/* CSS Reset and Base Styles */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    /* Color palette */
    --color-primary: #2563eb;
    --color-primary-dark: #1d4ed8;
    --color-secondary: #64748b;
    --color-accent: #f59e0b;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-background: #ffffff;
    --color-background-alt: #f9fafb;
    --color-border: #e5e7eb;
    --color-border-light: #f3f4f6;
    
    /* Typography */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 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;
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    
    /* Layout */
    --container-max-width: 1200px;
    --border-radius: 0.5rem;
    --border-radius-lg: 0.75rem;
    --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);
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
}

/* Base Elements */
html {
    scroll-behavior: smooth;
}

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

/* Screen Reader Only Content */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* Skip Link for Accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 6px;
    background: var(--color-primary);
    color: white;
    padding: var(--space-2) var(--space-4);
    text-decoration: none;
    border-radius: var(--border-radius);
    z-index: 1000;
    transition: var(--transition-fast);
}

.skip-link:focus {
    top: 6px;
}

/* Layout Components */
.container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.section {
    padding: var(--space-16) 0;
}

.section-title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--space-12);
    color: var(--color-text);
}

/* Header and Navigation */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border-light);
    z-index: 100;
    transition: var(--transition-normal);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) 0;
}

.logo h1 {
    font-size: var(--font-size-xl);
    font-weight: 700;
}

.logo-link {
    color: var(--color-text);
    text-decoration: none;
    transition: var(--transition-fast);
}

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

/* Mobile Navigation */
.nav {
    position: relative;
}

.nav-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--space-2);
    position: relative;
    z-index: 101;
}

.hamburger {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    position: relative;
    transition: var(--transition-fast);
}

.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 100%;
    height: 2px;
    background: var(--color-text);
    transition: var(--transition-fast);
}

.hamburger::before {
    top: -8px;
}

.hamburger::after {
    bottom: -8px;
}

.nav-toggle[aria-expanded="true"] .hamburger {
    background: transparent;
}

.nav-toggle[aria-expanded="true"] .hamburger::before {
    transform: rotate(45deg);
    top: 0;
}

.nav-toggle[aria-expanded="true"] .hamburger::after {
    transform: rotate(-45deg);
    bottom: 0;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--space-6);
    align-items: center;
}

.nav-link {
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
    padding: var(--space-2) var(--space-3);
    border-radius: var(--border-radius);
    transition: var(--transition-fast);
}

.nav-link:hover,
.nav-link:focus {
    color: var(--color-primary);
    background-color: var(--color-background-alt);
}

/* Language Switcher */
.language-switcher {
    display: flex;
    gap: var(--space-1);
}

.lang-btn {
    background: none;
    border: 1px solid var(--color-border);
    color: var(--color-text-light);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: var(--font-size-sm);
    font-weight: 500;
    transition: var(--transition-fast);
}

.lang-btn:hover,
.lang-btn.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

/* Main Content */
.main {
    margin-top: 80px; /* Account for fixed header */
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--color-background-alt) 0%, var(--color-background) 100%);
    padding: var(--space-20) 0;
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-12);
    align-items: center;
    text-align: center;
}

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

.hero-subtitle {
    font-size: var(--font-size-xl);
    color: var(--color-text-light);
    margin-bottom: var(--space-8);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.skills {
    margin-bottom: var(--space-8);
}

.skills-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--space-4);
    color: var(--color-text);
}

.skills-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    justify-content: center;
}

.skill-tag {
    background: var(--color-primary);
    color: white;
    padding: var(--space-2) var(--space-4);
    border-radius: var(--border-radius);
    font-size: var(--font-size-sm);
    font-weight: 500;
}

.hero-actions {
    display: flex;
    gap: var(--space-4);
    justify-content: center;
    flex-wrap: wrap;
}

.profile-img {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    object-fit: cover;
    border: 4px solid white;
    box-shadow: var(--shadow-lg);
    margin: 0 auto;
    display: block;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-3) var(--space-6);
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 600;
    font-size: var(--font-size-base);
    transition: var(--transition-fast);
    cursor: pointer;
    border: none;
    min-width: 120px;
}

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

.btn-primary:hover,
.btn-primary:focus {
    background: var(--color-primary-dark);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-secondary:hover,
.btn-secondary:focus {
    background: var(--color-primary);
    color: white;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.btn-outline:hover,
.btn-outline:focus {
    background: var(--color-text);
    color: white;
    border-color: var(--color-text);
}

.btn-full {
    width: 100%;
}

/* Skills and Education Section */
.skills-education {
    background: var(--color-background-alt);
    padding: var(--space-16) 0;
}

.compact-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-8);
}

.left-column, .right-column {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
}

.compact-box {
    background: white;
    border-radius: var(--border-radius-lg);
    padding: var(--space-6);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.compact-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--space-4);
}

/* Languages */
.language-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.language-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-2) 0;
}

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

.language-level {
    font-size: var(--font-size-sm);
    font-weight: 500;
    padding: var(--space-1) var(--space-3);
    border-radius: var(--border-radius);
}

.language-level.native {
    background: var(--color-primary);
    color: white;
}

.language-level.professional {
    background: var(--color-accent);
    color: white;
}

.language-level.basics {
    background: var(--color-background-alt);
    color: var(--color-text);
    border: 1px solid var(--color-border);
}

/* Education Compact */
.education-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.education-item-compact {
    display: flex;
    align-items: flex-start;
    gap: var(--space-2);
}

.education-bullet {
    color: var(--color-primary);
    font-weight: bold;
    margin-top: 2px;
}

.education-text {
    font-size: var(--font-size-sm);
    color: var(--color-text);
    line-height: 1.5;
}

/* Technical Skills Compact */
.skills-grid-compact {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-6);
}

.skill-section {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.skill-section-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text);
    border-bottom: 2px solid var(--color-border);
    padding-bottom: var(--space-2);
}

.skill-subsection {
    display: flex;
    align-items: flex-start;
    gap: var(--space-3);
    padding: var(--space-3);
    background: var(--color-background-alt);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border-light);
}

.skill-icon {
    font-size: var(--font-size-lg);
    min-width: 24px;
}

.skill-name {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: var(--space-1);
    line-height: 1.3;
}

.skill-details {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    line-height: 1.4;
    margin: 0;
}

/* Education Styles */
.education-item {
    padding: var(--space-5);
    border-left: 4px solid var(--color-primary);
    background: var(--color-background-alt);
    border-radius: 0 var(--border-radius) var(--border-radius) 0;
    margin-bottom: var(--space-5);
    position: relative;
}

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

.education-item::before {
    content: '';
    position: absolute;
    left: -8px;
    top: var(--space-5);
    width: 12px;
    height: 12px;
    background: var(--color-primary);
    border-radius: 50%;
    border: 3px solid white;
    box-shadow: 0 0 0 1px var(--color-primary);
}

.education-degree {
    font-size: var(--font-size-lg);
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--space-2);
    line-height: 1.3;
}

.education-institution {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: var(--space-1);
}

.education-year {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    font-weight: 500;
    margin-bottom: var(--space-2);
}

.education-description {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    line-height: 1.6;
}

.certification-list {
    margin-top: var(--space-3);
}

.certification-item {
    font-size: var(--font-size-sm);
    color: var(--color-text-light);
    margin-bottom: var(--space-1);
    line-height: 1.5;
}

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

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

.projects-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-8);
}

.project-card {
    background: white;
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition-normal);
}

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

.project-image {
    height: 200px;
    overflow: hidden;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition-normal);
}

.project-card:hover .project-image img {
    transform: scale(1.05);
}

.project-content {
    padding: var(--space-6);
}

.project-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--space-3);
    color: var(--color-text);
}

.project-description {
    color: var(--color-text-light);
    margin-bottom: var(--space-4);
    line-height: 1.7;
}

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    margin-bottom: var(--space-5);
}

.tech-tag {
    background: var(--color-background-alt);
    color: var(--color-text);
    padding: var(--space-1) var(--space-3);
    border-radius: var(--border-radius);
    font-size: var(--font-size-sm);
    font-weight: 500;
    border: 1px solid var(--color-border);
}

.project-links {
    display: flex;
    gap: var(--space-4);
}

.project-link {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    font-size: var(--font-size-sm);
    padding: var(--space-2) 0;
    border-bottom: 2px solid transparent;
    transition: var(--transition-fast);
}

.project-link:hover,
.project-link:focus {
    border-bottom-color: var(--color-primary);
}

/* Blog Section */
.blog-posts {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-6);
    margin-bottom: var(--space-10);
}

.blog-post {
    background: white;
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-lg);
    padding: var(--space-6);
    transition: var(--transition-fast);
}

.blog-post:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

.blog-post-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-bottom: var(--space-2);
}

.blog-post-title a {
    color: var(--color-text);
    text-decoration: none;
    transition: var(--transition-fast);
}

.blog-post-title a:hover {
    color: var(--color-primary);
}

.blog-post-meta {
    color: var(--color-text-light);
    font-size: var(--font-size-sm);
    margin-bottom: var(--space-4);
}

.blog-post-excerpt {
    color: var(--color-text-light);
    line-height: 1.7;
}

.blog-actions {
    text-align: center;
}

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

.contact-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-12);
    max-width: 800px;
    margin: 0 auto;
}

.contact-description {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    text-align: center;
    margin-bottom: var(--space-8);
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: var(--space-4);
}

.contact-method {
    display: flex;
    flex-direction: column;
    padding: var(--space-4);
    background: white;
    border-radius: var(--border-radius);
    text-decoration: none;
    transition: var(--transition-fast);
    border: 1px solid var(--color-border);
}

.contact-method:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-sm);
}

.contact-label {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text-light);
    margin-bottom: var(--space-1);
}

.contact-value {
    color: var(--color-primary);
    font-weight: 600;
}

/* Contact Form */
.contact-form {
    background: white;
    padding: var(--space-8);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-sm);
}

.form-group {
    margin-bottom: var(--space-5);
}

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--space-2);
    color: var(--color-text);
}

.form-input,
.form-textarea {
    width: 100%;
    padding: var(--space-3);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    font-size: var(--font-size-base);
    font-family: inherit;
    transition: var(--transition-fast);
    background: white;
}

.form-input:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 120px;
}

/* Footer */
.footer {
    background: var(--color-text);
    color: white;
    padding: var(--space-8) 0;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-4);
    text-align: center;
}

.footer-text {
    color: rgba(255, 255, 255, 0.8);
}

.footer-links {
    display: flex;
    gap: var(--space-6);
}

.footer-links a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition-fast);
}

.footer-links a:hover,
.footer-links a:focus {
    color: white;
}

/* Responsive Design - Mobile First Approach */

/* Tablet and up */
@media (min-width: 768px) {
    .container {
        padding: 0 var(--space-6);
    }
    
    .section {
        padding: var(--space-20) 0;
    }
    
    .section-title {
        font-size: var(--font-size-4xl);
    }
    
    .hero-content {
        grid-template-columns: 1fr 320px;
        text-align: left;
        gap: var(--space-16);
    }
    
    .hero-title {
        font-size: clamp(2.5rem, 5vw, 3.5rem);
    }
    
    .hero-subtitle {
        margin-left: 0;
        margin-right: 0;
    }
    
    .skills-list {
        justify-content: flex-start;
    }
    
    .hero-actions {
        justify-content: flex-start;
    }
    
    .compact-layout {
        grid-template-columns: 300px 1fr;
        gap: var(--space-12);
        align-items: start;
    }
    
    .skills-grid-compact {
        grid-template-columns: repeat(3, 1fr);
        gap: var(--space-6);
    }
    
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .blog-posts {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .contact-content {
        grid-template-columns: 1fr 1.2fr;
        gap: var(--space-16);
    }
    
    .contact-methods {
        gap: var(--space-6);
    }
    
    .contact-method {
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
    }
    
    .contact-label {
        margin-bottom: 0;
    }
    
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
        text-align: left;
    }
}

/* Desktop and up */
@media (min-width: 1024px) {
    .projects-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .blog-posts {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Mobile Navigation Styles */
@media (max-width: 767px) {
    .nav-toggle {
        display: block;
    }
    
    .nav-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(255, 255, 255, 0.98);
        backdrop-filter: blur(10px);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        transform: translateX(-100%);
        transition: var(--transition-normal);
        z-index: 100;
    }
    
    .nav-menu.active {
        transform: translateX(0);
    }
    
    .nav-link {
        font-size: var(--font-size-xl);
        padding: var(--space-4) var(--space-6);
    }
    
    .language-switcher {
        order: -1;
    }
}

/* Print Styles */
@media print {
    .header,
    .nav,
    .language-switcher,
    .contact-form,
    .footer {
        display: none;
    }
    
    .main {
        margin-top: 0;
    }
    
    .section {
        padding: var(--space-8) 0;
    }
    
    * {
        color: black !important;
        background: white !important;
    }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    :root {
        --color-text: #000000;
        --color-background: #ffffff;
        --color-primary: #0000ff;
        --color-border: #000000;
    }
}

/* Reduced Motion Support */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* Focus Styles for Better Accessibility */
*:focus {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

.btn:focus,
.form-input:focus,
.form-textarea:focus {
    outline: none;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.3);
}

/* Loading States */
.loading {
    opacity: 0.6;
    pointer-events: none;
}

.loading::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 20px;
    height: 20px;
    margin: -10px 0 0 -10px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-primary);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}