:root {
    --bg-primary: #1e1e1e;
    --bg-secondary: #252526;
    --bg-panel: #2d2d30;
    --bg-input: #3c3c3c;
    --bg-hover: #404040;
    --border: #3c3c3c;
    --border-light: #555555;
    --text: #cccccc;
    --text-dim: #808080;
    --text-bright: #ffffff;
    --accent: #007acc;
    --accent-hover: #1a8ad4;
    --danger: #cc3333;
    --swatch-border: #555555;
    --checkerboard-light: #3a3a3a;
    --checkerboard-dark: #2a2a2a;
}

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

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    background: var(--bg-primary);
    color: var(--text);
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    font-size: 13px;
    min-width: 1200px;
    user-select: none;
    -webkit-user-select: none;
}

#app {
    display: grid;
    grid-template-columns: 48px 1fr 280px;
    grid-template-rows: auto 1fr auto;
    grid-template-areas:
        "menubar menubar menubar"
        "toolbar canvas   rightpanel"
        "toolbar statusbar statusbar";
    width: 100%;
    height: 100%;
}

/* Menu bar */
#menubar {
    grid-area: menubar;
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 8px;
    height: 28px;
    gap: 2px;
}

#menubar .menu-item {
    padding: 4px 10px;
    cursor: pointer;
    border-radius: 3px;
    font-size: 12px;
}

#menubar .menu-item:hover {
    background: var(--bg-hover);
}

/* Left toolbar area */
#toolbar-area {
    grid-area: toolbar;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 4px 0;
    gap: 2px;
}

/* Center canvas area */
#canvas-area {
    grid-area: canvas;
    background: var(--bg-primary);
    overflow: hidden;
    position: relative;
    cursor: crosshair;
}

/* Right panel (layers + palette) */
#right-panel {
    grid-area: rightpanel;
    background: var(--bg-secondary);
    border-left: 1px solid var(--border);
    display: flex;
    flex-direction: column;
}

/* Status bar */
#statusbar {
    grid-area: statusbar;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 10px;
    height: 24px;
    font-size: 11px;
    color: var(--text-dim);
    gap: 16px;
}

/* Scrollbar styling */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

::-webkit-scrollbar-thumb {
    background: var(--bg-input);
    border-radius: 4px;
}

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

/* Panel section headers */
.panel-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 6px 10px;
    background: var(--bg-panel);
    border-bottom: 1px solid var(--border);
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    color: var(--text-dim);
}

.panel-header .panel-actions {
    display: flex;
    gap: 4px;
}

/* Generic small icon button */
.icon-btn {
    width: 22px;
    height: 22px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: none;
    border: 1px solid transparent;
    border-radius: 3px;
    color: var(--text);
    cursor: pointer;
    padding: 0;
    font-size: 12px;
}

.icon-btn:hover {
    background: var(--bg-hover);
    border-color: var(--border);
}

.icon-btn.active {
    background: var(--accent);
    color: var(--text-bright);
}