Bug reproduction

tinycss2bug.py

from tinycss2 import *
stylecss=parse_stylesheet("""#a1{
    fill: #000000;
}
#a2{
    fill: #FFFFFF;
}""",skip_whitespace=True)
print(stylecss[0].content[4].value)
print(stylecss[1].content[4].value)
stylecss[0].content[4].value="FFFFFF"
stylecss[1].content[4].value="000000"
print(stylecss[0].content[4].value)
print(stylecss[1].content[4].value)
final=serialize(stylecss)
print(final)

### OUTPUT
# 000000
# FFFFFF
# FFFFFF
# 000000
# #a1{
#     fill: #FFFFFF;
# }#a2{
#     fill: #\30 00000;
# }