:root {
    --primary-color: #2d3436;
    --secondary-color: #636e72;
    --accent-color: #0984e3;
    --background-color: #f5f6fa;
    --card-background: #ffffff;
    --text-color: #2d3436;
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
    line-height: 1.6;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
}

.payment-container {
    background-color: var(--card-background);
    width: 100%;
    max-width: 500px;
    padding: 40px;
    border-radius: var(--border-radius);
    box-shadow: 0 10px 25px rgba(0,0,0,0.05);
}

.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    font-size: 1.5rem;
    margin-bottom: 10px;
    color: var(--primary-color);
}

.product-info {
    padding: 15px;
    background: #f8f9fa;
    border-radius: var(--border-radius);
    margin-bottom: 25px;
}

.product-name {
    font-weight: 600;
    display: block;
    margin-bottom: 5px;
}

.product-price {
    font-size: 1.25rem;
    color: var(--accent-color);
    font-weight: 700;
}

.payment-methods {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
    margin-bottom: 30px;
}

.method-btn {
    padding: 12px;
    border: 1px solid #dfe6e9;
    background: white;
    border-radius: var(--border-radius);
    cursor: pointer;
    text-align: center;
    transition: var(--transition);
    font-weight: 500;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 5px;
}

.method-btn:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

.method-btn.active {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
}

.payment-details {
    text-align: center;
    margin-top: 20px;
}

.qr-container {
    margin: 20px 0;
    padding: 20px;
    border: 1px dashed #dfe6e9;
    border-radius: var(--border-radius);
}

.qr-container img {
    max-width: 200px;
    width: 100%;
}

.verification-form {
    display: none;
    margin-top: 30px;
    padding-top: 30px;
    border-top: 1px solid #dfe6e9;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-size: 0.9rem;
    font-weight: 500;
}

.form-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid #dfe6e9;
    border-radius: var(--border-radius);
    outline: none;
    transition: var(--transition);
}

.form-group input:focus {
    border-color: var(--accent-color);
}

.btn-submit {
    width: 100%;
    padding: 12px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    transition: var(--transition);
}

.btn-submit:hover {
    background: #000;
}

.btn-submit:disabled {
    background: var(--secondary-color);
    cursor: not-allowed;
}

.loading-spinner {
    display: none;
    text-align: center;
    padding: 40px;
}

#success-msg {
    display: none;
    text-align: center;
    color: #27ae60;
    margin-top: 20px;
}

.hidden { display: none; }

@media (max-width: 480px) {
    .payment-container {
        padding: 25px;
    }
}