var(--color-text-secondary);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    font-weight: var(--font-weight-medium);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

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

.contact {
    padding: var(--spacing-3xl) 0;
}

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

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

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: white;
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: var(--transition);
}

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

.contact-item i {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-accent);
    color: var(--color-primary);
    border-radius: var(--border-radius);
    font-size: 1.1rem;
}

.contact-item h4 {
    font-size: 1rem;
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-primary);
    margin-bottom: var(--spacing-xs);
}

.contact-item a {
    color: var(--color-primary);
    text-decoration: none;
    transition: var(--transition);
}

.contact-item a:hover {
    color: var(--color-primary-dark);
}

.contact-item p {
    color: var(--color-text-secondary);
    margin: 0;
}

.footer {
    background: var(--color-text-primary);
    color: white;
    padding: var(--spacing-xl) 0;
    text-align: center;
}

.footer p {
    color: var(--color-secondary);
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: var(--spacing-xl);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .profile-img {
        width: 250px;
        height: 250px;
    }
    
    .about-content {
        grid-template-columns: 1fr;
        gap: var(--spacing-xl);
    }
    
    .about-stats {
        flex-direction: row;
        justify-content: space-around;
    }
    
    .timeline-item {
        padding-left: 60px;
    }
    
    .timeline::before {
        left: 20px;
    }
    
    .timeline-marker {
        left: 12px;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }
    
    .btn {
        width: 200px;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }
    
    .hero {
        padding: calc(80px + var(--spacing-xl)) var(--spacing-md) var(--spacing-xl);
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .timeline-content {
        padding: var(--spacing-md);
    }
    
    .skill-category {
        padding: var(--spacing-md);
    }
    
    .contact-item {
        padding: var(--spacing-md);
    }
}