My attempt at providing the CSS to do this. This is where it turns into bikeshedding (T_T);

:root {
color-scheme: light dark;

--base-color: #828282;
--admin-color: #000000;
--top-color: #222222;
--top-sel: #ffffff;
--c00: #000000;
--c5a: #5a5a5a;
--c72: #737373;
--c82: #828282;
--c88: #888888;
--c9c: #9c9c9c;
--cae: #aeaeae;
--cbe: #bebebe;
--cce: #cecece;
--cdd: #dddddd;
--ca2: #a30000;
}

center>table {
background-color: #f6f6ef;
}
table#hnmain>tbody>tr:nth-child(1)>td {
background-color: #ff6600;
}
font {
color: #3c963c
}

@media (prefers-color-scheme: dark) {
:root {
--base-color: #909090;
--admin-color: #ffffff;
--top-color: #dddddd;
--top-sel: #000000;
--c00: #ffffff;
--c5a: #a5a5a5;
--c72: #8c8c8c;
--c82: #7d7d7d;
--c88: #777777;
--c9c: #636363;
--cae: #515151;
--cbe: #414141;
--cce: #313131;
--cdd: #222222;
--ca2: #a30000;
}

center>table {
background-color: #222;
}
table#hnmain>tbody>tr:nth-child(1)>td {
background-color: #a74300;
}

font {
color: #639663
}
}

body { font-family:Verdana, Geneva, sans-serif; font-size:10pt; color: var(--base-color); }
td { font-family:Verdana, Geneva, sans-serif; font-size:10pt; color: var(--base-color); }

.admin td { font-family:Verdana, Geneva, sans-serif; font-size:8.5pt; color: var(--admin-color); }
.subtext td { font-family:Verdana, Geneva, sans-serif; font-size: 7pt; color: var(--base-color); }

input { font-family:monospace; font-size:10pt; }
input[type='submit'] { font-family:Verdana, Geneva, sans-serif; }
textarea { font-family:monospace; font-size:10pt; resize:both; }

a:link { color: var(--admin-color); text-decoration:none; }
a:visited { color: var(--base-color); text-decoration:none; }

.default { font-family:Verdana, Geneva, sans-serif; font-size: 10pt; color: var(--base-color); }
.admin { font-family:Verdana, Geneva, sans-serif; font-size:8.5pt; color: var(--admin-color); }
.title { font-family:Verdana, Geneva, sans-serif; font-size: 10pt; color: var(--base-color); overflow:hidden; }
.subtext { font-family:Verdana, Geneva, sans-serif; font-size: 7pt; color: var(--base-color); }
.yclinks { font-family:Verdana, Geneva, sans-serif; font-size: 8pt; color: var(--base-color); }
.pagetop { font-family:Verdana, Geneva, sans-serif; font-size: 10pt; color: var(--top-color); line-height:12px; }
.comhead { font-family:Verdana, Geneva, sans-serif; font-size: 8pt; color: var(--base-color); }
.comment { font-family:Verdana, Geneva, sans-serif; font-size: 9pt; }
.hnname { margin-left:1px; margin-right: 5px; }

#hnmain { min-width: 796px; }

.title a { word-break: break-word; }

.comment a:link, .comment a:visited { text-decoration: underline; }
.noshow { display: none; }
.nosee { visibility: hidden; pointer-events: none; cursor: default }

.c00, .c00 a:link { color: var(--admin-color); }
.c5a, .c5a a:link, .c5a a:visited { color: var(--c5a); }
.c73, .c73 a:link, .c73 a:visited { color: var(--c73); }
.c82, .c82 a:link, .c82 a:visited { color: var(--c82); }
.c88, .c88 a:link, .c88 a:visited { color: var(--c88); }
.c9c, .c9c a:link, .c9c a:visited { color: var(--c9c); }
.cae, .cae a:link, .cae a:visited { color: var(--cae); }
.cbe, .cbe a:link, .cbe a:visited { color: var(--cbe); }
.cce, .cce a:link, .cce a:visited { color: var(--cce); }
.cdd, .cdd a:link, .cdd a:visited { color: var(--cdd); }
.ca2 { color: var(--ca2); }

.pagetop a:visited { color: var(--admin-color); }
.topsel a:link, .topsel a:visited { color: var(--top-cel); }

.subtext a:link, .subtext a:visited { color: var(--base-color); }
.subtext a:hover { text-decoration:underline; }

.comhead a:link, .subtext a:visited { color: var(--base-color); }
.comhead a:hover { text-decoration:underline; }

.hnmore a:link, a:visited { color: var(--base-color); }
.hnmore { text-decoration:underline; }

.default p { margin-top: 8px; margin-bottom: 0px; }

.pagebreak {page-break-before:always}

pre { overflow: auto; padding: 2px; white-space: pre-wrap; overflow-wrap:anywhere; }
pre:hover { overflow:auto }

.votearrow {
width: 10px;
height: 10px;
border: 0px;
margin: 3px 2px 6px;
background: url("triangle.svg"), linear-gradient(transparent, transparent) no-repeat;
background-size: 10px;
}

.votelinks.nosee div.votearrow.rotate180 {
display: none;
}

table.padtab td { padding:0px 10px }

@media only screen and (-webkit-min-device-pixel-ratio: 2), only screen and (min-device-pixel-ratio: 2) {
.votearrow {
background-size: 10px;
background-image: url("triangle.svg"), linear-gradient(transparent, transparent);
}
}

.rotate180 {
-webkit-transform: rotate(180deg); /* Chrome and other webkit browsers */
-moz-transform: rotate(180deg); /* FF */
-o-transform: rotate(180deg); /* Opera */
-ms-transform: rotate(180deg); /* IE9 */
transform: rotate(180deg); /* W3C complaint browsers */

/* IE8 and below */
-ms-filter: "progid:DXImageTransform.Microsoft.Matrix(M11=-1, M12=0, M21=0, M22=-1, DX=0, DY=0, SizingMethod='auto expand')";
}

/* mobile device */
@media only screen
and (min-width : 300px)
and (max-width : 750px) {
#hnmain { width: 100%; min-width: 0; }
body { padding: 0; margin: 0; width: 100%; }
td { height: inherit !important; }
.title, .comment { font-size: inherit; }
span.pagetop { display: block; margin: 3px 5px; font-size: 12px; line-height: normal }
span.pagetop b { display: block; font-size: 15px; }
table.comment-tree .comment a { display: inline-block; max-width: 200px; overflow: hidden; white-space: nowrap;
text-overflow: ellipsis; vertical-align:top; }
img[src='s.gif'][width='40'] { width: 12px; }
img[src='s.gif'][width='80'] { width: 24px; }
img[src='s.gif'][width='120'] { width: 36px; }
img[src='s.gif'][width='160'] { width: 48px; }
img[src='s.gif'][width='200'] { width: 60px; }
img[src='s.gif'][width='240'] { width: 72px; }
img[src='s.gif'][width='280'] { width: 84px; }
img[src='s.gif'][width='320'] { width: 96px; }
img[src='s.gif'][width='360'] { width: 108px; }
img[src='s.gif'][width='400'] { width: 120px; }
img[src='s.gif'][width='440'] { width: 132px; }
img[src='s.gif'][width='480'] { width: 144px; }
img[src='s.gif'][width='520'] { width: 156px; }
img[src='s.gif'][width='560'] { width: 168px; }
img[src='s.gif'][width='600'] { width: 180px; }
img[src='s.gif'][width='640'] { width: 192px; }
img[src='s.gif'][width='680'] { width: 204px; }
img[src='s.gif'][width='720'] { width: 216px; }
img[src='s.gif'][width='760'] { width: 228px; }
img[src='s.gif'][width='800'] { width: 240px; }
img[src='s.gif'][width='840'] { width: 252px; }
.title { font-size: 11pt; line-height: 14pt; }
.subtext { font-size: 9pt; }
.votearrow { transform: scale(1.3,1.3); margin-right: 6px; }
.votearrow.rotate180 {
-webkit-transform: rotate(180deg) scale(1.3,1.3); /* Chrome and other webkit browsers */
-moz-transform: rotate(180deg) scale(1.3,1.3); /* FF */
-o-transform: rotate(180deg) scale(1.3,1.3); /* Opera */
-ms-transform: rotate(180deg) scale(1.3,1.3); /* IE9 */
transform: rotate(180deg) scale(1.3,1.3); /* W3C complaint browsers */
}
.votelinks { min-width: 18px; }
.votelinks a { display: block; margin-bottom: 9px; }
input[type='text'], input[type='number'], textarea { font-size: 16px; width: 90%; }
}

.comment { max-width: 1215px; overflow-wrap:anywhere; }

@media only screen and (min-width : 300px) and (max-width : 389px) {
.comment { max-width: 270px; overflow: hidden }
}
@media only screen and (min-width : 390px) and (max-width : 509px) {
.comment { max-width: 350px; overflow: hidden }
}
@media only screen and (min-width : 510px) and (max-width : 599px) {
.comment { max-width: 460px; overflow: hidden }
}
@media only screen and (min-width : 600px) and (max-width : 689px) {
.comment { max-width: 540px; overflow: hidden }
}
@media only screen and (min-width : 690px) and (max-width : 809px) {
.comment { max-width: 620px; overflow: hidden }
}
@media only screen and (min-width : 810px) and (max-width : 899px) {
.comment { max-width: 730px; overflow: hidden }
}
@media only screen and (min-width : 900px) and (max-width : 1079px) {
.comment { max-width: 810px; overflow: hidden }
}
@media only screen and (min-width : 1080px) and (max-width : 1169px) {
.comment { max-width: 970px; overflow: hidden }
}
@media only screen and (min-width : 1170px) and (max-width : 1259px) {
.comment { max-width: 1050px; overflow: hidden }
}
@media only screen and (min-width : 1260px) and (max-width : 1349px) {
.comment { max-width: 1130px; overflow: hidden }
}

I get, it's long. Just taking the css that was served and editing it.