/* Checkout V4 — Instagram V4 style (light, iOS-like) */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

:root {
    --ig-blue: #0095F6;
    --ig-blue-dark: #0081d6;
    --text-primary: #1C1C1E;
    --text-secondary: #6e6e73;
    --text-tertiary: #aeaeb2;
    --divider: #e5e5ea;
    --bg: #ffffff;
    --bg-secondary: #f2f2f7;
    --card-bg: #ffffff;
    --green: #34C759;
    --error: #ff3b30;
    --input-bg: #f2f2f7;
    --input-border: #e5e5ea;
    --input-focus: #0095F6;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
    --shadow-md: 0 2px 8px rgba(0,0,0,0.08);
}

html { font-size: 16px; }

body {
    background: var(--bg);
    color: var(--text-primary);
    font-family: -apple-system, "SF Pro Display", "SF Pro Text", BlinkMacSystemFont, "Helvetica Neue", sans-serif;
    -webkit-font-smoothing: antialiased;
    min-height: 100vh;
    line-height: 1.5;
}

.checkout-wrap {
    max-width: 480px;
    margin: 0 auto;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header — instagramv4 style */
.checkout-header {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255,255,255,0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--divider);
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 14px 20px;
}

.checkout-header .header-title {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.step-indicator {
    display: flex;
    align-items: center;
    gap: 8px;
}

.step {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--bg-secondary);
    border: 2px solid var(--divider);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 600;
    color: var(--text-tertiary);
    transition: all 0.2s ease;
}

.step.active {
    background: var(--ig-blue);
    border-color: var(--ig-blue);
    color: white;
}

.step.completed {
    background: var(--green);
    border-color: var(--green);
    color: white;
}

.step-divider {
    width: 24px;
    height: 2px;
    background: var(--divider);
    transition: background 0.2s ease;
}

.step-divider.completed {
    background: var(--green);
}

/* Main */
.checkout-main {
    flex: 1;
    padding: 24px 20px 32px;
}

.step-container {
    display: none;
    animation: fadeIn 0.3s ease;
}

.step-container.active {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(8px); }
    to { opacity: 1; transform: translateY(0); }
}

.step-content {
    order: 0;
}

.order-summary {
    order: 1;
    position: static;
}

.step-header {
    margin-bottom: 20px;
}

.step-header h1 {
    font-size: 24px;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 6px;
    color: var(--text-primary);
}

.step-header p {
    font-size: 15px;
    color: var(--text-secondary);
}

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: none;
    border: none;
    color: var(--ig-blue);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    padding: 6px 0;
    margin-bottom: 12px;
    font-family: inherit;
    transition: opacity 0.15s ease;
}

.back-btn:hover {
    opacity: 0.8;
}

.back-btn:active {
    opacity: 0.7;
}

/* Form */
.checkout-form {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group label {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    width: 100%;
    padding: 14px 16px;
    background: var(--input-bg);
    border: 1px solid var(--input-border);
    border-radius: 10px;
    color: var(--text-primary);
    font-size: 16px;
    font-family: inherit;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.form-group input::placeholder {
    color: var(--text-tertiary);
}

.form-group input:focus {
    outline: none;
    border-color: var(--ig-blue);
    box-shadow: 0 0 0 3px rgba(0, 149, 246, 0.15);
}

.form-group.invalid input {
    border-color: var(--error);
}

.field-error {
    font-size: 13px;
    color: var(--error);
    line-height: 1.25;
    min-height: 0;
}

.input-wrapper {
    position: relative;
}

.input-prefix {
    position: absolute;
    left: 14px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-tertiary);
    pointer-events: none;
}

.input-wrapper input {
    padding-left: 44px;
}

.card-input-wrapper {
    position: relative;
}

.card-input-wrapper input {
    padding-right: 56px;
}

.card-icons {
    position: absolute;
    right: 14px;
    top: 50%;
    transform: translateY(-50%);
    display: flex;
    align-items: center;
    gap: 4px;
    pointer-events: none;
}

.card-icon {
    height: 18px;
    width: auto;
    object-fit: contain;
    opacity: 0.6;
}

.form-row {
    display: grid;
    grid-template-columns: 1.2fr 1fr;
    gap: 12px;
}

/* Buttons — instagramv4 style */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    padding: 16px 24px;
    border-radius: 12px;
    font-size: 17px;
    font-weight: 600;
    font-family: inherit;
    cursor: pointer;
    transition: background 0.15s ease, transform 0.1s ease;
    border: none;
    text-decoration: none;
    position: relative;
}

.btn-primary {
    background: var(--ig-blue);
    color: white;
    width: 100%;
}

.btn-primary:hover:not(:disabled) {
    background: var(--ig-blue-dark);
}

.btn-primary:active:not(:disabled) {
    transform: scale(0.98);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn-primary.loading span {
    opacity: 0;
}

.btn-primary.loading::after {
    content: '';
    position: absolute;
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255,255,255,0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.6s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* Plan upgrade block — instagramv4 card style */
.plan-upgrade-block {
    margin-bottom: 4px;
}

.plan-upgrade-card {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    padding: 14px 16px;
    border-radius: 12px;
    background: var(--bg);
    border: 1px solid var(--divider);
    position: relative;
    transition: border-color 0.2s, background 0.2s;
}

.plan-upgrade-card:hover {
    background: var(--bg-secondary);
}

.plan-upgrade-card:has(.plan-upgrade-checkbox:checked) {
    border-color: var(--ig-blue);
    background: rgba(0, 149, 246, 0.06);
}

.plan-upgrade-icon {
    font-size: 18px;
    flex-shrink: 0;
}

.plan-upgrade-label {
    flex: 1;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-primary);
}

.plan-upgrade-badge {
    font-size: 10px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.3px;
    color: var(--ig-blue);
    background: rgba(0, 149, 246, 0.12);
    border-radius: 6px;
    padding: 3px 8px;
}

.plan-upgrade-checkbox {
    position: absolute;
    opacity: 0;
    width: 0;
    height: 0;
}

.plan-upgrade-switch {
    flex-shrink: 0;
    width: 44px;
    height: 26px;
    border-radius: 13px;
    background: var(--divider);
    position: relative;
    transition: background 0.2s;
}

.plan-upgrade-switch::after {
    content: '';
    position: absolute;
    width: 22px;
    height: 22px;
    border-radius: 50%;
    background: white;
    top: 2px;
    left: 2px;
    box-shadow: var(--shadow-sm);
    transition: transform 0.2s ease;
}

.plan-upgrade-checkbox:checked + .plan-upgrade-switch {
    background: var(--ig-blue);
}

.plan-upgrade-checkbox:checked + .plan-upgrade-switch::after {
    transform: translateX(18px);
}

.step1-footer {
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--divider);
}

.secure-notice {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    font-size: 12px;
    color: var(--text-tertiary);
}

.secure-notice svg {
    color: var(--text-tertiary);
    flex-shrink: 0;
}

.terms-text {
    font-size: 12px;
    color: var(--text-secondary);
    text-align: center;
    margin-top: 8px;
    line-height: 1.5;
}

.terms-text a {
    color: var(--ig-blue);
    text-decoration: none;
}

.terms-text a:hover {
    text-decoration: underline;
}

/* Order Summary — instagramv4 card */
.summary-card {
    background: var(--card-bg);
    border: 1px solid var(--divider);
    border-radius: 14px;
    padding: 18px 20px;
    box-shadow: var(--shadow-sm);
}

.summary-card h3 {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.4px;
    margin-bottom: 12px;
}

.package-details {
    margin-bottom: 12px;
}

.package-name {
    font-size: 17px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 4px;
}

.package-username {
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: 4px;
}

.package-price {
    font-size: 22px;
    font-weight: 700;
    color: var(--ig-blue);
    margin-bottom: 2px;
}

.package-description {
    font-size: 13px;
    color: var(--text-secondary);
}

.package-price .per-month {
    font-weight: 500;
    color: var(--text-tertiary);
    font-size: 0.85em;
}

.summary-divider {
    height: 1px;
    background: var(--divider);
    margin: 12px 0;
}

.summary-row {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 14px;
    margin-bottom: 8px;
}

.summary-row.total {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 0;
}

.summary-row .price {
    color: var(--text-primary);
}

.summary-row.priority-addon-row {
    margin-bottom: 6px;
    font-size: 13px;
    color: var(--text-secondary);
}

.features-list {
    margin-top: 14px;
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.feature {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    color: var(--text-secondary);
}

.feature svg {
    flex-shrink: 0;
}

/* 3DS Modal */
.three-ds-modal {
    display: none;
    position: fixed;
    inset: 0;
    z-index: 9999;
    background: rgba(0,0,0,0.5);
    backdrop-filter: blur(8px);
    align-items: center;
    justify-content: center;
    padding: 20px;
    animation: fadeIn 0.2s ease;
}

.three-ds-modal.active {
    display: flex;
}

.three-ds-content {
    background: var(--card-bg);
    border: 1px solid var(--divider);
    border-radius: 16px;
    padding: 24px;
    width: 100%;
    max-width: 400px;
    box-shadow: var(--shadow-md);
}

.three-ds-content h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 16px;
    text-align: center;
    color: var(--text-primary);
}

.three-ds-content iframe {
    width: 100%;
    height: 420px;
    border: none;
    border-radius: 10px;
    background: #fff;
}

/* Responsive: larger screens show summary beside form */
@media (min-width: 640px) {
    .checkout-wrap {
        max-width: 900px;
    }

    .step-container.active {
        display: grid;
        grid-template-columns: 1fr 320px;
        gap: 32px;
        align-items: start;
    }

    .step-content {
        order: 0;
    }

    .order-summary {
        order: 0;
        position: sticky;
        top: 80px;
    }
}

@media (max-width: 480px) {
    .checkout-main {
        padding: 20px 16px 28px;
    }

    .step-header h1 {
        font-size: 22px;
    }

    .form-group input {
        font-size: 16px; /* prevent iOS zoom */
    }

    .step {
        width: 26px;
        height: 26px;
        font-size: 12px;
    }

    .step-divider {
        width: 18px;
    }

    .package-price .per-month-mobile-hidden {
        display: none;
    }
}

/* RTL (e.g. Arabic) */
[dir="rtl"] .checkout-main { text-align: right; }
[dir="rtl"] .step-header { text-align: right; }
[dir="rtl"] .form-group label { text-align: right; }
[dir="rtl"] .back-btn { flex-direction: row-reverse; }
[dir="rtl"] .summary-card { text-align: right; }
[dir="rtl"] .terms-text { text-align: right; }