/* flex布局 */
*{
    padding: 0; margin: 0;
    box-sizing: border-box;
}
.d-flex{ display: flex; }
.d-block{ display: block; }
.d-inline-block{ display: inline-block; }

.flex-1{ flex: 1; }
.flex-column{ flex-direction: column; }
.flex-row{ flex-direction: row; }
.flex-wrap{ flex-wrap: wrap; }
.flex-nowrap{ flex-wrap: nowrap; }
.flex-shrink{flex-shrink: 0;}
.j-start{ justify-content: flex-start; }
.j-center{ justify-content: center; }
.j-end{ justify-content: flex-end; }
.j-sb{ justify-content: space-between; }
.a-center{ align-items:center; }
.a-start{ align-items: flex-start; }
.a-end{ align-items:flex-end; }
.a-stretch{ align-items: stretch; }
.a-self-start{ align-self: flex-start; }
.a-self-auto{ align-self: auto; }
.a-self-end{ align-self: flex-end; }
.a-self-stretch{ align-self:stretch; }
.a-self-baseline{ align-self:baseline; }