OS Details

Samsung Galaxy A6s has been launched in November 2018.
Samsung Galaxy A6s have Android 8.0 (Oreo)

Screen Dimensions

Samsung Galaxy A6s screen size is 6.0 inch with ~ 77.9% body ratio of actual device size. Physical dimensions for Samsung Galaxy A6s device is 6.15 x 3.01 x 0.33 INCH or ( 156.1 x 76.4 x 8.4 MM).

Displaying of Units are in this order "Height x Width x Thickness"

Screen Pixel Density and CSS Pixel Ratio

"Pixel" is smallest unit/element of any display.

The total number of pixels that fit into an inch is referred to as "Screen Density" or "Pixel Density" and it measured as "Pixels Per Inch".
Pixel Desnsity have limits to display Pixels Per Inch depends on different screen sizes. When number of pixels per inch increases than it's screen-size limit, the Display resolution will increase but actual device width/height in pixels remain same. Actual device pixels are known as Device Independent Pixels or CSS Pixel Ratio.

Samsung Galaxy A6s resolution is 1080 x 2160 ^PX with ~ 402 pixel desnsity.
Samsung Galaxy A6s viewport size is 360 x 720 ^PX with ~ 134 actual pixel density, which means it have 3 xxhdpi display pixel density.

Screen Resolution and Viewport

The sum of pixels which are displaying on a device is called as "Screen Resolution". and sum of actual pixels of any device is reffered to as "Viewport".

Samsung Galaxy A6s have 6.0" physical screen size and its resolution is about 1080 x 2160 Pixels with approximately 402 PPI pixel density. Samsung Galaxy A6s has viewport size 360 x 720 Pixels and its pixel ratio is about 3.

For better understanding screen actual sizes, viewport sizes, display resolution and about their density click here.

CSS Media Queries

Samsung Galaxy A6s Media Queries (In terms of Mobile only)

@media only screen and (min-width: 360px) and (max-width: 767px) { /* Your Styles... */ }

Samsung Galaxy A6s Min-Width Media Queries

@media only screen and (min-width: 360px) { /* Your Styles... */ }

Samsung Galaxy A6s Min-Height Media Queries

@media only screen and (min-height: 720px) { /* Your Styles... */ }

Samsung Galaxy A6s Landscape Media Queries

@media only screen and (min-width: 720px) and (orientation: landscape) { /* Your Styles... */ }

Samsung Galaxy A6s Portrait Media Queries

@media only screen and (min-width: 360px) and (orientation: portrait) { /* Your Styles... */ }

Samsung Galaxy A6s Device Width Media Queries

@media only screen and (min-device-width: 360px) and (orientation: portrait) { /* Your Styles... */ }
@media only screen and (min-device-width: 720px) and (orientation: landscape) { /* Your Styles... */ }

Samsung Galaxy A6s Retina Media Queries

@media
  only screen and (-webkit-min-device-pixel-ratio: 3),
  only screen and (   min--moz-device-pixel-ratio: 3),
  only screen and (     -o-min-device-pixel-ratio: 3/1),
  only screen and (        min-device-pixel-ratio: 3),
  only screen and (                min-resolution: 402dpi),
  only screen and (                min-resolution: 3dppx) { 
    /* Retina styles here */
}
                                

Retina is actually based upon device pixel ratio. Devices mostly have 2x or 3x display so you can use general retina media queries to display high resolution content on all kind of devices. Retina 2x and Retina 3x media queries given below:

Retina 2x Media Query

@media
  only screen and (-webkit-min-device-pixel-ratio: 2),
  only screen and (   min--moz-device-pixel-ratio: 2),
  only screen and (     -o-min-device-pixel-ratio: 2/1),
  only screen and (        min-device-pixel-ratio: 2),
  only screen and (                min-resolution: 192dpi),
  only screen and (                min-resolution: 2dppx) { 
    /* Retina styles here */
}
                                

Retina 3x Media Query

@media
  only screen and (-webkit-min-device-pixel-ratio: 3),
  only screen and (   min--moz-device-pixel-ratio: 3),
  only screen and (     -o-min-device-pixel-ratio: 3/1),
  only screen and (        min-device-pixel-ratio: 3),
  only screen and (                min-resolution: 384dpi),
  only screen and (                min-resolution: 3dppx) { 
    /* Retina styles here */
}
                                

Samsung Galaxy A6s Specifications

• Launch Date November 2018
• Android 8.0
• Physical Screen Size 6.0 INCH
• Resolution 1080 x 2160 PX
• Viewport Size 360 x 720 PX
• Pixel Density 402 PPI
• Device-Independent Pixels 134 PPI
• Pixel Ratio 3 xxhdpi
• Width 1080 PX
• Height 2160 PX
• Device Width 360 PX
• Device Height 720 PX
• Dimensions 156.1 x 76.4 x 8.4 mm (6.15 x 3.01 x 0.33 in)
• Weight - g - - oz