Sargi is a pre-sunrise meal prepared for you by your mother-in-law. Karva Chauth Sargi is a balanced and energy-rich diet consisting of sweets like milk, dry fruits etc.
In Hindu customs, black is considered an inauspicious color during any worship. That's why wearing black clothes is not considered a good thing.
As mentioned earlier, your day can feel overwhelming and endless, so don't overwork yourself before the end of the day.
Married women and their family members should avoid eating non-vegetarian dishes on the day of Karva Chauth as they are considered to be tamasic in nature.