.pdf-preview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
    gap: 1.25rem;
    margin-top: 1.5rem;
}

.pdf-preview-card {
    position: relative;
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    padding: 1rem;
    background-color: #ffffff;
    box-shadow: 0 12px 32px rgba(15, 23, 42, 0.08);
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.pdf-preview-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 18px 40px rgba(15, 23, 42, 0.12);
}

.pdf-preview-card.is-loading::after {
    content: "Generating preview…";
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.82);
    color: #1f2937;
    font-weight: 600;
    border-radius: 14px;
}

.pdf-preview-thumbnail img {
    width: 100%;
    border-radius: 10px;
    box-shadow: inset 0 0 0 1px rgba(30, 41, 59, 0.05);
}

.pdf-preview-thumbnail .pdf-preview-placeholder-thumb {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 160px;
    border-radius: 10px;
    background: repeating-linear-gradient(45deg, #f1f5f9, #f1f5f9 12px, #e2e8f0 12px, #e2e8f0 24px);
    color: #64748b;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.pdf-preview-meta {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.pdf-preview-name {
    font-weight: 600;
    color: #111827;
    word-break: break-word;
}

.pdf-preview-details {
    font-size: 0.875rem;
    color: #64748b;
}

.pdf-preview-actions {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.5rem;
}

.pdf-preview-remove {
    border: none;
    background: #f87171;
    color: #fff;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    cursor: pointer;
    transition: background 0.2s ease;
}

.pdf-preview-remove:hover {
    background: #ef4444;
}

.pdf-preview-placeholder {
    border: 2px dashed #cbd5e1;
    border-radius: 14px;
    padding: 2rem;
    text-align: center;
    color: #64748b;
    background: #f8fafc;
    font-weight: 500;
}

.helper-message .alert {
    margin-bottom: 0;
}

.pdf-page-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 1rem;
}

.pdf-page-thumb {
    border: 2px solid transparent;
    border-radius: 14px;
    padding: 0.75rem;
    background: #ffffff;
    box-shadow: 0 10px 28px rgba(15, 23, 42, 0.08);
    cursor: pointer;
    transition: transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
    position: relative;
}

.pdf-page-thumb:hover {
    transform: translateY(-4px);
    box-shadow: 0 14px 36px rgba(15, 23, 42, 0.14);
}

.pdf-page-thumb.selected {
    border-color: #4c6ef5;
    box-shadow: 0 16px 40px rgba(76, 110, 245, 0.24);
}

.pdf-page-thumb img {
    width: 100%;
    border-radius: 10px;
}

.pdf-page-thumb .pdf-page-label {
    margin-top: 0.5rem;
    font-weight: 600;
    color: #1f2937;
}

.pdf-page-thumb.selected::after {
    content: "Selected";
    position: absolute;
    top: 12px;
    right: 12px;
    background: #4c6ef5;
    color: #fff;
    font-size: 0.7rem;
    font-weight: 600;
    padding: 0.25rem 0.75rem;
    border-radius: 999px;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

@media (max-width: 575.98px) {
    .pdf-preview-grid {
        grid-template-columns: 1fr;
    }

    .pdf-page-grid {
        grid-template-columns: 1fr 1fr;
    }
}