/* ===================================
   CSS RESET & BASE STYLES
   =================================== */

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

:root {
    /* Colors - Apple-inspired palette */
    --color-bg: #ffffff;
    --color-bg-secondary: #f5f5f7;
    --color-text: #1d1d1f;
    --color-text-secondary: #6e6e73;
    --color-accent: #0071e3;
    --color-accent-hover: #0077ed;
    --color-border: #d2d2d7;
    --color-shadow: rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, "Courier New", monospace;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Border radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 18px;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-medium: 0.3s ease;
    --transition-slow: 0.5s ease;
}

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

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

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

/* ===================================
   NAVIGATION
   =================================== */

#navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    z-index: 1000;
    transition: var(--transition-medium);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text);
    text-decoration: none;
    transition: var(--transition-fast);
}

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

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

.nav-link {
    color: var(--color-text);
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 400;
    transition: var(--transition-fast);
    padding: 0.5rem 0;
    position: relative;
}

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

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

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

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

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

/* ===================================
   HERO SECTION
   =================================== */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--spacing-xl) 0;
    background: linear-gradient(135deg, #f5f5f7 0%, #ffffff 100%);
}

.hero-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    text-align: center;
}

.hero-content {
    animation: fadeInUp 0.8s ease;
}

.hero-image {
    width: 200px;
    height: 200px;
    border-radius: 50%;
    object-fit: cover;
    margin-bottom: var(--spacing-md);
    border: 4px solid var(--color-bg);
    box-shadow: 0 10px 40px var(--color-shadow);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    line-height: 1.1;
    letter-spacing: -0.02em;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-text-secondary);
    margin-bottom: var(--spacing-lg);
    line-height: 1.4;
    max-width: 700px;
    margin-left: auto;
    margin-right: auto;
}

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

/* ===================================
   BUTTONS
   =================================== */

.btn {
    display: inline-block;
    padding: 0.875rem 2rem;
    border-radius: var(--radius-md);
    text-decoration: none;
    font-size: 1rem;
    font-weight: 500;
    transition: all var(--transition-fast);
    cursor: pointer;
    border: none;
    text-align: center;
}

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

.btn-primary:hover {
    background: var(--color-accent-hover);
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(0, 113, 227, 0.3);
}

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

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

.btn-small {
    padding: 0.5rem 1.25rem;
    font-size: 0.9rem;
}

/* ===================================
   SECTION STYLES
   =================================== */

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

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: var(--spacing-lg);
    text-align: center;
    letter-spacing: -0.02em;
}

/* ===================================
   PROJECTS SECTION
   =================================== */

.projects {
    background: var(--color-bg-secondary);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-md);
}

.project-card {
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: 0 4px 20px var(--color-shadow);
    transition: transform var(--transition-medium), box-shadow var(--transition-medium);
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px var(--color-shadow);
}

.project-image {
    width: 100%;
    height: 250px;
    overflow: hidden;
    background: var(--color-bg-secondary);
}

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

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

.project-image-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #1d1d1f 0%, #333 100%);
}

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

.project-title {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.project-company {
    color: var(--color-accent);
    font-size: 0.95rem;
    font-weight: 500;
    margin-bottom: var(--spacing-sm);
}

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

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

.tag {
    background: var(--color-bg-secondary);
    color: var(--color-text);
    padding: 0.35rem 0.75rem;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 500;
}

.project-expand {
    background: transparent;
    color: var(--color-accent);
    border: none;
    padding: 0.5rem 0;
    cursor: pointer;
    font-size: 0.95rem;
    font-weight: 500;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.project-details {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-medium) ease;
    margin-top: 0;
}

.project-details.active {
    max-height: 1000px;
    margin-top: var(--spacing-sm);
}

.project-details ul {
    list-style: none;
    padding-left: 0;
    margin-bottom: var(--spacing-sm);
}

.project-details li {
    padding-left: 1.5rem;
    margin-bottom: var(--spacing-xs);
    position: relative;
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.project-details li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--color-accent);
    font-weight: bold;
}

/* ===================================
   JOURNEY TIMELINE
   =================================== */

.journey {
    background: white;
}

.timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    padding-left: 3rem;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--color-border);
}

.timeline-item {
    position: relative;
    margin-bottom: var(--spacing-lg);
    animation: fadeInLeft 0.6s ease;
}

.timeline-marker {
    position: absolute;
    left: -3rem;
    top: 0;
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: var(--color-accent);
    border: 4px solid white;
    box-shadow: 0 0 0 2px var(--color-accent);
}

.timeline-content {
    background: var(--color-bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.timeline-item:hover .timeline-content {
    transform: translateX(5px);
    box-shadow: 0 4px 20px var(--color-shadow);
}

.timeline-year {
    color: var(--color-accent);
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.timeline-title {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.timeline-description {
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* ===================================
   SKILLS SECTION
   =================================== */

.skills {
    background: var(--color-bg-secondary);
}

.skills-grid {
    display: grid;
    gap: var(--spacing-sm);
    max-width: 900px;
    margin: 0 auto;
}

.skill-category {
    background: white;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: 0 2px 10px var(--color-shadow);
}

.skill-header {
    width: 100%;
    background: white;
    border: none;
    padding: var(--spacing-sm) var(--spacing-md);
    display: flex;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    transition: background var(--transition-fast);
}

.skill-header:hover {
    background: var(--color-bg-secondary);
}

.skill-header h3 {
    font-size: 1.25rem;
    font-weight: 600;
}

.skill-toggle {
    font-size: 1.5rem;
    font-weight: 300;
    color: var(--color-accent);
    transition: transform var(--transition-fast);
}

.skill-category.active .skill-toggle {
    transform: rotate(45deg);
}

.skill-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height var(--transition-medium) ease;
}

.skill-category.active .skill-content {
    max-height: 500px;
}

.skill-subsection {
    padding: var(--spacing-xs) var(--spacing-md);
    color: var(--color-text-secondary);
    line-height: 1.8;
}

.skill-subsection:last-child {
    padding-bottom: var(--spacing-md);
}

.skill-subsection strong {
    color: var(--color-text);
    font-weight: 600;
}

/* ===================================
   CONTACT SECTION
   =================================== */

.contact {
    background: white;
    text-align: center;
}

.contact-intro {
    color: var(--color-text-secondary);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.contact-links {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.contact-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    background: var(--color-bg-secondary);
    border-radius: var(--radius-md);
    text-decoration: none;
    color: var(--color-text);
    transition: all var(--transition-fast);
}

.contact-link:hover {
    background: var(--color-accent);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px var(--color-shadow);
}

.contact-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
}

.contact-resume {
    margin-top: var(--spacing-lg);
}

/* ===================================
   FOOTER
   =================================== */

.footer {
    background: var(--color-text);
    color: var(--color-bg-secondary);
    padding: var(--spacing-md) 0;
    text-align: center;
}

.footer-links {
    margin-top: var(--spacing-xs);
    color: var(--color-text-secondary);
}

.footer-links a {
    color: var(--color-bg-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
}

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

.footer-links span {
    margin: 0 var(--spacing-xs);
}

/* ===================================
   ANIMATIONS
   =================================== */

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

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* ===================================
   RESPONSIVE DESIGN
   =================================== */

@media (max-width: 768px) {
    :root {
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 60px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 60px);
        background: white;
        flex-direction: column;
        padding: var(--spacing-md);
        transition: left var(--transition-medium);
        box-shadow: 0 4px 20px var(--color-shadow);
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.25rem;
    }
    
    .hero-cta {
        flex-direction: column;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .timeline {
        padding-left: 2rem;
    }
    
    .timeline::before {
        left: 8px;
    }
    
    .timeline-marker {
        left: -2rem;
        width: 16px;
        height: 16px;
    }
    
    .contact-links {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-image {
        width: 150px;
        height: 150px;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-subtitle {
        font-size: 1.1rem;
    }
    
    .btn {
        padding: 0.75rem 1.5rem;
        font-size: 0.95rem;
    }
}

/* ===================================
   UTILITY CLASSES
   =================================== */

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

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

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

.mb-lg {
    margin-bottom: var(--spacing-lg);
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.mt-md {
    margin-top: var(--spacing-md);
}

.mt-lg {
    margin-top: var(--spacing-lg);
}