/* ============================================
   Main Layout
   ============================================ */
.app {
    display: grid;
    grid-template-columns: 220px 1fr 340px;
    height: 100vh;
}

/* ============================================
   Left Panel - Slide Manager
   ============================================ */
.slide-panel {
    background: var(--surface);
    border-right: 1px solid var(--border);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    overflow-y: auto;
}

.app-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border);
    margin-bottom: var(--spacing-sm);
}

.app-logo {
    font-size: 24px;
    line-height: 1;
}

.app-title {
    font-size: 15px;
    font-weight: 700;
    color: var(--text);
    letter-spacing: -0.3px;
}

.slide-controls {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border);
}

.mode-tabs {
    display: flex;
    gap: 0;
    background: var(--bg-dark);
    border-radius: var(--radius-md);
    padding: 3px;
    border: 1px solid var(--border);
}

.mode-tab {
    flex: 1;
    padding: 8px 12px;
    background: transparent;
    color: var(--text-muted);
    border: none;
    border-radius: var(--radius-sm);
    font-size: 12px;
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.mode-tab:hover {
    color: var(--text);
}

.mode-tab.active {
    background: var(--accent);
    color: var(--bg-dark);
    font-weight: 600;
}

.panel-section {
    padding: var(--spacing-md) 0;
    border-bottom: 1px solid var(--border);
}

.panel-label {
    display: block;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 8px;
}

.bg-presets {
    display: flex;
    gap: 6px;
    align-items: center;
    flex-wrap: wrap;
}

.bg-swatch {
    width: 26px;
    height: 26px;
    border-radius: var(--radius-md);
    border: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.bg-swatch:hover {
    transform: scale(1.1);
    border-color: var(--accent);
}

.bg-picker {
    width: 26px;
    height: 26px;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    padding: 0;
}

.bg-clear {
    width: 26px;
    height: 26px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    color: var(--text-muted);
    cursor: pointer;
    font-size: 12px;
    transition: all var(--transition-fast);
}

.bg-clear:hover {
    border-color: var(--danger);
    color: var(--danger);
}

.panel-select {
    width: 100%;
    background: var(--bg-dark);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 10px 12px;
    font-size: 13px;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.panel-select:hover {
    border-color: var(--accent);
}

.panel-select:focus {
    outline: none;
    border-color: var(--accent);
    box-shadow: 0 0 0 2px var(--accent-glow);
}

.panel-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-bottom: var(--spacing-sm);
}

.panel-title {
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.8px;
}

.btn-icon {
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent);
    color: var(--bg-dark);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    transition: all var(--transition-fast);
}

.btn-icon:hover {
    background: var(--accent-hover);
    transform: scale(1.05);
}

.slide-thumbnails {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    flex: 1;
    overflow-y: auto;
}

.slide-thumb {
    width: 100%;
    background: var(--bg-dark);
    border: 2px solid var(--border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    transition: all var(--transition-normal);
    flex-shrink: 0;
}

.slide-thumb:hover {
    border-color: var(--border-light);
}

.slide-thumb.active {
    border-color: var(--accent);
    box-shadow: var(--shadow-glow);
}

.slide-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.slide-number {
    position: absolute;
    top: 6px;
    left: 6px;
    background: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(4px);
    color: white;
    font-size: 10px;
    padding: 3px 8px;
    border-radius: var(--radius-md);
    font-weight: 600;
}

.slide-thumb .delete-slide {
    position: absolute;
    top: 6px;
    right: 6px;
    background: var(--danger);
    color: white;
    border: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 12px;
    display: none;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
}

.slide-thumb .delete-slide:hover {
    background: var(--danger-hover);
    transform: scale(1.1);
}

.thumb-text {
    position: absolute;
    font-family: 'Archivo Black', sans-serif;
    line-height: 1.2;
    white-space: pre-wrap;
    word-wrap: break-word;
    pointer-events: none;
    border-radius: 2px;
}

.slide-thumb:hover .delete-slide {
    display: flex;
}

/* ============================================
   Right Panel - Text Editor
   ============================================ */
.edit-panel {
    background: var(--surface);
    border-left: 1px solid var(--border);
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
    overflow-y: auto;
}

.edit-panel::-webkit-scrollbar {
    width: 6px;
}

.edit-panel::-webkit-scrollbar-track {
    background: transparent;
}

.edit-panel::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 3px;
}

.edit-panel::-webkit-scrollbar-thumb:hover {
    background: var(--border-light);
}

.section {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.section-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text);
    margin-bottom: var(--spacing-xs);
}

.divider {
    height: 1px;
    background: var(--border);
    margin: var(--spacing-sm) 0;
}

/* ============================================
   Mobile Navigation Tabs (for mobile only)
   ============================================ */
.mobile-nav {
    display: none;
}

/* ============================================
   Mobile Responsive Styles
   ============================================ */
@media (max-width: 900px) {
    /* Main Layout - Stack vertically */
    .app {
        display: flex;
        flex-direction: column;
        height: 100vh;
        height: 100dvh;
        overflow: hidden;
    }
    
    /* Mobile Navigation */
    .mobile-nav {
        display: flex;
        background: var(--surface);
        border-bottom: 1px solid var(--border);
        padding: 8px;
        gap: 4px;
        flex-shrink: 0;
    }
    
    .mobile-nav-btn {
        flex: 1;
        padding: 10px 12px;
        background: transparent;
        color: var(--text-muted);
        border: none;
        border-radius: var(--radius-md);
        font-size: 13px;
        font-weight: 500;
        cursor: pointer;
        transition: all 0.2s;
    }
    
    .mobile-nav-btn.active {
        background: var(--accent);
        color: var(--bg-dark);
        font-weight: 600;
    }
    
    /* Hide all panels by default on mobile */
    .slide-panel,
    .edit-panel {
        display: none;
        position: fixed;
        top: 50px;
        left: 0;
        right: 0;
        bottom: 0;
        z-index: 100;
        border: none;
    }
    
    .slide-panel.mobile-active,
    .edit-panel.mobile-active {
        display: flex;
    }
    
    /* Canvas panel - always in flow but adjustable */
    .canvas-panel {
        flex: 1;
        padding: 12px;
        overflow: auto;
        min-height: 0;
    }
    
    .canvas-panel.mobile-hidden {
        display: none;
    }
    
    /* Left Panel (Slides) mobile adjustments */
    .slide-panel {
        padding: 12px;
    }
    
    .app-header {
        padding-bottom: 12px;
        margin-bottom: 8px;
    }
    
    .slide-thumbnails {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
        gap: 8px;
    }
    
    .slide-thumb {
        aspect-ratio: 4/5;
    }
    
    /* Right Panel (Edit) mobile adjustments */
    .edit-panel {
        padding: 12px;
        padding-bottom: 24px;
    }
    
    .action-buttons {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 8px;
    }
    
    .action-buttons .btn {
        flex: 1;
        min-width: calc(50% - 4px);
    }
    
    .action-buttons .btn-block {
        width: auto;
    }
    
    /* Text editor mobile */
    #text-editor {
        padding-bottom: 16px;
    }
    
    .rich-text-editor {
        min-height: 80px;
    }
    
    .format-toolbar {
        flex-wrap: wrap;
    }
    
    .size-buttons,
    .style-buttons,
    .position-buttons {
        display: grid;
        grid-template-columns: repeat(4, 1fr);
        gap: 6px;
    }
    
    .style-buttons {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .position-buttons {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 480px) {
    .mobile-nav {
        padding: 6px;
    }
    
    .mobile-nav-btn {
        padding: 8px;
        font-size: 12px;
    }
    
    .canvas-panel {
        padding: 8px;
    }
    
    .dimension-select {
        min-width: auto;
        width: 100%;
        font-size: 12px;
    }
    
    .bg-control {
        flex-wrap: wrap;
        justify-content: center;
        gap: 6px;
        padding: 8px;
    }
    
    .stepper-divider {
        display: none;
    }
    
    .stepper-select {
        width: 100%;
    }
    
    .slide-panel,
    .edit-panel {
        padding: 10px;
    }
    
    .panel-header {
        flex-wrap: wrap;
        gap: 8px;
    }
}