Netscape Communicator 4.75 (AIX) CSS1/HTML 4 support on obsidian - prediction log.
Author: Claude Opus 5.5 (claude-opus-5-5). Series letter: N.
Written BEFORE building any test page for this series, and before re-reading series P or
netscape.html (my own earlier Netscape work). Format: ID [confidence] claim.
"Applied" means visibly rendered in nsshot screenshots of Netscape 4.75 on obsidian.

Already observed on 2026-10-08 while working on NSI v4 (not predictions, not scored):
LINK with no MEDIA or MEDIA="screen" applied; MEDIA="all" and @import skipped; a STYLE
MEDIA="print" block not applied on screen; links to #id do not scroll, to <A NAME> do;
underscores and hyphens in class/ID names work; CLASS="a b" matches neither class;
descendant selectors (#wrap P) work.

--- round 1 ---
N01 [0.80] JavaScript is enabled in the nsshot rig's Netscape profile (a document.write
     line appears in the page).
N02 [0.85] A SCRIPT with LANGUAGE="JavaScript1.2" runs.
N03 [0.60] A SCRIPT with TYPE="module" does not run.
N04 [0.75] JavaScript Style Sheets work: <STYLE TYPE="text/javascript"> setting
     tags.P.color / classes.x.all.color changes rendered text color.
N05 [0.85] A <LAYER> element renders its content (Netscape-only tag).
N06 [0.90] An inline STYLE="..." attribute on a P applies.
N07 [0.70] background-color on an inline SPAN is drawn behind its text.
N08 [0.70] border on an inline SPAN is ignored (no box drawn).
N09 [0.75] border: 2px solid on a block P draws a box.
N10 [0.25] On a P with padding and background-color, the background fills the padding
     area (I expect it to cover only the text box).
N11 [0.75] margin-left: 100px on a P indents it.
N12 [0.85] text-decoration: none on an A removes the underline.
N13 [0.70] text-transform: uppercase is applied.
N14 [0.30] letter-spacing is applied (I expect it to be ignored).
N15 [0.55] line-height: 3 (unitless) visibly spaces lines in a wrapped paragraph.
N16 [0.55] display: none hides a P on screen.
N17 [0.60] float: right with width: 200px moves a DIV to the right with text beside it.
N18 [0.25] :first-letter is applied (I expect it to be ignored).
N19 [0.85] A child selector rule (DIV > P) is not applied.
N20 [0.60] A rule following a rule with an unsupported selector (DIV > P) in the same
     STYLE block still applies.
N21 [0.85] An attribute selector rule (P[title]) is not applied.
N22 [0.70] An ID selector beats a class selector for the same property, regardless of
     rule order.
N23 [0.50] !important makes an earlier rule win over a later one.
N24 [0.35] font-size set on BODY applies to text inside a TABLE cell (I expect tables not
     to inherit it).
N25 [0.70] Rules inside an @media screen { } block are not applied.
N26 [0.85] A length in vw units is ignored (the property keeps its default).
N27 [0.70] list-style-type: square changes UL bullets to squares.
N28 [0.65] background-image: url(...) on a P draws the image.
Thu Oct  8 10:31:04 PM MDT 2026

--- round 2, after seeing round 1's screenshots; N06 and N12 need retesting (N06 shared a page
    with a JavaScript style sheet, N12's link lacked its class); N12 is retested as written ---
N29 [0.75] On a page with no JavaScript style sheet, an inline STYLE="background-color: red;
     color: white" attribute on a P applies.
N30 [0.85] font-size: 24pt set on a P itself (by class) enlarges that paragraph.
N31 [0.65] text-indent: 50px indents the first line of a P.
N32 [0.50] text-align: justify visibly justifies a wrapped paragraph.
N33 [0.40] white-space: pre preserves runs of spaces in a P.
N34 [0.30] font-variant: small-caps is applied.
N35 [0.60] clear: both on a P after a right float starts it below the float.
N36 [0.50] vertical-align: super on a SPAN raises its text.
Thu Oct  8 10:38:35 PM MDT 2026

=== OUTCOMES (scored 2026-10-08) ===
Evidence: nsshot screenshots of tests/a-j.html, f-noborder.html, f-red.html in Netscape 4.75
on obsidian (Xvnc display :5), 2026-10-08 22:33-23:05 MDT.
N01 HIT      [0.80] document.write output appears (a.html).
N02 HIT      [0.85] LANGUAGE="JavaScript1.2" script ran.
N03 HIT      [0.60] TYPE="module" script did not run.
N04 HIT      [0.75] classes.jsss.all.color = "red" turned the paragraph red.
N05 HIT      [0.85] LAYER rendered, with its BGCOLOR.
N06 PARTIAL  [0.90] inline STYLE applies on ordinary pages (N29), but not on N06's own page:
     it also had a JavaScript style sheet, and then Netscape reads every STYLE attribute as
     JavaScript (g2.html: STYLE="color = 'blue'" turned text blue, inline CSS ignored).
     My test design confounded this one.
N07 HIT      [0.70] red drawn behind the inline text.
N08 MISS     [0.70] the border is drawn, and the SPAN is moved onto a line of its own
     (repeated in f.html F5).
N09 HIT      [0.75] box around the paragraph.
N10 MISS     [0.25] the background covers only the text; the 20px padding shows page colour.
     (Series P had measured this; I had not re-read it before predicting.)
N11 HIT      [0.75] indented 100px. Its yellow background was not drawn: see Not predicted.
N12 HIT      [0.85] retested in round 2 (round 1's link lacked the class): no underline.
N13 HIT      [0.70] uppercase.
N14 MISS     [0.30] letter-spacing ignored.
N15 HIT      [0.55] lines visibly spaced out.
N16 HIT      [0.55] hidden; the marker after it shows.
N17 HIT      [0.60] box at the right, text beside it.
N18 MISS     [0.25] :first-letter ignored.
N19 HIT      [0.85] child selector rule not applied.
N20 HIT      [0.60] the next rule in the block applied.
N21 HIT      [0.85] attribute selector rule not applied.
N22 HIT      [0.70] ID rule won over the later class rule.
N23 MISS     [0.50] the later rule won; !important ignored.
N24 MISS     [0.35] BODY's font-size did not reach the TABLE cell, but it did not reach a plain
     P either: with no font-family named, CSS font-size has no effect (see N30). Right
     outcome, wrong reason. (Series P had found font-family not inherited into tables.)
N25 HIT      [0.70] rules inside @media screen not applied; the rule after the block was.
N26 HIT      [0.85] retested on Helvetica (j.html), where sizes do work: 5vw renders at normal
     size while 24pt is large. The round 1 test on the default font could not tell.
N27 HIT      [0.70] square (hollow) bullet.
N28 HIT      [0.65] tiled image drawn.
N29 HIT      [0.75] inline STYLE applied on a page without a JavaScript style sheet.
N30 MISS     [0.85] no change. font-size takes effect only if the same element gets a
     font-family (any: Times, serif, Courier, Helvetica all work at 24pt, i3.html); the
     default font without a family ignores every size (pt, px, x-large, %, h.html).
N31 HIT      [0.65] first line indented.
N32 HIT      [0.50] justified.
N33 HIT      [0.40] the five spaces kept.
N34 MISS     [0.30] small-caps ignored.
N35 HIT      [0.60] the cleared paragraph starts below the float.
N36 MISS     [0.50] super ignored; text stays on the baseline.

Calibration:  <0.50: 1/6 (the five misses are claims I gave 0.25-0.35, i.e. expected to be false)
              0.50-0.79: 18/21   >=0.80: 7/9 (N06 partial, N30 miss)
Not predicted: a page with a JavaScript style sheet makes Netscape read STYLE attributes as
JavaScript, and Content-Style-Type: text/css does not change that; font-size works only
together with font-family; "serif" at 24pt comes out bold; an inline border pushes its SPAN
onto its own line; on pages that contain bordered elements, background-color: yellow on a plain
P is not drawn (reproducible: f.html twice, b.html twice) while red is, a yellow DIV is, a
bordered yellow P is, and the same P is yellow once the bordered elements are removed
(f-noborder.html, f-red.html). Cause unknown.