/* --- HERO SECTION --- */
.course-hero {
    position: relative;
    background-size: cover;
    background-position: center;
    padding-top: 4rem;
    padding-bottom: 4rem;
    color: white;
}

/* Dark Overlay */
.course-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(90deg, rgba(15, 23, 42, 0.98) 0%, rgba(30, 41, 59, 0.9) 100%);
    z-index: 0;
}

.hero-content {
    position: relative;
    z-index: 2;
}

/* --- HEADER CARD (Right Side) --- */
.header-card {
    background: white;
    border-radius: 16px;
    overflow: hidden;
    color: var(--text-dark);
    box-shadow: var(--card-shadow);
    height: 100%;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

/* --- PREVIEW IMAGE & PLAY BUTTON --- */
.preview-box {
    position: relative;
    aspect-ratio: 16/9;
    background: #000;
    overflow: hidden;
    cursor: pointer;
}

.preview-box img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: 0.5s ease;
    opacity: 0.9;
}

.preview-box:hover img {
    transform: scale(1.05);
    opacity: 0.7;
}

.play-btn-overlay {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2;
}

.play-icon {
    width: 64px;
    height: 64px;
    background: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--brand-color);
    font-size: 1.5rem;
    box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.7);
    animation: pulse-white 2s infinite;
}

@keyframes pulse-white {
    0% {
        transform: scale(0.95);
        box-shadow: 0 0 0 0 rgba(255, 255, 255, 0.7);
    }

    70% {
        transform: scale(1);
        box-shadow: 0 0 0 15px rgba(255, 255, 255, 0);
    }

    100% {
        transform: scale(0.95);
        box-shadow: 0 0 0 0 rgba(255, 255, 255, 0);
    }
}

/* --- BUTTONS --- */
.price-area {
    display: flex;
    align-items: flex-end;
    gap: 10px;
    margin-bottom: 1.5rem;
}

.current-price {
    font-size: 2.2rem;
    font-weight: 800;
    color: var(--text-dark);
    line-height: 1;
}

.old-price {
    text-decoration: line-through;
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 5px;
}

.btn-buy-now {
    background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    color: white;
    font-weight: 700;
    padding: 16px;
    border: none;
    border-radius: 10px;
    width: 100%;
    font-size: 1.1rem;
    transition: all 0.3s ease;
}

.btn-buy-now:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px -5px rgba(99, 102, 241, 0.4);
    color: white;
}

.btn-outline-custom {
    background: transparent;
    color: var(--text-dark);
    border: 2px dotted #e2e8f0;
    font-weight: 600;
    padding: 12px;
    width: 100%;
    border-radius: 10px;
    transition: all 0.2s;
    margin-top: 10px;
}

.btn-outline-custom:hover {
    border-color: var(--brand-color);
    color: var(--brand-color);
    background: #f8fafc;
}

/* --- TABS --- */
.nav-tabs-modern {
    border-bottom: 2px solid #e2e8f0;
    gap: 2rem;
    display: flex;
    margin-bottom: 2rem;
}

.nav-tabs-modern .nav-link {
    border: none;
    background: transparent;
    color: var(--text-muted);
    font-weight: 600;
    padding: 1rem 0;
    position: relative;
    font-size: 1.05rem;
}

.nav-tabs-modern .nav-link.active {
    color: var(--brand-color);
}

.nav-tabs-modern .nav-link.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--brand-color);
}

/* --- SIDEBAR WIDGETS --- */
.sidebar-widget {
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.widget-title {
    font-weight: 700;
    font-size: 1.1rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 8px;
}

.check-list li {
    margin-bottom: 0.8rem;
    font-size: 0.95rem;
    color: #475569;
    display: flex;
    gap: 10px;
    align-items: flex-start;
}

.check-list i {
    color: var(--brand-color);
    margin-top: 4px;
}

/* --- CURRICULUM ITEMS --- */
.lesson-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 14px 18px;
    border-bottom: 1px solid #f1f5f9;
    text-decoration: none;
    color: var(--text-dark);
    transition: 0.2s;
}

.lesson-item:hover {
    background: #f8fafc;
    color: var(--brand-color);
}

/* --- VOUCHER INPUT STYLE --- */
.voucher-input {
    text-transform: uppercase;
    letter-spacing: 2px;
    font-weight: 700;
    color: var(--brand-dark);
}

.voucher-input::placeholder {
    letter-spacing: 1px;
    font-weight: 400;
    color: #ccc;
}