/* ========================================
VARIABLES DE COLOR Y DISEÑO
======================================== */
:root {
    /* Colores principales */
    --color-primary-blue: #3b82f6;
    --color-primary-blue-hover: #2563eb;
    --color-primary-blue-dark: #1e40af;
    
    /* Colores neutralos */
    --color-bg-light: #f8fafc;
    --color-bg-white: #ffffff;
    --color-bg-gray: #f1f5f9;
    --color-bg-gray-dark: #e2e8f0;
    --color-bg-blue-dark: #1e40af;
    --color-bg-blue: #3b82f6;

    --color-border: #e2e8f0;

    --color-text-primary: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-light: #94a3b8;
    --color-text-white: #ffffff;
    
    /* Espaciado */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Tipografía */
    --font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    
    /* Sombras */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    
    /* Border radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    
    /* Transiciones */
    --transition-fast: 150ms ease-in-out;
    --transition-normal: 300ms ease-in-out;
}

/* ========================================
RESET Y ESTILOS BASE
======================================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html, body {
    width: 100%;
    height: 100%;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    color: var(--color-text-primary);
    background-color: var(--color-bg-light);
    line-height: 1.5;
}

/* ========================================
ESTRUCTURA PRINCIPAL
======================================== */
.app-container {
    display: grid;
    grid-template-columns: 1fr 3fr;
    height: 100vh;
    background-color: var(--color-bg-light);
    gap: 0;
}

/* Panel Izquierdo: Selector */
.panel-selector {
    grid-column: 1;
    background-color: var(--color-bg-light);
    border-right: 1px solid var(--color-border);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    justify-content: flex-start;
    align-items: stretch;
    overflow-y: auto;
    box-shadow: var(--shadow-sm);
}

.selector-wrapper {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.selector-title {
    font-size: var(--font-size-xl);
    font-weight: 700;
    color: var(--color-text-primary);
    text-align: center;
    margin-bottom: var(--spacing-sm);
}

/* Panel Derecho: Visor */
.panel-viewer {
    grid-column: 2;
    display: flex;
    flex-direction: column;
    background-color: var(--color-bg-light);
    height: auto;
    overflow: hidden;
}

/* ========================================
HEADER DEL PDF
======================================== */
.pdf-header {
    background-color: var(--color-bg-blue-dark);
    border-bottom: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-lg);
    box-shadow: var(--shadow-sm);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: flex-start;
}

.pdf-title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--color-text-white);
    margin: 0;
    text-truncate: ellipsis;
}

/* ========================================
CONTENEDOR DEL PDF
======================================== */
.pdf-container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: auto;
    background-color: var(--color-bg-light);
    padding: var(--spacing-lg);
}

.pdf-viewer {
    width: 100%;
    height: 100%;
    background-color: var(--color-bg-white);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: auto;
    box-shadow: var(--shadow-md);
    position: relative;
}

.pdf-viewer canvas {
    display: block;
    margin: 0 auto;
    max-width: 100%;
}

.placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--color-text-light);
    gap: var(--spacing-md);
}

.placeholder-icon {
    width: 80px;
    height: 80px;
    color: var(--color-border);
    opacity: 0.5;
}

.placeholder p {
    font-size: var(--font-size-lg);
    color: var(--color-text-secondary);
}

/* ========================================
FOOTER CON BOTÓN DE DESCARGA
======================================== */
.pdf-footer {
    background-color: var(--color-bg-gray-dark);
    border-top: 1px solid var(--color-border);
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    justify-content: center;
    align-items: center;
    box-shadow: var(--shadow-sm);
}

/* ========================================
FORMULARIO Y INPUTS
======================================== */
.form-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.label {
    font-size: var(--font-size-sm);
    font-weight: 600;
    color: var(--color-text-primary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.select-input {
    padding: var(--spacing-sm);
    font-size: var(--font-size-base);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    background-color: var(--color-bg-white);
    color: var(--color-text-primary);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-family);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%233b82f6' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right var(--spacing-sm) center;
    padding-right: var(--spacing-xl);
}

.select-input:hover {
    border-color: var(--color-primary-blue);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.select-input:focus {
    outline: none;
    border-color: var(--color-primary-blue);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.select-input:disabled {
    background-color: var(--color-bg-gray);
    cursor: not-allowed;
    opacity: 0.6;
}

/* ========================================
BOTONES
======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: var(--font-size-base);
    font-weight: 600;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    font-family: var(--font-family);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    box-shadow: var(--shadow-sm);
}

.btn:focus {
    outline: none;
    box-shadow: var(--shadow-lg);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    box-shadow: none;
}

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

.btn-download:hover:not(:disabled) {
    background-color: var(--color-primary-blue-hover);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.btn-download:active:not(:disabled) {
    background-color: var(--color-primary-blue-dark);
    transform: translateY(0);
}

.btn-icon {
    width: 20px;
    height: 20px;
}

/* ========================================
CAJA DE INFORMACIÓN
======================================== */
.info-box {
    background-color: var(--color-bg-gray);
    border-left: 4px solid var(--color-primary-blue);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin-top: var(--spacing-md);
}

.info-text {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
    margin: 0;
    line-height: 1.6;
}

/* ========================================
DIÁLOGO DE CARGA
======================================== */
.loading-dialog {
    border: none;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    background-color: var(--color-bg-white);
    padding: var(--spacing-xl);
    margin: auto;
}

.loading-dialog::backdrop {
    background-color: rgba(0, 0, 0, 0.4);
}

.loading-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-lg);
    min-width: 300px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid var(--color-border);
    border-top-color: var(--color-primary-blue);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.loading-text {
    font-size: var(--font-size-base);
    font-weight: 600;
    color: var(--color-text-primary);
    margin: 0;
}

/* ========================================
RESPONSIVE
======================================== */
@media (max-width: 1024px) {
    .app-container {
        grid-template-columns: 25% 75%;
    }
    
    .selector-title {
        font-size: var(--font-size-lg);
    }
    
    .pdf-title {
        font-size: var(--font-size-base);
    }
}

@media (max-width: 768px) {
    .app-container {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr;
    }
    
    .panel-selector {
        grid-column: 1;
        grid-row: 1;
        border-right: none;
        border-bottom: 1px solid var(--color-border);
        padding: var(--spacing-md);
    }
    
    .panel-viewer {
        grid-column: 1;
        grid-row: 2;
    }
    
    .selector-wrapper {
        max-width: 100%;
    }
    
    .form-group {
        flex-direction: row;
        align-items: center;
        gap: var(--spacing-md);
    }
    
    .label {
        min-width: 150px;
    }
    
    .select-input {
        flex: 1;
    }
    
    .info-box {
        display: none;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 1rem;
        --spacing-md: 0.75rem;
        --font-size-xl: 1.25rem;
    }
    
    .panel-selector {
        padding: var(--spacing-md);
    }
    
    .pdf-footer {
        padding: var(--spacing-md);
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .form-group {
        flex-direction: column;
        align-items: stretch;
    }
    
    .label {
        min-width: unset;
    }
}