/* Variables globales de diseño */
:root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent: #6366f1;
    --accent-hover: #4f46e5;
    --accent-success: #10b981;
    --accent-danger: #ef4444;
    --border-color: #475569;
    --font-sans: 'Outfit', sans-serif;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    padding: 2rem 1rem;
}

/* Contenedor principal */
.app-container {
    width: 100%;
    max-width: 1100px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* Cabecera */
.app-header {
    text-align: center;
    margin-bottom: 1rem;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.75rem;
    margin-bottom: 0.5rem;
}

.icon-logo {
    font-size: 2.5rem;
    color: var(--accent);
    filter: drop-shadow(0 0 8px rgba(99, 102, 241, 0.4));
}

.logo h1 {
    font-size: 2.5rem;
    font-weight: 800;
    letter-spacing: -0.05em;
}

.logo h1 span {
    color: var(--accent);
}

.subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 300;
}

/* Área de Carga */
.upload-section {
    width: 100%;
}

.drop-zone {
    background-color: var(--bg-secondary);
    border: 2px dashed var(--border-color);
    border-radius: 1rem;
    padding: 4rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    box-shadow: var(--shadow-md);
}

.drop-zone:hover, .drop-zone.dragover {
    border-color: var(--accent);
    background-color: rgba(99, 102, 241, 0.05);
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.1);
}

.upload-icon {
    font-size: 3.5rem;
    color: var(--accent);
    margin-bottom: 0.5rem;
    transition: var(--transition);
}

.drop-zone:hover .upload-icon {
    transform: translateY(-5px);
}

.drop-zone h3 {
    font-size: 1.3rem;
    font-weight: 600;
}

.drop-zone p {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.file-input-hidden {
    display: none;
}

/* Área de trabajo (Grid de páginas) */
.workspace-section {
    background-color: var(--bg-secondary);
    border-radius: 1rem;
    padding: 1.5rem;
    box-shadow: var(--shadow-lg);
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    animation: fadeIn 0.4s ease-out;
}

.workspace-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

.info-badge {
    background-color: var(--bg-tertiary);
    padding: 0.5rem 1rem;
    border-radius: 2rem;
    font-size: 0.9rem;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    border: 1px solid var(--border-color);
}

.workspace-actions {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.filename-input-container {
    display: flex;
    align-items: center;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    overflow: hidden;
}

.filename-input {
    background: transparent;
    border: none;
    color: var(--text-primary);
    padding: 0.65rem 0.75rem;
    font-family: var(--font-sans);
    font-size: 0.95rem;
    outline: none;
    width: 150px;
}

.filename-input:focus {
    background-color: rgba(255, 255, 255, 0.05);
}

.filename-ext {
    padding: 0.65rem 0.75rem 0.65rem 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
}

/* Botones */
.btn {
    font-family: var(--font-sans);
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.65rem 1.25rem;
    border-radius: 0.5rem;
    border: none;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition);
}

.btn-primary {
    background-color: var(--accent);
    color: white;
}

.btn-primary:hover {
    background-color: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.btn-secondary {
    background-color: transparent;
    border: 1px solid var(--border-color);
    color: var(--text-primary);
}

.btn-secondary:hover {
    background-color: var(--bg-tertiary);
    border-color: var(--text-secondary);
}

/* Grid de Páginas */
.pages-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 1.5rem;
    min-height: 200px;
    padding: 0.5rem;
}

/* Tarjeta de Página Individual */
.page-card {
    background-color: var(--bg-tertiary);
    border-radius: 0.75rem;
    overflow: hidden;
    position: relative;
    border: 2px solid transparent;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    cursor: grab;
    user-select: none;
    display: flex;
    flex-direction: column;
}

.page-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: var(--border-color);
}

.page-card:active {
    cursor: grabbing;
}

/* Estado de arrastre */
.page-card.dragging {
    opacity: 0.4;
    border: 2px dashed var(--accent);
    background-color: rgba(99, 102, 241, 0.1);
}

/* Miniatura del Canvas */
.page-preview {
    width: 100%;
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #f1f5f9; /* fondo claro para que contraste el PDF */
    overflow: hidden;
    position: relative;
}

.page-preview canvas {
    max-width: 90%;
    max-height: 90%;
    object-fit: contain;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
    transition: transform 0.3s ease;
}

.page-preview canvas.rotate-90 {
    transform: rotate(90deg);
}

.page-preview canvas.rotate-180 {
    transform: rotate(180deg);
}

.page-preview canvas.rotate-270 {
    transform: rotate(270deg);
}

/* Información al pie de la tarjeta */
.page-info {
    padding: 0.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--bg-secondary);
    font-size: 0.8rem;
    border-top: 1px solid var(--border-color);
}

.page-number {
    font-weight: 600;
    color: var(--text-primary);
    background-color: var(--bg-tertiary);
    width: 20px;
    height: 20px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.source-filename {
    color: var(--text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 90px;
}

/* Acciones en la tarjeta (Eliminar / Rotar) */
.page-actions {
    position: absolute;
    top: 0.5rem;
    right: 0.5rem;
    display: flex;
    gap: 0.35rem;
    opacity: 0;
    transition: var(--transition);
}

.page-card:hover .page-actions {
    opacity: 1;
}

.action-btn {
    background-color: rgba(15, 23, 42, 0.8);
    border: none;
    border-radius: 0.25rem;
    color: var(--text-primary);
    width: 26px;
    height: 26px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 0.8rem;
    transition: var(--transition);
}

.action-btn:hover {
    background-color: var(--accent);
}

.action-btn.delete-btn:hover {
    background-color: var(--accent-danger);
}

/* Footer */
.app-footer {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: auto;
    padding: 1rem 0;
}

.app-footer i {
    color: var(--accent-success);
    margin-right: 0.25rem;
}

/* Loader / Spinner */
.loader-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.85);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.loader-content {
    background-color: var(--bg-secondary);
    padding: 2.5rem;
    border-radius: 1rem;
    text-align: center;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1.5rem;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--border-color);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

/* Utilidades */
.hidden {
    display: none !important;
}

/* Animaciones */
@keyframes spin {
    to { transform: rotate(360deg); }
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* Responsividad */
@media (max-width: 640px) {
    .workspace-header {
        flex-direction: column;
        align-items: stretch;
    }
    .workspace-actions {
        flex-direction: column;
    }
    .btn {
        justify-content: center;
    }
}