/* ============================================
   CSS Variables - Single Accent Color Theme
   ============================================ */
:root {
    /* Colors */
    --bg-primary: #0a0a0a;
    --bg-secondary: #1a1a1a;
    --text-primary: #e0e0e0;
    --text-secondary: #888888;
    --accent-color: #00d4ff; /* Single vibrant accent color */
    --accent-hover: #00b8e6;
    --border-color: #333333;
    
    /* Typography */
    --font-heading: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Container */
    --container-max-width: 1200px;
    --container-padding: 1.5rem;
}

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

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }

p {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

a {
    color: var(--accent-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

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

img {
    max-width: 100%;
    height: auto;
    display: block;
}

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

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

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

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

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

.nav-brand a {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

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

.nav-menu a {
    color: var(--text-primary);
    padding: var(--spacing-xs) var(--spacing-sm);
    transition: color 0.3s ease;
}

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.nav-toggle span {
    width: 25px;
    height: 2px;
    background-color: var(--text-primary);
    transition: all 0.3s ease;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-block;
    padding: 0.75rem 2rem;
    border-radius: 4px;
    font-weight: 600;
    text-align: center;
    transition: all 0.3s ease;
    cursor: pointer;
    border: 2px solid transparent;
}

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

.btn-primary:hover {
    background-color: var(--accent-hover);
    border-color: var(--accent-hover);
    color: var(--bg-primary);
}

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

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

/* ============================================
   Hero Section
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding-top: 80px;
    background: linear-gradient(135deg, var(--bg-primary) 0%, var(--bg-secondary) 100%);
}

.hero-title {
    font-size: 4rem;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-color) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

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

.hero-description {
    max-width: 600px;
    margin: 0 auto var(--spacing-md);
    font-size: 1.1rem;
    color: var(--text-secondary);
}

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

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

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

.about-image {
    text-align: center;
}

.profile-img {
    width: 250px;
    height: 250px;
    border-radius: 50%;
    object-fit: cover;
    margin: 0 auto;
    border: 3px solid var(--accent-color);
}

.about-text p {
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
}

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

.project-card {
    background-color: var(--bg-secondary);
    border-radius: 8px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 212, 255, 0.2);
    border-color: var(--accent-color);
}

.project-image {
    width: 100%;
    height: 200px;
    overflow: hidden;
    background-color: var(--bg-primary);
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

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

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

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

.project-summary {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

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

.stack-tag {
    padding: 0.25rem 0.75rem;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 4px;
    font-size: 0.875rem;
    color: var(--accent-color);
}

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

.project-link {
    color: var(--accent-color);
    font-weight: 600;
    padding: 0.5rem 1rem;
    border-bottom: 2px solid transparent;
    transition: border-color 0.3s ease;
}

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

.projects-cta {
    text-align: center;
}

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

.education-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-sm);
    max-width: 100%;
    margin: 0 auto;
    width: 100%;
    padding: 0 var(--container-padding);
}

.education-item {
    background-color: var(--bg-primary);
    padding: var(--spacing-md);
    border-radius: 8px;
    border-left: 4px solid var(--accent-color);
    border-top: 1px solid var(--border-color);
    border-right: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
    width: 100%;
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-md);
    position: relative;
}

.education-item-alt {
    background-color: rgba(0, 212, 255, 0.03);
    border-left-color: var(--accent-hover);
}

.education-item:hover {
    border-left-width: 6px;
    transform: translateX(4px);
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.1);
}

.education-icon {
    font-size: 1.5rem;
    line-height: 1;
    flex-shrink: 0;
    width: 2.5rem;
    height: 2.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: rgba(0, 212, 255, 0.1);
    border-radius: 50%;
    padding: 0.5rem;
}

.education-text {
    flex: 1;
    min-width: 0;
}

.education-title {
    font-size: 1.25rem;
    color: var(--accent-color);
    margin-bottom: var(--spacing-xs);
    margin-top: 0;
}

.education-institution {
    font-size: 1rem;
    color: var(--text-primary);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    margin-top: 0;
}

.education-period {
    font-size: 0.9rem;
    color: var(--text-secondary);
    font-style: italic;
    margin: 0;
}

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

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--spacing-md);
    max-width: 800px;
    margin: 0 auto;
}

.skill-item {
    text-align: center;
    padding: var(--spacing-md);
    background-color: var(--bg-secondary);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    border-top: 3px solid var(--accent-color);
    transition: all 0.3s ease;
    position: relative;
}

.skill-item:nth-child(even) {
    background-color: rgba(0, 212, 255, 0.02);
}

.skill-item:hover {
    border-color: var(--accent-color);
    border-top-width: 4px;
    transform: translateY(-5px);
    box-shadow: 0 6px 20px rgba(0, 212, 255, 0.15);
}

.skill-icon {
    font-size: 2rem;
    font-weight: 700;
    color: var(--accent-color);
    margin-bottom: var(--spacing-xs);
}

.skill-name {
    display: block;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ============================================
   Testimonials Section
   ============================================ */
.testimonials-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
    max-width: 1000px;
    margin: 0 auto;
}

.testimonial-card {
    background-color: var(--bg-primary);
    padding: var(--spacing-md);
    border-radius: 8px;
    border-left: 4px solid var(--accent-color);
    border-top: 1px solid var(--border-color);
    border-right: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
    position: relative;
}

.testimonial-card:nth-child(even) {
    background-color: rgba(0, 212, 255, 0.03);
    border-left-color: var(--accent-hover);
}

.testimonial-card:hover {
    border-left-width: 6px;
    transform: translateX(4px);
    box-shadow: 0 4px 12px rgba(0, 212, 255, 0.1);
}

.testimonial-text {
    font-style: italic;
    font-size: 1.1rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    position: relative;
    padding-left: var(--spacing-sm);
}

.testimonial-text::before {
    content: '"';
    font-size: 3rem;
    color: var(--accent-color);
    opacity: 0.3;
    position: absolute;
    left: -10px;
    top: -10px;
    font-family: Georgia, serif;
}

.testimonial-author {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.testimonial-avatar {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    overflow: hidden;
    border: 2px solid var(--accent-color);
    flex-shrink: 0;
}

.testimonial-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.testimonial-name {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0;
}

.testimonial-role {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

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

.contact-intro {
    text-align: center;
    max-width: 600px;
    margin: 0 auto var(--spacing-lg);
    font-size: 1.1rem;
}

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

.form-group {
    margin-bottom: var(--spacing-md);
}

.form-group label {
    display: block;
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
    font-weight: 600;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-left: 3px solid transparent;
    border-radius: 4px;
    color: var(--text-primary);
    font-family: var(--font-body);
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    border-left-color: var(--accent-color);
    border-left-width: 4px;
    box-shadow: 0 0 0 3px rgba(0, 212, 255, 0.1);
}

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

.contact-form .btn {
    width: 100%;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    border-top: 1px solid var(--border-color);
    padding: var(--spacing-md) 0;
}

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

.footer-text {
    color: var(--text-secondary);
    margin-bottom: 0;
}

.footer-social {
    display: flex;
    gap: var(--spacing-md);
}

.footer-social a {
    color: var(--text-secondary);
    transition: color 0.3s ease;
}

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

/* ============================================
   Back to Top Button
   ============================================ */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background-color: var(--accent-color);
    color: var(--bg-primary);
    border: none;
    border-radius: 50%;
    font-size: 1.5rem;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    background-color: var(--accent-hover);
    transform: translateY(-5px);
}

/* ============================================
   Lightbox
   ============================================ */
.lightbox {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0, 0, 0, 0.95);
    z-index: 2000;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-md);
}

.lightbox.active {
    display: flex;
}

.lightbox-close {
    position: absolute;
    top: 2rem;
    right: 2rem;
    background: none;
    border: none;
    color: var(--text-primary);
    font-size: 3rem;
    cursor: pointer;
    width: 50px;
    height: 50px;
    transition: color 0.3s ease;
}

.lightbox-close:hover {
    color: var(--accent-color);
}

.lightbox-image {
    max-width: 90%;
    max-height: 90vh;
    object-fit: contain;
}

/* ============================================
   Responsive Design - Mobile First
   ============================================ */

/* Tablet (768px and up) */
@media (min-width: 768px) {
    :root {
        --container-padding: 2rem;
    }
    
    h1 { font-size: 3.5rem; }
    h2 { font-size: 2.5rem; }
    
    .hero-title {
        font-size: 5rem;
    }
    
    .about-content {
        grid-template-columns: 300px 1fr;
    }
    
    .projects-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .testimonials-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .education-content {
        grid-template-columns: repeat(2, 1fr);
        max-width: 900px;
        gap: var(--spacing-sm);
    }
    
    .education-item {
        flex-direction: row;
        align-items: flex-start;
    }
    
    .education-icon {
        width: 2.5rem;
        height: 2.5rem;
    }
    
    .skills-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Desktop (1024px and up) */
@media (min-width: 1024px) {
    section {
        padding: var(--spacing-xl) 0;
    }
    
    .projects-grid {
        grid-template-columns: repeat(3, 1fr);
    }
    
    .education-content {
        grid-template-columns: repeat(3, 1fr);
        max-width: 1100px;
        gap: var(--spacing-sm);
    }
    
    .education-item {
        flex-direction: column;
        align-items: flex-start;
        padding: var(--spacing-md);
    }
    
    .education-icon {
        width: 3rem;
        height: 3rem;
        margin-bottom: var(--spacing-xs);
    }
    
    .education-text {
        width: 100%;
    }
    
    .hero-cta {
        flex-wrap: nowrap;
    }
    
    .nav-toggle {
        display: none;
    }
    
    .nav-menu {
        display: flex !important;
    }
}

/* Mobile Navigation */
@media (max-width: 767px) {
    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: var(--bg-primary);
        flex-direction: column;
        padding: var(--spacing-md);
        border-top: 1px solid var(--border-color);
        display: none;
    }
    
    .nav-menu.active {
        display: flex;
    }
    
    .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);
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
}

/* Small Mobile (320px - 480px) */
@media (max-width: 480px) {
    :root {
        --container-padding: 1rem;
        --spacing-xl: 3rem;
        --spacing-lg: 2rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-cta {
        flex-direction: column;
        width: 100%;
    }
    
    .hero-cta .btn {
        width: 100%;
    }
    
    .back-to-top {
        bottom: 1rem;
        right: 1rem;
        width: 40px;
        height: 40px;
        font-size: 1.25rem;
    }
}