/* CSS Variables for Easy Customization */
:root {
    --primary-color: #1a56db;
    --secondary-color: #7c3aed;
    --text-dark: #1f2937;
    --text-medium: #4b5563;
    --text-light: #f3f4f6;
    --bg-light: #f9fafb;
    --bg-dark: #111827;
    --white: #ffffff;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 6px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px rgba(0,0,0,0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    scroll-behavior: smooth;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 2rem;
}

.section {
    padding: 5rem 0;
}

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

.bg-dark {
    background-color: var(--bg-dark);
}

.text-light {
    color: var(--text-light) !important;
}

/* Header & Navigation */
.header {
    position: fixed;
    top: 0;
    width: 100%;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: var(--transition);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 2rem;
}

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: var(--transition);
    position: relative;
}

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

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

/* Hero Section */
.hero {
    margin-top: 80px;
    padding: 6rem 0;
    text-align: center;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.hero-description {
    font-size: 1.125rem;
    max-width: 700px;
    margin: 0 auto 2rem;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    padding: 0.75rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    display: inline-block;
}

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

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

/* Section Titles */
.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 3rem;
}

/* Timeline for Experience */
.timeline {
    position: relative;
    max-width: 900px;
    margin: 0 auto;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 2px;
    height: 100%;
    background: var(--border-color);
}

.timeline-item {
    position: relative;
    margin-bottom: 3rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.timeline-date {
    background: var(--primary-color);
    color: var(--white);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-weight: 600;
    width: 180px;
    text-align: center;
}

.timeline-content {
    width: 45%;
    background: var(--white);
    padding: 1.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
}

/* Cards for Education */
.cards-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--white);
    padding: 2rem;
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    border-left: 4px solid var(--primary-color);
}

/* Skills Section */
.skill-categories {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.skill-category h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

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

.skill-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-color);
}

/* Contact Section */
.contact-grid {
    max-width: 800px;
    margin: 0 auto;
}

.contact-details {
    list-style: none;
    margin-top: 1.5rem;
}

.contact-details li {
    display: flex;
    align-items: center;
    margin-bottom: 1rem;
    color: var(--text-light);
}

.icon {
    width: 24px;
    height: 24px;
    margin-right: 1rem;
}

/* Footer */
.footer {
    background: var(--bg-dark);
    color: var(--text-light);
    text-align: center;
    padding: 2rem 0;
}

/* Mobile Responsiveness */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        background: var(--white);
        flex-direction: column;
        padding: 2rem;
        box-shadow: var(--shadow-md);
        transition: var(--transition);
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-toggle {
        display: block;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .timeline::before {
        left: 20px;
    }

    .timeline-item {
        flex-direction: column !important;
        align-items: flex-start;
        margin-left: 60px;
    }

    .timeline-content {
        width: 100%;
    }
}