/* ===========================
   CSS Variables & Reset
   =========================== */
:root {
    /* Color Palette */
    --bg-primary: #0a0a0a;
    --bg-secondary: #121212;
    --bg-card: #1a1a1a;
    --text-primary: #f5f5f5;
    --text-secondary: #e0e0e0;
    --text-muted: #a0a0a0;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --border-color: #2a2a2a;
    
    /* 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', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    --font-size-base: 16px;
    --font-size-sm: 0.875rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.875rem;
    --font-size-3xl: 2.25rem;
    --font-size-4xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
}

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

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

body {
    font-family: var(--font-primary);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

section {
    padding: var(--spacing-xl) 0;
    min-height: auto;
}

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

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-sm) var(--spacing-md);
}

.nav-brand a {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--accent);
    text-decoration: none;
    transition: var(--transition-fast);
}

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

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

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: var(--transition-fast);
    padding: var(--spacing-xs) 0;
    position: relative;
}

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

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

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

/* Mobile Navigation Toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 0.25rem;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition-base);
}

/* ===========================
   Hero Section
   =========================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 80px;
}

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

.hero-title {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

.hero-title .accent {
    color: var(--accent);
}

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

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

.hero-cta {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
}

/* ===========================
   Buttons
   =========================== */
.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: 600;
    font-size: var(--font-size-base);
    transition: var(--transition-base);
    cursor: pointer;
    border: 2px solid transparent;
}

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

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

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

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

/* ===========================
   Section Titles
   =========================== */
.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-lg);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background-color: var(--accent);
    margin: var(--spacing-sm) auto 0;
    border-radius: var(--radius-sm);
}

/* ===========================
   About Section
   =========================== */
.about {
    background-color: var(--bg-secondary);
}

.about-content {
    max-width: 800px;
    margin: 0 auto;
}

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

.about-text p:last-child {
    margin-bottom: 0;
}

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

.skill-card {
    background-color: var(--bg-card);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: var(--transition-base);
    text-align: center;
}

.skill-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.1);
}

.skill-icon {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.skill-card h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.skill-card p {
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

/* ===========================
   Projects Section
   =========================== */
.projects {
    background-color: var(--bg-secondary);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.project-card {
    background-color: var(--bg-card);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: var(--transition-base);
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent);
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.1);
}

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

.project-header h3 {
    font-size: var(--font-size-xl);
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

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

.tag {
    background-color: rgba(59, 130, 246, 0.1);
    color: var(--accent);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.project-description {
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
    flex-grow: 1;
}

.project-links {
    margin-top: auto;
}

.project-link {
    color: var(--accent);
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    transition: var(--transition-fast);
}

.project-link:hover {
    color: var(--accent-hover);
    transform: translateX(5px);
}

/* ===========================
   Education Section
   =========================== */
.education-content {
    max-width: 700px;
    margin: 0 auto var(--spacing-lg);
}

.education-card {
    background-color: var(--bg-card);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.education-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
    flex-wrap: wrap;
    gap: var(--spacing-sm);
}

.education-header h3 {
    font-size: var(--font-size-xl);
    color: var(--text-primary);
}

.education-year {
    color: var(--accent);
    font-weight: 600;
}

.education-field {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
}

.education-institution {
    color: var(--text-muted);
    margin-bottom: 0.25rem;
}

.education-location {
    color: var(--text-muted);
    font-size: var(--font-size-sm);
}

/* Achievements */
.achievements {
    max-width: 700px;
    margin: 0 auto;
}

.achievements-title {
    font-size: var(--font-size-2xl);
    margin-bottom: var(--spacing-md);
    text-align: center;
}

.achievements-list {
    list-style: none;
    padding: 0;
}

.achievements-list li {
    background-color: var(--bg-card);
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--accent);
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

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

/* ===========================
   Contact Section
   =========================== */
.contact {
    background-color: var(--bg-secondary);
}

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

.contact-intro {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.7;
}

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

.contact-item {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background-color: var(--bg-card);
    border-radius: var(--radius-md);
    border: 1px solid var(--border-color);
    transition: var(--transition-base);
}

.contact-item:hover {
    border-color: var(--accent);
    transform: translateY(-2px);
}

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

.contact-item a {
    color: var(--text-primary);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-fast);
}

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

/* ===========================
   Footer
   =========================== */
.footer {
    background-color: var(--bg-primary);
    padding: var(--spacing-lg) 0;
    text-align: center;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-muted);
    margin-bottom: var(--spacing-xs);
}

.footer-note {
    font-size: var(--font-size-sm);
    font-style: italic;
}

/* ===========================
   Responsive Design
   =========================== */

/* Tablet */
@media (max-width: 768px) {
    :root {
        --font-size-4xl: 2.25rem;
        --font-size-3xl: 1.875rem;
        --font-size-2xl: 1.5rem;
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 60px;
        flex-direction: column;
        background-color: var(--bg-secondary);
        width: 100%;
        text-align: center;
        transition: var(--transition-base);
        box-shadow: 0 10px 27px rgba(0, 0, 0, 0.3);
        border-bottom: 1px solid var(--border-color);
        padding: var(--spacing-md) 0;
        gap: var(--spacing-sm);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }
    
    .nav-toggle.active span:nth-child(2) {
        opacity: 0;
    }
    
    .nav-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }
    
    .skills-grid,
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .education-header {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* Mobile */
@media (max-width: 480px) {
    :root {
        --font-size-4xl: 1.875rem;
        --font-size-3xl: 1.5rem;
        --spacing-md: 1.5rem;
        --spacing-lg: 2.5rem;
        --spacing-xl: 3rem;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        text-align: center;
    }
}

/* Large screens */
@media (min-width: 1400px) {
    .container {
        max-width: 1320px;
    }
}