.courses-master {
    display: grid;
    grid-template-columns: 300px 1fr;
    gap: 40px;
}

/* Filter Sidebar */
.filter-sidebar {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: 30px;
    height: fit-content;
    position: sticky;
    top: 100px;
    display: flex;
    flex-direction: column;
    gap: 24px;
    box-shadow: var(--shadow-premium);
}

.filter-section-title {
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 1.1rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 8px;
}

.filter-input-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.filter-input-group label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.filter-search-box {
    position: relative;
}

.filter-search-box i {
    position: absolute;
    top: 50%;
    left: 14px;
    transform: translateY(-50%);
    color: var(--text-muted);
}

.filter-search-box input {
    width: 100%;
    padding: 12px 14px 12px 40px;
    background-color: hsl(222, 47%, 4%);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-main);
    font-family: var(--font-body);
    font-size: 0.9rem;
}

.filter-search-box input:focus {
    border-color: var(--primary);
    outline: none;
}

.filter-dropdown {
    width: 100%;
    padding: 12px 14px;
    background-color: hsl(222, 47%, 4%);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-main);
    font-family: var(--font-body);
    font-size: 0.9rem;
    appearance: none;
    background-image: url("data:image/svg+xml;charset=UTF-8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='24' height='24' viewBox='0 0 24 24' fill='none' stroke='rgba(148,163,184,0.8)' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpolyline points='6 9 12 15 18 9'%3E%3C/polyline%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 14px center;
    background-size: 16px;
}

.filter-dropdown:focus {
    border-color: var(--primary);
    outline: none;
}

.btn-reset-filters {
    background: rgba(255,255,255,0.03);
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-family: var(--font-display);
    font-weight: 700;
    font-size: 0.9rem;
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-reset-filters:hover {
    background: var(--bg-card-hover);
    border-color: var(--text-muted);
}

/* Content Area */
.catalog-container {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.catalog-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.catalog-header h2 {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 800;
}

.catalog-results-count {
    color: var(--text-muted);
    font-size: 0.9rem;
}

.empty-state {
    grid-column: 1 / -1;
    background: var(--bg-card);
    border: 1px dashed var(--border-color);
    border-radius: 16px;
    padding: 60px 40px;
    text-align: center;
    color: var(--text-muted);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 16px;
}

.empty-state i {
    font-size: 3rem;
    color: var(--primary);
}

.empty-state h3 {
    font-family: var(--font-display);
    color: var(--text-main);
    font-size: 1.3rem;
    font-weight: 700;
}

/* Simple List toolbar row */
.toolbar-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 20px;
}

.toolbar-row h2 {
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 800;
}

.search-input-box {
    position: relative;
    width: 320px;
}

.search-input-box i {
    position: absolute;
    top: 50%;
    left: 14px;
    transform: translateY(-50%);
    color: var(--text-muted);
}

.search-input-box input {
    width: 100%;
    padding: 12px 14px 12px 40px;
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-main);
    font-family: var(--font-body);
    font-size: 0.9rem;
}

.search-input-box input:focus {
    border-color: var(--primary);
    outline: none;
}

/* Schedules Cards specific styling */
.schedule-ui-card {
    cursor: pointer;
}

.pdf-thumbnail {
    position: relative;
    width: 100%;
    height: 160px;
    background-color: hsl(222, 47%, 4%);
    overflow: hidden;
    border-bottom: 1px solid var(--border-color);
}

.pdf-thumbnail-frame {
    width: 100%;
    height: 250px;
    border: none;
    transform: scale(0.7);
    transform-origin: top center;
    pointer-events: none;
    overflow: hidden;
}

.thumbnail-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(0deg, var(--bg-card), transparent);
}

.card-actions-row {
    display: flex;
    gap: 10px;
    margin-top: auto;
}

.btn-card-action {
    flex: 1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 8px 12px;
    font-size: 0.8rem;
    font-family: var(--font-display);
    font-weight: 700;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    background: rgba(255,255,255,0.02);
    color: var(--text-main);
    cursor: pointer;
}

.btn-card-action:hover {
    background: var(--bg-card-hover);
    border-color: var(--text-muted);
}

.btn-blue-action {
    background: var(--primary-glow);
    border-color: var(--primary);
}

.btn-blue-action:hover {
    background: var(--primary);
}

/* Modals */
.modal-overlay-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(9, 13, 26, 0.9);
    backdrop-filter: blur(8px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2000;
}

.modal-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    width: 90%;
    max-width: 500px;
    padding: 40px;
    position: relative;
    box-shadow: 0 20px 50px rgba(0,0,0,0.8);
    text-align: center;
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 20px;
    background: none;
    border: none;
    color: var(--text-muted);
    font-size: 1.4rem;
    cursor: pointer;
    z-index: 10;
}

.modal-close:hover {
    color: var(--text-main);
}

.pdf-preview-modal-card {
    max-width: 900px;
    width: 95%;
    height: 85vh;
    padding: 40px 20px 20px;
    background-color: hsl(222, 47%, 8%);
}

.pdf-frame-wrapper {
    width: 100%;
    height: calc(100% - 20px);
    background-color: #000;
    border-radius: 8px;
    overflow: hidden;
}

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

@media (max-width: 992px) {
    .courses-master {
        grid-template-columns: 1fr;
    }

    .filter-sidebar {
        position: relative;
        top: 0;
    }
}