<style> .rainbow-text { background-image: repeating-linear-gradient(90deg, violet, indigo, blue, green, yellow, orange, red, violet, indigo, blue, green, yellow, orange, red, violet); text-align: center; background-size: 200% 100%; -webkit-background-clip: text; -webkit-text-fill-color: transparent; font-size: 24px; animation: rainbow 2s linear infinite; } @keyframes rainbow { 0%{background-position:0%} 100%{background-position:100%} } </style>

<span class="rainbow-text">testificate</span>