/* E-Books Page Specific Styles */
:root {
    --ebook-primary: #512da8;
    /* Deep Purple */
    --ebook-gradient: linear-gradient(135deg, #12005e 0%, #512da8 100%);
}

/* --- Hero Section --- */
.ebook-hero {
    background: var(--ebook-gradient);
    color: white;
    padding: 80px 0 100px;
    /* Extra bottom padding for overlap effect */
    text-align: center;
    position: relative;
    clip-path: ellipse(150% 100% at 50% 0%);
    margin-bottom: -40px;
    /* Pull content up */
}

.ebook-hero h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -1px;
    text-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
}

.ebook-hero p {
    font-size: 1.2rem;
    opacity: 0.9;
    max-width: 600px;
    margin: 0 auto;
    font-weight: 300;
}

/* --- Filter Bar Beautification --- */
.filter-bar {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 50px;
    flex-wrap: wrap;
    position: relative;
    z-index: 10;
}

.filter-btn {
    background: white;
    color: #555;
    border: none;
    /* Remove default border */
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.08);
    /* Soft shadow */
    padding: 10px 25px;
    border-radius: 50px;
    /* Pill shape */
    font-weight: 600;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    /* Bouncy transition */
    font-size: 0.95rem;
}

.filter-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.12);
    color: var(--ebook-primary);
}

.filter-btn.active {
    background: var(--ebook-primary);
    color: white;
    box-shadow: 0 8px 25px rgba(81, 45, 168, 0.4);
    /* Colored shadow */
    transform: scale(1.05);
}

/* --- 3D Book Card Effect --- */
.course-card .course-thumbnail {
    perspective: 1000px;
    /* Enable 3D space */
    overflow: visible;
    /* Allow book to pop out */
    background: transparent;
    /* Remove gray bg */
}

.course-card .course-thumbnail img {
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.4s ease;
    box-shadow: 5px 5px 15px rgba(0, 0, 0, 0.15);
    /* Initial shadow */
    transform-origin: left center;
    /* Swing from spine */
    border-radius: 4px 12px 12px 4px;
    /* Book shape rounded corners */
}

/* Add Spine Effect */
.course-card .course-thumbnail img::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 20px;
    height: 100%;
    background: linear-gradient(to right, rgba(255, 255, 255, 0.2) 0%, rgba(0, 0, 0, 0.1) 100%);
    z-index: 10;
}

.course-card:hover .course-thumbnail img {
    transform: rotateY(-15deg) translateX(10px) scale(1.05);
    box-shadow: 15px 10px 30px rgba(0, 0, 0, 0.25);
    /* Deep shadow on lift */
}

/* Enhance existing card elements to match theme */
.course-card {
    border: none;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
    /* Softer global shadow */
    transition: transform 0.3s, box-shadow 0.3s;
}

.course-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
}

.course-title {
    font-family: 'Poppins', sans-serif;
    font-weight: 600;
}

.play-icon-container {
    display: none;
    /* Hide play icon for books */
}

/* PDF/Book Badge Overrides */
.price-badge-top {
    background: rgba(0, 0, 0, 0.7);
    padding: 2px 8px;
    border-radius: 4px;
    backdrop-filter: blur(4px);
}