webkit justify-content center not working code example

Example 1: justify content css

/* Positional alignment */
justify-content: center;     /* Pack items around the center */
justify-content: start;      /* Pack items from the start */
justify-content: end;        /* Pack items from the end */
justify-content: flex-start; /* Pack flex items from the start */
justify-content: flex-end;   /* Pack flex items from the end */
justify-content: left;       /* Pack items from the left */
justify-content: right;      /* Pack items from the right */

/* Baseline alignment */
/* justify-content does not take baseline values */

/* Normal alignment */
justify-content: normal;

/* Distributed alignment */
justify-content: space-between; /* Distribute items evenly
                                   The first item is flush with the start,
                                   the last is flush with the end */
justify-content: space-around;  /* Distribute items evenly
                                   Items have a half-size space
                                   on either end */
justify-content: space-evenly;  /* Distribute items evenly
                                   Items have equal space around them */
justify-content: stretch;       /* Distribute items evenly
                                   Stretch 'auto'-sized items to fit
                                   the container */

/* Overflow alignment */
justify-content: safe center;
justify-content: unsafe center;

/* Global values */
justify-content: inherit;
justify-content: initial;
justify-content: unset;

Example 2: justify content

/* Positional alignment */
justify-content: center;     /* Pack items around the center */
justify-content: start;      /* Pack items from the start */
justify-content: end;        /* Pack items from the end */
justify-content: flex-start; /* Pack flex items from the start */
justify-content: flex-end;   /* Pack flex items from the end */
justify-content: left;       /* Pack items from the left */
justify-content: right;      /* Pack items from the right */

/* Baseline alignment */
/* justify-content does not take baseline values */

/* Normal alignment */
justify-content: normal;

/* Distributed alignment */
justify-content: space-between; /* Distribute items evenly
                                   The first item is flush with the start,
                                   the last is flush with the end */
justify-content: space-around;  /* Distribute items evenly
                                   Items have a half-size space
                                   on either end */
justify-content: space-evenly;  /* Distribute items evenly
                                   Items have equal space around them */
justify-content: stretch;       /* Distribute items evenly
                                   Stretch 'auto'-sized items to fit
                                   the container */

/* Overflow alignment */
justify-content: safe center;
justify-content: unsafe center;

/* Global values */
justify-content: inherit;
justify-content: initial;
justify-content: unset;

Example 3: gap between two flex items

.upper
{
  margin:30px;
  display:flex;
  flex-direction:row;
  width:300px;
  height:80px;
  border:1px red solid;

  padding:5px; /* this */
}

.upper > div
{
  flex:1 1 auto;
  border:1px red solid;
  text-align:center;

  margin:5px;  /* and that, will result in a 10px gap */
}

.upper.mc /* multicol test */
{flex-direction:column;flex-wrap:wrap;width:200px;height:200px;}