css之制作三角形

箭头向上三角形

#triangle-up {
    width: 0;
    height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-bottom: 100px solid red;
}

箭头向下三角形

#triangle-down {
    width: 0;
    height: 0;
    border-left: 50px solid transparent;
    border-right: 50px solid transparent;
    border-top: 100px solid red;
}

箭头向左三角形

#triangle-left {
    width: 0;
    height: 0;
    border-top: 50px solid transparent;
    border-right: 100px solid red;
    border-bottom: 50px solid transparent;
}

箭头向右三角形

#triangle-right {
    width: 0;
    height: 0;
    border-top: 50px solid transparent;
    大专栏  css之制作三角形rule">border-left: 100px solid red;
    border-bottom: 50px solid transparent;
}

左上角三角形

#triangle-topleft {
    width: 0;
    height: 0;
    border-top: 100px solid red;
    border-right: 100px solid transparent;
}

右上角三角形

#triangle-topright {
    width: 0;
    height: 0;
    border-top: 100px solid red;
    border-left: 100px solid transparent; 
}

左下角三角形

#triangle-bottomleft {
    width: 0;
    height: 0;
    border-bottom: 100px solid red;
    border-right: 100px solid transparent;
}

右下角三角形

#triangle-bottomright {
    width: 0;
    height: 0;
    border-bottom: 100px solid red;
    border-left: 100px solid transparent;
}