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

:root {
    --primary-color: #3b82f6;
    --primary-dark: #2563eb;
    --secondary-color: #8b5cf6;
    --accent-color: #06b6d4;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --text-light: #9ca3af;
    
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    
    --border-color: #e5e7eb;
    --border-light: #f3f4f6;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    
    /* Additional variables for installation guide */
    --card-bg: var(--bg-primary);
    --border-radius: var(--radius-lg);
    --border-radius-sm: var(--radius-sm);
    --shadow: var(--shadow-md);
    --bg-light: var(--bg-secondary);
    --code-bg: var(--bg-tertiary);
    --code-color: var(--text-primary);
    --link-color: var(--primary-color);
    --link-hover: var(--primary-dark);
    --danger-color: var(--error-color);
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    --transition: all 0.3s ease;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--bg-primary);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.25;
    margin-bottom: 1rem;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: 1rem;
    color: var(--text-secondary);
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: white;
    padding: 2rem 0;
    text-align: center;
}

.header-content {
    max-width: 800px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.logo i {
    font-size: 3rem;
    color: var(--accent-color);
}

.logo h1 {
    font-size: 2.5rem;
    color: white;
    margin-bottom: 0;
}

.subtitle {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 0;
}

/* Navigation */
.navigation {
    background: white;
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-sm);
}

.nav-header {
    display: none;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-primary);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.mobile-menu-toggle:hover {
    background: var(--bg-secondary);
    color: var(--primary-color);
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
    justify-content: center;
    padding: 1rem 0;
}

.nav-menu a {
    text-decoration: none;
    color: var(--text-primary);
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    transition: var(--transition);
}

.nav-menu a:hover {
    background: var(--bg-secondary);
    color: var(--primary-color);
}

.nav-menu a.active {
    background: var(--primary-color);
    color: white;
}

/* Main Content */
.main-content {
    padding: 2rem 0;
}

.section {
    margin-bottom: 4rem;
}

.section-title {
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text-primary);
}

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-tertiary) 100%);
    padding: 4rem 0;
    margin-bottom: 4rem;
}

.hero-content {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.hero-content h2 {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
}

.hero-description {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: var(--text-secondary);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-top: 2rem;
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--primary-color);
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Tech Stack */
.tech-stack {
    margin-top: 3rem;
}

.tech-stack h3 {
    text-align: center;
    margin-bottom: 2rem;
    color: var(--text-primary);
}

.tech-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.tech-item {
    text-align: center;
    padding: 2rem;
    background: white;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.tech-item:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.tech-item i {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.tech-item .fab.fa-html5 { color: #e34f26; }
.tech-item .fab.fa-css3-alt { color: #1572b6; }
.tech-item .fab.fa-js-square { color: #f7df1e; }
.tech-item .fab.fa-php { color: #777bb4; }
.tech-item .fas.fa-database { color: #4479a1; }

.tech-item h4 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.tech-item p {
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* Course Parts */
.parts-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: 2rem;
}

.part-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 2rem;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    position: relative;
}

.part-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.part-number {
    position: absolute;
    top: -15px;
    left: 2rem;
    background: var(--primary-color);
    color: white;
    width: 3rem;
    height: 3rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.25rem;
}

.part-card h3 {
    margin-top: 1rem;
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.part-card p {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.part-card ul {
    list-style: none;
    padding-left: 0;
}

.part-card ul li {
    padding: 0.5rem 0;
    border-bottom: 1px solid var(--border-light);
    color: var(--text-secondary);
    position: relative;
    padding-left: 1.5rem;
}

.part-card ul li:before {
    content: "✓";
    position: absolute;
    left: 0;
    color: var(--success-color);
    font-weight: bold;
}

.part-card ul li:last-child {
    border-bottom: none;
}

.part-actions {
    margin-top: 2rem;
    display: flex;
    gap: 0.75rem;
    flex-wrap: wrap;
}

.part-actions .btn {
    flex: 1;
    min-width: 120px;
    text-align: center;
    font-size: 0.875rem;
    padding: 0.625rem 1rem;
}

/* Prerequisites */
.prerequisites-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.prerequisite-card {
    background: white;
    padding: 2rem;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    text-align: center;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
}

.prerequisite-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.prerequisite-card i {
    font-size: 3rem;
    color: var(--accent-color);
    margin-bottom: 1rem;
}

.prerequisite-card h3 {
    margin-bottom: 1rem;
    color: var(--text-primary);
}

.prerequisite-card p {
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* Get Started */
.start-content {
    text-align: center;
}

.start-content p {
    font-size: 1.25rem;
    margin-bottom: 2rem;
    color: var(--text-secondary);
}

.start-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    text-decoration: none;
    border-radius: var(--radius-md);
    font-weight: 500;
    text-align: center;
    transition: var(--transition);
    border: none;
    cursor: pointer;
    font-size: 0.875rem;
}

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

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

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

.btn-secondary:hover {
    background: #7c3aed;
    transform: translateY(-2px);
}

/* Footer */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    padding: 3rem 0 1rem;
    margin-top: 4rem;
    text-align: center;
    color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-content h2 {
        font-size: 2rem;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .nav-menu {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-header {
        display: flex;
        justify-content: flex-end;
        padding: 0.5rem 0;
    }
    
    .mobile-menu-toggle {
        display: block;
    }
    
    .nav-menu {
        display: none;
        flex-direction: column;
        gap: 1rem;
        padding: 1rem 0;
        border-top: 1px solid var(--border-light);
    }
    
    .nav-menu.nav-menu-open {
        display: flex;
    }
    
    .parts-grid {
        grid-template-columns: 1fr;
    }
    
    .tech-grid {
        grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    }
    
    .start-actions {
        flex-direction: column;
        align-items: center;
    }
    
    .start-actions .btn {
        width: 100%;
        max-width: 300px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.5rem;
    }
    
    .hero-section {
        padding: 2rem 0;
    }
    
    .section {
        margin-bottom: 2rem;
    }
    
    .part-card,
    .prerequisite-card {
        padding: 1.5rem;
    }
    
    .logo h1 {
        font-size: 2rem;
    }
}