/* ==== Body ==== */
body {
    margin: 0;
    padding: 0;
    font-family: 'Open Sans', sans-serif;
    background: linear-gradient(135deg, #89253e, #3a6186);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    color: #fff;
    text-align: center;
}

/* ==== Heading with gradient animation ==== */
.heading {
    font-size: clamp(2.5rem, 8vw, 5rem);
    font-weight: 900;
    text-transform: uppercase;
    background: linear-gradient(90deg, #ff0055, #ffbb00, #00ffaa, #6600ff);
    background-size: 300%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: rainbowMove 5s linear infinite;
    margin-bottom: 2rem;
    text-shadow: 2px 2px 8px rgba(0,0,0,0.3);
}

/* ==== Gradient animation keyframes ==== */
@keyframes rainbowMove {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* ==== Input container ==== */
.input-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    background-color: rgba(255,255,255,0.08);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.3);
    margin-bottom: 2rem;
    width: 75%;
    max-width: 400px;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.input-container:hover {
    transform: scale(1.05);
    box-shadow: 0 15px 35px rgba(0,0,0,0.4);
}

/* ==== Labels and inputs ==== */
label {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
    color: #fff;
}

.input {
    padding: 0.8rem 1.5rem;
    font-size: 1.2rem;
    border-radius: 2rem;
    border: none;
    width: 100%;
    text-align: center;
    outline: none;
    transition: all 0.3s ease;
}

.input:focus {
    box-shadow: 0 0 10px rgba(255,255,255,0.6);
}

p{
    font-size: 1.2rem;
    margin-top: 1rem;
    font-weight: bold;
    color: #fff;
    text-shadow: 1px 1px 4px rgba(0,0,0,0.5);
}

/* ==== Output ==== */
#output {
    font-size: clamp(2rem, 6vw, 3rem);
    font-weight: bold;
    margin-top: 1rem;
    color: #ffeb3b;
    text-shadow: 1px 1px 4px rgba(0,0,0,0.5);
}

/* ==== Error message ==== */
#error {
    color: #ff4d4d;
    font-weight: bold;
    font-size: 1.2rem;
    margin-top: 1rem;
    display: none; 
}

/* ==== Responsive ==== */
@media (max-width: 480px) {
    .heading {
        font-size: clamp(2rem, 10vw, 4rem);
    }

    .input-container {
        padding: 1.5rem;
    }

    .input {
        font-size: 1rem;
        padding: 0.6rem 1rem;
    }

    #output {
        font-size: clamp(1.5rem, 8vw, 2.5rem);
    }
}