Answers for "flex 1 with responsive"

responsive flexbox in css

.flex-container {
  display: flex;
  flex-direction: row;
}

/* Responsive layout - makes a one column layout instead of a two-column layout */
@media (max-width: 800px) {
  .flex-container {
    flex-direction: column;
  }
}

flex item: 1;

The default values are set to 1 1 0% (which are the shorthand values for flex-grow flex-shrink flex-basis respectively) probably because these are the values that make the most sense for "flex" items. Here are what exactly those values mean: