:root {
    --text: #1a1f36;
    --muted: #64748b;
    --page: #f6f9fc;
    --card: #ffffff;
    --border: #dfe3eb;
    --primary: #15a900;
    --primary-hover: #108400;
    --primary-soft: #eaf8e8;
    --error: #b42318;
}

* { box-sizing: border-box; }

body {
    min-width: 320px;
    margin: 0;
    color: var(--text);
    background: var(--page);
    font-family: Arial, Helvetica, sans-serif;
    font-size: 16px;
    line-height: 1.45;
}

.site-header {
    height: 64px;
    display: flex;
    align-items: center;
    padding: 0 max(24px, calc((100% - 960px) / 2));
    background: #fff;
    border-bottom: 1px solid var(--border);
}

.brand { color: var(--text); font-size: 17px; font-weight: 700; letter-spacing: -.2px; text-decoration: none; }

.page-shell { display: flex; justify-content: center; padding: 56px 24px 80px; }

.support-card {
    width: min(100%, 560px);
    padding: 40px;
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 12px;
    box-shadow: 0 2px 5px rgba(26, 31, 54, .04), 0 12px 24px rgba(26, 31, 54, .06);
}

.eyebrow { margin: 0 0 9px; color: var(--muted); font-size: 12px; font-weight: 700; letter-spacing: .07em; }
h1 { margin: 0; font-size: 30px; font-weight: 700; letter-spacing: -.6px; line-height: 1.2; }
.intro { margin: 13px 0 32px; color: var(--muted); font-size: 16px; line-height: 1.55; }

fieldset { margin: 0 0 26px; padding: 0; border: 0; }
legend { margin-bottom: 10px; color: #30384f; font-size: 14px; font-weight: 700; }

.segmented { display: grid; grid-template-columns: 1fr 1fr; gap: 0; border: 1px solid var(--border); border-radius: 8px; overflow: hidden; }
.segmented input { position: absolute; opacity: 0; }
.segmented span { display: block; padding: 12px 14px; color: #3f475c; text-align: center; cursor: pointer; }
.segmented label + label span { border-left: 1px solid var(--border); }
.segmented input:checked + span { color: #0d7200; background: var(--primary-soft); font-weight: 700; }
.segmented input:focus-visible + span { position: relative; outline: 2px solid var(--primary); outline-offset: -2px; }

.amount-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.amount-button { min-height: 48px; padding: 10px 6px; color: #30384f; background: #fff; border: 1px solid var(--border); border-radius: 8px; font: inherit; font-weight: 700; cursor: pointer; }
.amount-button:hover { border-color: #9a94ff; background: #fafaff; }
.amount-button.is-selected { color: #0d7200; background: var(--primary-soft); border-color: var(--primary); box-shadow: inset 0 0 0 1px var(--primary); }

.custom-label { display: block; margin: 21px 0 8px; color: #30384f; font-size: 14px; font-weight: 700; }
.amount-input-wrap { position: relative; }
.amount-input-wrap input { width: 100%; height: 48px; padding: 12px 44px 12px 13px; color: var(--text); background: #fff; border: 1px solid var(--border); border-radius: 8px; font: inherit; font-size: 16px; }
.amount-input-wrap input::placeholder { color: #94a0b5; }
.amount-input-wrap input:focus { outline: 3px solid rgba(99, 91, 255, .18); border-color: var(--primary); }
.amount-input-wrap span { position: absolute; top: 50%; right: 15px; color: var(--muted); transform: translateY(-50%); }
.hint, .error { min-height: 18px; margin: 7px 0 0; font-size: 13px; }
.hint { color: var(--muted); }
.error { color: var(--error); }

.primary-button { width: 100%; min-height: 50px; display: flex; align-items: center; justify-content: center; gap: 10px; padding: 13px 18px; color: #fff; background: var(--primary); border: 1px solid var(--primary); border-radius: 8px; font: inherit; font-weight: 700; cursor: pointer; transition: background .15s ease; }
.primary-button:hover { background: var(--primary-hover); border-color: var(--primary-hover); }
.primary-button:disabled { cursor: wait; opacity: .7; }
.secure-note { margin: 13px 0 0; color: var(--muted); font-size: 12px; line-height: 1.45; text-align: center; }
.manage-link { margin: 16px 0 0; font-size: 13px; text-align: center; }
.manage-link a { color: #0d7200; text-decoration: none; }
.manage-link a:hover { text-decoration: underline; }
.notice { margin: 0 0 24px; padding: 12px; color: #8c2d23; background: #fff3f0; border: 1px solid #f7c7bf; border-radius: 8px; font-size: 14px; }
.success-card { text-align: center; }
.success-card .intro { max-width: 450px; margin-right: auto; margin-left: auto; }
.success-icon { width: 44px; height: 44px; display: grid; place-items: center; margin: 0 auto 20px; color: #087443; background: #e8f7ef; border-radius: 50%; font-size: 22px; font-weight: 700; }
.link-button { max-width: 320px; margin: 0 auto; text-decoration: none; }
.subscription-card { max-width: 510px; }
.info-box { margin: 0 0 26px; padding: 17px 18px 14px; color: #30384f; background: #f8faf9; border: 1px solid var(--border); border-radius: 8px; font-size: 14px; }
.info-box strong { display: block; margin-bottom: 7px; }
.info-box ol { margin: 0; padding-left: 20px; }
.info-box li + li { margin-top: 5px; }

@media (max-width: 560px) {
    .site-header { padding: 0 20px; }
    .page-shell { padding: 28px 16px 48px; }
    .support-card { padding: 28px 20px; }
    h1 { font-size: 26px; }
    .amount-grid { grid-template-columns: repeat(2, 1fr); }
}