* {
    box-sizing: border-box;
}

html,
body {
    min-height: 100%;
}

body {
    margin: 0;
    background: #f6f7f9;
    color: #111827;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, "Helvetica Neue", sans-serif;
    line-height: 1.45;
}

button {
    font: inherit;
}

.checkout-shell {
    min-height: 100vh;
    padding: 28px 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    background: #f5f5f5;
}

.checkout-shell::before,
.checkout-shell::after {
    content: "";
    position: absolute;
    left: 0;
    width: 100%;
    pointer-events: none;
}

.checkout-shell::before {
    top: 0;
    height: 28vh;
    min-height: 190px;
    max-height: 280px;
    background: linear-gradient(90deg, #075b96 0%, #178fc7 48%, #63cef5 100%);
}

.checkout-shell::after {
    bottom: 0;
    height: 18vh;
    background: linear-gradient(180deg, rgba(245, 245, 245, 0) 0%, rgba(15, 23, 42, 0.12) 100%);
}

.checkout-card {
    width: 100%;
    max-width: 430px;
    padding: 24px;
    background: #ffffff;
    border: 1px solid #e6eaf0;
    border-radius: 8px;
    box-shadow: 0 18px 48px rgba(15, 23, 42, 0.10);
    position: relative;
    z-index: 1;
}

.amount-section {
    padding: 0 0 22px;
    border-bottom: 1px solid #edf0f5;
    text-align: center;
}

.amount-section p {
    margin: 0;
    color: #6b7280;
    font-size: 13px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.amount-section h2 {
    margin: 4px 0 0;
    font-size: 42px;
    font-weight: 800;
    line-height: 1.08;
    letter-spacing: 0;
    overflow-wrap: anywhere;
}

.method-section {
    padding-top: 20px;
}

.method-section h3 {
    margin: 0 0 12px;
    font-size: 16px;
    font-weight: 700;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.payment-options {
    min-height: 64px;
}

.payment-option {
    width: 100%;
    min-height: 64px;
    margin: 0 0 10px;
    padding: 10px 12px;
    border: 1px solid #dbe1ea;
    border-radius: 8px;
    background: #ffffff;
    color: #111827;
    cursor: pointer;
    display: flex;
    align-items: center;
    text-align: left;
    transition: border-color 160ms ease, box-shadow 160ms ease, background-color 160ms ease;
}

.payment-option:hover {
    border-color: #9db7f5;
    background: #f8fbff;
}

.payment-option:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.18);
    outline-offset: 2px;
}

.payment-option.is-selected {
    border-color: #2563eb;
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.10);
}

.method-icon {
    width: 48px;
    height: 36px;
    flex: 0 0 48px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.method-icon img {
    width: 100%;
    height: 100%;
    display: block;
    object-fit: contain;
}

.method-copy {
    min-width: 0;
    margin-left: 14px;
    flex: 1 1 auto;
}

.method-name {
    display: block;
    font-size: 15px;
    font-weight: 500;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.method-check {
    width: 20px;
    height: 20px;
    margin-left: 10px;
    border: 2px solid #cbd5e1;
    border-radius: 50%;
    flex: 0 0 20px;
    position: relative;
}

.payment-option.is-selected .method-check {
    border-color: #16a34a;
    background: #16a34a;
}

.payment-option.is-selected .method-check::after {
    content: "";
    position: absolute;
    left: 5px;
    top: 2px;
    width: 5px;
    height: 9px;
    border: solid #ffffff;
    border-width: 0 2px 2px 0;
    transform: rotate(45deg);
}

.pay-button {
    width: 100%;
    min-height: 50px;
    margin-top: 8px;
    padding: 13px 18px;
    border: 0;
    border-radius: 8px;
    background: #2563eb;
    color: #ffffff;
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    letter-spacing: 0;
    transition: background-color 120ms ease, box-shadow 120ms ease;
}

.pay-button:hover {
    background: #1d4ed8;
}

.pay-button:active {
    background: #1e40af;
    box-shadow: inset 0 2px 4px rgba(15, 23, 42, 0.28);
}

.pay-button:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.24);
    outline-offset: 2px;
}

@media (max-width: 480px) {
    .checkout-shell {
        padding: 16px 12px;
    }

    .checkout-card {
        padding: 20px;
    }

    .amount-section h2 {
        font-size: 36px;
    }
}