/* ========================================
   CSS Variables & Reset
   ======================================== */
:root {
    /* Light Mode Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f8f8;
    --text-primary: #1a1a1a;
    --text-secondary: #666666;
    --text-light: #999999;
    --border-color: #e5e5e5;
    --accent-color: #1a1a1a;
    --hover-color: #333333;
    
    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-weight-light: 300;
    --font-weight-regular: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-normal: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Layout */
    --container-max-width: 1200px;
    --container-padding: 2rem;
}

[data-theme="dark"] {
    --bg-primary: #0a0a0a;
    --bg-secondary: #141414;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --text-light: #808080;
    --border-color: #2a2a2a;
    --accent-color: #ffffff;
    --hover-color: #e5e5e5;
}

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

html {
    scroll-behavior: smooth;
}

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

/* ========================================
   Typography
   ======================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: var(--font-weight-semibold);
    line-height: 1.2;
    color: var(--text-primary);
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--transition-fast);
}

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

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

/* ========================================
   Navigation
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: background-color var(--transition-normal), border-color var(--transition-normal);
    backdrop-filter: blur(10px);
    background-color: rgba(255, 255, 255, 0.9);
}

[data-theme="dark"] .navbar {
    background-color: rgba(10, 10, 10, 0.9);
}

.nav-container {
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 1.5rem var(--container-padding);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.25rem;
    font-weight: var(--font-weight-semibold);
    letter-spacing: -0.02em;
}

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

.nav-link {
    font-size: 0.9rem;
    font-weight: var(--font-weight-regular);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    position: relative;
    padding: 0.5rem 0;
}

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

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.5rem;
    transition: transform var(--transition-fast);
}

.theme-toggle:hover {
    transform: rotate(180deg);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    gap: 4px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background-color: var(--text-primary);
    transition: var(--transition-fast);
}

/* ========================================
   Hero Section
   ======================================== */
.hero {
    margin-top: 80px;
    height: calc(100vh - 80px);
    position: relative;
    overflow: hidden;
}

.hero-image {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.3);
}

.hero-content {
    position: relative;
    z-index: 2;
    text-align: center;
    color: white;
    padding: 2rem;
    max-width: 800px;
}

.hero-title {
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: var(--font-weight-light);
    letter-spacing: -0.03em;
    margin-bottom: 1.5rem;
    line-height: 1.1;
}

.hero-tagline {
    font-size: clamp(1rem, 2vw, 1.25rem);
    font-weight: var(--font-weight-regular);
    margin-bottom: 2.5rem;
    opacity: 0.95;
}

/* ========================================
   Buttons
   ======================================== */
.cta-button, .secondary-button {
    display: inline-block;
    padding: 1rem 2.5rem;
    font-size: 0.9rem;
    font-weight: var(--font-weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    border: 2px solid currentColor;
    transition: all var(--transition-normal);
    cursor: pointer;
}

.cta-button {
    background-color: transparent;
    color: white;
    border-color: white;
}

.cta-button:hover {
    background-color: white;
    color: var(--text-primary);
}

.secondary-button {
    background-color: transparent;
    color: var(--text-primary);
    border-color: var(--text-primary);
}

.secondary-button:hover {
    background-color: var(--text-primary);
    color: var(--bg-primary);
}

/* ========================================
   Featured Section
   ======================================== */
.featured-section {
    padding: var(--spacing-xl) 0;
    background-color: var(--bg-primary);
}

.section-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: var(--font-weight-light);
    letter-spacing: -0.02em;
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

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

/* ========================================
   Project Cards
   ======================================== */
.project-card, .portfolio-item {
    display: block;
    transition: transform var(--transition-normal);
}

.project-card:hover, .portfolio-item:hover {
    transform: translateY(-8px);
}

.project-image, .portfolio-image {
    width: 100%;
    aspect-ratio: 4/3;
    overflow: hidden;
    margin-bottom: 1rem;
}

.placeholder-image {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.5rem;
    font-weight: var(--font-weight-light);
}

.project-info, .portfolio-info {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.project-category, .portfolio-category {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
}

.project-title, .portfolio-title {
    font-size: 1.25rem;
    font-weight: var(--font-weight-medium);
    color: var(--text-primary);
}

/* ========================================
   About Section
   ======================================== */
.about-section {
    padding: var(--spacing-xl) 0;
    margin-top: 80px;
}

.page-title {
    font-size: clamp(2.5rem, 5vw, 4rem);
    font-weight: var(--font-weight-light);
    letter-spacing: -0.03em;
    margin-bottom: var(--spacing-md);
}

.page-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-lg);
    max-width: 600px;
}

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

.about-text {
    max-width: none;
}

.section-subtitle {
    font-size: 1.5rem;
    font-weight: var(--font-weight-semibold);
    margin-bottom: 1.5rem;
    letter-spacing: -0.01em;
}

.bio-text {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.skills-section {
    margin-top: 3rem;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
    margin-top: 1.5rem;
}

.skill-item {
    padding: 1rem;
    border: 1px solid var(--border-color);
    transition: border-color var(--transition-fast);
}

.skill-item:hover {
    border-color: var(--text-primary);
}

.skill-name {
    font-size: 0.9rem;
    font-weight: var(--font-weight-medium);
}

.about-image {
    display: flex;
    align-items: flex-start;
    justify-content: center;
}

.portrait-frame {
    width: 100%;
    max-width: 400px;
    aspect-ratio: 3/4;
    border: 1px solid var(--border-color);
    padding: 1rem;
    background-color: var(--bg-secondary);
}

.portrait-placeholder {
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, #e5e5e5 0%, #f5f5f5 100%);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-light);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

[data-theme="dark"] .portrait-placeholder {
    background: linear-gradient(135deg, #2a2a2a 0%, #1a1a1a 100%);
}

/* ========================================
   Portfolio Section
   ======================================== */
.portfolio-section {
    padding: var(--spacing-xl) 0;
    margin-top: 80px;
}

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

.filter-container {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-lg);
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border-color);
}

.filter-btn {
    background: none;
    border: 1px solid var(--border-color);
    padding: 0.75rem 1.5rem;
    font-size: 0.875rem;
    font-weight: var(--font-weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    cursor: pointer;
    transition: all var(--transition-fast);
    color: var(--text-secondary);
}

.filter-btn:hover, .filter-btn.active {
    border-color: var(--text-primary);
    color: var(--text-primary);
    background-color: var(--bg-secondary);
}

.portfolio-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
}

.portfolio-item.hidden {
    display: none;
}

/* ========================================
   Project Detail Section
   ======================================== */
.project-detail-section {
    padding: var(--spacing-xl) 0;
    margin-top: 80px;
}

.back-link {
    display: inline-block;
    margin-bottom: 2rem;
    font-size: 0.9rem;
    font-weight: var(--font-weight-medium);
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

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

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

.project-title-large {
    font-size: clamp(2.5rem, 5vw, 4.5rem);
    font-weight: var(--font-weight-light);
    letter-spacing: -0.03em;
    margin-bottom: 1rem;
}

.project-category-large {
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
}

.project-overview {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.project-overview-text p {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.project-meta {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.meta-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.meta-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
}

.meta-value {
    font-size: 1rem;
    font-weight: var(--font-weight-medium);
}

.project-section {
    margin-bottom: var(--spacing-xl);
}

.project-section-title {
    font-size: 2rem;
    font-weight: var(--font-weight-semibold);
    margin-bottom: 1.5rem;
    letter-spacing: -0.01em;
}

.project-section-text {
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 2rem;
    max-width: 800px;
}

.project-image-large {
    margin-bottom: 2rem;
}

.project-image-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin-bottom: 2rem;
}

.project-image-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 2rem;
}

.process-steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.process-step {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.step-number {
    font-size: 3rem;
    font-weight: var(--font-weight-light);
    color: var(--text-light);
    line-height: 1;
}

.process-step h3 {
    font-size: 1.25rem;
    font-weight: var(--font-weight-semibold);
    margin-bottom: 0.5rem;
}

.process-step p {
    font-size: 0.9rem;
    line-height: 1.6;
    color: var(--text-secondary);
}

.project-navigation {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 2rem;
    margin-top: var(--spacing-xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.nav-project {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    padding: 1.5rem;
    border: 1px solid var(--border-color);
    transition: all var(--transition-fast);
}

.nav-project:hover {
    border-color: var(--text-primary);
    background-color: var(--bg-secondary);
}

.nav-project.next {
    text-align: right;
    align-items: flex-end;
}

.nav-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    color: var(--text-secondary);
    font-weight: var(--font-weight-medium);
}

.nav-title {
    font-size: 1.125rem;
    font-weight: var(--font-weight-medium);
}

/* ========================================
   Services Section
   ======================================== */
.services-section {
    padding: var(--spacing-xl) 0;
    margin-top: 80px;
}

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

.services-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: var(--spacing-xl);
}

.service-card {
    padding: 2rem;
    border: 1px solid var(--border-color);
    transition: all var(--transition-normal);
}

.service-card:hover {
    border-color: var(--text-primary);
    transform: translateY(-4px);
}

.service-icon {
    margin-bottom: 1.5rem;
}

.service-title {
    font-size: 1.5rem;
    font-weight: var(--font-weight-semibold);
    margin-bottom: 1rem;
    letter-spacing: -0.01em;
}

.service-description {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.service-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.service-list li {
    font-size: 0.9rem;
    color: var(--text-secondary);
    position: relative;
    padding-left: 1.5rem;
}

.service-list li::before {
    content: '—';
    position: absolute;
    left: 0;
    color: var(--text-primary);
}

.services-cta {
    text-align: center;
    padding: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.services-cta p {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

/* ========================================
   Contact Section
   ======================================== */
.contact-section {
    padding: var(--spacing-xl) 0;
    margin-top: 80px;
}

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

.contact-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--spacing-xl);
    margin-top: var(--spacing-lg);
}

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

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-size: 0.875rem;
    font-weight: var(--font-weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    padding: 1rem;
    border: 1px solid var(--border-color);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-primary);
    font-size: 1rem;
    transition: border-color var(--transition-fast);
    resize: vertical;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--text-primary);
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.contact-text {
    font-size: 1.0625rem;
    line-height: 1.7;
    color: var(--text-secondary);
}

.contact-details {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.contact-detail-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.contact-detail-item strong {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-primary);
    font-weight: var(--font-weight-medium);
}

.contact-detail-item a,
.contact-detail-item span {
    font-size: 1rem;
    color: var(--text-secondary);
}

.contact-detail-item a:hover {
    color: var(--text-primary);
}

.social-links-large {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.social-title {
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    font-weight: var(--font-weight-medium);
    margin-bottom: 0.5rem;
}

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

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.footer-content p {
    font-size: 0.875rem;
    color: var(--text-secondary);
}

.social-links {
    display: flex;
    gap: 2rem;
}

.social-link {
    font-size: 0.875rem;
    font-weight: var(--font-weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-secondary);
    transition: color var(--transition-fast);
}

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

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    :root {
        --container-padding: 1.5rem;
        --spacing-lg: 3rem;
        --spacing-xl: 4rem;
    }

    .menu-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background-color: var(--bg-primary);
        border-bottom: 1px solid var(--border-color);
        flex-direction: column;
        padding: 2rem;
        gap: 1.5rem;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-normal);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .about-content,
    .project-overview,
    .contact-content {
        grid-template-columns: 1fr;
    }

    .featured-grid,
    .portfolio-grid {
        grid-template-columns: 1fr;
    }

    .project-image-grid,
    .project-image-grid-3 {
        grid-template-columns: 1fr;
    }

    .project-navigation {
        grid-template-columns: 1fr;
    }

    .nav-project.next {
        text-align: left;
        align-items: flex-start;
    }

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

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

    .process-steps {
        grid-template-columns: 1fr;
    }

    .footer-content {
        flex-direction: column;
        text-align: center;
    }
}

@media (max-width: 480px) {
    .hero {
        height: 70vh;
    }

    .cta-button, .secondary-button {
        padding: 0.875rem 2rem;
        font-size: 0.875rem;
    }

    .filter-container {
        gap: 0.5rem;
    }

    .filter-btn {
        padding: 0.5rem 1rem;
        font-size: 0.75rem;
    }
}

/* ========================================
   Accessibility
   ======================================== */
@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-visible {
    outline: 2px solid var(--text-primary);
    outline-offset: 2px;
}

/* ========================================
   Utility Classes
   ======================================== */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}