/* CSS Variables */
:root {
    --primary: #0d7bdb;
    --secondary: #764ba2;
    --bg: #000000;
    --surface: #111111;
    --text: #ffffff;
    --text-dim: #888888;
    --accent: rgba(13, 123, 219, 0.1);
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --section-padding: 6rem;
    --nav-height: 80px;
}

[data-theme="light"] {
    --bg: #ffffff;
    --surface: #f8f9fa;
    --text: #000000;
    --text-dim: #666666;
    --accent: rgba(13, 123, 219, 0.05);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Inter', 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.5;
    transition: background-color var(--transition), color var(--transition);
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Improve text rendering */
body {
    text-rendering: optimizeLegibility;
}

/* Skip to main content for accessibility */
.skip-to-main {
    position: absolute;
    top: -100px;
    left: 0;
    background: var(--primary);
    color: white;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    z-index: 10000;
    font-weight: 600;
    border-radius: 0 0 8px 0;
    transition: top 0.3s ease;
}

.skip-to-main:focus {
    top: 0;
    outline: 2px solid white;
    outline-offset: -2px;
}

/* Navigation */
nav[aria-label="Main navigation"] {
    position: fixed;
    top: 1rem;
    left: 50%;
    transform: translateX(-50%);
    z-index: 1000;
    backdrop-filter: blur(20px);
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 50px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    transition: all var(--transition);
    will-change: transform;
}

[data-theme="light"] nav[aria-label="Main navigation"] {
    background: rgba(255, 255, 255, 0.3);
    border-color: rgba(0, 0, 0, 0.1);
}

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

.logo {
    font-size: 1.25rem;
    font-weight: 800;
    color: var(--primary);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.logo:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 4px;
    border-radius: 4px;
}

.nav-menu {
    display: flex;
    gap: 1rem;
    list-style: none;
    margin: 0;
}

.nav-menu a {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9rem;
    transition: all var(--transition);
    opacity: 0.8;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    display: inline-block;
}

.nav-menu a:hover,
.nav-menu a:focus-visible {
    opacity: 1;
    color: var(--primary);
    background: var(--accent);
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

.nav-actions {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.theme-btn,
.lang-btn {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all var(--transition);
    color: var(--text);
    font-weight: 600;
    font-size: 0.75rem;
}

.theme-btn:hover,
.theme-btn:focus-visible,
.lang-btn:hover,
.lang-btn:focus-visible {
    transform: scale(1.1);
    background: var(--primary);
    color: white;
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Hero Section */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: radial-gradient(ellipse at center, rgba(13, 123, 219, 0.15) 0%, transparent 70%);
    scroll-margin-top: var(--nav-height);
    will-change: transform;
    /* Add containment for better performance */
    contain: layout style paint;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    padding: 0 2rem;
}

.hero h1 {
    font-size: clamp(3rem, 6vw, 6rem);
    font-weight: 900;
    margin-bottom: 2rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
    letter-spacing: -0.01em;
    /* Prevent text selection issues with gradient text */
    user-select: none;
}

.hero p {
    font-size: 1.5rem;
    color: var(--text-dim);
    margin-bottom: 3rem;
    font-weight: 400;
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 2rem;
    background: var(--primary);
    color: white;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 600;
    transition: all var(--transition);
    box-shadow: 0 4px 20px rgba(13, 123, 219, 0.3);
}

.hero-cta:hover,
.hero-cta:focus-visible {
    transform: translateY(-2px) scale(1.03);
    box-shadow: 0 8px 30px rgba(13, 123, 219, 0.4);
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Sections */
.section {
    padding: var(--section-padding) 2rem;
    max-width: 1200px;
    margin: 0 auto;
    scroll-margin-top: var(--nav-height);
    /* Add containment */
    contain: layout style;
}

.section-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 3rem;
    text-align: center;
    letter-spacing: -0.02em;
}

/* About Section */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
    max-width: 900px;
    margin: 0 auto;
}

.about-text {
    font-size: 1.25rem;
    color: var(--text-dim);
    line-height: 1.7;
    text-align: center;
}

.about-visual {
    width: 100%;
    max-width: 300px;
    height: 380px;
    border-radius: 2rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    overflow: hidden;
    margin: 0 auto;
    /* Improve image rendering performance */
    contain: strict;
}

.about-visual img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    /* Lazy load images for better performance */
    loading: lazy;
    /* Improve image rendering */
    image-rendering: -webkit-optimize-contrast;
}

/* Jobs Timeline */
.jobs-timeline {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.job-card {
    background: var(--surface);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1rem;
    padding: 2rem;
    transition: all var(--transition);
    display: flex;
    gap: 1.5rem;
    align-items: center;
    opacity: 0;
    transform: translateY(30px);
    /* Add containment */
    contain: layout style paint;
}

.job-card.animated {
    animation: fadeInUp 0.6s ease forwards;
}

.job-card:hover {
    transform: translateY(-8px) scale(1.02);
    border-color: var(--primary);
    box-shadow: 0 15px 40px rgba(13, 123, 219, 0.3);
}

.job-icon {
    width: 48px;
    height: 48px;
    border-radius: 12px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    flex-shrink: 0;
}

.job-info h3 {
    font-size: 1.2rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.job-company {
    font-size: 1rem;
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.job-period {
    font-size: 0.9rem;
    color: var(--text-dim);
    display: block;
}

/* Skills Tabs */
.tabs-menu {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 2.5rem;
    padding: 0.5rem;
    background: var(--surface);
    border-radius: 50px;
    border: 1px solid rgba(255, 255, 255, 0.1);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.tab-btn {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: transparent;
    border: none;
    border-radius: 50px;
    color: var(--text-dim);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    white-space: nowrap;
    font-family: inherit;
}

.tab-btn:hover {
    color: var(--text);
    background: rgba(255, 255, 255, 0.05);
    transform: scale(1.03);
}

.tab-btn.active {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 12px rgba(13, 123, 219, 0.3);
}

.tab-btn:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

.tabs-content {
    position: relative;
    min-height: 300px;
}

.tab-panel {
    display: none;
    animation: fadeIn 0.4s ease;
}

.tab-panel.active {
    display: block;
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.skill-card {
    background: var(--surface);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1rem;
    padding: 2rem;
    transition: all var(--transition);
    opacity: 0;
    transform: translateY(30px);
    /* Add containment */
    contain: layout style paint;
}

.skill-card.animated {
    animation: fadeInUp 0.6s ease forwards;
}

.skill-card:hover {
    transform: translateY(-8px) scale(1.02);
    border-color: var(--primary);
    box-shadow: 0 15px 40px rgba(13, 123, 219, 0.3);
}

.skill-card h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.skill-card p {
    color: var(--text-dim);
    font-size: 0.9rem;
}

/* Certification Links */
.cert-link {
    text-decoration: none;
    color: inherit;
    display: block;
}

.cert-link .skill-card:hover {
    cursor: pointer;
}

.cert-link:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 4px;
    border-radius: 1rem;
}

.cert-date {
    display: block;
    margin-top: 1rem;
    color: var(--text-dim);
    font-size: 0.85rem;
}

/* Contact Section */
.contact {
    text-align: center;
    background: var(--surface);
    border-radius: 2rem;
    padding: 4rem 3rem;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.contact-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 2rem;
    margin-top: 2.5rem;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1.25rem 2.5rem;
    background: var(--primary);
    color: white;
    text-decoration: none;
    border-radius: 50px;
    font-weight: 600;
    font-size: 1.1rem;
    transition: all var(--transition);
}

.contact-link:hover {
    transform: translateY(-5px) scale(1.03);
    box-shadow: 0 15px 40px rgba(13, 123, 219, 0.4);
}

.contact-link:focus-visible {
    outline: 2px solid white;
    outline-offset: 2px;
}

/* Footer */
footer {
    background: var(--surface);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: 3rem 2rem;
    text-align: center;
    color: var(--text-dim);
}

footer p {
    margin-bottom: 1rem;
    font-size: 0.95rem;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 1rem;
}

.footer-links a {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 50px;
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all var(--transition);
}

.footer-links a:hover,
.footer-links a:focus-visible {
    color: var(--primary);
    background: var(--accent);
    border-color: var(--primary);
    transform: translateY(-3px) scale(1.03);
    box-shadow: 0 8px 20px rgba(13, 123, 219, 0.25);
}

.footer-links a:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

/* Focus visible styles for better accessibility */
:focus-visible {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Responsive Design */
@media (max-width: 768px) {
    :root {
        --section-padding: 4rem;
    }

    .nav-menu {
        display: none;
    }

    .nav-container {
        padding: 1rem;
    }

    .hero h1 {
        font-size: 3.5rem;
    }

    .about-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }

    .about-visual {
        max-width: 100%;
    }

    .section {
        padding: 4rem 1rem;
    }

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

    .job-card {
        padding: 1.5rem;
    }

    .job-icon {
        width: 40px;
        height: 40px;
    }

    .job-info h3 {
        font-size: 1rem;
    }

    .tabs-menu {
        border-radius: 1rem;
        padding: 0.25rem;
        gap: 0.25rem;
    }

    .tab-btn {
        padding: 0.6rem 1rem;
        font-size: 0.85rem;
    }

    .tab-btn span {
        display: none;
    }

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

    .contact {
        padding: 3rem 1.5rem;
    }

    .contact-links {
        flex-direction: column;
        gap: 1rem;
    }

    .contact-link {
        width: 100%;
        padding: 1rem 2rem;
        font-size: 1rem;
        justify-content: center;
    }

    .footer-links {
        flex-direction: column;
        align-items: center;
        gap: 0.75rem;
    }

    .footer-links a {
        width: 100%;
        max-width: 180px;
        padding: 0.65rem 1.25rem;
        font-size: 0.85rem;
        justify-content: center;
    }
}

/* Print styles */
@media print {
    nav,
    .theme-btn,
    .lang-btn,
    .hero-cta {
        display: none !important;
    }

    body {
        background: white;
        color: black;
    }

    .section {
        page-break-inside: avoid;
    }
}

/* 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;
    }

    .hero {
        will-change: auto;
    }
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --primary: #0066cc;
        --text-dim: #555555;
    }

    [data-theme="light"] {
        --text-dim: #444444;
    }

    .nav-menu a,
    .tab-btn,
    .skill-card,
    .job-card {
        border: 2px solid currentColor;
    }
}