.loader {
    width: 96px;
    height: 96px;
    border: 20px solid #FFF;
    border-radius: 50%;
    position: relative;
    transform: rotate(45deg);
    box-sizing: border-box;
}
.loader::before {
    content: "";
    position: absolute;
    box-sizing: border-box;
    inset: -20px;
    border-radius: 50%;
    border: 20px solid #FF3D00;
    animation: prixClipFix 2s infinite linear;
}

    @keyframes prixClipFix {
        0%   {clip-path:polygon(50% 50%,0 0,0 0,0 0,0 0,0 0)}
        25%  {clip-path:polygon(50% 50%,0 0,100% 0,100% 0,100% 0,100% 0)}
        50%  {clip-path:polygon(50% 50%,0 0,100% 0,100% 100%,100% 100%,100% 100%)}
        75%  {clip-path:polygon(50% 50%,0 0,100% 0,100% 100%,0 100%,0 100%)}
        100% {clip-path:polygon(50% 50%,0 0,100% 0,100% 100%,0 100%,0 0)}
    }