OS Details

OnePlus 9 Pro has been launched in March 2021.
OnePlus 9 Pro have Android 11 , OxygenOS 11

Screen Dimensions

OnePlus 9 Pro screen size is 6.7 inch with ~ 90.3% body ratio of actual device size. Physical dimensions for OnePlus 9 Pro device is 6.43 x 2.90 x 0.34 INCH or ( 163.2 x 73.6 x 8.7 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.

OnePlus 9 Pro resolution is 1440 x 3216 ^PX with ~ 525 pixel desnsity.
OnePlus 9 Pro viewport size is 412 x 919 ^PX with ~ 150 actual pixel density, which means it have 3.5 xxxhdpi 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".

OnePlus 9 Pro have 6.7" physical screen size and its resolution is about 1440 x 3216 Pixels with approximately 525 PPI pixel density. OnePlus 9 Pro has viewport size 412 x 919 Pixels and its pixel ratio is about 3.5.

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

CSS Media Queries

OnePlus 9 Pro css media queries will help developers to write styles specifically for OnePlus 9 Pro. Here are details:

OnePlus 9 Pro Media Queries (In terms of Mobile only)

@media only screen and (min-width: 412px) and (max-width: 767px) { /* Your Styles... */ }

OnePlus 9 Pro Min-Width Media Queries

@media only screen and (min-width: 412px) { /* Your Styles... */ }

OnePlus 9 Pro Min-Height Media Queries

@media only screen and (min-height: 919px) { /* Your Styles... */ }

OnePlus 9 Pro Landscape Media Queries

@media only screen and (min-width: 919px) and (orientation: landscape) { /* Your Styles... */ }

OnePlus 9 Pro Portrait Media Queries

@media only screen and (min-width: 412px) and (orientation: portrait) { /* Your Styles... */ }

OnePlus 9 Pro Device Width Media Queries

@media only screen and (min-device-width: 412px) and (orientation: portrait) { /* Your Styles... */ }
@media only screen and (min-device-width: 919px) and (orientation: landscape) { /* Your Styles... */ }

OnePlus 9 Pro Retina Media Queries

@media
  only screen and (-webkit-min-device-pixel-ratio: 3.5),
  only screen and (   min--moz-device-pixel-ratio: 3.5),
  only screen and (     -o-min-device-pixel-ratio: 3.5/1),
  only screen and (        min-device-pixel-ratio: 3.5),
  only screen and (                min-resolution: 525dpi),
  only screen and (                min-resolution: 3.5dppx) { 
    /* 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 (for all 2x resolution supported devices)

@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 (for all 3x resolution supported devices)

@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 */
}
                                

OnePlus 9 Pro Specifications

• Launch Date March 2021
• Android 11.0
• Physical Screen Size 6.7 INCH
• Resolution 1440 x 3216 PX
• Viewport Size 412 x 919 PX
• Pixel Density 525 PPI
• Device-Independent Pixels 150 PPI
• Pixel Ratio 3.5 xxxhdpi
• Width 1440 PX
• Height 3216 PX
• Device Width 412 PX
• Device Height 919 PX
• Dimensions 163.2 x 73.6 x 8.7 mm (6.43 x 2.90 x 0.34 in)
• Weight 197 g - 6.95 oz