In one sentence, describe what the following article is about:

For a blonde shade, use cassia powder with water or citrus juice. For strawberry blonde, add henna. Use pure cassia powder for blonde, or 80% cassia powder and 20% henna powder for strawberry blonde. Use water to transform the powder into a paste, or if you want an extra lightening effect, orange or lemon juice. Add liquid to the powder a little at a time until its consistency is similar to yogurt. Put the mixture in the refrigerator and let it sit for twelve hours. Use cassia obovata for blonde or gray hair. If you have gray hairs but the rest of your hair is darker than blonde, cassia obovata alone will only brighten and condition your darker hair, not lighten it to blonde. Use one box (100 grams) of cassia powder for short hair. Use two to three boxes (200-300 grams) of cassia powder for shoulder-length hair. Use four to five boxes (400-500 grams) of cassia powder for long hair. Mix into henna powder three teaspoons of amla powder, one teaspoon of coffee powder, and a little bit of curd or plain yogurt. Stir the ingredients well. Slowly add one to two cups of hot water (not boiling) to the henna paste in a bowl until the paste is thick, not runny. Mix the contents. Close the bowl with a lid or tight plastic wrap. Let it sit for twelve hours to twenty-four hours, unrefrigerated before using it on your hair. Amla (Indian gooseberry) is nondrying and adds coolness to the red so that it is not quite so bright. You can omit the amla if you want a very vibrant orange-red. Amla volumizes hair as well as enhances texture and curls. Use 100 grams of henna powder for hair up to medium length, or 200 grams of henna for long hair. Henna can be drying, so you may want to add a conditioner to the paste the next morning, such as two to three tablespoons of olive oil and 1/5 cup moisturizing conditioner. Once henna paste has sat for twelve to twenty-four hours, mix in indigo powder well. If the paste is not the consistency of thick yogurt, add warm water little by little until you achieve the right texture. Let the paste sit for fifteen minutes. If you have short hair, use one box (100 grams) of indigo. If you have shoulder-length hair, use two to three boxes (200-300 grams) of indigo. If you have long hair, use four to five boxes (400 to 500 grams) of indigo. Put gloves on. Section your hair and apply the paste to damp or dry hair with your gloved hands, a pastry brush, or a coloring brush from a beauty supply store. Make sure that you cover all of your hair to the roots. You may find it handy to clip sections of hair back once you've finished coating them. Henna paste is thick, so don't try to rake it through your hair. Apply the paste to the roots of your hair first, since that is typically where the most hue and processing time is needed. If you have long hair, you may want to pull it up first into a clip. Use plastic wrap or a shower cap to protect the dye. For red hair, leave the paste on for about four hours. For brown or black hair, leave the paste in your hair for one to six hours. You can check the color by scraping off a little bit of the henna to see the result. When you've reached your desired color, you can rinse off the henna. Wear gloves when you're rinsing out the dye, or it will stain your hands. Use a mild shampoo to wash your hair. You can use moisturizing conditioner afterwards if desired. For red hair, you can dry and style as usual. For black hair, you'll follow this with indigo dye. Add warm water to indigo powder little by little until you achieve a yogurt-like consistency. Mix in one teaspoon of salt per 100 grams of indigo powder. Let the paste sit for fifteen minutes. Apply the paste to damp or dry hair. Wear gloves. Put the paste on in sections, starting at the back of your head and moving forward. Coat the hair thoroughly to the roots. For short hair, use one box (100 grams) of indigo. For shoulder-length hair, use two to three boxes (200-300 grams) of indigo. For long hair, use four to five boxes (400 to 500 grams) of indigo. Once your hair is saturated with the paste, use a clip or hair pin to put your hair up. Wrap plastic wrap or a shower cap over your head. Let the paste sit in your hair for one to two hours. After one to two hours of processing time, rinse the paste completely out. You can use conditioner if desired. Dry and style your hair as usual.
Consider cassia obovata to get blonde to strawberry blonde hair. Prepare henna paste for red, brown or black hair. Add indigo powder to the paste for brown hair. Apply the paste to your hair. Cover your hair and let the paste soak in. Rinse out the paste thoroughly. Follow with indigo paste to get black hair.