:root {
    --bg-dark: #121216;
    --panel-bg: #1e1e24;
    --accent-color: #00ffcc;
    --accent-hover: #00e6b8;
    --text-main: #e0e0e0;
    --text-muted: #888;
    --border-color: #333;
}

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

body {
    font-family: 'Segoe UI', system-ui, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-main);
    height: 100vh;
    overflow: hidden;
}

.app-container {
    display: flex;
    height: 100%;
}

.sidebar {
    width: 320px;
    background-color: var(--panel-bg);
    border-right: 1px solid var(--border-color);
    padding: 20px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.logo {
    font-size: 1.5rem;
    color: var(--accent-color);
    text-shadow: 0 0 10px rgba(0, 255, 204, 0.3);
    margin-bottom: 10px;
}

.control-group {
    background: #18181d;
    padding: 15px;
    border-radius: 8px;
    border: 1px solid #2a2a30;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.control-group h3 {
    font-size: 0.9rem;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 5px;
    margin-bottom: 5px;
}

label { font-size: 0.85rem; }

input[type="range"] { width: 100%; accent-color: var(--accent-color); }
input[type="file"] { font-size: 0.8rem; }
select {
    background: var(--bg-dark); color: var(--text-main);
    border: 1px solid var(--border-color); padding: 5px; border-radius: 4px;
}

.btn {
    background: transparent; color: var(--text-main);
    border: 1px solid var(--border-color); padding: 8px 12px;
    border-radius: 4px; cursor: pointer; transition: all 0.2s;
    font-size: 0.85rem;
}
.btn:hover { border-color: var(--accent-color); color: var(--accent-color); }
.btn.primary { background: var(--accent-color); color: #000; font-weight: bold; }
.btn.primary:hover { background: var(--accent-hover); box-shadow: 0 0 10px var(--accent-color); }
.btn.active { border-color: var(--accent-color); color: var(--accent-color); background: rgba(0,255,204,0.1); }
.flex-row { display: flex; gap: 10px; align-items: center; }
.flex-row .btn { flex: 1; }

.workspace {
    flex: 1; display: flex; flex-direction: column;
}

.toolbar {
    padding: 15px 20px; background: var(--panel-bg);
    border-bottom: 1px solid var(--border-color);
    display: flex; gap: 10px; align-items: center;
}

.preview-container {
    flex: 1; display: flex; padding: 20px; gap: 20px;
    overflow: auto;
}

.canvas-wrapper {
    flex: 1; display: flex; flex-direction: column; align-items: center; gap: 10px;
}

canvas {
    width: 100%;          /* 关键修正：让画布在预览区视觉上撑满 */
    max-width: 480px;     /* 设定视觉上限，避免在大屏上过于夸张 */
    height: auto;
    object-fit: contain;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 12px rgba(0,0,0,0.5);
    /* 核心：放大时保持像素绝对锐利 */
    image-rendering: pixelated; 
}

/* 预览背景预设 */
.bg-checkerboard {
    background-image: 
        linear-gradient(45deg, #333 25%, transparent 25%), 
        linear-gradient(-45deg, #333 25%, transparent 25%), 
        linear-gradient(45deg, transparent 75%, #333 75%), 
        linear-gradient(-45deg, transparent 75%, #333 75%);
    background-size: 16px 16px;
    background-position: 0 0, 0 8px, 8px -8px, -8px 0px;
    background-color: #222;
}
.bg-black { background-color: #000; }
.bg-white { background-color: #fff; }
.bg-green { background-color: #00ff00; }
.bg-red { background-color: #ff0000; }