:root {
    /* Refined underground palette */
    --primary-color: #29b6f6;  /* cyber blue */
    --secondary-color: #00e676; /* neon green */
    --background-color: #121212; /* off-black */
    --text-color: #e0e0e0;      /* light gray for text */
    --card-background: #1e1e1e; /* dark surface */
    --card-border: #2c2c2c;     /* subtle border */
    --shadow: 0 4px 8px rgba(0, 0, 0, 0.6);
}

body {
    font-family: 'Poppins', sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    margin: 0;
    font-size: 16px; /* base size */
    line-height: 1.7; /* more comfortable */
    letter-spacing: 0.03em; /* subtle tracking */
}

/* Headings */
h1, .h1 {
    font-size: 2.5rem;
    font-weight: 700;
    line-height: 1.2;
    color: var(--primary-color);
    margin-top: 0;
}

h2, .h2 {
    font-size: 1.8rem;
    font-weight: 600;
    line-height: 1.3;
    margin-top: 0;
}

h3, .h3 {
    font-size: 1.4rem;
    font-weight: 600;
    line-height: 1.4;
    margin-top: 0;
}

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

/* Flex layout only for header container */
.header .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

/* Header redesign */
.header {
    position: sticky;
    top: 0;
    z-index: 999;
    background-color: rgba(18, 18, 18, 0.85);
    backdrop-filter: blur(8px);
    padding: 1rem 0.5rem;
    border-bottom: 1px solid var(--card-border);
    box-shadow: 0 2px 4px rgba(0,0,0,0.5);
}

.logo {
    display: flex;
    align-items: center;
}

.logo img {
    height: 72px;
    width: auto;
}

.main {
    padding: 2rem 0;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 1.75rem;
}

@media (min-width: 1200px) {
    .grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (min-width: 768px) and (max-width: 1199px) {
    .grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* Card */
.card {
    position: relative;
    background-color: var(--card-background);
    border: 1px solid var(--card-border);
    border-radius: 12px;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    box-shadow: var(--shadow);
}

.card::before {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(180deg, transparent 60%, rgba(0,0,0,0.6) 100%);
    transition: opacity 0.3s ease;
    opacity: 0;
    pointer-events: none;
}

.card:hover::before {
    opacity: 1;
}

.card:hover {
    transform: translateY(-6px) scale(1.02);
    box-shadow: 0 10px 18px rgba(0, 0, 0, 0.4);
    border-color: var(--primary-color);
}

.card-img {
    width: 100%;
    height: 180px;
    object-fit: cover;
}

.card-body {
    padding: 1.5rem;
}

.card-title {
    font-size: 1.25rem;
    margin: 0 0 0.5rem;
    color: var(--text-color);
    font-weight: 700;
}

.card-author {
    font-size: 0.9rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.card-text {
    font-size: 0.95rem;
    margin: 1rem 0;
}

.footer {
    background-color: #000;
    color: var(--text-color);
    padding: 2rem 0;
    text-align: center;
    margin-top: 2rem;
}

/* Single Course Page */
.course-single {
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}

@media (min-width: 992px) {
    .course-single {
        grid-template-columns: 2fr 1fr;
    }
}

.course-main, .course-sidebar {
    background-color: var(--card-background);
    padding: 2rem;
    border-radius: 8px;
    box-shadow: var(--shadow);
}

.course-img-single {
    width: 100%;
    border-radius: 8px;
    margin-bottom: 1.5rem;
}

.course-single h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin: 0 0 0.5rem;
}

.course-single .author {
    font-size: 1.1rem;
    color: var(--secondary-color);
    margin-bottom: 1.5rem;
}

.category-tag {
    display: inline-block;
    background-color: var(--primary-color);
    color: white;
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    text-decoration: none;
    margin-right: 0.5rem;
    font-size: 0.85rem;
}

/* Refined Download Box */
.guruflix-box {
    background: linear-gradient(145deg, #1b1b1b 0%, #111 100%);
    border: 2px solid var(--primary-color);
    border-radius: 16px;
    padding: 2.2rem 1.8rem;
    text-align: center;
    margin-bottom: 2rem;
    box-shadow: 0 8px 22px rgba(0, 255, 136, 0.15);
}

.guruflix-box h2 {
    margin: 0 0 1rem;
    font-size: 2rem;
    background: linear-gradient(90deg, #ff0077 0%, #29b6f6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 10px rgba(41,182,246,0.35);
}

.guruflix-box p {
    margin: 0 0 1.6rem;
    color: #9ea3ad;
    font-size: 1.05rem;
}

.guruflix-button {
    display: inline-block;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    color: #000;
    padding: 0.9rem 1.8rem;
    border-radius: 50px;
    text-decoration: none;
    font-weight: 700;
    box-shadow: 0 4px 12px rgba(0,0,0,0.4);
    transition: background 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
}

.guruflix-button:hover {
    background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
    transform: translateY(-3px);
    box-shadow: 0 6px 14px rgba(0,0,0,0.6);
}

.reviews-section {
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid #eee;
}

.reviews-section h2 {
    font-size: 1.8rem;
    margin-bottom: 1rem;
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

.review {
    display: flex;
    align-items: flex-start;
    padding: 20px 0;
    border-bottom: 1px solid #eee;
}

.review:last-child {
    border-bottom: none;
}

.review-avatar {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background-color: var(--primary-color);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: bold;
    margin-right: 20px;
    flex-shrink: 0;
}

.review-content {
    flex-grow: 1;
}

.review-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.review-author {
    font-weight: 600;
    color: var(--text-color);
}

.review-date {
    font-size: 0.85em;
    color: #999;
}

.star-rating {
    margin-bottom: 10px;
}

.star {
    font-size: 20px;
    color: #ffc107;
}

.star.empty {
    color: #e0e0e0;
}

.star.half {
    position: relative;
    display: inline-block;
    color: #e0e0e0;
}

.star.half::before {
    content: '\2605'; /* Filled star character */
    position: absolute;
    left: 0;
    top: 0;
    width: 50%;
    overflow: hidden;
    color: #ffc107;
}

.course-info {
    margin-top: 1.5rem;
}

.info-item {
    display: flex;
    justify-content: space-between;
    padding: 0.8rem 0;
    border-bottom: 1px solid var(--card-border);
}

.info-label {
    font-weight: bold;
}

.back-btn {
    display: inline-block;
    margin-bottom: 1.5rem;
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 500;
}

.back-btn:hover {
    text-decoration: underline;
}

.search-bar {
    width: 100%;
    padding: 1rem;
    font-size: 1.1rem;
    border-radius: 8px;
    border: 1px solid var(--card-border);
    margin-bottom: 2rem;
    background-color: var(--card-background);
    color: var(--text-color);
} 

/* Enhanced Review Styling */
.review {
    display: flex;
    align-items: flex-start;
    gap: 1.5rem;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    background-color: var(--card-background);
    border: 1px solid var(--card-border);
    border-radius: 10px;
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.review:hover {
    transform: translateY(-4px);
    box-shadow: 0 6px 10px rgba(0, 0, 0, 0.12);
}

.review-avatar {
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-color) 0%, #004c7f 100%);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 26px;
    font-weight: 700;
    flex-shrink: 0;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
}

.review-content p {
    background-color: var(--card-border);
    padding: 0.8rem 1rem;
    border-radius: 6px;
    position: relative;
    font-style: italic;
    line-height: 1.5;
    margin: 0.5rem 0 0 0;
    color: var(--text-color);
    border-left: 3px solid var(--primary-color);
}

.review-content p::before {
    content: "\201C"; /* Left double quotation mark */
    font-size: 2rem;
    color: var(--primary-color);
    position: absolute;
    left: -10px;
    top: -10px;
}

.review-content p::after {
    content: "\201D"; /* Right double quotation mark */
    font-size: 2rem;
    color: var(--primary-color);
    position: absolute;
    right: -10px;
    bottom: -10px;
} 

/*====================================
  Guruflix Offer – Conversion Boost
====================================*/
@media (min-width: 992px) {
    .course-sidebar {
        position: sticky;
        top: 2rem; /* keeps the box visible while scrolling */
        align-self: flex-start;
    }
}

.guruflix-box {
    background: linear-gradient(135deg, #fff4e6 0%, #ffe8cc 100%);
    border: 2px solid #ffb775;
    border-radius: 12px;
    padding: 2rem 1.5rem;
    text-align: center;
    margin-bottom: 2rem;
    box-shadow: 0 6px 16px rgba(0, 0, 0, 0.1);
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.guruflix-box:hover {
    transform: scale(1.03);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.15);
}

.guruflix-box h2 {
    font-size: 1.85rem;
    color: #e66a00;
    margin: 0 0 0.75rem;
    font-weight: 700;
}

.guruflix-box p {
    font-size: 1.05rem;
    margin: 0 0 1.25rem;
}

@keyframes cta-pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.guruflix-button {
    display: inline-block;
    background: linear-gradient(135deg, #ff7f0e 0%, #ffb347 100%);
    color: #fff;
    padding: 1rem 2rem;
    border-radius: 50px;
    text-decoration: none;
    font-size: 1.125rem;
    font-weight: 700;
    box-shadow: 0 4px 12px rgba(255, 127, 14, 0.4);
    transition: background 0.3s ease, transform 0.3s ease, box-shadow 0.3s ease;
    animation: cta-pulse 2.5s infinite;
}

.guruflix-button:hover {
    background: linear-gradient(135deg, #ff9a1b 0%, #ffc15e 100%);
    transform: translateY(-3px);
    box-shadow: 0 6px 14px rgba(255, 127, 14, 0.5);
} 

/* Responsive visibility for duplicated Guruflix boxes */
/* Remove hide of desktop box on mobile */
@media (max-width: 991.98px) {
    /* .guruflix-box-desktop { display: none !important; } */
}
@media (min-width: 992px) {
    .guruflix-box-mobile { display: none !important; }
} 

/* Hero Section */
.hero {
    position: relative;
    background: radial-gradient(circle at top left, rgba(41,182,246,0.25), transparent 70%),
                radial-gradient(circle at bottom right, rgba(0,230,118,0.25), transparent 70%),
                #1a1a1a;
    color: var(--text-color);
    text-align: center;
    padding: 6rem 1.5rem 5rem;
    border: 2px solid var(--primary-color);
    border-radius: 16px;
    overflow: hidden;
    margin-bottom: 3rem;
}

.hero::after {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent 0%, rgba(41,182,246,0.1) 50%, transparent 100%);
    pointer-events: none;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin: 0 0 0.75rem;
    color: var(--primary-color);
}

.hero-subtitle {
    font-size: 1.25rem;
    max-width: 800px;
    margin: 0 auto 2.5rem;
    line-height: 1.6;
    color: var(--text-color);
}

.hero-search .search-bar {
    max-width: 600px;
    margin: 0 auto;
    background-color: var(--card-background);
    color: var(--text-color);
}

.category-section {
    margin-bottom: 1.5rem;
    text-align: center;
}

/* No results message */
.no-results {
    text-align: center;
    font-size: 1.1rem;
    color: var(--secondary-color);
    margin-top: 2rem;
} 

/* Course Meta */
.course-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin: 1rem 0 2rem;
}

.meta-item {
    background-color: var(--card-background);
    border: 1px solid var(--card-border);
    border-radius: 6px;
    padding: 0.5rem 0.8rem;
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    column-gap: 0.25rem;
}

.meta-label {
    font-weight: 600;
    color: var(--secondary-color);
}

.meta-value {
    color: var(--text-color);
}

.meta-value a {
    color: var(--text-color);
    text-decoration: none;
}

.meta-value a:hover {
    color: var(--primary-color);
} 

.author-link {
    color: var(--primary-color);
    text-decoration: none;
}

.author-link:hover {
    text-decoration: underline;
    color: var(--secondary-color);
}