Computed style of an element whose parent's 'display' value is 'none':
align-content: normal
align-items: normal
align-self: auto
alignment-baseline: auto
background-attachment: scroll
background-clip: border-box
background-color: rgb(0, 128, 0)
background-image: none
background-origin: padding-box
background-position: 0% 0%
background-repeat: repeat
background-size: auto
baseline-shift: baseline
border-bottom-color: rgb(0, 0, 0)
border-bottom-left-radius: 0px
border-bottom-right-radius: 0px
border-bottom-style: none
border-bottom-width: 0px
border-collapse: separate
border-image-outset: 0px
border-image-repeat: stretch
border-image-slice: 100%
border-image-source: none
border-image-width: 1
border-left-color: rgb(0, 0, 0)
border-left-style: none
border-left-width: 0px
border-right-color: rgb(0, 0, 0)
border-right-style: none
border-right-width: 0px
border-top-color: rgb(0, 0, 0)
border-top-left-radius: 0px
border-top-right-radius: 0px
border-top-style: solid
border-top-width: 16px
bottom: auto
box-shadow: none
box-sizing: content-box
buffered-rendering: auto
caption-side: top
clear: none
clip: auto
clip-path: none
clip-rule: nonzero
color: rgb(0, 0, 0)
color-interpolation: sRGB
color-interpolation-filters: linearRGB
color-rendering: auto
column-count: auto
column-fill: balance
column-gap: normal
column-rule-color: rgb(0, 0, 0)
column-rule-style: none
column-rule-width: 0px
column-span: none
column-width: auto
content: 
counter-increment: none
counter-reset: none
cursor: auto
direction: ltr
display: block
dominant-baseline: auto
empty-cells: show
fill: rgb(0, 0, 0)
fill-opacity: 1
fill-rule: nonzero
filter: none
flex-basis: auto
flex-direction: row
flex-flow: row nowrap
flex-grow: 0
flex-shrink: 1
flex-wrap: nowrap
float: none
flood-color: rgb(0, 0, 0)
flood-opacity: 1
font-optical-sizing: auto
font-size: 16px
font-style: normal
font-synthesis: style weight small-caps
font-variant: normal
font-variant-alternates: normal
font-variant-caps: normal
font-variant-east-asian: normal
font-variant-ligatures: normal
font-variant-numeric: normal
font-variant-position: normal
font-weight: normal
glyph-orientation-horizontal: 0deg
glyph-orientation-vertical: auto
grid-auto-columns: auto
grid-auto-flow: row
grid-auto-rows: auto
grid-column-end: auto
grid-column-start: auto
grid-row-end: auto
grid-row-start: auto
grid-template-columns: none
grid-template-rows: none
hanging-punctuation: none
height: 100px
image-rendering: auto
justify-content: normal
justify-items: normal
justify-self: auto
kerning: 0
left: auto
letter-spacing: normal
lighting-color: rgb(255, 255, 255)
line-height: normal
list-style-image: none
list-style-position: outside
list-style-type: disc
margin-bottom: 0px
margin-left: auto
margin-right: 0px
margin-top: 0px
marker-end: none
marker-mid: none
marker-start: none
mask: none
mask-type: luminance
max-height: none
max-width: none
min-height: 0px
min-width: 0px
object-fit: fill
object-position: 50% 50%
opacity: 1
order: 0
orphans: auto
outline-color: rgb(0, 0, 0)
outline-offset: 0px
outline-style: none
outline-width: 0px
overflow-wrap: normal
overflow-x: visible
overflow-y: visible
padding-bottom: 0px
padding-left: 0px
padding-right: 0px
padding-top: 0px
page-break-after: auto
page-break-before: auto
page-break-inside: auto
paint-order: normal
perspective: none
perspective-origin: 50% 50%
pointer-events: auto
position: static
resize: none
right: auto
shape-image-threshold: 0
shape-margin: 0px
shape-outside: none
shape-rendering: auto
stop-color: rgb(0, 0, 0)
stop-opacity: 1
stroke: none
stroke-dasharray: none
stroke-dashoffset: 0px
stroke-linecap: butt
stroke-linejoin: miter
stroke-miterlimit: 4
stroke-opacity: 1
stroke-width: 1px
tab-size: 8
table-layout: auto
text-align: start
text-anchor: start
text-decoration: none
text-indent: 0px
text-overflow: clip
text-rendering: auto
text-shadow: none
text-transform: none
top: auto
transform: none
transform-origin: 50% 50%
transform-style: flat
transition-delay: 0s
transition-duration: 0s
transition-property: all
transition-timing-function: ease
unicode-bidi: normal
vector-effect: none
vertical-align: baseline
visibility: visible
white-space: normal
widows: auto
width: 50%
will-change: auto
word-break: normal
word-spacing: 0px
word-wrap: normal
writing-mode: horizontal-tb
z-index: auto
zoom: 1
-webkit-appearance: none
-webkit-backface-visibility: visible
-webkit-background-clip: border-box
-webkit-background-composite: source-over
-webkit-background-origin: padding-box
-webkit-background-size: auto
-webkit-border-fit: border
-webkit-border-horizontal-spacing: 0px
-webkit-border-image: none
-webkit-border-vertical-spacing: 0px
-webkit-box-align: stretch
-webkit-box-decoration-break: slice
-webkit-box-direction: normal
-webkit-box-flex: 0
-webkit-box-flex-group: 1
-webkit-box-lines: single
-webkit-box-ordinal-group: 1
-webkit-box-orient: horizontal
-webkit-box-pack: start
-webkit-box-reflect: none
-webkit-box-shadow: none
-webkit-column-axis: auto
-webkit-column-break-after: auto
-webkit-column-break-before: auto
-webkit-column-break-inside: auto
-webkit-font-kerning: auto
-webkit-font-smoothing: auto
-webkit-hyphenate-character: auto
-webkit-hyphenate-limit-after: auto
-webkit-hyphenate-limit-before: auto
-webkit-hyphenate-limit-lines: no-limit
-webkit-hyphens: manual
-webkit-line-align: none
-webkit-line-box-contain: block inline replaced
-webkit-line-clamp: none
-webkit-line-grid: none
-webkit-line-snap: none
-webkit-locale: auto
-webkit-margin-after-collapse: collapse
-webkit-margin-before-collapse: collapse
-webkit-marquee-direction: auto
-webkit-marquee-increment: 6px
-webkit-marquee-repetition: infinite
-webkit-marquee-style: scroll
-webkit-mask-box-image: none
-webkit-mask-box-image-outset: 0px
-webkit-mask-box-image-repeat: stretch
-webkit-mask-box-image-slice: 0 fill
-webkit-mask-box-image-source: none
-webkit-mask-box-image-width: auto
-webkit-mask-clip: border-box
-webkit-mask-composite: source-over
-webkit-mask-image: none
-webkit-mask-origin: border-box
-webkit-mask-position: 0% 0%
-webkit-mask-repeat: repeat
-webkit-mask-size: auto
-webkit-nbsp-mode: normal
-webkit-print-color-adjust: economy
-webkit-rtl-ordering: logical
-webkit-text-combine: none
-webkit-text-decorations-in-effect: none
-webkit-text-emphasis-color: rgb(0, 0, 0)
-webkit-text-emphasis-position: over right
-webkit-text-emphasis-style: none
-webkit-text-fill-color: rgb(0, 0, 0)
-webkit-text-orientation: mixed
-webkit-text-security: none
-webkit-text-stroke-color: rgb(0, 0, 0)
-webkit-text-stroke-width: 0px
-webkit-transform-style: flat
-webkit-user-drag: auto
-webkit-user-modify: read-only
-webkit-user-select: text
background-position-x: 0%
background-position-y: 0%
border-spacing: 0px 0px
overflow: visible
-webkit-mask-position-x: 0%
-webkit-mask-position-y: 0%

After changing grandparent's 'color' and the parent's 'font-size' inherited properties:
border-top-width: 18px
color: rgb(0, 0, 255)

After changing the parent's 'display' property to 'block', so that the child gets a renderer:
height: 100px
margin-left: 350px
width: 350px

After changing the parent's 'display' property back to 'none':
height: 100px
margin-left: auto
width: 50%