.checkout-container{max-width:500px;margin:2rem auto;padding:2rem;background-color:var(--color-background-secondary);border-radius:8px}#payment-form{margin-top:2rem}#card-element{padding:10px;border:1px solid #ccc;border-radius:4px;margin-bottom:20px}#submit-button{width:100%;padding:10px;background-color:var(--primary-color);color:#fff;border:none;border-radius:4px;cursor:pointer;font-size:1em}#submit-button:hover{opacity:.9}#error-message{margin-top:10px;color:red}