<s>
Responsive	B-General_Concept
web	I-General_Concept
design	I-General_Concept
(	O
RWD	O
)	O
or	O
responsive	B-General_Concept
design	I-General_Concept
is	O
an	O
approach	O
to	O
web	O
design	O
that	O
aims	O
to	O
make	O
web	O
pages	O
render	O
well	O
on	O
a	O
variety	O
of	O
devices	O
and	O
window	O
or	O
screen	O
sizes	O
from	O
minimum	O
to	O
maximum	O
display	O
size	O
to	O
ensure	O
usability	O
and	O
satisfaction	O
.	O
</s>
<s>
A	O
responsive	B-General_Concept
design	I-General_Concept
adapts	O
the	O
web-page	O
layout	O
to	O
the	O
viewing	O
environment	O
by	O
using	O
techniques	O
such	O
as	O
fluid	O
proportion-based	O
grids	O
,	O
flexible	O
images	O
,	O
and	O
CSS3	O
media	O
queries	O
,	O
an	O
extension	O
of	O
the	O
@media	O
rule	O
,	O
in	O
the	O
following	O
ways	O
:	O
</s>
<s>
The	O
fluid	O
grid	O
concept	O
calls	O
for	O
page	O
element	B-General_Concept
sizing	O
to	O
be	O
in	O
relative	O
units	O
like	O
percentages	O
,	O
rather	O
than	O
absolute	O
units	O
like	O
pixels	B-Algorithm
or	O
points	O
.	O
</s>
<s>
Flexible	O
images	O
are	O
also	O
sized	O
in	O
relative	O
units	O
,	O
so	O
as	O
to	O
prevent	O
them	O
from	O
displaying	O
outside	O
their	O
containing	O
element	B-General_Concept
.	O
</s>
<s>
Responsive	B-General_Concept
web	I-General_Concept
design	I-General_Concept
became	O
more	O
important	O
as	O
users	O
of	O
mobile	O
devices	O
came	O
to	O
account	O
for	O
the	O
majority	O
of	O
website	O
visitors	O
.	O
</s>
<s>
In	O
2015	O
,	O
for	O
instance	O
,	O
Google	O
announced	O
Mobilegeddon	B-Application
and	O
started	O
to	O
boost	O
the	O
page	B-Algorithm
ranking	I-Algorithm
of	O
mobile-friendly	O
sites	O
when	O
searching	O
from	O
a	O
mobile	O
device	O
.	O
</s>
<s>
Responsive	B-General_Concept
web	I-General_Concept
design	I-General_Concept
is	O
an	O
example	O
of	O
user	O
interface	O
plasticity	O
.	O
</s>
<s>
Mobile-first	B-General_Concept
design	I-General_Concept
and	O
progressive	O
enhancement	O
are	O
related	O
concepts	O
that	O
predate	O
RWD	O
.	O
</s>
<s>
Browsers	O
of	O
basic	O
mobile	O
phones	O
do	O
not	O
understand	O
JavaScript	O
or	O
media	O
queries	O
,	O
so	O
a	O
recommended	O
practice	O
was	O
to	O
create	O
a	O
basic	O
web	O
site	O
and	O
enhance	O
it	O
for	O
smartphones	B-Application
and	O
personal	B-Device
computers	I-Device
,	O
rather	O
than	O
rely	O
on	O
graceful	B-General_Concept
degradation	I-General_Concept
to	O
make	O
a	O
complex	O
,	O
image-heavy	O
site	O
work	O
on	O
mobile	O
phones	O
.	O
</s>
<s>
He	O
suggested	O
that	O
,	O
compared	O
with	O
a	O
simple	O
HWD	O
approach	O
,	O
device	O
experience	O
or	O
RESS	O
(	O
responsive	B-General_Concept
web	I-General_Concept
design	I-General_Concept
with	O
server-side	O
components	O
)	O
approaches	O
can	O
provide	O
a	O
user	O
experience	O
that	O
is	O
better	O
optimized	O
for	O
mobile	O
devices	O
.	O
</s>
<s>
Server-side	O
CSS	O
generator	O
implementation	O
of	O
stylesheet	O
languages	O
like	O
Sass	B-Language
can	O
be	O
part	O
of	O
such	O
an	O
approach	O
.	O
</s>
<s>
Google	O
has	O
recommended	O
responsive	B-General_Concept
design	I-General_Concept
for	O
smartphone	B-Application
websites	O
over	O
other	O
approaches	O
.	O
</s>
<s>
Although	O
many	O
publishers	O
have	O
implemented	O
responsive	B-General_Concept
designs	I-General_Concept
,	O
one	O
challenge	O
for	O
RWD	O
adoption	O
was	O
that	O
some	O
banner	O
advertisements	O
and	O
videos	O
were	O
not	O
fluid	O
.	O
</s>
<s>
However	O
,	O
search	O
advertising	O
and	O
(	O
banner	O
)	O
display	O
advertising	O
came	O
to	O
support	O
specific	O
device	O
platform	O
targeting	O
and	O
different	O
advertisement	O
size	O
formats	O
for	O
desktop	O
,	O
smartphone	B-Application
,	O
and	O
basic	O
mobile	O
devices	O
.	O
</s>
<s>
Different	O
landing	O
page	O
URLs	O
have	O
been	O
used	O
for	O
different	O
platforms	O
,	O
or	O
Ajax	B-General_Concept
has	O
been	O
used	O
to	O
display	O
different	O
advertisement	O
variants	O
on	O
a	O
page	O
.	O
</s>
<s>
The	O
Chrome	O
,	O
Firefox	O
and	O
Safari	O
browsers	O
and	O
developer	O
tools	O
have	O
offered	O
responsive	B-General_Concept
design	I-General_Concept
viewport	O
resizing	O
tools	O
,	O
as	O
do	O
third	O
parties	O
.	O
</s>
<s>
Many	O
web	O
developers	O
resorted	O
to	O
ordinary	O
HTML	B-General_Concept
tables	I-General_Concept
as	O
a	O
way	O
to	O
customize	O
the	O
layout	O
and	O
bring	O
some	O
basic	O
responsiveness	O
to	O
their	O
websites	O
at	O
the	O
same	O
time	O
.	O
</s>
<s>
Ethan	O
Marcotte	O
coined	O
the	O
term	O
responsive	B-General_Concept
web	I-General_Concept
design	I-General_Concept
—	O
and	O
defined	O
it	O
to	O
mean	O
fluid	O
grid	O
/	O
flexible	O
images	O
/	O
media	O
queries	O
—	O
in	O
a	O
May	O
2010	O
article	O
in	O
A	O
List	O
Apart	O
.	O
</s>
<s>
He	O
described	O
the	O
theory	O
and	O
practice	O
of	O
responsive	B-General_Concept
web	I-General_Concept
design	I-General_Concept
in	O
his	O
brief	O
2011	O
book	O
titled	O
Responsive	B-General_Concept
Web	I-General_Concept
Design	I-General_Concept
.	O
</s>
<s>
Responsive	B-General_Concept
design	I-General_Concept
was	O
listed	O
as	O
#2	O
in	O
Top	O
Web	O
Design	O
Trends	O
for	O
2012	O
by	O
.net	O
magazine	O
after	O
progressive	O
enhancement	O
at	O
#1	O
.	O
</s>
<s>
Mashable	O
called	O
2013	O
the	O
Year	O
of	O
Responsive	B-General_Concept
Web	I-General_Concept
Design	I-General_Concept
.	O
</s>
