/* ... 前面的通用样式保持不变 ... */
body {
    font-family: 'Segoe UI', sans-serif;
    margin: 0; padding: 20px; background: #f0f2f5;
    height: 100vh; display: flex; gap: 15px; box-sizing: border-box;
}

.panel { background: #fff; border-radius: 12px; box-shadow: 0 4px 15px rgba(0,0,0,0.05); padding: 20px; display: flex; flex-direction: column; }
.left-panel { flex: 3; overflow: hidden; } /* 禁止外层滚动，让内容撑满 */
.right-panel { flex: 1; min-width: 260px; }

h2 { margin: 0 0 15px 0; font-size: 20px; border-bottom: 3px solid #007bff; padding-bottom: 10px; }

/* 导数容器横向排列 */
.derivative-container {
    display: flex;
    gap: 10px;
    margin-bottom: 10px;
}
.derivative-box {
    flex: 1; /* 平分宽度 */
    background: #fcfcfc;
    border: 1px solid #eee;
    border-radius: 8px;
    padding: 8px 12px;
}

.derivative-header { display: flex; align-items: center; justify-content: space-between; }
.checkbox-label { font-size: 14px; display: flex; align-items: center; gap: 5px; }

/* 紧凑的高级设置面板 */
.advanced-panel {
    display: none;
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px dashed #ddd;
    gap: 8px;
    align-items: center;
    justify-content: space-between;
}
.advanced-panel.show { display: flex; }
.setting-item { font-size: 12px; display: flex; align-items: center; gap: 3px; }

input[type="number"] { width: 35px; padding: 2px; }
input[type="color"] { width: 20px; height: 20px; border: none; padding: 0; background: none; cursor: pointer; }
select { font-size: 12px; padding: 2px; }

/* 画布自适应 */
.canvas-wrapper {
    flex: 1; /* 占据剩余所有垂直空间 */
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    background: #fff;
}
canvas { width: 100%; height: 100%; display: block; }

/* ... 其他辅助样式保持 v9 的逻辑 ... */
.badge-pro { font-size: 11px; background: #28a745; color: white; padding: 2px 5px; border-radius: 3px; margin-left: 5px; }
.toolbar { display: flex; gap: 5px; flex-wrap: wrap; margin-bottom: 15px; padding: 10px; background: #f8f9fa; border-radius: 8px; }
.btn-tool { background: #fff; border: 1px solid #ddd; padding: 4px 8px; font-size: 12px; border-radius: 4px; cursor: pointer; }
.control-row { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
input[type="text"] { flex: 1; padding: 8px; border: 1px solid #ddd; border-radius: 6px; }
button { cursor: pointer; border: none; border-radius: 4px; }
.btn-primary { background: #007bff; color: #fff; padding: 8px 15px; }
.settings-toggle { background: none; color: #007bff; font-size: 11px; text-decoration: underline; }