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

:root {
    /* Color Palette */
    --primary-color: #2563eb;
    --primary-dark: #1e40af;
    --secondary-color: #64748b;
    --accent-color: #0ea5e9;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-tertiary: #f1f5f9;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
    
    /* Typography */
    --font-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    --font-mono: 'Courier New', Courier, monospace;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Transitions */
    --transition-fast: 150ms ease-in-out;
    --transition-base: 250ms ease-in-out;
    --transition-slow: 350ms ease-in-out;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    overflow-x: hidden;
}

/* ===========================
   Typography
   =========================== */
h1, h2, h3, h4, h5, h6 {
    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; }
h4 { font-size: 1.25rem; }

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

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

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

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

/* ===========================
   Header & Navigation
   =========================== */
.header {
    background-color: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: var(--shadow-sm);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

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

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

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
}

.nav-links a:hover {
    color: var(--primary-color);
}

.back-link {
    color: var(--text-secondary);
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    transition: color var(--transition-fast);
}

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

/* ===========================
   Hero Section
   =========================== */
.hero {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: var(--spacing-2xl) 0;
    text-align: center;
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    padding: var(--spacing-xl) 0;
}

.hero-title {
    font-size: 3.5rem;
    margin-bottom: var(--spacing-md);
    animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-lg);
    opacity: 0.95;
    animation: fadeInUp 1s ease-out;
}

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

/* ===========================
   Buttons
   =========================== */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: all var(--transition-base);
    border: none;
    font-size: 1rem;
}

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

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

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

/* ===========================
   Projects Section
   =========================== */
.projects {
    padding: var(--spacing-2xl) 0;
    background-color: var(--bg-secondary);
}

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

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

.project-card {
    background-color: var(--bg-primary);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
}

.project-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-xl);
}

.project-image {
    height: 250px;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-icon {
    width: 80px;
    height: 80px;
    stroke-width: 1.5;
    color: rgba(255, 255, 255, 0.8);
}

.project-content {
    padding: var(--spacing-lg);
    flex: 1;
    display: flex;
    flex-direction: column;
}

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

.project-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    flex: 1;
}

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

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

/* ===========================
   Project Detail Page
   =========================== */
.project-detail {
    padding: var(--spacing-xl) 0;
}

.project-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    padding: var(--spacing-xl) 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: var(--radius-lg);
}

.project-detail-title {
    font-size: 3rem;
    margin-bottom: var(--spacing-sm);
}

.project-detail-subtitle {
    font-size: 1.25rem;
    opacity: 0.95;
}

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

.project-section h2 {
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: var(--spacing-sm);
}

.project-text {
    color: var(--text-secondary);
    font-size: 1.125rem;
    line-height: 1.8;
    margin-bottom: var(--spacing-md);
}

.feature-list {
    list-style: none;
    padding: 0;
}

.feature-list li {
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-sm);
    background-color: var(--bg-secondary);
    border-left: 4px solid var(--primary-color);
    border-radius: var(--radius-sm);
}

.feature-list strong {
    color: var(--primary-color);
}

.tech-grid,
.architecture-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.tech-item,
.architecture-item {
    background-color: var(--bg-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.tech-item h3,
.architecture-item h3 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-sm);
    font-size: 1.25rem;
}

.tech-item ul,
.architecture-item ul {
    list-style: none;
    padding: 0;
}

.tech-item li,
.architecture-item li {
    padding: var(--spacing-xs) 0;
    color: var(--text-secondary);
}

.tech-item li:before {
    content: "▸ ";
    color: var(--primary-color);
    font-weight: bold;
}

.highlight-box {
    background-color: var(--bg-secondary);
    border-left: 4px solid var(--accent-color);
    padding: var(--spacing-lg);
    margin-bottom: var(--spacing-md);
    border-radius: var(--radius-sm);
}

.highlight-box h3 {
    color: var(--accent-color);
    margin-bottom: var(--spacing-sm);
}

.highlight-box p {
    color: var(--text-secondary);
    line-height: 1.8;
}

/* Media Grid */
.media-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--spacing-md);
    margin-top: var(--spacing-md);
}

.media-item {
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform var(--transition-base);
}

.media-item img {
    width: 100%;
    height: auto;
    display: block;
    object-fit: contain;
}

.media-item:hover {
    transform: scale(1.02);
}

.media-item.placeholder {
    height: 250px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #e0e7ff 0%, #cffafe 100%);
}

.media-item.placeholder.video {
    background: linear-gradient(135deg, #fce7f3 0%, #ddd6fe 100%);
}

.media-item p {
    color: var(--text-secondary);
    font-weight: 600;
}

.media-note {
    margin-top: var(--spacing-md);
    color: var(--text-secondary);
    font-style: italic;
    text-align: center;
}

.project-cta {
    text-align: center;
    margin-top: var(--spacing-2xl);
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--border-color);
}

/* ===========================
   Contact Section
   =========================== */
.contact {
    padding: var(--spacing-2xl) 0;
    text-align: center;
}

.contact-text {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
}

.contact-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.contact-link {
    padding: var(--spacing-md) var(--spacing-lg);
    background-color: var(--bg-secondary);
    border-radius: var(--radius-md);
    font-weight: 600;
    transition: all var(--transition-base);
    box-shadow: var(--shadow-sm);
}

.contact-link:hover {
    background-color: var(--primary-color);
    color: white;
    transform: translateY(-4px);
    box-shadow: var(--shadow-md);
}

/* ===========================
   Footer
   =========================== */
.footer {
    background-color: var(--text-primary);
    color: white;
    text-align: center;
    padding: var(--spacing-lg) 0;
    margin-top: var(--spacing-2xl);
}

.footer p {
    margin: 0;
    opacity: 0.8;
}

/* ===========================
   Responsive Design
   =========================== */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2.5rem;
    }
    
    .hero-subtitle {
        font-size: 1.125rem;
    }
    
    .nav-links {
        gap: var(--spacing-md);
    }
    
    .projects-grid {
        grid-template-columns: 1fr;
    }
    
    .project-detail-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .tech-grid,
    .architecture-grid {
        grid-template-columns: 1fr;
    }
    
    .contact-links {
        flex-direction: column;
        align-items: center;
    }
    
    .contact-link {
        width: 100%;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .nav-links {
        flex-direction: column;
        gap: var(--spacing-xs);
        font-size: 0.875rem;
    }
    
    h1 { font-size: 2rem; }
    h2 { font-size: 1.75rem; }
    h3 { font-size: 1.25rem; }
    
    .project-card {
        margin-bottom: var(--spacing-md);
    }
}

/* ===========================
   Utility Classes
   =========================== */
.text-center { text-align: center; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }