/* ==========================================================================
   Text Book Light Theme Components (t-book.css) — Red & Gold Theme
   ========================================================================== */

/* Language Switcher Section */
.lang-selection-section {
    margin: 30px 0 20px 0;
    text-align: center;
}

.section-title {
    color: #b91c1c;
    font-size: 0.9rem;
    letter-spacing: 1.5px;
    margin-bottom: 12px;
}

.lang-tabs {
    display: flex;
    justify-content: center;
    gap: 15px;
}

.lang-tab-btn {
    background: rgba(255, 255, 255, 0.7);
    border: 1px solid rgba(0, 0, 0, 0.1);
    color: #52525b;
    padding: 12px 35px;
    border-radius: 30px;
    font-weight: 700;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(8px);
}

.lang-tab-btn:hover {
    background: rgba(234, 179, 8, 0.15);
    border-color: rgba(234, 179, 8, 0.45);
    color: #b45309;
}

.lang-tab-btn.active {
    background: linear-gradient(135deg, #dc2626, #b91c1c);
    color: #ffffff;
    border-color: transparent;
    box-shadow: 0 4px 20px rgba(185, 28, 28, 0.4);
}

/* Grade Pills Selector (Red & Gold Light Scheme) */
.grade-selector {
    background: rgba(255, 255, 255, 0.75);
    border-radius: 18px;
    padding: 20px 24px;
    margin-bottom: 28px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    border: 1px solid rgba(0, 0, 0, 0.08);
    backdrop-filter: blur(12px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
    animation: fadeIn 0.4s ease;
}

.grade-selector-label {
    font-weight: 700;
    font-size: 1rem;
    color: #0f172a;
    letter-spacing: 0.3px;
}

.grade-pills {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 10px;
    flex: 1;
}

.grade-pill {
    padding: 9px 20px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 0.88rem;
    background: rgba(0, 0, 0, 0.03);
    color: #52525b;
    border: 1px solid rgba(0, 0, 0, 0.1);
    cursor: pointer;
    transition: all 0.25s ease;
    user-select: none;
}

.grade-pill:hover {
    background: rgba(234, 179, 8, 0.15);
    border-color: rgba(234, 179, 8, 0.45);
    color: #b45309;
    transform: translateY(-2px);
}

.grade-pill.active {
    background: linear-gradient(135deg, #dc2626, #b91c1c);
    color: #ffffff;
    border-color: transparent;
    box-shadow: 0 4px 16px rgba(185, 28, 28, 0.35);
}

/* Subject List & Cards */
.subject-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
    margin-bottom: 40px;
}

.subject-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(255, 255, 255, 0.75);
    border: 1px solid rgba(0, 0, 0, 0.08);
    padding: 14px 20px;
    border-radius: 16px;
    backdrop-filter: blur(10px);
    transition: all 0.25s ease;
    flex-wrap: wrap;
    gap: 12px;
    animation: slideUp 0.3s ease;
}

.subject-item:hover {
    border-color: rgba(185, 28, 28, 0.3);
    box-shadow: 0 8px 24px rgba(185, 28, 28, 0.1);
    transform: translateY(-2px);
}

.subject-left {
    display: flex;
    align-items: center;
    gap: 14px;
}

.subject-icon {
    width: 38px;
    height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(234, 179, 8, 0.15);
    border-radius: 10px;
    color: #b45309;
    flex-shrink: 0;
}

.subject-icon svg {
    width: 20px;
    height: 20px;
    stroke: currentColor;
}

.subject-name {
    font-weight: 600;
    font-size: 0.98rem;
    color: #0f172a;
}

.subject-actions {
    display: flex;
    gap: 10px;
    align-items: center;
}

/* Action Buttons */
.action-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 18px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 0.82rem;
    border: none;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.25s ease;
}

.action-btn.preview {
    background: rgba(234, 179, 8, 0.12);
    color: #b45309;
    border: 1px solid rgba(234, 179, 8, 0.35);
}

.action-btn.preview:hover {
    background: rgba(234, 179, 8, 0.25);
    color: #92400e;
    box-shadow: 0 4px 12px rgba(234, 179, 8, 0.25);
}

.action-btn.download {
    background: linear-gradient(135deg, #dc2626, #b91c1c);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(185, 28, 28, 0.35);
}

.action-btn.download:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 18px rgba(185, 28, 28, 0.5);
}

.action-btn svg {
    width: 16px;
    height: 16px;
}

.no-file {
    color: #71717a;
    font-size: 0.82rem;
    font-style: italic;
}

/* Empty State / Not Found Card */
.no-docs {
    text-align: center;
    padding: 45px 20px;
    color: #71717a;
    font-weight: 500;
    font-size: 0.98rem;
    background: rgba(255, 255, 255, 0.6);
    border-radius: 18px;
    border: 1px dashed rgba(0, 0, 0, 0.15);
    backdrop-filter: blur(8px);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.no-docs-icon {
    font-size: 2.2rem;
    margin-bottom: 4px;
}

/* PDF Preview Modal Overlay */
.preview-overlay {
    position: fixed;
    inset: 0;
    background: rgba(15, 23, 42, 0.6);
    backdrop-filter: blur(10px);
    z-index: 99999;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.preview-overlay.active {
    display: flex;
    animation: fadeIn 0.3s ease;
}

.preview-modal {
    background: #ffffff;
    border-radius: 20px;
    max-width: 1000px;
    width: 100%;
    height: 85vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    border: 1px solid rgba(0, 0, 0, 0.12);
    box-shadow: 0 25px 60px rgba(0, 0, 0, 0.25);
}

.preview-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 16px 24px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
    background: rgba(254, 252, 232, 0.9);
}

.preview-header h4 {
    font-size: 1rem;
    font-weight: 600;
    color: #0f172a;
}

.preview-close {
    background: rgba(220, 38, 38, 0.15);
    color: #dc2626;
    border: 1px solid rgba(220, 38, 38, 0.4);
    font-size: 20px;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
}

.preview-close:hover {
    background: #dc2626;
    color: #ffffff;
    transform: scale(1.08);
}

.preview-body {
    flex: 1;
    background: #f8fafc;
}

.preview-body iframe {
    width: 100%;
    height: 100%;
    border: none;
}

/* Keyframe Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes slideUp {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Mobile Responsive Adjustments */
@media (max-width: 768px) {
    .grade-selector {
        padding: 16px;
    }
    .grade-pill {
        padding: 7px 14px;
        font-size: 0.8rem;
    }
    .subject-item {
        padding: 12px 16px;
    }
    .subject-actions {
        width: 100%;
        justify-content: flex-end;
    }
}

/* UI Enhancements for Cards & Preview Buttons */
.subject-list {
    display: flex;
    flex-direction: column;
    gap: 14px;
    margin-top: 20px;
}

.subject-card {
    background: #ffffff;
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: 16px;
    padding: 16px 20px;
    display: flex;
    flex-direction: column;
    gap: 14px;
    transition: transform 0.2s ease, border-color 0.2s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.04);
}

.subject-card:hover {
    border-color: rgba(185, 28, 28, 0.3);
    box-shadow: 0 8px 24px rgba(185, 28, 28, 0.1);
}

.subject-header {
    display: flex;
    align-items: center;
    gap: 12px;
}

.subject-icon-red {
    color: #dc2626;
    width: 24px;
    height: 24px;
    flex-shrink: 0;
}

.subject-title {
    color: #0f172a;
    font-size: 1.05rem;
    font-weight: 600;
}

.subject-actions {
    display: flex;
    align-items: center;
    gap: 12px;
    justify-content: flex-end;
}

.action-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 22px;
    border-radius: 12px;
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.2s ease;
    border: none;
}

.btn-preview {
    background: rgba(234, 179, 8, 0.12);
    color: #b45309;
    border: 1px solid rgba(234, 179, 8, 0.35);
}

.btn-preview:hover {
    background: rgba(234, 179, 8, 0.25);
    color: #92400e;
    box-shadow: 0 4px 12px rgba(234, 179, 8, 0.25);
}

.btn-download {
    background: linear-gradient(135deg, #dc2626, #b91c1c);
    color: #ffffff;
    box-shadow: 0 4px 14px rgba(185, 28, 28, 0.35);
}

.btn-download:hover {
    background: linear-gradient(135deg, #ef4444, #dc2626);
    box-shadow: 0 6px 18px rgba(185, 28, 28, 0.5);
}

/* Fullscreen PDF Preview Modal Styling */
.pdf-preview-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(5px);
    z-index: 9999;
    display: none;
    align-items: center;
    justify-content: center;
    padding: 15px;
}

.pdf-preview-overlay.active {
    display: flex;
}

.pdf-preview-box {
    position: relative;
    width: 100%;
    max-width: 900px;
    height: 88vh;
    background: #ffffff;
    border-radius: 18px;
    overflow: hidden;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.25);
}

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

.close-pdf-circle {
    position: absolute;
    top: 15px;
    right: 15px;
    width: 38px;
    height: 38px;
    background: #dc2626;
    color: #ffffff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 20px;
    font-weight: bold;
    z-index: 10;
    border: 2px solid #ffffff;
    box-shadow: 0 4px 12px rgba(185, 28, 28, 0.35);
    transition: transform 0.2s ease;
}

.close-pdf-circle:hover {
    transform: scale(1.1);
    background: #b91c1c;
}

.no-docs-card {
    background: #ffffff;
    border: 1px dashed rgba(0, 0, 0, 0.15);
    border-radius: 16px;
    padding: 40px 20px;
    text-align: center;
    color: #71717a;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.04);
}

.no-docs-card svg {
    width: 48px;
    height: 48px;
    margin-bottom: 12px;
    opacity: 0.7;
    color: #b45309;
}