:root {
    --primary-color: #2563eb;
    --secondary-color: #1e40af;
    --accent-color: #3b82f6;
    --text-color: #1f2937;
    --text-light: #6b7280;
    --background-light: #f8fafc;
    --white: #ffffff;
    --border-color: #e5e7eb;
    --success-color: #10b981;
    --warning-color: #f59e0b;
}

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

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

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

/* Header & Navigation */
header {
    background: var(--white);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
    text-decoration: none;
}

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

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    transition: color 0.3s;
}

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

.user-actions {
    display: flex;
    gap: 1rem;
    align-items: center;
}

/* Sections */
.section {
    padding: 4rem 0;
}

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

/* Hero Section */
#hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: 6rem 0;
    text-align: center;
}

#hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
}

#hero p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0.9;
}

/* Buttons */
.cta-button {
    background: var(--accent-color);
    color: var(--white);
    padding: 0.75rem 2rem;
    border: none;
    border-radius: 6px;
    text-decoration: none;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-block;
}

.cta-button:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

.btn-small {
    padding: 0.5rem 1rem;
    font-size: 0.9rem;
}

/* Cards & Grids */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s;
}

.feature-card:hover {
    transform: translateY(-5px);
}

.categories-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.category-card {
    background: var(--white);
    border-radius: 10px;
    overflow: hidden;
    text-decoration: none;
    color: var(--text-color);
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s;
}

.category-card:hover {
    transform: translateY(-5px);
}

.category-img {
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    padding: 2rem;
    text-align: center;
    color: var(--white);
}

.category-img i {
    font-size: 3rem;
}

.category-content {
    padding: 1.5rem;
}

.price-free {
    color: var(--success-color);
    font-weight: 600;
    margin-top: 0.5rem;
}

/* Testimonials */
.testimonial-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    max-width: 600px;
    margin: 0 auto;
    text-align: center;
}

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

footer a {
    color: var(--white);
    text-decoration: none;
    margin: 0 0.5rem;
}

footer a:hover {
    text-decoration: underline;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
}

.modal-content {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    max-width: 600px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
}

.close-modal {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
}

.hidden {
    display: none !important;
}

/* Books Grid */
.books-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.book-card {
    background: var(--white);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s;
}

.book-card:hover {
    transform: translateY(-5px);
}

.book-img {
    background: linear-gradient(135deg, #667eea, #764ba2);
    padding: 2rem;
    text-align: center;
    color: var(--white);
}

.book-img i {
    font-size: 3rem;
}

.book-content {
    padding: 1.5rem;
}

.book-meta {
    display: flex;
    justify-content: space-between;
    margin: 0.5rem 0;
    font-size: 0.9rem;
    color: var(--text-light);
}

.book-actions {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* Filter */
.books-filter {
    display: flex;
    gap: 1rem;
    margin: 2rem 0;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    background: var(--white);
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s;
}

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

/* Login Overlay */
.login-overlay {
    text-align: center;
    padding: 3rem;
    background: var(--white);
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

/* Progress Stats */
.progress-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.stat-card {
    background: var(--white);
    padding: 1.5rem;
    border-radius: 10px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
}

.stat-value {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: var(--text-light);
    font-size: 0.9rem;
}

/* Plans */
.plans-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.plan-card {
    background: var(--white);
    padding: 2rem;
    border-radius: 10px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    position: relative;
    transition: transform 0.3s;
}

.plan-card:hover {
    transform: translateY(-5px);
}

.plan-card.popular {
    border: 2px solid var(--primary-color);
}

.popular-badge {
    position: absolute;
    top: -10px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--primary-color);
    color: var(--white);
    padding: 0.25rem 1rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.plan-name {
    font-size: 1.5rem;
    font-weight: bold;
    margin-bottom: 1rem;
    text-align: center;
}

.plan-price {
    font-size: 2.5rem;
    font-weight: bold;
    text-align: center;
    margin-bottom: 2rem;
    color: var(--primary-color);
}

.plan-price span {
    font-size: 1rem;
    color: var(--text-light);
}

.plan-features {
    list-style: none;
    margin-bottom: 2rem;
}

.plan-features li {
    padding: 0.5rem 0;
    display: flex;
    align-items: center;
}

.plan-features i {
    margin-right: 0.5rem;
    width: 20px;
}

.plan-features .fa-check {
    color: var(--success-color);
}

.plan-features .fa-times {
    color: var(--text-light);
}

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

.video-card {
    background: var(--white);
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s;
}

.video-card:hover {
    transform: translateY(-5px);
}

.video-thumbnail {
    position: relative;
    background: linear-gradient(135deg, #667eea, #764ba2);
    height: 180px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--white);
}

.video-thumbnail i {
    font-size: 3rem;
}

.video-content {
    padding: 1.5rem;
}

.video-meta {
    display: flex;
    justify-content: space-between;
    margin: 0.5rem 0;
    font-size: 0.9rem;
    color: var(--text-light);
}

/* Video Player */
#videoPlayer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.9);
    z-index: 3000;
    display: flex;
    align-items: center;
    justify-content: center;
}

.video-player-container {
    background: var(--white);
    border-radius: 10px;
    overflow: hidden;
    max-width: 90%;
    max-height: 90%;
    width: 800px;
}

.video-player-header {
    padding: 1rem;
    background: var(--text-color);
    color: var(--white);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.video-player-content {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    height: 0;
}

.video-player-content iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

/* PDF Viewer */
#pdfViewer {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--white);
    z-index: 3000;
    display: flex;
    flex-direction: column;
}

.pdf-header {
    padding: 1rem;
    background: var(--text-color);
    color: var(--white);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.pdf-container {
    flex: 1;
    position: relative;
}

.pdf-container iframe {
    width: 100%;
    height: 100%;
    border: none;
}

/* Responsive */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    #hero h1 {
        font-size: 2rem;
    }
    
    .features-grid,
    .categories-grid,
    .plans-grid {
        grid-template-columns: 1fr;
    }
    
    .books-filter {
        justify-content: center;
    }
}
/* Add these to your existing main.css */

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 2000;
    padding: 20px;
}

.modal-content {
    background: var(--white);
    padding: 2rem;
    border-radius: 15px;
    max-width: 600px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.close-modal {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background 0.3s;
}

.close-modal:hover {
    background: var(--background-light);
}

.hidden {
    display: none !important;
}