print(const char[]) doesn't know that your const char[] is in PROGMEM
use the PROGMEM version of print() by casting the parameter to __FlashStringHelper used by F() macro
client.println((__FlashStringHelper*) StyleHTML);
print(const char[]) doesn't know that your const char[] is in PROGMEM
use the PROGMEM version of print() by casting the parameter to __FlashStringHelper used by F() macro
client.println((__FlashStringHelper*) StyleHTML);