*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:Arial,sans-serif;
}

body{
    background:#111827;
    color:#fff;
    display:flex;
    justify-content:center;
    align-items:center;
    min-height:100vh;
    padding:20px;
}

.container{
    width:100%;
    max-width:500px;
    background:#1f2937;
    border-radius:15px;
    padding:25px;
    box-shadow:0 0 20px rgba(0,0,0,.4);
}

h2{
    text-align:center;
    margin-bottom:20px;
}

h3{
    margin:15px 0 8px;
    font-size:15px;
}

input,
textarea{
    width:100%;
    padding:12px;
    border:none;
    outline:none;
    border-radius:8px;
    background:#374151;
    color:#fff;
    font-size:14px;
    margin-bottom:10px;
    resize:none;
}

input::placeholder{
    color:#9ca3af;
}

button{
    width:100%;
    padding:12px;
    border:none;
    border-radius:8px;
    background:#2563eb;
    color:#fff;
    font-size:15px;
    font-weight:bold;
    cursor:pointer;
    transition:.2s;
    margin-bottom:10px;
}

button:hover{
    background:#1d4ed8;
}

button:disabled{
    background:#6b7280;
    cursor:not-allowed;
}

#result{
    margin-top:20px;
    border-top:1px solid #374151;
    padding-top:20px;
}

@media(max-width:600px){

    .container{
        padding:20px;
    }

    h2{
        font-size:22px;
    }

}