-
Notifications
You must be signed in to change notification settings - Fork 1
/
Copy pathdraft-ietf-dkim-replay-problem-00.html
2092 lines (2027 loc) · 80.7 KB
/
draft-ietf-dkim-replay-problem-00.html
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
<!DOCTYPE html>
<html lang="en" class="Internet-Draft">
<head>
<meta charset="utf-8">
<meta content="Common,Latin" name="scripts">
<meta content="initial-scale=1.0" name="viewport">
<title>DKIM Replay Problem Statement</title>
<meta content="Weihaw Chuang" name="author">
<meta content="Dave Crocker" name="author">
<meta content="Allen Robinson" name="author">
<meta content="Bron Gondwana" name="author">
<meta content="
DomainKeys Identified Mail (DKIM, RFC6376) permits claiming some
responsibility for a message by cryptographically associating a domain name
with the message. For data covered by the cryptographic signature, this also
enables detecting changes made during transit. DKIM survives basic email
relaying. In a Replay Attack, a recipient of a DKIM-signed message re-posts
the message to other recipients,while retaining the original, validating
signature, and thereby leveraging the reputation of the original signer. This
document discusses the resulting damage to email delivery, interoperability,
and associated mail flows. A significant challenge to mitigating this
problem is that it is difficult for receivers to differentiate between
legitimate forwarding flows and a DKIM Replay Attack.
" name="description">
<meta content="xml2rfc 3.17.1" name="generator">
<meta content="DKIM" name="keyword">
<meta content="Replay" name="keyword">
<meta content="draft-ietf-dkim-replay-problem-00" name="ietf.draft">
<!-- Generator version information:
xml2rfc 3.17.1
Python 3.10.11
appdirs 1.4.4
ConfigArgParse 1.5.3
google-i18n-address 2.5.2
intervaltree 3.1.0
Jinja2 3.1.2
lxml 4.9.2
pycountry 22.3.5
PyYAML 6.0
requests 2.28.2
setuptools 67.6.1
six 1.16.0
wcwidth 0.2.6
-->
<link href="draft-ietf-dkim-replay-problem-00.xml" rel="alternate" type="application/rfc+xml">
<link href="#copyright" rel="license">
<style type="text/css">/*
NOTE: Changes at the bottom of this file overrides some earlier settings.
Once the style has stabilized and has been adopted as an official RFC style,
this can be consolidated so that style settings occur only in one place, but
for now the contents of this file consists first of the initial CSS work as
provided to the RFC Formatter (xml2rfc) work, followed by itemized and
commented changes found necessary during the development of the v3
formatters.
*/
/* fonts */
@import url('https://fonts.googleapis.com/css?family=Noto+Sans'); /* Sans-serif */
@import url('https://fonts.googleapis.com/css?family=Noto+Serif'); /* Serif (print) */
@import url('https://fonts.googleapis.com/css?family=Roboto+Mono'); /* Monospace */
:root {
--font-sans: 'Noto Sans', Arial, Helvetica, sans-serif;
--font-serif: 'Noto Serif', 'Times', 'Times New Roman', serif;
--font-mono: 'Roboto Mono', Courier, 'Courier New', monospace;
}
@viewport {
zoom: 1.0;
}
@-ms-viewport {
width: extend-to-zoom;
zoom: 1.0;
}
/* general and mobile first */
html {
}
body {
max-width: 90%;
margin: 1.5em auto;
color: #222;
background-color: #fff;
font-size: 14px;
font-family: var(--font-sans);
line-height: 1.6;
scroll-behavior: smooth;
}
.ears {
display: none;
}
/* headings */
#title, h1, h2, h3, h4, h5, h6 {
margin: 1em 0 0.5em;
font-weight: bold;
line-height: 1.3;
}
#title {
clear: both;
border-bottom: 1px solid #ddd;
margin: 0 0 0.5em 0;
padding: 1em 0 0.5em;
}
.author {
padding-bottom: 4px;
}
h1 {
font-size: 26px;
margin: 1em 0;
}
h2 {
font-size: 22px;
margin-top: -20px; /* provide offset for in-page anchors */
padding-top: 33px;
}
h3 {
font-size: 18px;
margin-top: -36px; /* provide offset for in-page anchors */
padding-top: 42px;
}
h4 {
font-size: 16px;
margin-top: -36px; /* provide offset for in-page anchors */
padding-top: 42px;
}
h5, h6 {
font-size: 14px;
}
#n-copyright-notice {
border-bottom: 1px solid #ddd;
padding-bottom: 1em;
margin-bottom: 1em;
}
/* general structure */
p {
padding: 0;
margin: 0 0 1em 0;
text-align: left;
}
div, span {
position: relative;
}
div {
margin: 0;
}
.alignRight.art-text {
background-color: #f9f9f9;
border: 1px solid #eee;
border-radius: 3px;
padding: 1em 1em 0;
margin-bottom: 1.5em;
}
.alignRight.art-text pre {
padding: 0;
}
.alignRight {
margin: 1em 0;
}
.alignRight > *:first-child {
border: none;
margin: 0;
float: right;
clear: both;
}
.alignRight > *:nth-child(2) {
clear: both;
display: block;
border: none;
}
svg {
display: block;
}
svg[font-family~="serif" i], svg [font-family~="serif" i] {
font-family: var(--font-serif);
}
svg[font-family~="sans-serif" i], svg [font-family~="sans-serif" i] {
font-family: var(--font-sans);
}
svg[font-family~="monospace" i], svg [font-family~="monospace" i] {
font-family: var(--font-mono);
}
.alignCenter.art-text {
background-color: #f9f9f9;
border: 1px solid #eee;
border-radius: 3px;
padding: 1em 1em 0;
margin-bottom: 1.5em;
}
.alignCenter.art-text pre {
padding: 0;
}
.alignCenter {
margin: 1em 0;
}
.alignCenter > *:first-child {
display: table;
border: none;
margin: 0 auto;
}
/* lists */
ol, ul {
padding: 0;
margin: 0 0 1em 2em;
}
ol ol, ul ul, ol ul, ul ol {
margin-left: 1em;
}
li {
margin: 0 0 0.25em 0;
}
.ulCompact li {
margin: 0;
}
ul.empty, .ulEmpty {
list-style-type: none;
}
ul.empty li, .ulEmpty li {
margin-top: 0.5em;
}
ul.ulBare, li.ulBare {
margin-left: 0em !important;
}
ul.compact, .ulCompact,
ol.compact, .olCompact {
line-height: 100%;
margin: 0 0 0 2em;
}
/* definition lists */
dl {
}
dl > dt {
float: left;
margin-right: 1em;
}
/*
dl.nohang > dt {
float: none;
}
*/
dl > dd {
margin-bottom: .8em;
min-height: 1.3em;
}
dl.compact > dd, .dlCompact > dd {
margin-bottom: 0em;
}
dl > dd > dl {
margin-top: 0.5em;
margin-bottom: 0em;
}
/* links */
a {
text-decoration: none;
}
a[href] {
color: #22e; /* Arlen: WCAG 2019 */
}
a[href]:hover {
background-color: #f2f2f2;
}
figcaption a[href],
a[href].selfRef,
.iref + a[href].internal {
color: #222;
}
/* XXX probably not this:
a.selfRef:hover {
background-color: transparent;
cursor: default;
} */
/* Figures */
tt, code, pre {
background-color: #f9f9f9;
font-family: var(--font-mono);
}
pre {
border: 1px solid #eee;
margin: 0;
padding: 1em;
}
img {
max-width: 100%;
}
figure {
margin: 0;
}
figure blockquote {
margin: 0.8em 0.4em 0.4em;
}
figcaption {
font-style: italic;
margin: 0 0 1em 0;
}
@media screen {
pre {
overflow-x: auto;
max-width: 100%;
max-width: calc(100% - 22px);
}
}
/* aside, blockquote */
aside, blockquote {
margin-left: 0;
padding: 1.2em 2em;
}
blockquote {
background-color: #f9f9f9;
color: #111; /* Arlen: WCAG 2019 */
border: 1px solid #ddd;
border-radius: 3px;
margin: 1em 0;
}
cite {
display: block;
text-align: right;
font-style: italic;
}
/* tables */
table {
width: 100%;
margin: 0 0 1em;
border-collapse: collapse;
border: 1px solid #eee;
}
th, td {
text-align: left;
vertical-align: top;
padding: 0.5em 0.75em;
}
th {
text-align: left;
background-color: #e9e9e9;
}
tr:nth-child(2n+1) > td {
background-color: #f5f5f5;
}
table caption {
font-style: italic;
margin: 0;
padding: 0;
text-align: left;
}
table p {
/* XXX to avoid bottom margin on table row signifiers. If paragraphs should
be allowed within tables more generally, it would be far better to select on a class. */
margin: 0;
}
/* pilcrow */
a.pilcrow {
color: #666; /* Arlen: AHDJ 2019 */
text-decoration: none;
visibility: hidden;
user-select: none;
-ms-user-select: none;
-o-user-select:none;
-moz-user-select: none;
-khtml-user-select: none;
-webkit-user-select: none;
-webkit-touch-callout: none;
}
@media screen {
aside:hover > a.pilcrow,
p:hover > a.pilcrow,
blockquote:hover > a.pilcrow,
div:hover > a.pilcrow,
li:hover > a.pilcrow,
pre:hover > a.pilcrow {
visibility: visible;
}
a.pilcrow:hover {
background-color: transparent;
}
}
/* misc */
hr {
border: 0;
border-top: 1px solid #eee;
}
.bcp14 {
font-variant: small-caps;
}
.role {
font-variant: all-small-caps;
}
/* info block */
#identifiers {
margin: 0;
font-size: 0.9em;
}
#identifiers dt {
width: 3em;
clear: left;
}
#identifiers dd {
float: left;
margin-bottom: 0;
}
/* Fix PDF info block run off issue */
@media print {
#identifiers dd {
float: none;
}
}
#identifiers .authors .author {
display: inline-block;
margin-right: 1.5em;
}
#identifiers .authors .org {
font-style: italic;
}
/* The prepared/rendered info at the very bottom of the page */
.docInfo {
color: #666; /* Arlen: WCAG 2019 */
font-size: 0.9em;
font-style: italic;
margin-top: 2em;
}
.docInfo .prepared {
float: left;
}
.docInfo .prepared {
float: right;
}
/* table of contents */
#toc {
padding: 0.75em 0 2em 0;
margin-bottom: 1em;
}
nav.toc ul {
margin: 0 0.5em 0 0;
padding: 0;
list-style: none;
}
nav.toc li {
line-height: 1.3em;
margin: 0.75em 0;
padding-left: 1.2em;
text-indent: -1.2em;
}
/* references */
.references dt {
text-align: right;
font-weight: bold;
min-width: 7em;
}
.references dd {
margin-left: 8em;
overflow: auto;
}
.refInstance {
margin-bottom: 1.25em;
}
.references .ascii {
margin-bottom: 0.25em;
}
/* index */
.index ul {
margin: 0 0 0 1em;
padding: 0;
list-style: none;
}
.index ul ul {
margin: 0;
}
.index li {
margin: 0;
text-indent: -2em;
padding-left: 2em;
padding-bottom: 5px;
}
.indexIndex {
margin: 0.5em 0 1em;
}
.index a {
font-weight: 700;
}
/* make the index two-column on all but the smallest screens */
@media (min-width: 600px) {
.index ul {
-moz-column-count: 2;
-moz-column-gap: 20px;
}
.index ul ul {
-moz-column-count: 1;
-moz-column-gap: 0;
}
}
/* authors */
address.vcard {
font-style: normal;
margin: 1em 0;
}
address.vcard .nameRole {
font-weight: 700;
margin-left: 0;
}
address.vcard .label {
font-family: var(--font-sans);
margin: 0.5em 0;
}
address.vcard .type {
display: none;
}
.alternative-contact {
margin: 1.5em 0 1em;
}
hr.addr {
border-top: 1px dashed;
margin: 0;
color: #ddd;
max-width: calc(100% - 16px);
}
/* temporary notes */
.rfcEditorRemove::before {
position: absolute;
top: 0.2em;
right: 0.2em;
padding: 0.2em;
content: "The RFC Editor will remove this note";
color: #9e2a00; /* Arlen: WCAG 2019 */
background-color: #ffd; /* Arlen: WCAG 2019 */
}
.rfcEditorRemove {
position: relative;
padding-top: 1.8em;
background-color: #ffd; /* Arlen: WCAG 2019 */
border-radius: 3px;
}
.cref {
background-color: #ffd; /* Arlen: WCAG 2019 */
padding: 2px 4px;
}
.crefSource {
font-style: italic;
}
/* alternative layout for smaller screens */
@media screen and (max-width: 1023px) {
body {
padding-top: 2em;
}
#title {
padding: 1em 0;
}
h1 {
font-size: 24px;
}
h2 {
font-size: 20px;
margin-top: -18px; /* provide offset for in-page anchors */
padding-top: 38px;
}
#identifiers dd {
max-width: 60%;
}
#toc {
position: fixed;
z-index: 2;
top: 0;
right: 0;
padding: 0;
margin: 0;
background-color: inherit;
border-bottom: 1px solid #ccc;
}
#toc h2 {
margin: -1px 0 0 0;
padding: 4px 0 4px 6px;
padding-right: 1em;
min-width: 190px;
font-size: 1.1em;
text-align: right;
background-color: #444;
color: white;
cursor: pointer;
}
#toc h2::before { /* css hamburger */
float: right;
position: relative;
width: 1em;
height: 1px;
left: -164px;
margin: 6px 0 0 0;
background: white none repeat scroll 0 0;
box-shadow: 0 4px 0 0 white, 0 8px 0 0 white;
content: "";
}
#toc nav {
display: none;
padding: 0.5em 1em 1em;
overflow: auto;
height: calc(100vh - 48px);
border-left: 1px solid #ddd;
}
}
/* alternative layout for wide screens */
@media screen and (min-width: 1024px) {
body {
max-width: 724px;
margin: 42px auto;
padding-left: 1.5em;
padding-right: 29em;
}
#toc {
position: fixed;
top: 42px;
right: 42px;
width: 25%;
margin: 0;
padding: 0 1em;
z-index: 1;
}
#toc h2 {
border-top: none;
border-bottom: 1px solid #ddd;
font-size: 1em;
font-weight: normal;
margin: 0;
padding: 0.25em 1em 1em 0;
}
#toc nav {
display: block;
height: calc(90vh - 84px);
bottom: 0;
padding: 0.5em 0 0;
overflow: auto;
}
img { /* future proofing */
max-width: 100%;
height: auto;
}
}
/* pagination */
@media print {
body {
width: 100%;
}
p {
orphans: 3;
widows: 3;
}
#n-copyright-notice {
border-bottom: none;
}
#toc, #n-introduction {
page-break-before: always;
}
#toc {
border-top: none;
padding-top: 0;
}
figure, pre {
page-break-inside: avoid;
}
figure {
overflow: scroll;
}
.breakable pre {
break-inside: auto;
}
h1, h2, h3, h4, h5, h6 {
page-break-after: avoid;
}
h2+*, h3+*, h4+*, h5+*, h6+* {
page-break-before: avoid;
}
pre {
white-space: pre-wrap;
word-wrap: break-word;
font-size: 10pt;
}
table {
border: 1px solid #ddd;
}
td {
border-top: 1px solid #ddd;
}
}
/* This is commented out here, as the string-set: doesn't
pass W3C validation currently */
/*
.ears thead .left {
string-set: ears-top-left content();
}
.ears thead .center {
string-set: ears-top-center content();
}
.ears thead .right {
string-set: ears-top-right content();
}
.ears tfoot .left {
string-set: ears-bottom-left content();
}
.ears tfoot .center {
string-set: ears-bottom-center content();
}
.ears tfoot .right {
string-set: ears-bottom-right content();
}
*/
@page :first {
padding-top: 0;
@top-left {
content: normal;
border: none;
}
@top-center {
content: normal;
border: none;
}
@top-right {
content: normal;
border: none;
}
}
@page {
size: A4;
margin-bottom: 45mm;
padding-top: 20px;
/* The following is commented out here, but set appropriately by in code, as
the content depends on the document */
/*
@top-left {
content: 'Internet-Draft';
vertical-align: bottom;
border-bottom: solid 1px #ccc;
}
@top-left {
content: string(ears-top-left);
vertical-align: bottom;
border-bottom: solid 1px #ccc;
}
@top-center {
content: string(ears-top-center);
vertical-align: bottom;
border-bottom: solid 1px #ccc;
}
@top-right {
content: string(ears-top-right);
vertical-align: bottom;
border-bottom: solid 1px #ccc;
}
@bottom-left {
content: string(ears-bottom-left);
vertical-align: top;
border-top: solid 1px #ccc;
}
@bottom-center {
content: string(ears-bottom-center);
vertical-align: top;
border-top: solid 1px #ccc;
}
@bottom-right {
content: '[Page ' counter(page) ']';
vertical-align: top;
border-top: solid 1px #ccc;
}
*/
}
/* Changes introduced to fix issues found during implementation */
/* Make sure links are clickable even if overlapped by following H* */
a {
z-index: 2;
}
/* Separate body from document info even without intervening H1 */
section {
clear: both;
}
/* Top align author divs, to avoid names without organization dropping level with org names */
.author {
vertical-align: top;
}
/* Leave room in document info to show Internet-Draft on one line */
#identifiers dt {
width: 8em;
}
/* Don't waste quite as much whitespace between label and value in doc info */
#identifiers dd {
margin-left: 1em;
}
/* Give floating toc a background color (needed when it's a div inside section */
#toc {
background-color: white;
}
/* Make the collapsed ToC header render white on gray also when it's a link */
@media screen and (max-width: 1023px) {
#toc h2 a,
#toc h2 a:link,
#toc h2 a:focus,
#toc h2 a:hover,
#toc a.toplink,
#toc a.toplink:hover {
color: white;
background-color: #444;
text-decoration: none;
}
}
/* Give the bottom of the ToC some whitespace */
@media screen and (min-width: 1024px) {
#toc {
padding: 0 0 1em 1em;
}
}
/* Style section numbers with more space between number and title */
.section-number {
padding-right: 0.5em;
}
/* prevent monospace from becoming overly large */
tt, code, pre {
font-size: 95%;
}
/* Fix the height/width aspect for ascii art*/
.sourcecode pre,
.art-text pre {
line-height: 1.12;
}
/* Add styling for a link in the ToC that points to the top of the document */
a.toplink {
float: right;
margin-right: 0.5em;
}
/* Fix the dl styling to match the RFC 7992 attributes */
dl > dt,
dl.dlParallel > dt {
float: left;
margin-right: 1em;
}
dl.dlNewline > dt {
float: none;
}
/* Provide styling for table cell text alignment */
table td.text-left,
table th.text-left {
text-align: left;
}
table td.text-center,
table th.text-center {
text-align: center;
}
table td.text-right,
table th.text-right {
text-align: right;
}
/* Make the alternative author contact information look less like just another
author, and group it closer with the primary author contact information */
.alternative-contact {
margin: 0.5em 0 0.25em 0;
}
address .non-ascii {
margin: 0 0 0 2em;
}
/* With it being possible to set tables with alignment
left, center, and right, { width: 100%; } does not make sense */
table {
width: auto;
}
/* Avoid reference text that sits in a block with very wide left margin,
because of a long floating dt label.*/
.references dd {
overflow: visible;
}
/* Control caption placement */
caption {
caption-side: bottom;
}
/* Limit the width of the author address vcard, so names in right-to-left
script don't end up on the other side of the page. */
address.vcard {
max-width: 30em;
margin-right: auto;
}
/* For address alignment dependent on LTR or RTL scripts */
address div.left {
text-align: left;
}
address div.right {
text-align: right;
}
/* Provide table alignment support. We can't use the alignX classes above
since they do unwanted things with caption and other styling. */
table.right {
margin-left: auto;
margin-right: 0;
}
table.center {
margin-left: auto;
margin-right: auto;
}
table.left {
margin-left: 0;
margin-right: auto;
}
/* Give the table caption label the same styling as the figcaption */
caption a[href] {
color: #222;
}
@media print {
.toplink {
display: none;
}
/* avoid overwriting the top border line with the ToC header */
#toc {
padding-top: 1px;
}
/* Avoid page breaks inside dl and author address entries */
.vcard {
page-break-inside: avoid;
}
}
/* Tweak the bcp14 keyword presentation */
.bcp14 {
font-variant: small-caps;
font-weight: bold;
font-size: 0.9em;
}
/* Tweak the invisible space above H* in order not to overlay links in text above */
h2 {
margin-top: -18px; /* provide offset for in-page anchors */
padding-top: 31px;
}
h3 {
margin-top: -18px; /* provide offset for in-page anchors */
padding-top: 24px;
}
h4 {
margin-top: -18px; /* provide offset for in-page anchors */
padding-top: 24px;
}
/* Float artwork pilcrow to the right */
@media screen {
.artwork a.pilcrow {
display: block;
line-height: 0.7;
margin-top: 0.15em;
}
}
/* Make pilcrows on dd visible */
@media screen {
dd:hover > a.pilcrow {
visibility: visible;