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

body {
    font-family: Arial, sans-serif;
    background: linear-gradient(135deg, #1e293b, #0f172a);
    min-height: 100vh;

    display: flex;
    justify-content: center;
    align-items: center;
}

.card {
    width: 350px;
    padding: 40px;

    background: rgba(255,255,255,0.08);
    backdrop-filter: blur(12px);

    border-radius: 16px;
    text-align: center;
    color: white;
}

.card h1 {
    margin-bottom: 20px;
}

input {
    width: 100%;
    padding: 14px;
    margin-bottom: 15px;

    font-size: 32px;
    font-weight: bold;
    text-align: center;
    text-transform: uppercase;
    letter-spacing: 3px;

    border: none;
    border-radius: 10px;
}

button {
    width: 100%;
    padding: 14px;

    font-size: 32px;
    font-weight: bold;

    border: none;
    border-radius: 10px;

    background: #3b82f6;
    color: white;

    cursor: pointer;
}

button:hover {
    background: #2563eb;
}

.error {
    margin-top: 15px;
    color: #f87171;
}