-
Notifications
You must be signed in to change notification settings - Fork 790
Expand file tree
/
Copy pathOverview.bs
More file actions
569 lines (499 loc) · 25.1 KB
/
Overview.bs
File metadata and controls
569 lines (499 loc) · 25.1 KB
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
<h1>CSS Backgrounds and Borders Module Level 4</h1>
<pre class='metadata'>
Shortname: css-backgrounds
Level: 4
Status: ED
Group: csswg
TR: http://www.w3.org/TR/css-backgrounds-4/
ED: http://dev.w3.org/csswg/css-backgrounds-4/
Editor: Bert Bos, W3C, bert@w3.org
Editor: Elika J. Etemad, Invited Expert, http://fantasai.inkedblade.net/contact
Editor: Lea Verou, Invited Expert, http://lea.verou.me/about/
Abstract: This module contains the features of CSS relating to the borders and backgrounds of boxes on the page. It includes and extends the functionality of <a href="http://www.w3.org/TR/css3-background/">CSS Backgrounds and Borders Level 3</a>. [[CSS3BG]] The main extensions compared to level 3
8000
are shaping ('corner-shape') and clipping borders ('border-clip'), logical background positions ('background-position'), and the ''extend'' ability of 'background-repeat'.
Ignored Terms:
</pre>
<h2 id="intro">
Introduction</h2>
<p class="issue">
This module is currently maintained as a diff against Level 3.
We will fold in the text once it's all formatted up and in CR again,
as this will reduce the effort of keeping them in sync
(source diffs will be accurate in reflecting the differences).
<h2 id="backgrounds">
Backgrounds</h2>
<h3 id="the-background-position">
Background Positioning: the 'background-position' property</h3>
<pre class='propdef'>
Name: backround-position
Value: <<position>>#
Initial: top left
Applies to: all
Inherited: no
Percentages: refer to size of background positioning area <em>minus</em> size of background image
Media: visual
Computed value: A list, each item consisting of: a pair of offsets and an origin, each offset given as a combination of an absolute length and a percentage
</pre>
See [[CSS3BG]] for definition.
<p>Where
<pre class=prod><dfn><var><position></var></dfn> = [
[ left | center | right | top | bottom | <var><percentage></var> | <var><length></var> ]
|
[ left | center | right | <var><percentage></var> | <var><length></var> ]
[ top | center | bottom | <var><percentage></var> | <var><length></var> ]
|
[ center | [ left | right ] [ <var><percentage></var> | <var><length></var> ]? ] &&
[ center | [ top | bottom ] [ <var><percentage></var> | <var><length></var> ]? ]
]</pre>
<p class="issue">Add logical keywords
<h2 id="corners">
Corners</h2>
<h3 id=corner-sizing>
Corner Sizing: the 'border-radius property</h3>
<pre class='propdef'>
Name: border-radius
Value: [ <<length>> | <<percentage>> ]{1,4} [ / [ <<length>> | <<percentage>> ]{1,4} ]?
Initial: 0
Applies to: all elements, except table element when 'border-collapse' is ''collapse''
Inherited: no
Percentages: n/a
Media: visual
Computed value: specified value
Animatable: no
Canonical order: n/a
</pre>
See [[CSS3BG]].
<h3 id=corner-shaping>
Corner Shaping: the 'corner-shape' property</h3>
<pre class='propdef'>
Name: corner-shape
Value: [round | bevel | scoop | notch]{1,4}
Initial: round
Applies to: all elements, except table element when 'border-collapse' is ''collapse''
Inherited: no
Percentages: n/a
Media: visual
Computed value: specified value
Animatable: no
Canonical order: n/a
</pre>
By default, non-zero border-radii define
a quarter-ellipse that rounds the affected corners.
However in some cases, other corner shapes are desired.
The 'corner-shape' property specifies a reinterpretation of the radii
to define other corner shapes.
<dl dfn-type="value" dfn-for="corner-shape">
<dt><dfn>''round''</dfn>
<dd>Border radii define a convex elliptical curve at the corner.
<dt><dfn>''bevel''</dfn>
<dd>Border radii define a diagonal slice at the corner.
<dt><dfn>''scoop''</dfn>
<dd>Border radii define a concave elliptical curve at the corner.
<dt><dfn>''notch''</dfn>
<dd>Border radii define a concave rectangular notch at the corner.
</dl>
<div class="example">
For example, the following declarations create a right-pointing next button.
<pre>
a {
border-radius: 0 2em 2em 0;
corner-shape: bevel;
padding: 0.5em 2em 0.5em 0.5em;
</pre>
As a fallback in UAs that don't support 'border-radius',
the right side would be rounded rather than pointy.
</div>
<p class="issue">
For ''scoop'' and ''notch'', how do the color/style/width transitions work?
Do they transition once in the middle, or alternate to match the topness/sideness of that segment of the border?
<p class="issue">
Add a ''cubic-bezier()'' function for random other shapes?
Or some other functions?
<h3 id="corners-shorthand">
Corner Shape and Size: the 'corners' shorthand</h3>
<pre class='propdef'>
Name: corners
Value: <<'corner-shape'>> || <<'border-radius'>>
Initial: see ind
8000
ividual properties
Applies to: see individual properties
Inherited: see individual properties
Percentages: see individual properties
Media: visual
Computed value: see individual properties
</pre>
The 'corners' shorthand sets 'corner-shape' and 'border-radius' in the same declaration.
If either is omitted, it is reset to its initial value.
<div class="example">
For example, the following declaration creates a diamond shape.
<pre>corners: bevel 50%;</pre>
In UAs that don't support 'corner-shape', the declaration is ignored
(falls back to a rectangle).
</div>
<div class="example">
In this example, the first declaration creates tabs with vertical sides and rounded corners using 'border-radius',
while the second example makes them trapezoid-shaped in UAs that support 'corners'.
<pre>
border-radius: 0.25em 0.25em 0 0;
corners: bevel 0.25em 0.25em 0 0 / 50% 50% 0 0;
</pre>
</div>
<h2 id="partial-borders">
Partial borders</h2>
<p>CSS borders traditionally cover an entire border edge. Sometimes,
however, it can be useful to hide some parts of the border.
<p class="issue">
Here are two proposals for doing this:
the second one is from GCPM, the first one is an attempt to recast it more readably.
The names are terrible, known problem, proposals accepted.
There is a problem with conceiving this as clipping:
if you have dotted borders, you want whole dots always, not parts of dots.
So it should be a drawing limit, not a clip.
<h3 id="partial-borders">
Partial Borders: the 'border-limit' property</h3>
<table class=propdef>
<tr>
<th>Name:
<td><dfn>border-limit</dfn>
<tr>
<th>Value:
<td>all | [ sides | corners ] [ <length> | <percentage> ]?
| [ top | right | bottom | left ] [ <length> | <percentage> ]
<tr>
<th>Initial:
<td>round
<tr>
<th>Applies to:
<td>all elements, except table element when 'border-collapse' is
''collapse''
<tr>
<th>Inherited:
<td>no
<tr>
<th>Percentages:
<td>relative to border-box
<tr>
<th>Media:
<td>visual
<tr>
<th>Computed value:
<td>as specified
</table>
<p>By default, the entire border is drawn. However, border rendering can be
limited to only part of a border. The keyword specifies which part, and
the length or percentage specifies how much.
<dl dfn-type="value" dfn-for="border-limit">
<dt><dfn>''sides''</dfn>
<dd>The sides are drawn up to but not including the corners (as defined
by the border radii). A length or percentage is measured from the center
of each side: ''50%'' draws the middle 50% of the border; by default the
entire side is drawn.
<dt><dfn>''corners''</dfn>
<dd>The corners are drawn plus the specified distance into the sides if
specified. A length is measured from the closest edge of the corner area.
A percentage is measured from the absolute corner of the border box.
<dt><dfn>''left''</dfn>
<dt><dfn>''right''</dfn>
<dd>For the left and right (vertical) sides, draws the entire side and
corner. For the top and bottom (horizontal) sides, draws the left/right
portion, as specified. Distances are measured as for ''corners''.
<dt><dfn>''top''</dfn>
<dt><dfn>''bottom''</dfn>
<dd>For the top and bottom (horizontal) sides, draws the entire side and
corner. For the left and right (vertical) sides, draws the top/bottom
portion, as specified. Distances are measured as for ''corners''.
</dl>
<div class="example">
<p>The following example draws only the middle 50% of the sides.</p>
<pre>box { border: solid; border-parts: sides 50% }</pre>
<p>The following example draws only the curved parts of the corners.</p>
<pre>box { border: solid; border-radius: 1em 2em; border-parts: corners; }</pre>
<p>The following example draws only the left 4em of the top border.</p>
<pre>box { border-top: solid; border-parts: left 4em; }
<p>The following example draws only the first 10px of each corner:</p>
<pre>box { border: solid; border-parts: corners 10px; }</pre>
<p>The following example draws the curved part of the corner plus 5px
along ths sides:</p>
<pre>box { border: solid; border-radius: 5px; border-shape: scoop; border-parts: corners 5px; }</pre>
<p>The following example draws the curved part of the corner and all of
the side except the middle 40%.</p>
<pre>box { border: solid; border-radius: 5px; border-shape: scoope; border-parts: corners 30%; }</pre>
</div>
<h3 id="border-clip">
The 'border-clip' properties</h3>
<table class=propdef>
<tr>
<th>Name:
<td><dfn>border-clip</dfn>, <dfn>border-clip
77F4
-top</dfn>, <dfn>border-clip-right</dfn>, <dfn>border-clip-bottom</dfn>, <dfn>border-clip-left</dfn>
<tr>
<th>Value:
<td>normal | [ <length> | <percentage> | <fraction> ]+
<tr>
<th>Initial:
<td>normal
<tr>
<th>Applies to:
<td>all elements
<tr>
<th>Inherited:
<td>no
<tr>
<th>Percentages:
<td>refer to length of border-edge side
<tr>
<th>Media:
<td>visual
<tr>
<th>Computed value:
<td>''normal'', or a list consisting of absolute lengths, or percentages as specified
</table>
<p class=issue>Should these properties be simplified to only accept <code>normal | [ <length> | <percentage> ] +</code>?
<p>These properties split their respective borders into parts along
the border edge. The first part is visible, the second is invisible,
the third part is visible, etc. Parts can be specified with lengths,
percentages, or fractions (expressed by the ''fr'' unit, as per
[[CSS3GRID]] or its <a href="http://dev.w3.org/csswg/css3-grid/">editor's
edition</a>). The ''normal'' value means
that the border is not split, but shown normally.
<p>'border-clip' is a shorthand property for the four individual properties.
<p>If the listed parts are shorter than the border, any remaining
border is split proportionally between the specified fractions. If
there are no fractions, the behavior is as if ''1fr'' had been
specified at the end of the list.
<p>If the listed parts are longer than the border, the specified parts
will be shown in full until the end of the border. In this case, all
fractions will be zero.
<p>For horizontal borders, parts are listed from left to right. For
vertical borders, parts are listed from top to bottom.
<p>The exact border parts are determined by laying out the specified border
parts with all fractions initially set to zero. Any remaining border is
split proportionally between the fractions specified.
<div class="example">
<pre>border-clip: 10px 1fr 10px;</pre>
<div style="position: relative; width: 250px; height: 150px; background: white;">
<div style="border: 2px solid black; width: 200px; height: 100px; position: absolute; top: 20px; left: 20px">
<div style="position: absolute; background: white; left: 15px; top: -5px; height: 110px; width: 170px"></div>
<div style="position: absolute; background: white; left: -5px; top: 15px; height: 70px; width: 210px"></div>
</div>
</div>
</div>
<div class="example">
<pre>
border-clip-top: 10px 1fr 10px;
border-clip-bottom: 10px 1fr 10px;
border-clip-right: 5px 1fr 5px;
border-clip-left: 5px 1fr 5px;
</pre>
<div style="position: relative; width: 250px; height: 150px; background: white;">
<div style="border: 2px solid black; width: 200px; height: 100px; position: absolute; top: 20px; left: 20px">
<div style="position: absolute; background: white; left: 15px; top: -5px; height: 110px; width: 170px"></div>
<div style="position: absolute; background: white; left: -5px; top: 5px; height: 90px; width: 210px"></div>
</div>
</div>
</div>
<div class="example">
<p>By making the first part have zero length, the inverse border of
the previous example can easily be created:
<pre>
border-clip-top: 0 10px 1fr 10px;
border-clip-bottom: 0 10px 1fr 10px;
border-clip-right: 0 5px 1fr 5px;
border-clip-left: 0 5px 1fr 5px;
</pre>
<div style="position: relative; width: 250px; height: 150px; background: white;">
<div style="border: 2px solid black; width: 200px; height: 100px; position: absolute; top: 20px; left: 20px">
<div style="position: absolute; background: white; left: -5px; top: -5px; height: 10px; width: 15px"></div>
<div style="position: absolute; background: white; right: -5px; top: -5px; height: 10px; width: 15px"></div>
<div style="position: absolute; background: white; left: -5px; top: 95px; height: 10px; width: 15px"></div>
<div style="position: absolute; background: white; right: -5px; top: 95px; height: 10px; width: 15px"></div>
</div>
</div>
</div>
<div class="example">
<pre>
border: thin solid black;
border-clip: 0 1fr; /* hide borders */
border-clip-top: 10px 1fr 10px; /* make certain borders visible */
border-clip-bottom: 10px 1fr 10px;
</pre>
<div style="position: relative; width: 250px; height: 150px; background: white;">
<div style="border: 2px solid black; width: 200px; height: 100px; position: absolute; top: 20px; left: 20px">
<div style="position: absolute; background: white; left: 15px; top: -5px; height: 110px; width: 170px"></div>
<div styl
93D4
e="position: absolute; background: white; left: -5px; top: 0px; height: 100px; width: 210px"></div>
</div>
</div>
</div>
<div class="example">
<pre>
<!-- -->border-top: thin solid black;
<!-- -->border-bottom: thin solid black;
<!-- -->border-clip-top: 10px;
<!-- -->border-clip-bottom: 10px;
<!-- --></pre>
<div style="position: relative; width: 250px; height: 150px; background: white;">
<div style="border: 2px solid black; width: 200px; height: 100px; position: absolute; top: 20px; left: 20px">
<div style="position: absolute; background: white; left: 15px; top: -5px; height: 110px; width: 200px"></div>
<div style="position: absolute; background: white; left: -5px; top: 0px; height: 100px; width: 210px"></div>
</div>
</div>
</div>
<div class="example">
<pre>
border-top: thin solid black;
border-clip: 10px;
</pre>
<div style="position: relative; width: 250px; height: 150px; background: white;">
<div style="border: 2px solid black; width: 200px; height: 100px; position: absolute; top: 20px; left: 20px">
<div style="position: absolute; background: white; left: 15px; top: -5px; height: 110px; width: 200px"></div>
<div style="position: absolute; background: white; left: -5px; top: 0px; height: 110px; width: 210px"></div>
</div>
</div>
</div>
<div class="example">
<p>This rendering:
<div style="background: white; padding: 0.2em 0.5em">
<pre style="margin-left: 0">
A sentence consists of words¹.
</pre>
<div style="width: 3em; height: 2px; background: black"></div>
<pre style="margin-left: 0">
¹ Most often.
</pre>
</div>
can be achieved with this style sheet:
<pre>
@footnote {
border-top: thin solid black;
border-clip: 4em;
}
</pre>
</div>
<div class="example">
<pre>
border: 2px solid black;
border-top-parts: repeat(10px 10px);
</pre>
<p>In this example, the repeat pattern is shown five times and there is, by coincidence, no remaining border.
<div style="position: relative; width: 100px; background: white; padding: 20px">
<div style="border: 2px solid black; height: 40px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 30px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 50px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 70px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 90px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 110px"></div>
</div>
</div>
<div class="example">
<pre>
border: 2px solid black;
border-top-parts: repeat(10px 10px);
</pre>
<p>In this example, the repeat pattern is shown five times. The box in this example is slightly wider than the box in the previous example. The remaining border is taken up by a fraction, as if this code had been specified:
<pre>
border: 2px solid black;
border-top-parts: repeat(10px 10px) 1fr;
</pre>
<div style="position: relative; width: 105px; background: white; padding: 20px">
<div style="border: 2px solid black; height: 40px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 30px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 50px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 70px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 90px"></div>
<div style="position: absolute; background: white; width: 10px; height: 2px; top: 20px; left: 110px"></div>
<div style="position: absolute; background: red; width: 5px; height: 2px; top: 20px; left: 120px"></div>
</div>
<p>The fragment is shown in red for illustrative purposes; it should be shown in black by a compliant UA.
</div>
<div class="example">
<pre>
border: 4px solid black;
border-top-parts: 40px 20px 0 1fr repeat(20px 20px) 0 1fr 40px;
</pre>
<p>In this example, there will be a visible 40px border part on each end of the top border. Inside the 40px border parts, there will be an invisible border part of at least 20px. Inside these invisible border parts, there will be visible border parts, each 20px long with 20px invisible border parts between them.
<div style="position: relative; width: 192px; background: white; padding: 40px">
<div style="border: 4px solid black; height: 40px"></div>
<div style="position: absolute; background: white; width: 20px; height: 4px; top: 40px; left: 80px"></div>
<div style="position: absolute; background: red; width: 6px; height: 4px; top: 40px; left: 100px"></div>
<div style="position: absolute; background: white; width: 20px; height: 4px; top: 40px; left: 126px"></div>
<div style="position: absolute; background: white; width: 20px; height: 4px; top: 40px; left: 166px"></div>
<div style="position: absolute; background: red; width: 6px; height: 4px; top: 40px; left: 186px"></div>
</div>
<p>The fragments are shown in red for illustrative purposes; they should not be visible in compliant UAs.
</div>
<div class="example">
<pre>
border: 4px solid black;
border-top-parts: 40px 20px 0 1fr 20px 20px 0 1fr 40px;
</pre>
<p>In this example, there will be a visible 40px border part on each end of the top border. Inside the 40px border parts, there will be an invisible border part of at least 20px. Inside these invisible border parts, there will be visible border parts, each 20px long with 20px invisible border parts between them.
<div style="position: relative; width: 192px; background: white; padding: 40px">
<div style="border: 4px solid black; height: 40px"></div>
<div style="position: absolute; background: white; width: 20px; height: 4px; top: 40px; left: 80px"></div>
<div style="position: absolute; background: red; width: 6px; height: 4px; top: 40px; left: 100px"></div>
<div style="position: absolute; background: white; width: 20px; height: 4px; top: 40px; left: 126px"></div>
<div style="position: absolute; background: white; width: 20px; height: 4px; top: 40px; left: 166px"></div>
<div style="position: absolute; background: red; width: 6px; height: 4px; top: 40px; left: 186px"></div>
</div>
<p>The fragments are shown in red for illustrative purposes; they should not be visible in compliant UAs.
</div>
<div class="example">
<pre>
border: 4px solid black;
border-clip-top: 3fr 10px 2fr 10px 1fr 10px 10px 10px 1fr 10px 2fr 10px 3fr;
</pre>
<p>All but one of the visible border parts are represented as fractions in this example. The length of these border parts will change when the width of the element changes. Here is one rendering where 1fr ends up being 10px:
<div style=&q
77EC
uot;position: relative; width: 190px; background: white; padding: 40px">
<div style="border: 4px solid black; border-top: none; height: 40px"></div>
<div style="position: absolute; background: red; width: 30px; height: 4px; top: 40px; left: 40px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 70px"></div>
<div style="position: absolute; background: red; width: 20px; height: 4px; top: 40px; left: 80px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 100px"></div>
<div style="position: absolute; background: red; width: 10px; height: 4px; top: 40px; left: 110px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 120px"></div>
<div style="position: absolute; background: black; width: 10px; height: 4px; top: 40px; left: 130px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 140px"></div>
<div style="position: absolute; background: red; width: 10px; height: 4px; top: 40px; left: 150px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 160px"></div>
<div style="position: absolute; background: red; width: 20px; height: 4px; top: 40px; left: 170px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 190px"></div>
<div style="position: absolute; background: red; width: 30px; height: 4px; top: 40px; left: 200px"></div>
</div>
<p>Here is another rendering where 1fr ends up being 30px:
<div style="position: relative; width: 440px; background: white; padding: 40px">
<div style="border: 4px solid black; border-top: none; height: 40px"></div>
<div style="position: absolute; background: red; width: 90px; height: 4px; top: 40px; left: 40px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 130px"></div>
<div style="position: absolute; background: red; width: 60px; height: 4px; top: 40px; left: 140px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 200px"></div>
<div style="position: absolute; background: red; width: 30px; height: 4px; top: 40px; left: 210px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 240px"></div>
<div style="position: absolute; background: black; width: 10px; height: 4px; top: 40px; left: 250px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 260px"></div>
<div style="position: absolute; background: red; width: 30px; height: 4px; top: 40px; left: 270px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 300px"></div>
<div style="position: absolute; background: red; width: 60px; height: 4px; top: 40px; left: 310px"></div>
<div style="position: absolute; background: white; width: 10px; height: 4px; top: 40px; left: 370px"></div>
<div style="position: absolute; background: red; width: 90px; height: 4px; top: 40px; left: 390px"></div>
</div>
<p>The fragments are shown in red for illustrative purposes; they should be black in compliant UAs.
</div>
<h2 id="changes">
Changes</h2>
<h3 id="level-changes">
Additions Since Level 3</h3>
<p class="issue">Additions are a work in progress... here's what we're planning to add. :)
<ul>
<li>logical 'background-position' values (''start'', ''end'')
<li>the ''extend'' keyword of 'background-repeat'
<li>'corner-shape'
<li>multiple borders per element
<li>logical border properties
<li><a href="#partial-borders">Partial Borders</a> (make part of border shorthand as well!)
<li><a href="http://lists.w3.org/Archives/Public/www-style/2012Oct/0314.html">More 'border-radius' shorthands</a> for doing both corners on a side at once.
<li>Splitting horizontal / vertical spread radius for box-shadow, if we can come up with a sane syntax for it.
</ul>
<h2 id="acknowledgments">Acknowledgments</h2>
<p>In addition to the many contributors to the [[CSS1]], [[CSS21]],
and [[CSS3BG]] predecessors to this module,
the editors would like to thank
Tab Atkins,
and Håkon Wium Lie
for their suggestions and feedback specifically for this Level 4.