fix(cutout): fix z-index issue

Author: arturbien

src/components/Cutout/Cutout.js

@@ -19,7 +19,6 @@ const StyledCutout = styled.div`
     position: absolute;
     left: 0;
     top: 0;
-    z-index: 1;
     content: '';
     width: calc(100% - 4px);
     height: calc(100% - 4px);

src/components/Select/Select.styles.js

@@ -98,7 +98,6 @@ export const StyledNativeSelect = styled.select`
 export const StyledDropdownButton = styled(Button)`
   width: 30px;
   padding: 0;
-  z-index: 1;
   flex-shrink: 0;
   ${({ variant }) =>
     variant === 'flat'
@@ -169,7 +168,7 @@ export const StyledDropdownMenu = styled.ul`
   padding: 2px;
   border-top: none;
   cursor: default;
-  z-index: 99;
+  z-index: 1;
   cursor: pointer;
   box-shadow: ${props => (props.shadow ? commonShadow : 'none')};
   ${({ variant }) =>

src/components/Slider/Slider.js

@@ -154,9 +154,6 @@ const StyledFlatGroove = styled(Cutout)`
 `;
 const Thumb = styled.span`
   position: relative;
-
-  z-index: 1;
-  
   ${({ vertical }) =>
     vertical
       ? css`

src/components/SwitchBase/SwitchBase.js

@@ -12,7 +12,7 @@ export const StyledInput = styled.input`
   width: ${size}px;
   height: ${size}px;
   opacity: 0;
-  z-index: -99;
+  z-index: -1;
 `;
 
 export const StyledLabel = styled.label`

src/components/Tooltip/Tooltip.js

@@ -8,7 +8,7 @@ const Tip = styled.span`
   position: absolute;
   bottom: -4px;
   left: 50%;
-  z-index: 10;
+  z-index: 1;
   transform: translate(-50%, 100%);
   display: ${props => (props.show ? 'block' : 'none')};
   padding: 4px;