df_color.py

import matplotlib 

def bg_color(value, min_, max_, center_=None):
    min_ = float(min_)
    max_ = float(max_)

    if center_ is None:
        center_ = (max_ - min_) / 2
    cmap = matplotlib.cm.get_cmap('coolwarm')

    vv = 0
    if value < center_:
        v = (center_ - value) / (center_ - min_)
        vv  = 0.5 - (0.5 * v)
    else:
        v = (value - center_) / (max_ - center_)
        vv = 0.5 + (0.5 * v)
    if vv > 1:
        return 'background-color: {}'.format('#111111')
    return 'background-color: {}'.format(matplotlib.colors.to_hex(cmap(vv)))

print(bg_color(-0.5, -1, 1, 0))
print(bg_color(0, -1, 1, 0))
print(bg_color(1, -1, 1, 0))

#8db0fe
#dddcdc
#b40426
df.corr().style.applymap(lambda x: bg_color(x, -1, 0.999, 0))