Arduino uno "dies" with CSS code

Dear Mates,

I would like to share my problem and ask if anybody has idea what can cause it.
I am using an arduino uno with ethernet shield to make a web server in order to be able to switch on-off a relay through the web page.
Normally the solution works well, but the web page looks so small on mobile device browser, so I wanted to make style to the html using css. The same thing works well if I save this page into html file and open on PC.
However when I insert the CSS code into the arduino sketch (sketch attached), it will not work any more. Even the arduino will not respond to a a ping at all. It seems the execution "dies" after Serial.begin(9600);
Another interesting point:
If I remove these 2 lines from the sketch:
client.println("<form method="get">");
client.println("");

Then it will already answer for ping, but webserver does not start at all. Probabaly it will die after this command: Ethernet.begin(mac, ip);

Do you have any idea what can cause this?
Maybe some memory problem?
The sketch size itself is round 16k.

Thanks for any comments,
Andras

sketch.txt (8.03 KB)

You've got a lot of HTML in RAM, when it could/should be in flash.
Could that be the problem?

Also if you use CSS in the page the browser is likely to come back with a GET for the .css
file concurrent with the page fetch (browsers are multi-threaded these days), which is
going to complicate things.

If your page body is small enough to fit in one TCP packet and you use "Connection: close"
that will probably help keep things saner.

Thanks for your answers. Yes, probably the problem is the lack of RAM.

I have just found on this page a very good example for webserver:
http://playground.arduino.cc/Code/WebServer

Can you tell how to set up the WebServer.h ?
There is no WebServer.cpp attached.. and also during compile I have error:
WebServer.h: No such file or directory

I put the WebServer.h file in the sketch folder.

thanks for suggestion

Actually I put the WebServer.h into wrong place.
It should be under the Libraries folder in sketch folder, default: C:\Users\user\Documents\Arduino\libraries