A complete guide to some uncommon but useful CSS attribute operations

::selection {
  background: red;
  color: black;
}

video::-internal-media-controls-download-button {
    display:none;
}

video::-webkit-media-controls-enclosure {
    overflow:hidden;
}

video::-webkit-media-controls-panel {
    width: calc(100% + 30px); 
}

/* * You can change other selectors*/
*::-webkit-scrollbar {
    width: 2px;
  height: 2px;
}
*::-webkit-scrollbar-thumb {
  border-radius: 5px;
  box-shadow: inset 0 0 5px rgba(0, 0, 0, 0.2);
    -webkit-box-shadow: inset 0 0 5px rgba(0, 0, 0, 0.2);
  background: #00063a;
}
*::-webkit-scrollbar-track {
  box-shadow: inset 0 0 5px rgba(0, 0, 0, 0.2);
    -webkit-box-shadow: inset 0 0 5px rgba(0, 0, 0, 0.2);
    border-radius: 0;
  background: #00063a;
}

input::-webkit-outer-spin-button,
input::-webkit-inner-spin-button {
    -webkit-appearance: none;
}
input[type="number"]{
    -moz-appearance:textfield;
}

<style>
    .box {
        width: 150px;
        border: 2px dashed #fff;
        background: linear-gradient(to bottom, #34538b, #cd0000);
        background-origin: border-box;
    }
    .content {
        height: 100px;
        background-color: #fff;
    }
</style>
<div class="box">
    <div class="content"></div>
</div> 

<style type="text/css">
	.content { 
		width: 100px; 
	   	height: 100px; 
	    box-sizing: border-box; 
	    padding: 5px; 
	    border-radius: 50%; 
	    background-image: -webkit-linear-gradient(top, red 0%, blue 30%, yellow 60%, green 90%);  
	    background-image: -moz-linear-gradient(top, red 0%, blue 30%, yellow 60%, green 90%); 
	    background-image: linear-gradient(top, red 0%, blue 30%, yellow 60%, green 90%);  
	}
	.box { 
		width:100%; 
	    height:100%; 
	    border-radius:50%; 
	    background:#fff; 
	}
</style>
<div class="content">
	<div class="box"></div>
</div> 

input{
    caret-color: red;
} 

.box {
    width: 300px; height: 300px;
    background: conic-gradient(from 45deg, white, black, white);
} 

wavy
    display: block;
    height: .5em;
    white-space: nowrap;
    letter-spacing: 100vw;
    padding-top: .5em;
    overflow: hidden;
}
wavy::before {
    content: "\2000\2000";
    /* IE browser solid line instead*/
    text-decoration: overline;
    /* Modern browsers */
    text-decoration: overline wavy;
} 

<style type="text/css" media="screen">
.div1{
	width: 0;
	height: 0;
	border: 100px solid;
	<!--Top right bottom left-->
	border-color: red transparent transparent transparent;
}
</style>
<div class="div1"></div> 

background: url(https://img.alicdn.com/imgextra/i4/1881744325/O1CN01JBktT81hotb8c6Py0_!!1881744325.png) center no-repeat, linear-gradient(to bottom, red, #3c3f40); 

/*Define the scroll bar width, height and background. The width and height correspond to the size of the horizontal and vertical scroll bars respectively*/
::-webkit-scrollbar {
    width: 5px;
    height: 5px;
    background-color: rgba(245, 245, 245, 0.47);
}
 
/*Define the scroll bar track, inner shadow and rounded corners*/
::-webkit-scrollbar-track {
    -webkit-box-shadow: inset 0 0 6px rgba(0, 0, 0, .3);
    border-radius: 10px;
    background-color: #f5f5f5;
}
 
/*Define slider, inner shadow and rounded corners*/
::-webkit-scrollbar-thumb {
    /*width: 10px;*/
    height: 20px;
    border-radius: 10px;
    -webkit-box-shadow: inset 0 0 6px rgba(0, 0, 0, .3);
    background-color: rgba(85, 85, 85, 0.25);
}

input::-webkit-input-placeholder { 
    /* WebKit browsers */ 
    font-size:14px;
    color: #333;
} 
input::-moz-placeholder { 
    /* Mozilla Firefox 19+ */ 
    font-size:14px;
    color: #333;
} 
input:-ms-input-placeholder { 
    /* Internet Explorer 10+ */ 
    font-size:14px;
    color: #333;
}