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

:root {
    /* Color Palette - Modern & Minimal */
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --border-color: #e5e7eb;
    --accent-color: #3b82f6;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    --font-size-base: 16px;

    /* Layout */
    --max-width: 1200px;
    --navbar-height: 70px;

    /* Transitions */
    --transition-base: all 0.3s ease;
}

html {
    scroll-behavior: smooth;
    font-size: var(--font-size-base);
}

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

/* ============================================
   Navigation
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: var(--transition-base);
}

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

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
    transition: var(--transition-base);
}

.logo:hover {
    color: var(--primary-dark);
}

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

.nav-link {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 6px;
    transition: var(--transition-base);
}

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

/* ============================================
   Hero Section
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #f9fafb 0%, #e5e7eb 100%);
    padding: var(--spacing-xl) var(--spacing-md);
    margin-top: var(--navbar-height);
}

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

.hero h1 {
    font-size: 4rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    letter-spacing: -0.02em;
}

.subtitle {
    font-size: 1.5rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
}

.description {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.cta-buttons {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    margin-top: var(--spacing-md);
}

.btn {
    padding: 0.875rem 2rem;
    border-radius: 8px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-base);
    font-size: 1rem;
    display: inline-block;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(37, 99, 235, 0.3);
}

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

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

/* ============================================
   Shared Section Styles
   ============================================ */
.section {
    padding: var(--spacing-xl) var(--spacing-md);
}

.section:nth-child(even) {
    background-color: var(--bg-secondary);
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--text-primary);
}

/* ============================================
   About Section
   ============================================ */
.about-content {
    max-width: 800px;
    margin: 0 auto;
}

.about-text p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

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

.project-card {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: var(--spacing-md);
    transition: var(--transition-base);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    border-color: var(--primary-color);
}

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

.project-header h3 {
    font-size: 1.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.project-tag {
    background-color: var(--bg-tertiary);
    color: var(--primary-color);
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

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

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-sm);
}

.tech-tag {
    background-color: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: 6px;
    font-size: 0.875rem;
}

.project-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition-base);
}

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

/* ============================================
   Skills Section
   ============================================ */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
}

.skill-category {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: var(--spacing-md);
}

.skill-category h3 {
    font-size: 1.25rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
}

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

.skill-category li {
    color: var(--text-secondary);
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
}

.skill-category li:before {
    content: "→";
    position: absolute;
    left: 0;
    color: var(--primary-color);
}

/* ============================================
   Contact Section
   ============================================ */
.contact-intro {
    text-align: center;
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

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

.contact-links {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    max-width: 900px;
    margin: 0 auto;
}

.contact-links .contact-item {
    flex: 0 1 250px;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    text-decoration: none;
    color: var(--text-primary);
    transition: var(--transition-base);
}

.contact-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
}

.contact-icon {
    font-size: 1.5rem;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background-color: var(--text-primary);
    color: white;
    text-align: center;
    padding: var(--spacing-md);
}

/* ============================================
   Animations
   ============================================ */
.fade-in {
    animation: fadeIn 1s ease-in;
}

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

.fade-in:nth-child(1) { animation-delay: 0.1s; }
.fade-in:nth-child(2) { animation-delay: 0.2s; }
.fade-in:nth-child(3) { animation-delay: 0.3s; }
.fade-in:nth-child(4) { animation-delay: 0.4s; }

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .subtitle {
        font-size: 1.25rem;
    }

    .description {
        font-size: 1rem;
    }

    .nav-menu {
        gap: var(--spacing-sm);
    }

    .nav-link {
        padding: 0.5rem;
        font-size: 0.9rem;
    }

    .cta-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 300px;
    }

    .section {
        padding: var(--spacing-lg) var(--spacing-sm);
    }

    .section-title {
        font-size: 2rem;
    }

    .projects-grid {
        grid-template-columns: 1fr;
    }

    .skills-grid {
        grid-template-columns: 1fr;
    }

    .contact-links {
        flex-direction: column;
    }

    .contact-links .contact-item {
        flex: 1 1 auto;
    }
}

@media (max-width: 480px) {
    .hero h1 {
        font-size: 2rem;
    }

    .nav-container {
        padding: 0 var(--spacing-sm);
    }

    .logo {
        font-size: 1.25rem;
    }
}