/* Global Styles */
:root {
    --primary-color: #4361ee;
    --secondary-color: #3a0ca3;
    --accent-color: #4cc9f0;
    --text-color: #2b2d42;
    --light-text: #8d99ae;
    --background-color: #f8f9fa;
    --white: #ffffff;
    --shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    --border-radius: 8px;
}

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

body {
    font-family: 'Inter', sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

a {
    text-decoration: none;
    color: var(--primary-color);
    transition: all 0.3s ease;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
}

.btn {
    display: inline-block;
    padding: 12px 24px;
    border-radius: var(--border-radius);
    font-weight: 600;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.btn-primary:hover {
    background-color: var(--secondary-color);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

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

.btn-secondary:hover {
    background-color: var(--primary-color);
    color: var(--white);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.section-header {
    text-align: center;
    margin-bottom: 50px;
}

.section-header h2 {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--secondary-color);
}

.section-header p {
    color: var(--light-text);
    max-width: 700px;
    margin: 0 auto;
    font-size: 1.1rem;
}

/* Header Styles */
header {
    background-color: var(--white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    position: sticky;
    top: 0;
    z-index: 100;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 15px;
}

.logo h1 {
    font-size: 1.8rem;
    color: var(--primary-color);
}

.logo span {
    color: var(--secondary-color);
    font-weight: 700;
}

nav ul {
    display: flex;
}

nav ul li {
    margin-left: 30px;
}

nav ul li a {
    color: var(--text-color);
    font-weight: 500;
    position: relative;
}

nav ul li a:after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

nav ul li a:hover:after,
nav ul li a.active:after {
    width: 100%;
}

nav ul li a.active {
    color: var(--primary-color);
    font-weight: 600;
}

/* Hero Section */
.hero {
    padding: 80px 0;
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 50px;
    align-items: center;
}

.hero-content h1 {
    font-size: 3rem;
    line-height: 1.2;
    margin-bottom: 20px;
    color: var(--secondary-color);
}

.hero-content p {
    font-size: 1.1rem;
    color: var(--text-color);
    margin-bottom: 30px;
}

.cta-buttons {
    display: flex;
    gap: 15px;
}

/* Overview Section */
.overview {
    padding: 80px 0;
    background-color: var(--white);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.stat-card {
    background: var(--white);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    text-align: center;
    transition: transform 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-10px);
}

.stat-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.stat-value {
    font-size: 2rem;
    font-weight: 700;
    color: var(--secondary-color);
    margin-bottom: 5px;
}

.stat-label {
    color: var(--light-text);
    font-size: 1rem;
}

/* Chapters Preview Section */
.chapters-preview {
    padding: 80px 0;
    background-color: var(--background-color);
}

.chapters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.chapter-card {
    background: var(--white);
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: transform 0.3s ease;
    position: relative;
}

.chapter-card:hover {
    transform: translateY(-10px);
}

.chapter-number {
    font-size: 3rem;
    font-weight: 700;
    color: rgba(67, 97, 238, 0.1);
    position: absolute;
    top: 10px;
    right: 20px;
}

.chapter-card h3 {
    font-size: 1.5rem;
    margin-bottom: 15px;
    color: var(--secondary-color);
}

.chapter-card p {
    color: var(--light-text);
    margin-bottom: 20px;
}

.read-more {
    font-weight: 600;
    color: var(--primary-color);
    display: flex;
    align-items: center;
    gap: 5px;
}

.read-more i {
    transition: transform 0.3s ease;
}

.read-more:hover i {
    transform: translateX(5px);
}

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

/* Getting Started Section */
.getting-started {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: var(--white);
}

.getting-started-content {
    text-align: center;
    max-width: 700px;
    margin: 0 auto;
}

.getting-started-content h2 {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.getting-started-content p {
    margin-bottom: 30px;
    font-size: 1.1rem;
}

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

.getting-started .btn-primary:hover {
    background-color: rgba(255, 255, 255, 0.9);
    color: var(--secondary-color);
}

/* Footer */
footer {
    background-color: #2b2d42;
    color: var(--white);
    padding: 70px 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 50px;
    margin-bottom: 50px;
}

.footer-logo h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    color: var(--white);
}

.footer-logo span {
    color: var(--accent-color);
}

.footer-logo p {
    color: #8d99ae;
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.link-column h3 {
    font-size: 1.2rem;
    margin-bottom: 20px;
    color: var(--white);
}

.link-column ul li {
    margin-bottom: 10px;
}

.link-column ul li a {
    color: #8d99ae;
    transition: color 0.3s ease;
}

.link-column ul li a:hover {
    color: var(--accent-color);
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

.footer-bottom p {
    color: #8d99ae;
    font-size: 0.9rem;
}

/* Responsive Styles */
@media screen and (max-width: 992px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
    }
    
    .hero-content {
        order: 2;
    }
    
    .hero-image {
        order: 1;
        margin-bottom: 30px;
    }
    
    .cta-buttons {
        justify-content: center;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .footer-links {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

@media screen and (max-width: 768px) {
    html {
        font-size: 14px;
    }
    
    header .container {
        flex-direction: column;
    }
    
    nav ul {
        margin-top: 20px;
    }
    
    nav ul li {
        margin: 0 15px;
    }
    
    .stat-card, .chapter-card {
        padding: 20px;
    }
}

@media screen and (max-width: 480px) {
    nav ul {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    nav ul li {
        margin: 5px 10px;
    }
    
    .cta-buttons {
        flex-direction: column;
        gap: 10px;
    }
    
    .hero-content h1 {
        font-size: 2.2rem;
    }
    
    .section-header h2 {
        font-size: 2rem;
    }
}