How to add an offsetted outline to a CSS shape?

问题

I have a bit of a problem with creating a block with beveled edges, in addition I need a border to be beveled and slightly off the main block. The problem is that this block can be Reponsive according to the screen.

I do not know the exact way to do it, hope everyone helps.

This is what I do now

.box {
  display: flex;
  padding: 20px;
  height: 200px;
  width: 300px;
  color: #ffffff;
  background: red;
  position: relative;
}

.box .edge {
  width: 18px;
  height: 10px;
  background: #ffffff;
  position: absolute;
}

.box .edge.top-left {
  top: -4px;
  left: -8px;
  transform: rotate(-45deg);
}

.box .edge.top-right {
  top: -4px;
  right: -8px;
  transform: rotate(45deg);
}

.box .edge.bottom-left {
  bottom: -4px;
  left: -8px;
  transform: rotate(45deg);
}

.box .edge.bottom-right {
  bottom: -4px;
  right: -8px;
  transform: rotate(-45deg);
}

<div class="box">
  <div class="edge top-left"></div>
  <div class="edge top-right"></div>
  <div class="edge bottom-left"></div>
  <div class="edge bottom-right"></div>
  <div class="content">
    content
  </div>
</div>

回答1:

Here is an idea based on this previous answer. Simply adjust the different variables to get the result you want:

.box {
  --c:10px; /* the corner */
  --b:3px;  /* border thickness*/
  --o:-10px,-15px; /* offset*/
  --border-color:green;
  --bg-color:red;

  width: 200px;
  height: 100px;
  display:inline-block;
  margin:30px;
  position:relative;
  z-index:0;
}

.box:before,
.box:after{
  content:"";
  position:absolute;
  z-index:-1;
  top:0;
  left:0;
  right:0;
  bottom:0;
  clip-path: polygon(var(--c) 0%, calc(100% - var(--c)) 0%, 100% var(--c), 100% calc(100% - var(--c)), calc(100% - var(--c)) 100%, var(--c) 100%, 0% calc(100% - var(--c)), 0% var(--c));
  background:var(--bg-color);
}

.box:after {
  --grad:transparent 49.5%,var(--border-color) 50%;
  background: 
    linear-gradient(to top right   ,var(--grad)) top    right,
    linear-gradient(to top left    ,var(--grad)) top    left,
    linear-gradient(to bottom right,var(--grad)) bottom right,
    linear-gradient(to bottom left ,var(--grad)) bottom left;
  background-size:calc(var(--c) - var(--b)) calc(var(--c) - var(--b));
  background-repeat:no-repeat;
  border: var(--b) solid var(--border-color);
  transform:translate(var(--o));
}

<div class='box'></div>

<div class='box' style="--c:40px;--b:2px;--o:10px,-20px;--border-color:blue;--bg-color:orange"></div>

回答2:

You can use outline property to create border which can give create border off the main block using outline-offset property. And hide the overflow element at the corner side using overflow:hidden property.

For example:

.box{
     outline:5px solid black;
     outline-offset:5px;
     overflow:hidden;
    }

来源：https://stackoverflow.com/questions/62945968/how-to-add-an-offsetted-outline-to-a-css-shape

标签

html

css

css-shapes