body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: #2c2f3a;
    margin: 0;
    padding: 40px 20px;
    color: #e0e6f0;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-height: 100vh;
    box-sizing: border-box;
}

h2 {
    color: #4dabf7;
    margin-bottom: 30px;
    text-align: center;
    font-weight: 600;
    text-shadow: 0 0 8px rgba(77,171,247,0.7);
}

.form-container {
    background: #1e222b;
    padding: 30px 40px;
    border-radius: 8px;
    width: 100%;
    max-width: 480px;
    box-shadow:
        0 0 20px 4px rgba(77, 171, 247, 0.8),
        0 8px 24px rgba(0, 0, 0, 0.8);
    box-sizing: border-box;
}

label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: #7ea9f7;
    text-shadow: 0 0 6px rgba(77,171,247,0.5);
}

input[type="email"] {
    width: 100%;
    padding: 12px 15px;
    font-size: 16px;
    border-radius: 5px;
    border: 1px solid #4dabf7;
    background-color: #2b2f3a;
    color: #e0e6f0;
    margin-bottom: 20px;
    box-sizing: border-box;
    transition: border-color 0.3s ease;
}

input[type="email"]:focus {
    border-color: #7bb5f7;
    outline: none;
    box-shadow: 0 0 8px rgba(77,171,247,0.9);
}

#card-element {
    background-color: #2b2f3a;
    padding: 12px;
    border-radius: 5px;
    border: 1px solid #4dabf7;
    margin-bottom: 25px;
    box-sizing: border-box;
}

button#submit {
    width: 100%;
    background-color: #4dabf7;
    color: white;
    font-weight: 700;
    font-size: 18px;
    padding: 14px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    box-shadow: 0 0 10px rgba(77,171,247,0.8);
    transition: background-color 0.3s ease;
    display: flex;
    justify-content: center;
    align-items: center;
}

button#submit:hover {
    background-color: #3a8ad6;
    box-shadow: 0 0 15px rgba(59,138,214,0.9);
}

.spinner {
    border: 3px solid #ffffff50;
    border-top: 3px solid white;
    border-radius: 50%;
    width: 20px;
    height: 20px;
    margin-left: 12px;
    animation: spin 1s linear infinite;
    display: none; /* výchozí skrytí */
}

/* Když tlačítko má třídu loading, spinner se zobrazí a btn-text zmizí */
button#submit.loading .spinner {
    display: inline-block;
}

button#submit.loading .btn-text {
    display: none;
}

#payment-request-button {
    margin-bottom: 20px;
}

#protected {
    margin-top: 30px;
    color: #7a84a1;
    font-size: 14px;
    text-align: center;
    user-select: none;
}

.payment-logos {
    margin-bottom: 12px;
}

.payment-logos img {
    max-height: 30px;
    margin: 0 10px;
    vertical-align: middle;
}

@keyframes spin {
    0% { transform: rotate(0deg);}
    100% { transform: rotate(360deg);}
}