/**
 * MaxtDesign PDF Viewer - Frontend Styles
 *
 * Zero-CLS PDF viewer with accessible, responsive design.
 *
 * @package MaxtDesign\PDFViewer
 * @since 1.0.0
 */

/* ==========================================================================
   CSS Custom Properties (Theme Variables)
   ========================================================================== */

:root {
    /* Colors */
    --mdpv-color-bg: #f8f9fa;
    --mdpv-color-bg-dark: #1a1a2e;
    --mdpv-color-border: #dee2e6;
    --mdpv-color-text: #212529;
    --mdpv-color-text-muted: #6c757d;
    --mdpv-color-primary: #0d6efd;
    --mdpv-color-primary-hover: #0b5ed7;
    --mdpv-color-error: #dc3545;
    --mdpv-color-error-bg: #f8d7da;
    --mdpv-color-overlay: rgba(0, 0, 0, 0.7);
    --mdpv-color-overlay-light: rgba(0, 0, 0, 0.5);
    
    /* Toolbar */
    --mdpv-toolbar-bg: #ffffff;
    --mdpv-toolbar-border: #e9ecef;
    --mdpv-toolbar-shadow: 0 -2px 10px rgba(0, 0, 0, 0.1);
    
    /* Sizing */
    --mdpv-border-radius: 8px;
    --mdpv-border-radius-sm: 4px;
    --mdpv-spacing-xs: 0.25rem;
    --mdpv-spacing-sm: 0.5rem;
    --mdpv-spacing-md: 1rem;
    --mdpv-spacing-lg: 1.5rem;
    
    /* Typography */
    --mdpv-font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --mdpv-font-size-sm: 0.875rem;
    --mdpv-font-size-base: 1rem;
    
    /* Transitions */
    --mdpv-transition-fast: 150ms ease;
    --mdpv-transition-base: 250ms ease;
    
    /* Z-index layers */
    --mdpv-z-preview: 1;
    --mdpv-z-overlay: 10;
    --mdpv-z-toolbar: 20;
    --mdpv-z-loading: 30;
    --mdpv-z-fullscreen: 999999;
}

/* ==========================================================================
   Base Viewer Container
   ========================================================================== */

.mdpv-viewer {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--mdpv-color-bg);
    border: 1px solid var(--mdpv-color-border);
    border-radius: var(--mdpv-border-radius);
    overflow: hidden;
    font-family: var(--mdpv-font-family);
    line-height: 1.5;
    
    /* Container query support for future use */
    container-type: inline-size;
    container-name: mdpv-viewer;
}

/* Ensure aspect-ratio works correctly */
.mdpv-viewer::before {
    content: '';
    display: block;
}

/* ==========================================================================
   Preview Image
   ========================================================================== */

.mdpv-preview {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: contain;
    object-position: center top;
    z-index: var(--mdpv-z-preview);
    background-color: var(--mdpv-color-bg);
}

/* Fade out preview when loading */
.mdpv-viewer.mdpv-loading-active .mdpv-preview {
    opacity: 0.4;
    transition: opacity var(--mdpv-transition-base);
}

/* Hide preview when viewer is fully active */
.mdpv-viewer.mdpv-active .mdpv-preview {
    display: none;
}

/* ==========================================================================
   Placeholder (No Preview Available)
   ========================================================================== */

.mdpv-placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: var(--mdpv-spacing-lg);
    text-align: center;
    color: var(--mdpv-color-text-muted);
}

.mdpv-placeholder-icon {
    width: 64px;
    height: 64px;
    margin-bottom: var(--mdpv-spacing-md);
    opacity: 0.5;
    stroke: currentColor;
}

.mdpv-placeholder-text {
    font-size: var(--mdpv-font-size-sm);
    max-width: 200px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

/* ==========================================================================
   Activate Button
   ========================================================================== */

.mdpv-activate {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: var(--mdpv-z-overlay);
    
    display: inline-flex;
    align-items: center;
    gap: var(--mdpv-spacing-sm);
    padding: var(--mdpv-spacing-sm) var(--mdpv-spacing-lg);
    
    background-color: var(--mdpv-color-overlay);
    color: #ffffff;
    border: none;
    border-radius: var(--mdpv-border-radius);
    
    font-family: inherit;
    font-size: var(--mdpv-font-size-base);
    font-weight: 500;
    line-height: 1.5;
    text-decoration: none;
    white-space: nowrap;
    
    cursor: pointer;
    transition: background-color var(--mdpv-transition-fast),
                transform var(--mdpv-transition-fast),
                box-shadow var(--mdpv-transition-fast);
}

.mdpv-activate:hover {
    background-color: var(--mdpv-color-overlay-light);
    transform: translate(-50%, -50%) scale(1.02);
}

.mdpv-activate:focus {
    outline: none;
}

.mdpv-activate:focus-visible {
    outline: 3px solid var(--mdpv-color-primary);
    outline-offset: 2px;
    box-shadow: 0 0 0 6px rgba(13, 110, 253, 0.25);
}

.mdpv-activate:active {
    transform: translate(-50%, -50%) scale(0.98);
}

.mdpv-activate-icon {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
}

.mdpv-activate-text {
    /* Text styling handled by button */
}

/* Hide activate button when loading or active */
.mdpv-viewer.mdpv-loading-active .mdpv-activate,
.mdpv-viewer.mdpv-active .mdpv-activate {
    display: none;
}

/* ==========================================================================
   Loading State
   ========================================================================== */

.mdpv-loading {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: var(--mdpv-z-loading);
    
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--mdpv-spacing-sm);
    
    padding: var(--mdpv-spacing-md);
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: var(--mdpv-border-radius);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    
    color: var(--mdpv-color-text);
    font-size: var(--mdpv-font-size-sm);
}

.mdpv-loading[hidden] {
    display: none;
}

/* Spinner */
.mdpv-spinner {
    width: 32px;
    height: 32px;
    border: 3px solid var(--mdpv-color-border);
    border-top-color: var(--mdpv-color-primary);
    border-radius: 50%;
    animation: mdpv-spin 0.8s linear infinite;
}

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

/* ==========================================================================
   Error States
   ========================================================================== */

.mdpv-error {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--mdpv-spacing-lg);
    text-align: center;
}

.mdpv-error p {
    margin: 0;
    padding: var(--mdpv-spacing-md);
    background-color: var(--mdpv-color-error-bg);
    border: 1px solid var(--mdpv-color-error);
    border-radius: var(--mdpv-border-radius-sm);
    color: var(--mdpv-color-error);
    font-size: var(--mdpv-font-size-sm);
}

.mdpv-error-container {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    z-index: var(--mdpv-z-loading);
    max-width: 90%;
}

.mdpv-error-container[hidden] {
    display: none;
}

.mdpv-error-message {
    padding: var(--mdpv-spacing-md) var(--mdpv-spacing-lg);
    background-color: var(--mdpv-color-error-bg);
    border: 1px solid var(--mdpv-color-error);
    border-radius: var(--mdpv-border-radius-sm);
    color: var(--mdpv-color-error);
    font-size: var(--mdpv-font-size-sm);
    text-align: center;
}

/* ==========================================================================
   Active Viewer State
   ========================================================================== */

.mdpv-viewer.mdpv-active {
    background-color: var(--mdpv-color-bg-dark);
}

/* Focus indicator for keyboard navigation */
.mdpv-viewer.mdpv-active:focus {
    outline: 2px solid var(--mdpv-color-primary);
    outline-offset: 2px;
}

.mdpv-viewer.mdpv-active:focus:not(:focus-visible) {
    outline: none;
}

.mdpv-viewer.mdpv-active:focus-visible {
    outline: 3px solid var(--mdpv-color-primary);
    outline-offset: 2px;
    box-shadow: 0 0 0 6px rgba(13, 110, 253, 0.25);
}

/* Canvas container for PDF.js */
.mdpv-canvas-container {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: auto;
    -webkit-overflow-scrolling: touch;
}

.mdpv-canvas-container canvas {
    display: block;
    margin: 0 auto;
}

/* ==========================================================================
   Toolbar (Added by JavaScript)
   ========================================================================== */

.mdpv-toolbar {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    z-index: var(--mdpv-z-toolbar);
    
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--mdpv-spacing-sm);
    padding: var(--mdpv-spacing-sm) var(--mdpv-spacing-md);
    
    background-color: var(--mdpv-toolbar-bg);
    border-top: 1px solid var(--mdpv-toolbar-border);
    box-shadow: var(--mdpv-toolbar-shadow);
}

.mdpv-toolbar-group {
    display: flex;
    align-items: center;
    gap: var(--mdpv-spacing-xs);
}

/* Toolbar buttons */
.mdpv-toolbar-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    padding: 0;
    
    background-color: transparent;
    border: 1px solid var(--mdpv-color-border);
    border-radius: var(--mdpv-border-radius-sm);
    
    color: var(--mdpv-color-text);
    cursor: pointer;
    transition: all var(--mdpv-transition-fast);
}

.mdpv-toolbar-btn:hover {
    background-color: var(--mdpv-color-bg);
    border-color: var(--mdpv-color-primary);
    color: var(--mdpv-color-primary);
}

.mdpv-toolbar-btn:focus-visible {
    outline: 2px solid var(--mdpv-color-primary);
    outline-offset: 2px;
}

.mdpv-toolbar-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.mdpv-toolbar-btn svg {
    width: 20px;
    height: 20px;
}

/* Page navigation */
.mdpv-toolbar-page-info {
    display: flex;
    align-items: center;
    gap: var(--mdpv-spacing-xs);
    font-size: var(--mdpv-font-size-sm);
    color: var(--mdpv-color-text);
}

.mdpv-toolbar-page-input {
    width: 3.5em;
    padding: var(--mdpv-spacing-xs);
    border: 1px solid var(--mdpv-color-border);
    border-radius: var(--mdpv-border-radius-sm);
    font-size: var(--mdpv-font-size-sm);
    text-align: center;
}

.mdpv-toolbar-page-input:focus {
    outline: none;
    border-color: var(--mdpv-color-primary);
    box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.15);
}

/* Zoom controls */
.mdpv-toolbar-zoom {
    display: flex;
    align-items: center;
    gap: var(--mdpv-spacing-xs);
}

.mdpv-toolbar-zoom-label {
    min-width: 3.5em;
    font-size: var(--mdpv-font-size-sm);
    text-align: center;
}

/* ==========================================================================
   Fullscreen Mode
   ========================================================================== */

.mdpv-viewer.mdpv-fullscreen {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    width: 100%;
    height: 100%;
    max-width: none;
    margin: 0;
    border: none;
    border-radius: 0;
    z-index: var(--mdpv-z-fullscreen);
}

/* Reset aspect ratio in fullscreen */
.mdpv-viewer.mdpv-fullscreen {
    aspect-ratio: auto !important;
}

/* ==========================================================================
   Responsive Design
   ========================================================================== */

/* Small screens */
@media (max-width: 576px) {
    .mdpv-activate {
        padding: var(--mdpv-spacing-xs) var(--mdpv-spacing-md);
        font-size: var(--mdpv-font-size-sm);
    }
    
    .mdpv-activate-icon {
        width: 20px;
        height: 20px;
    }
    
    .mdpv-toolbar {
        padding: var(--mdpv-spacing-xs) var(--mdpv-spacing-sm);
        flex-wrap: wrap;
    }
    
    .mdpv-toolbar-btn {
        width: 32px;
        height: 32px;
    }
    
    .mdpv-toolbar-btn svg {
        width: 16px;
        height: 16px;
    }
    
    .mdpv-toolbar-page-info {
        font-size: 0.75rem;
    }
    
    .mdpv-placeholder-icon {
        width: 48px;
        height: 48px;
    }
}

/* ==========================================================================
   Accessibility: Reduced Motion
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
    .mdpv-spinner {
        animation: none;
        border-top-color: var(--mdpv-color-primary);
        opacity: 0.7;
    }
    
    .mdpv-activate,
    .mdpv-toolbar-btn,
    .mdpv-preview {
        transition: none;
    }
}

/* ==========================================================================
   Accessibility: High Contrast Mode
   ========================================================================== */

@media (prefers-contrast: high) {
    .mdpv-viewer {
        border-width: 2px;
    }
    
    .mdpv-activate {
        background-color: #000000;
        border: 2px solid #ffffff;
    }
    
    .mdpv-activate:focus-visible {
        outline-width: 3px;
    }
    
    .mdpv-toolbar-btn {
        border-width: 2px;
    }
}

/* ==========================================================================
   Print Styles
   ========================================================================== */

@media print {
    .mdpv-viewer {
        break-inside: avoid;
        border: 1px solid #000;
    }
    
    .mdpv-activate,
    .mdpv-loading,
    .mdpv-toolbar {
        display: none !important;
    }
    
    .mdpv-preview {
        position: static;
        max-width: 100%;
        height: auto;
    }
}

/* ==========================================================================
   Dark Mode Support (Optional - respects user preference)
   ========================================================================== */

@media (prefers-color-scheme: dark) {
    .mdpv-viewer {
        --mdpv-color-bg: #2d2d2d;
        --mdpv-color-border: #404040;
        --mdpv-color-text: #e9ecef;
        --mdpv-color-text-muted: #adb5bd;
        --mdpv-toolbar-bg: #1a1a1a;
        --mdpv-toolbar-border: #333333;
    }
    
    .mdpv-loading {
        background-color: rgba(45, 45, 45, 0.95);
    }
}