/* ========== CSS Variables ========== */
:root {
    /* Colors */
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --bg-color: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-dark: #111827;
    --border-color: #e5e7eb;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --highlight-color: #3b82f6;
    --card-bg: #ffffff;
    --input-bg: #ffffff;
    --header-bg: rgba(255, 255, 255, 0.98);
    --header-bg-scroll: rgba(255, 255, 255, 1);

    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    --font-secondary: 'Georgia', serif;

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

    /* Border Radius */
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;

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

/* ========== Dark Mode ========== */
[data-theme="dark"] {
    --primary-color: #3b82f6;
    --secondary-color: #60a5fa;
    --accent-color: #93bbfd;
    --text-color: #f3f4f6;
    --text-light: #9ca3af;
    --bg-color: #111827;
    --bg-secondary: #1f2937;
    --bg-dark: #030712;
    --border-color: #374151;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --highlight-color: #60a5fa;
    --card-bg: #1f2937;
    --input-bg: #374151;
    --header-bg: rgba(17, 24, 39, 0.98);
    --header-bg-scroll: rgba(17, 24, 39, 1);
}

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

html {
    scroll-behavior: smooth;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ========== Skip Link ========== */
.skip-link {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    background-color: var(--primary-color);
    color: white;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    z-index: 10000;
    text-decoration: none;
    font-weight: 600;
    transition: top 0.2s;
}

.skip-link:focus {
    top: 1rem;
}

/* ========== Focus Visible ========== */
:focus-visible {
    outline: 3px solid var(--primary-color);
    outline-offset: 2px;
}

/* ========== Header & Navigation ========== */
#header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: var(--header-bg);
    box-shadow: 0 2px 10px var(--shadow-color);
    z-index: 1000;
    transition: var(--transition);
}

.navbar {
    padding: 1rem 0;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

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

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

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

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

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

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: var(--transition);
}

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

.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.hamburger .bar {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    transition: var(--transition);
    border-radius: 3px;
}

/* ========== Theme Toggle ========== */
.theme-toggle {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid var(--border-color);
    background-color: var(--bg-secondary);
    color: var(--text-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    transition: var(--transition);
}

.theme-toggle:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

/* ========== Hero Section ========== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-md);
}

.hero-content {
    max-width: 800px;
    animation: fadeInUp 1s ease;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
}

.highlight {
    color: #fbbf24;
}

.hero-subtitle {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: rgba(255, 255, 255, 0.9);
}

.hero-description {
    font-size: 1.125rem;
    margin-bottom: var(--spacing-md);
    color: rgba(255, 255, 255, 0.85);
}

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

.scroll-down {
    position: absolute;
    bottom: 2rem;
    left: 50%;
    transform: translateX(-50%);
    animation: bounce 2s infinite;
}

.scroll-down a {
    color: white;
    font-size: 2rem;
    text-decoration: none;
}

/* ========== Buttons ========== */
.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    cursor: pointer;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background-color: transparent;
    color: white;
    border-color: white;
}

.btn-secondary {
    background-color: transparent;
    color: white;
    border-color: white;
}

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

/* ========== Section Styles ========== */
section {
    padding: var(--spacing-xl) 0;
}

.section-title {
    font-size: 2.5rem;
    text-align: center;
    margin-bottom: var(--spacing-sm);
    color: var(--text-color);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background-color: var(--primary-color);
    margin: 1rem auto 0;
    border-radius: 2px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    margin-bottom: var(--spacing-lg);
    font-size: 1.125rem;
}

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

.about-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: var(--spacing-lg);
    align-items: center;
}

.about-image img {
    width: 300px;
    height: 300px;
    border-radius: 50%;
    object-fit: cover;
    display: block;
    margin: 0 auto;
}

.about-text h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-color);
}

.about-text p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-light);
    line-height: 1.8;
}

.about-info {
    margin-top: var(--spacing-md);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.info-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    color: var(--text-color);
}

.info-item i {
    color: var(--primary-color);
    font-size: 1.25rem;
}

.info-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.info-item a:hover {
    text-decoration: underline;
}

/* ========== Projects Section ========== */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.project-card {
    background-color: var(--card-bg);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 4px 6px var(--shadow-color);
    transition: var(--transition);
}

.project-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 12px 24px var(--shadow-color);
}

.project-image .image-placeholder {
    height: 200px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-image .image-placeholder i {
    font-size: 4rem;
    color: white;
}

.project-content {
    padding: var(--spacing-md);
}

.project-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-color);
}

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

.project-tech {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: var(--spacing-sm);
}

.tech-tag {
    background-color: var(--bg-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    color: var(--primary-color);
    font-weight: 500;
}

.project-links {
    display: flex;
    gap: var(--spacing-sm);
}

.project-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

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

/* ========== Project Impact ========== */
.project-impact {
    font-style: italic;
    font-size: 0.9rem;
    color: var(--text-light);
    border-left: 3px solid var(--primary-color);
    padding-left: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

/* ========== Skills Section ========== */
.skills {
    background-color: var(--bg-color);
}

.skills-container {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-md);
}

.skill-category {
    background-color: var(--card-bg);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 6px var(--shadow-color);
}

.category-title {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-color);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.category-title i {
    color: var(--primary-color);
}

.skill-items {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-sm);
}

.skill-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.skill-item:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-3px);
}

.skill-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
    transition: var(--transition);
}

.skill-item:hover i {
    color: white;
}

/* ========== Contact Section ========== */
.contact-content {
    display: flex;
    justify-content: flex-start;
}

.contact-info {
    max-width: 600px;
    text-align: left;
}

.contact-info h3 {
    font-size: 1.75rem;
    margin-bottom: var(--spacing-sm);
    color: var(--text-color);
}

.contact-info p {
    color: var(--text-light);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

.contact-details {
    display: inline-flex;
    flex-direction: column;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    text-align: left;
}

.contact-item {
    display: flex;
    gap: var(--spacing-sm);
    align-items: flex-start;
}

.contact-item i {
    font-size: 1.5rem;
    color: var(--primary-color);
    margin-top: 0.25rem;
}

.contact-item h4 {
    font-size: 1rem;
    margin-bottom: 0.25rem;
    color: var(--text-color);
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

.contact-item p {
    margin-bottom: 0;
}

.social-links {
    display: flex;
    justify-content: flex-start;
    gap: var(--spacing-sm);
}

.social-link {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    transition: var(--transition);
}

.social-link:hover {
    background-color: var(--accent-color);
    transform: translateY(-3px);
}

.social-link i {
    font-size: 1.25rem;
}

/* ========== Footer ========== */
.footer {
    background-color: var(--bg-dark);
    color: white;
    padding: var(--spacing-md) 0;
    position: relative;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.footer-links {
    display: flex;
    gap: var(--spacing-sm);
}

.footer-links a {
    color: white;
    font-size: 1.25rem;
    transition: var(--transition);
}

.footer-links a:hover {
    color: var(--accent-color);
}

.scroll-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: none;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    box-shadow: 0 4px 12px var(--shadow-color);
    transition: var(--transition);
    z-index: 999;
}

.scroll-top:hover {
    background-color: var(--accent-color);
    transform: translateY(-3px);
}

.scroll-top.show {
    display: flex;
}

/* ========== Experience / Timeline Section ========== */
.experience {
    background-color: var(--bg-color);
}

.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-md) 0;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 3px;
    height: 100%;
    background-color: var(--primary-color);
    top: 0;
}

.timeline-item {
    position: relative;
    padding: 0 0 var(--spacing-md) 0;
    width: 50%;
}

.timeline-item:nth-child(odd) {
    left: 0;
    padding-right: var(--spacing-lg);
}

.timeline-item:nth-child(even) {
    left: 50%;
    padding-left: var(--spacing-lg);
}

.timeline-marker {
    position: absolute;
    width: 16px;
    height: 16px;
    background-color: var(--primary-color);
    border-radius: 50%;
    top: 0.5rem;
    z-index: 1;
    border: 3px solid var(--bg-color);
}

.timeline-item:nth-child(odd) .timeline-marker {
    right: -8px;
}

.timeline-item:nth-child(even) .timeline-marker {
    left: -8px;
}

.timeline-content {
    background-color: var(--card-bg);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 6px var(--shadow-color);
}

.timeline-content h3 {
    font-size: 1.25rem;
    color: var(--text-color);
    margin-bottom: 0.25rem;
}

.timeline-content .timeline-company {
    font-size: 1rem;
    color: var(--primary-color);
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.timeline-content .timeline-date {
    font-size: 0.875rem;
    color: var(--text-light);
    margin-bottom: var(--spacing-sm);
}

.timeline-content p:last-child {
    color: var(--text-light);
    line-height: 1.6;
    margin-bottom: 0;
}

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

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

.certs-container {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--spacing-md);
}

.cert-category {
    background-color: var(--card-bg);
    padding: var(--spacing-md);
    border-radius: var(--radius-lg);
    box-shadow: 0 4px 6px var(--shadow-color);
}

.cert-category h3 {
    font-size: 1.25rem;
    color: var(--text-color);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.cert-category h3 i {
    color: var(--primary-color);
}

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

.cert-list li {
    padding: var(--spacing-xs) 0;
    color: var(--text-light);
    border-bottom: 1px solid var(--border-color);
    line-height: 1.6;
}

.cert-list li:last-child {
    border-bottom: none;
}

/* ========== Animations ========== */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateX(-50%) translateY(0);
    }
    40% {
        transform: translateX(-50%) translateY(-10px);
    }
    60% {
        transform: translateX(-50%) translateY(-5px);
    }
}

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

    html {
        scroll-behavior: auto;
    }
}