:root {
    --bg-dark: #1e1e1e;
    --bg-panel: #252526;
    --bg-canvas-area: #121212;
    --text-main: #cccccc;
    --text-light: #ffffff;
    --accent: #007acc;
    --border: #333333;
    --hover: #2a2d2e;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
}

/* Topbar */
.topbar {
    height: 40px;
    background-color: var(--bg-panel);
    border-bottom: 1px solid var(--border);
    display: flex;
    align-items: center;
    padding: 0 15px;
}
.logo { font-weight: bold; color: var(--text-light); margin-right: 20px; }
.menu button {
    background: none; border: none; color: var(--text-main);
    padding: 5px 10px; cursor: pointer; font-size: 13px;
}
.menu button:hover { background-color: var(--hover); color: var(--text-light); }

/* Workspace Layout */
.workspace {
    display: flex;
    flex: 1;
    overflow: hidden;
}

/* Toolbar */
.toolbar {
    width: 50px;
    background-color: var(--bg-panel);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    align-items: center;
    padding-top: 10px;
}
.tool-btn {
    width: 36px; height: 36px;
    background: none; border: 1px solid transparent; border-radius: 4px;
    color: var(--text-main); cursor: pointer; margin-bottom: 5px;
    font-weight: bold;
}
.tool-btn:hover { background-color: var(--hover); }
.tool-btn.active { background-color: var(--accent); color: white; }

/* Canvas Area */
.canvas-container {
    flex: 1;
    background-color: var(--bg-canvas-area);
    overflow: auto; /* Cho phép pan sau này */
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
}
.canvas-wrapper {
    background: url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAMUlEQVQ4T2NkYGAQYcAP3uCTZhw1gGGYhAGBZIA/ENF5gOEYjWvUAMbgN4xPwiBHAwB5bgoV/6429gAAAABJRU5ErkJggg==') repeat;
    box-shadow: 0 0 20px rgba(0,0,0,0.5);
}
#main-canvas { display: block; }

/* Right Panel (Layers) */
.right-panel {
    width: 280px;
    background-color: var(--bg-panel);
    border-left: 1px solid var(--border);
    display: flex;
    flex-direction: column;
}
.panel-header {
    padding: 10px; font-size: 14px; font-weight: bold;
    border-bottom: 1px solid var(--border); background-color: #2d2d2d;
}
.layer-list {
    flex: 1; overflow-y: auto; padding: 5px;
}
.layer-item {
    display: flex; justify-content: space-between; align-items: center;
    padding: 8px; margin-bottom: 4px; background-color: var(--bg-dark);
    border: 1px solid transparent; border-radius: 4px; cursor: pointer;
    font-size: 13px;
}
.layer-item.active { border-color: var(--accent); background-color: #2b3033; }
.layer-actions {
    padding: 10px; border-top: 1px solid var(--border);
    display: flex; justify-content: flex-end;
}
.layer-actions button {
    background-color: var(--hover); border: 1px solid var(--border);
    color: white; padding: 5px 10px; cursor: pointer; border-radius: 4px;
}