/**
 * Layers Layout
 * Main application layout - canvas + layers panel
 */

/* Reset & Base */
*, *::before, *::after {
    box-sizing: border-box;
}

html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    background-color: var(--color-bg);
    color: var(--color-text-primary);
    font-family: var(--font-body);
    font-size: 16px;
    line-height: 1.5;
}

/* App Container */
#app {
    display: grid;
    grid-template-rows: var(--ui-titlebar-height) 1fr;
    grid-template-columns: 1fr 320px;
    width: 100%;
    height: 100%;
    overflow: hidden;
}

/* Canvas Panel */
#canvas-panel {
    grid-row: 2;
    grid-column: 1;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: var(--color-bg);
    overflow: auto;
    padding: 16px;
}

.canvas-container {
    position: relative;
    width: 100%;
    height: 100%;
    display: grid;
    place-items: center;
}

/* Stack canvases in same grid cell */
.canvas-container > canvas {
    grid-area: 1 / 1;
}

#canvas {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    /* Checkerboard pattern for transparency */
    background-color: var(--checkerboard-bg);
    background-image:
        linear-gradient(45deg, var(--checkerboard-check) 25%, transparent 25%),
        linear-gradient(-45deg, var(--checkerboard-check) 25%, transparent 25%),
        linear-gradient(45deg, transparent 75%, var(--checkerboard-check) 75%),
        linear-gradient(-45deg, transparent 75%, var(--checkerboard-check) 75%);
    background-size: 16px 16px;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
    box-shadow: var(--shadow-lg);
}

/* Layers Panel */
#layers-panel {
    grid-row: 1 / 3;
    grid-column: 2;
    display: flex;
    flex-direction: column;
    background-color: var(--color-bg-elevated);
    overflow: hidden;
    margin: 12px 12px 12px 0;
    border-radius: var(--radius-md);
}

.layers-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 16px;
    border-bottom: 1px solid var(--color-border-muted);
    flex-shrink: 0;
}

.layers-header h2 {
    font-family: var(--font-accent);
    font-size: 16px;
    font-weight: 600;
    color: var(--color-text-secondary);
    margin: 0;
}

.layers-header-buttons {
    display: flex;
    gap: 2px;
}

.layers-header .add-layer-btn {
    background: none;
    border: none;
    color: var(--color-ui);
    cursor: pointer;
    padding: 4px;
    line-height: 1;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.layers-header .add-layer-btn:hover {
    color: var(--color-ui-hover);
    background: var(--color-ui-muted);
}

.layers-header .add-layer-btn .icon-material {
    font-size: 20px;
}

/* Layer Stack Container */
.layers-list {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding: 8px;
}

/* Scrollbar styling */
.layers-list::-webkit-scrollbar {
    width: 6px;
}

.layers-list::-webkit-scrollbar-track {
    background: transparent;
}

.layers-list::-webkit-scrollbar-thumb {
    background: var(--color-border);
    border-radius: 3px;
}

.layers-list::-webkit-scrollbar-thumb:hover {
    background: var(--color-text-muted);
}

/* Empty State */
.empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 48px 24px;
    text-align: center;
    color: var(--color-text-muted);
}

.empty-state .icon-material {
    font-size: 48px;
    margin-bottom: 16px;
    opacity: 0.5;
}

.empty-state p {
    margin: 0 0 16px;
    font-size: 14px;
}

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

/* Responsive adjustments */

/* Medium screens: layers panel moves below menu bar, menu goes full width */
@media (max-width: 910px) {
    #layers-panel {
        grid-row: 2;
        margin: 0;
        border-radius: 0;
    }
}

/* Small screens: layers panel at bottom */
@media (max-width: 700px) {
    #app {
        grid-template-columns: 1fr;
        grid-template-rows: var(--ui-titlebar-height) 1fr auto;
    }

    #layers-panel {
        grid-row: 3;
        grid-column: 1;
        border-left: none;
        border-top: 1px solid var(--color-border-muted);
        max-height: 250px;
        margin: 0;
        border-radius: 0;
    }
}