Adjust toolbar style

[samdark]

https://github.com/yiisoft/yii-dev-panel/blob/master/packages/yii-dev-toolbar/src/Module/Toolbar/Component/Toolbar/DebugToolbar.tsx#L44-L56

box-shadow: rgba(0, 0, 0, 0.2) 0px 0px 0px 0px, rgba(0, 0, 0, 0.14) 0px -2px 12px -2px, rgba(0, 0, 0, 0.12) 0px 4px 14px 2px;

background-color: #fff

[samdark]

Goals:

• Make it contrast but less distracting than current bright-blue.
• Make it a bit more compact.
• Make it customizable.