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

:root {
    --primary-color: #00979D;
    --secondary-color: #E47128;
    --dark-color: #2C3E50;
    --light-color: #ECF0F1;
    --text-color: #333;
    --border-radius: 8px;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: #f5f5f5;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Navigation */
.navbar {
    background-color: var(--dark-color);
    color: white;
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

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

.logo h1 {
    font-size: 1.5rem;
}

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

.nav-menu a {
    color: white;
    text-decoration: none;
    transition: color 0.3s;
    font-weight: 500;
}

.nav-menu a:hover,
.nav-menu a.active {
    color: var(--primary-color);
}

/* Hero Section */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

/* Buttons */
.btn-primary, .btn-secondary {
    display: inline-block;
    padding: 12px 30px;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: bold;
    transition: all 0.3s;
}

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

.btn-primary:hover {
    background-color: var(--light-color);
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

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

.btn-secondary:hover {
    background-color: #007d82;
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

/* Main Content */
main {
    padding: 3rem 0;
}

section {
    margin-bottom: 4rem;
}

h2 {
    color: var(--dark-color);
    margin-bottom: 1.5rem;
    font-size: 2rem;
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

h3 {
    color: var(--dark-color);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

/* Feature Grid */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.feature-card {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 20px rgba(0,0,0,0.15);
}

.icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

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

.feature-card p {
    margin-bottom: 1.5rem;
    color: #666;
}

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

.step {
    text-align: center;
    padding: 2rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
}

.step-number {
    width: 60px;
    height: 60px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: bold;
    margin: 0 auto 1rem;
}

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

.req-col {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
}

.req-col h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.req-col ul {
    list-style-position: inside;
    color: #666;
}

.req-col li {
    padding: 0.5rem 0;
    border-bottom: 1px solid #eee;
}

.req-col li:last-child {
    border-bottom: none;
}

/* Lesson Content */
.lesson-content {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

.lesson-nav {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 3px 10px rgba(0,0,0,0.1);
    margin-bottom: 2rem;
}

.lesson-nav ul {
    list-style: none;
}

.lesson-nav li {
    padding: 0.8rem;
    border-left: 3px solid transparent;
    transition: all 0.3s;
}

.lesson-nav li:hover {
    background-color: var(--light-color);
    border-left-color: var(--primary-color);
}

.lesson-nav a {
    color: var(--text-color);
    text-decoration: none;
    display: block;
}

/* Code Block */
.code-block {
    background-color: #282c34;
    color: #abb2bf;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    overflow-x: auto;
    margin: 1.5rem 0;
    position: relative;
}

.code-block pre {
    margin: 0;
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9rem;
    line-height: 1.5;
}

.code-header {
    background-color: #21252b;
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius) var(--border-radius) 0 0;
    font-weight: bold;
    font-size: 0.9rem;
}

.code-container {
    margin: 1.5rem 0;
}

/* Alert Boxes */
.alert {
    padding: 1rem 1.5rem;
    border-radius: var(--border-radius);
    margin: 1.5rem 0;
    border-left: 4px solid;
}

.alert-info {
    background-color: #d1ecf1;
    border-color: #0c5460;
    color: #0c5460;
}

.alert-warning {
    background-color: #fff3cd;
    border-color: #856404;
    color: #856404;
}

.alert-success {
    background-color: #d4edda;
    border-color: #155724;
    color: #155724;
}

.alert-danger {
    background-color: #f8d7da;
    border-color: #721c24;
    color: #721c24;
}

/* Table */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    background: white;
}

table th {
    background-color: var(--primary-color);
    color: white;
    padding: 1rem;
    text-align: left;
}

table td {
    padding: 1rem;
    border-bottom: 1px solid #ddd;
}

table tr:hover {
    background-color: var(--light-color);
}

/* Image */
img {
    max-width: 100%;
    height: auto;
    border-radius: var(--border-radius);
    margin: 1rem 0;
}

/* Footer */
footer {
    background-color: var(--dark-color);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 4rem;
}

footer p {
    margin: 0.5rem 0;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-menu {
        flex-direction: column;
        gap: 1rem;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .feature-grid,
    .steps,
    .req-columns {
        grid-template-columns: 1fr;
    }
}

/* Syntax Highlighting */
.keyword { color: #c678dd; }
.function { color: #61afef; }
.string { color: #98c379; }
.comment { color: #5c6370; font-style: italic; }
.number { color: #d19a66; }