How to create a full width triangle at the bottom?

Question

I want just to do that:

However I have a lot of troubles to do it with css... Someone can help me?

This is my better try:

.flag.vertical {
    background-color: #dd7758;
    height: 0;
    padding-bottom: 25px;
    text-align: center;
    color: white;
    border-style: solid;
    border-width: 0 10px 10px 10px;
    border-color: transparent transparent white transparent;
}

<div class="flag-wrapper"><span class="flag vertical">-5%</span></div>

My doubts are about to make this white triangle on the bottom. Doesn't matter here the vertical align of the text and the font family.

Answer 1

Here is an idea with gradient where it will be responsive and you will have better support than clip path:

.flag-wrapper {
    background-color: #dd7758;
    padding:10px 5px 30px;
    margin:10px;
    text-align: center;
    color: white;
    display:inline-block;
    background:
      linear-gradient(to top left,transparent 48%,#dd7758 50%) bottom left/50% 15px,
      linear-gradient(to top right,transparent 48%,#dd7758 50%) bottom right/50% 15px,
      linear-gradient(#dd7758,#dd7758)top/100% calc(100% - 15px);
    background-repeat:no-repeat;
}

body {
  background:#ccc;
}

<div class="flag-wrapper">-5%</div>
<div class="flag-wrapper">-25%</div>
<div class="flag-wrapper">-100%</div>

You can also make it working with image as background but you lose transparency:

.flag-wrapper {
    background-color: #dd7758;
    padding:10px 5px 30px;
    margin:10px;
    text-align: center;
    color: white;
    display:inline-block;
    background:
      linear-gradient(to bottom right,transparent 48%,#ccc 50%) bottom left/50.1% 15px,
      linear-gradient(to bottom left,transparent 48%,#ccc 50%) bottom right/50.1% 15px,
     url(https://picsum.photos/200/300?image=1069)center/cover;
    background-repeat:no-repeat;
}

body {
  background:#ccc;
}

<div class="flag-wrapper">-5%</div>
<div class="flag-wrapper">-25%</div>
<div class="flag-wrapper">-100%</div>