Tạo hiệu ứng chữ Neon tuyệt đẹp chỉ bằng CSS

CSS

/* bacsiwindowscom.blogspot.com */
body{
    user-select:none;
    overflow:hidden
}
.text-effect{
    overflow:hidden;
    position:relative;
    -webkit-filter:contrast(110%) brightness(190%);
    filter:contrast(110%) brightness(190%)
}
.neon-bsw-text{
    position:relative;
    background:black;
    color:transparent
}
.neon-bsw-text::before,.neon-bsw-text::after{
    content:attr(data-text);
    color:white;
    -webkit-filter:blur(0.02em);
    filter:blur(0.02em);
    position:absolute;
    top:0;
    left:0;
    pointer-events:none
}
.neon-bsw-text::after{
    mix-blend-mode:difference
}
.gradient,.spotlight-bsw-bg{
    position:absolute;
    top:0;
    left:0;
    bottom:0;
    right:0;
    pointer-events:none;
    z-index:10
}
.gradient{
    background:linear-gradient(45deg,red,blue);
    mix-blend-mode:multiply
}
.spotlight-bsw-bg{
    -webkit-animation:light 5s infinite linear;
    animation:light 5s infinite linear;
    background:radial-gradient(circle,white,transparent 25%) 0 0/25% 25%,radial-gradient(circle,white,black 25%) 50% 50%/12.5% 12.5%;
    top:-100%;
    left:-100%;
    mix-blend-mode:color-dodge
}
@-webkit-keyframes light{
    100%{
        -webkit-transform:translate3d(50%,50%,0);
        transform:translate3d(50%,50%,0)
    }
}
@keyframes light{
    100%{
        -webkit-transform:translate3d(50%,50%,0);
        transform:translate3d(50%,50%,0)
    }
}
.neon-bsw-text{
    font:700 220px '
    Roboto Slab'
    ,sans-serif;
    text-transform:uppercase;
    text-align:center;
    margin:0
}
.neon-bsw-text:focus{
    outline:none;
    border:1px dotted white
}
body{
    background:black;
    display:-webkit-box;
    display:-ms-flexbox;
    display:flex;
    min-height:100vh;
    -webkit-box-pack:center;
    -ms-flex-pack:center;
    justify-content:center;
    -ms-flex-line-pack:center;
    align-content:center;
    -webkit-box-align:center;
    -ms-flex-align:center;
    align-items:center
}

HTML

<div class='text-effect'>
  <h1 class='neon-bsw-text' data-text='Trường Nguyễn'>Trường Nguyễn</h1>
  <div class='gradient'/>
  <div class='spotlight-bsw-bg'/>
</div>

Result