OTP verification UI animation | HTML, CSS & JavaScript

<h1>OTP Verification</h1>
    <p class="subtitle">
        Enter the 6-digit verification code sent to your mobile number
    </p>

<button class="verify-btn">Verify OTP</button>

<div class="timer">
        <div class="dot"></div>
        <span>Code expires in 00:59</span>
    </div>

<div class="footer">
        Didn't receive the code? <a href="#">Resend OTP</a>
    </div>
</div>

*{
    margin:0;
    padding:0;
    box-sizing:border-box;
}

body{
    min-height:100vh;
    display:flex;
    align-items:center;
    justify-content:center;
    font-family:'Inter',sans-serif;
    background: radial-gradient(circle at top left,#1e3a8a,#0f172a 60%,#020617);
    overflow:hidden;
}

/* Animated background */
body::before,
body::after{
    content:'';
    position:absolute;
    width:400px;
    height:400px;
    border-radius:50%;
    filter:blur(80px);
    animation: float 8s ease-in-out infinite;
}

body::before{
    background:#3b82f6;
    top:-120px;
    left:-120px;
}

body::after{
    background:#8b5cf6;
    bottom:-120px;
    right:-120px;
    animation-delay:-4s;
}

@keyframes float{
    0%,100%{transform:translateY(0) scale(1);}
    50%{transform:translateY(20px) scale(1.1);}
}

.card{
    position:relative;
    width:420px;
    padding:40px 35px;
    border-radius:28px;
    background:rgba(255,255,255,0.08);
    backdrop-filter:blur(20px);
    border:1px solid rgba(255,255,255,0.15);
    box-shadow:
        0 25px 60px rgba(0,0,0,0.45),
        inset 0 1px 0 rgba(255,255,255,0.1);
    z-index:2;
    overflow:hidden;
}

/* Animated border */
.card::before{
    content:'';
    position:absolute;
    inset:-2px;
    border-radius:30px;
    background:linear-gradient(90deg,#3b82f6,#8b5cf6,#06b6d4,#3b82f6);
    background-size:300% 300%;
    animation:borderMove 6s linear infinite;
    z-index:-1;
}

.card::after{
    content:'';
    position:absolute;
    inset:2px;
    border-radius:26px;
    background:rgba(15,23,42,0.92);
    z-index:-1;
}

@keyframes borderMove{
    0%{background-position:0% 50%;}
    100%{background-position:300% 50%;}
}

.icon{
    width:72px;
    height:72px;
    margin:0 auto 24px;
    border-radius:22px;
    display:flex;
    align-items:center;
    justify-content:center;
    background:linear-gradient(135deg,#2563eb,#7c3aed);
    box-shadow:0 10px 30px rgba(59,130,246,0.45);
    animation:pulse 2s infinite;
}

.icon svg{
    width:34px;
    height:34px;
    fill:white;
}

@keyframes pulse{
    0%,100%{transform:scale(1);}
    50%{transform:scale(1.08);}
}

h1{
    color:#fff;
    text-align:center;
    font-size:28px;
    margin-bottom:10px;
}

.subtitle{
    color:#94a3b8;
    text-align:center;
    line-height:1.6;
    margin-bottom:30px;
    font-size:14px;
}

.otp-wrapper{
    display:flex;
    justify-content:center;
    gap:12px;
    margin-bottom:30px;
}

.otp-box{
    position:relative;
}

.otp-box input{
    width:52px;
    height:64px;
    border:none;
    outline:none;
    border-radius:18px;
    background:rgba(255,255,255,0.06);
    border:2px solid rgba(255,255,255,0.08);
    color:#fff;
    font-size:24px;
    font-weight:700;
    text-align:center;
    transition:all 0.3s ease;
    box-shadow:
        inset 0 2px 6px rgba(0,0,0,0.25),
        0 4px 10px rgba(0,0,0,0.2);
}

/* Interactive focus animation */
.otp-box input:focus{
    transform:translateY(-6px) scale(1.05);
    border-color:#60a5fa;
    background:rgba(59,130,246,0.12);
    box-shadow:
        0 0 0 4px rgba(96,165,250,0.15),
        0 0 25px rgba(96,165,250,0.45),
        inset 0 2px 6px rgba(255,255,255,0.08);
}

/* Floating glow ring */
.otp-box::after{
    content:'';
    position:absolute;
    inset:-6px;
    border-radius:22px;
    background:linear-gradient(135deg,#3b82f6,#8b5cf6);
    opacity:0;
    filter:blur(12px);
    transition:0.3s;
    z-index:-1;
}

.otp-box:has(input:focus)::after{
    opacity:0.9;
}

/* Verify button */
.verify-btn{
    width:100%;
    padding:16px;
    border:none;
    border-radius:18px;
    font-size:16px;
    font-weight:700;
    color:#fff;
    cursor:pointer;
    background:linear-gradient(135deg,#2563eb,#7c3aed);
    position:relative;
    overflow:hidden;
    transition:all 0.3s ease;
    box-shadow:0 10px 25px rgba(37,99,235,0.35);
}

.verify-btn:hover{
    transform:translateY(-3px);
    box-shadow:0 16px 35px rgba(37,99,235,0.5);
}

.verify-btn::before{
    content:'';
    position:absolute;
    top:0;
    left:-120%;
    width:100%;
    height:100%;
    background:linear-gradient(90deg,transparent,rgba(255,255,255,0.35),transparent);
    transition:0.7s;
}

.verify-btn:hover::before{
    left:120%;
}

.footer{
    margin-top:24px;
    text-align:center;
    color:#94a3b8;
    font-size:13px;
}

.footer a{
    color:#60a5fa;
    text-decoration:none;
    font-weight:600;
}

.timer{
    display:flex;
    justify-content:center;
    align-items:center;
    gap:8px;
    margin-top:18px;
    color:#cbd5e1;
    font-size:14px;
}

.timer .dot{
    width:8px;
    height:8px;
    border-radius:50%;
    background:#22c55e;
    animation:blink 1.2s infinite;
}

@keyframes blink{
    0%,100%{opacity:1;}
    50%{opacity:0.2;}
}

/*==============================
SUCCESS & ERROR MESSAGE
===============================*/

.message{
    margin-top:22px;
    padding:16px 18px;
    border-radius:18px;
    display:flex;
    align-items:center;
    gap:14px;
    font-size:15px;
    font-weight:600;
    overflow:hidden;
    position:relative;
    animation:slideUp .6s ease;
}

.message::before{
    content:"";
    position:absolute;
    top:0;
    left:0;
    width:5px;
    height:100%;
}

.success{
    background:rgba(34,197,94,.12);
    border:1px solid rgba(34,197,94,.35);
    color:#86efac;
    box-shadow:0 0 25px rgba(34,197,94,.15);
}

.success::before{
    background:#22c55e;
}

.error{
    background:rgba(239,68,68,.12);
    border:1px solid rgba(239,68,68,.35);
    color:#fca5a5;
    box-shadow:0 0 25px rgba(239,68,68,.15);
    animation:shake .45s;
}

.error::before{
    background:#ef4444;
}

.msg-icon{
    width:46px;
    height:46px;
    border-radius:50%;
    display:flex;
    align-items:center;
    justify-content:center;
    font-size:24px;
    flex-shrink:0;
}

.success .msg-icon{
    background:#22c55e;
    color:#fff;
    animation:successPulse 1.5s infinite;
}

.error .msg-icon{
    background:#ef4444;
    color:#fff;
}

.message h3{
    color:#fff;
    margin-bottom:4px;
    font-size:16px;
}

.message p{
    color:#cbd5e1;
    font-size:13px;
    line-height:1.5;
}

@keyframes slideUp{
    from{
        opacity:0;
        transform:translateY(20px);
    }
    to{
        opacity:1;
        transform:translateY(0);
    }
}

@keyframes successPulse{
    0%,100%{
        transform:scale(1);
        box-shadow:0 0 0 rgba(34,197,94,.4);
    }
    50%{
        transform:scale(1.08);
        box-shadow:0 0 18px rgba(34,197,94,.6);
    }
}

@keyframes shake{
    20%{transform:translateX(-8px);}
    40%{transform:translateX(8px);}
    60%{transform:translateX(-6px);}
    80%{transform:translateX(6px);}
    100%{transform:translateX(0);}
}

@media(max-width:480px){
    .card{
        width:92%;
        padding:32px 20px;
    }

.otp-wrapper{
        gap:8px;
    }

.otp-box input{
        width:44px;
        height:58px;
        font-size:22px;
    }
}

- OTP verification UI animation

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