:root {
    --bg-color: #f4f7f6;
    --sidebar-bg: #ffffff;
    --primary: #3498db;
    --primary-hover: #2980b9;
    --danger: #e74c3c;
    --text-main: #2c3e50;
    --border: #dcdde1;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: 'Pretendard', -apple-system, sans-serif; background: var(--bg-color); color: var(--text-main); height: 100vh; display: flex; flex-direction: column; overflow: hidden; }

.header { display: flex; justify-content: space-between; align-items: center; padding: 15px 30px; background: var(--sidebar-bg); border-bottom: 1px solid var(--border); box-shadow: 0 2px 10px rgba(0,0,0,0.05); z-index: 10; }
.header h1 { font-size: 1.2rem; margin: 0; }
.header-actions { display: flex; gap: 10px; }

.btn { padding: 8px 16px; border: none; border-radius: 6px; cursor: pointer; font-size: 0.9rem; font-weight: 600; background: #ecf0f1; color: var(--text-main); transition: all 0.2s; }
.btn:hover { background: #bdc3c7; }
.btn.primary { background: var(--primary); color: white; }
.btn.primary:hover { background: var(--primary-hover); }
.btn.danger { background: var(--danger); color: white; }
.btn.full-width { width: 100%; margin-bottom: 8px; }

.main-content { display: flex; flex: 1; overflow: hidden; }

.sidebar { width: 250px; background: var(--sidebar-bg); padding: 20px; border-right: 1px solid var(--border); overflow-y: auto; display: flex; flex-direction: column; gap: 20px; }
.right-sidebar { border-right: none; border-left: 1px solid var(--border); }
.sidebar h2 { font-size: 1rem; border-bottom: 2px solid var(--border); padding-bottom: 10px; margin-bottom: 15px; }

.tool-section { display: flex; flex-direction: column; gap: 5px; }
#scale-info { font-size: 0.8rem; color: #7f8c8d; }

.form-group { display: flex; flex-direction: column; gap: 5px; }
.form-group label { font-size: 0.85rem; font-weight: 600; }
.form-group input { padding: 8px; border: 1px solid var(--border); border-radius: 4px; }
.form-group input[type="color"] { width: 100%; padding: 2px; height: 35px; }

.canvas-container { flex: 1; display: flex; justify-content: center; align-items: center; overflow: hidden; background: #e0e6ed; position: relative; }
.canvas-container canvas { box-shadow: 0 4px 20px rgba(0,0,0,0.1); }