вравнивание по центру css

.parent1{
  width: 300px;
  height: 300px;
  background: black;
}

.chield1{
  background: orange;
  width: 100px;
  height: 100px;

}

/*metod 1*/

.p1{
  position: relative;
}

.c1 {
  position: absolute;
  /*top: 50%;*/
  left: 50%;
  transform: translate(-50%, 0);
}

/*metod 2*/

.p2 {
  position: relative;
}

.c2 {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  margin: auto;
}

.p3 {
  position: relative;
}

.c3 {
  position: absolute;
  inset: 0;
  margin: auto;
}

.p4 {
  display: flex;
  justify-content: center;
  /*align-items: center;*/
}

.c4 {
  align-self: center;
}

.p5 {
  display: flex;
}

.c5 {
  margin: auto;
}

.p6 {
  display: grid;
  justify-content: center;
  align-items: center;
}

.c6 {
}

.p7 {
  display: grid;
  place-items: center;
}

.c7 {
}

.p8 {
  display: grid;
}

.c8 {
  align-self: center;
  justify-self: center;
}

.p9 {
  display: grid;
}

.c9 {
  place-self: center;
}

.p10 {
  display: grid;
}

.c10 {
  margin: auto;
}