:root {
    color-scheme: light;
    --ink: #132442;
    --muted: #485b75;
    --accent: #234fa7;
    --accent-hover: #163b85;
    --line: #dce5f2;
    --surface: #f3f7fd;
    font-family: system-ui, "Microsoft YaHei", sans-serif;
    color: var(--ink);
}

* { box-sizing: border-box; }
body { margin: 0; background: #fff; line-height: 1.65; }
h1, h2, h3, p { margin: 0; }
a { color: inherit; }
a:focus-visible, summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 4px; }
.frame { width: min(1120px, calc(100% - 48px)); margin-inline: auto; }
.skip { position: fixed; top: 12px; left: 12px; z-index: 1; transform: translateY(-200%); }
.skip:focus { transform: none; padding: 8px 16px; background: #fff; }

.site-header, .hero { border-bottom: 1px solid var(--line); }
.header-inner, .footer-inner, .account-links, .main-nav, .hero-links, .footer-links {
    display: flex; align-items: center; flex-wrap: wrap; gap: 12px 20px;
}
.header-inner, .footer-inner { justify-content: space-between; padding-block: 14px; }
.header-inner a, .footer-inner a { text-decoration: none; }
.main-nav, .footer-links { color: var(--muted); }
.main-nav a:hover, .footer-links a:hover, .plain-link:hover { text-decoration: underline; }
.wordmark { display: inline-flex; align-items: center; gap: 9px; font-size: 1.3rem; font-weight: 760; }
.brand-icon { display: grid; place-items: center; width: 32px; height: 32px; border-radius: 9px; background: var(--accent); }
.brand-icon::before {
    content: ""; width: 13px; height: 10px; border: 1.5px solid #fff;
    border-radius: 3px 3px 3px 0; transform: translateY(-1px);
}
.locale-picker { position: relative; }
.locale-picker summary {
    display: flex; align-items: center; justify-content: center; gap: 7px;
    min-height: 44px; min-width: 86px; padding: 6px 9px; border: 1px solid var(--line);
    border-radius: 9px; background: #fff; color: var(--ink); font-size: .9rem;
    font-weight: 650; white-space: nowrap; cursor: pointer; list-style: none;
}
.locale-picker summary::-webkit-details-marker { display: none; }
.locale-picker summary:hover, .locale-picker[open] summary {
    border-color: #bdcbe4; background: var(--surface); color: var(--accent);
}
.locale-sr { position: absolute; width: 1px; height: 1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; }
.locale-globe {
    display: grid; position: relative; place-items: center; flex: 0 0 16px;
    width: 16px; height: 16px; border: 1.5px solid currentColor; border-radius: 50%;
}
.locale-globe::before { content: ""; position: absolute; inset: -1px 3px; border: 1px solid currentColor; border-radius: 50%; }
.locale-globe::after { content: ""; position: absolute; inset-inline: 0; top: 50%; border-top: 1px solid currentColor; }
.locale-chevron {
    width: 6px; height: 6px; margin: -3px 1px 0 2px;
    border: solid currentColor; border-width: 0 1.5px 1.5px 0; transform: rotate(45deg);
}
.locale-picker[open] .locale-chevron { margin-top: 3px; transform: rotate(225deg); }
.locale-options {
    position: absolute; z-index: 2; inset-inline-end: 0; top: calc(100% + 6px);
    min-width: 154px; margin: 0; padding: 5px; list-style: none; border: 1px solid var(--line);
    border-radius: 12px; background: #fff; box-shadow: 0 10px 28px #24468220;
}
.locale-options a {
    display: flex; justify-content: space-between; align-items: center; gap: 10px;
    min-height: 44px; padding: 6px 10px; border-radius: 7px; white-space: nowrap;
}
.locale-options a:hover, .locale-options a[aria-current="page"] { background: var(--surface); color: var(--accent); }
.locale-options a[aria-current="page"]::after {
    content: ""; width: 6px; height: 10px; margin-right: 3px; margin-top: -3px;
    border: solid currentColor; border-width: 0 2px 2px 0; transform: rotate(45deg);
}
.locale-suggestion {
    display: inline-flex; align-items: center; gap: 8px; margin-top: 12px; color: var(--accent);
}
.locale-suggestion[hidden] { display: none; }
.locale-suggestion a { display: inline-flex; align-items: center; min-height: 44px; font-weight: 650; }
.locale-suggestion button {
    width: 44px; height: 44px; padding: 0; border: 0; border-radius: 7px;
    background: transparent; color: var(--muted); font: inherit; font-size: 1.25rem; cursor: pointer;
}
.locale-suggestion button:hover { background: var(--surface); color: var(--ink); }
.locale-suggestion button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.button {
    display: inline-flex; min-height: 44px; align-items: center; justify-content: center;
    padding: 8px 16px; border: 1px solid transparent; border-radius: 9px;
    text-decoration: none; font-weight: 680;
}
.primary { color: #fff; background: var(--accent); }
.primary:hover { background: var(--accent-hover); }
.secondary { color: var(--accent); border-color: #bdcbe4; background: #fff; }
.secondary:hover { border-color: var(--accent); }

.hero { background: linear-gradient(135deg, #fff 0%, #f6f9fe 52%, #eaf1fe 100%); }
.hero-inner {
    display: grid; grid-template-columns: minmax(0, 1.18fr) minmax(0, 1fr);
    align-items: center; gap: clamp(28px, 7vw, 92px); padding-block: clamp(48px, 8vw, 112px);
}
h1 { font-size: clamp(2.1rem, 5vw, 4.15rem); line-height: 1.1; letter-spacing: -.04em; }
:lang(zh-CN) h1 { letter-spacing: -.015em; }
.intro { max-width: 40em; margin-top: 20px; color: var(--muted); font-size: clamp(1rem, 1.7vw, 1.14rem); }
.hero-links { margin-top: 26px; }
.preview { border: 1px solid var(--line); border-radius: 18px; background: #fff; box-shadow: 0 16px 42px #24468217; }
.preview-head {
    display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 4px 12px;
    padding: 15px clamp(15px, 3vw, 24px); border-bottom: 1px solid var(--line);
}
.preview-head h2 { font-size: 1rem; }
.preview-head span { color: var(--muted); font-size: .83rem; }
.preview-list { margin: 0; padding: 6px clamp(15px, 3vw, 24px); list-style: none; }
.preview-list li { position: relative; display: grid; gap: 3px; padding: 12px 0 12px 22px; }
.preview-list li + li { border-top: 1px solid var(--line); }
.preview-list li::before {
    content: ""; position: absolute; top: 19px; left: 0; width: 9px; height: 9px;
    border-radius: 50%; background: var(--accent); box-shadow: 0 0 0 3px #e7eefc;
}
.preview-list span, .section p, .callout p { color: var(--muted); }

.section { padding-block: clamp(36px, 6vw, 76px); }
.section h2, .callout h2 { font-size: clamp(1.5rem, 2.8vw, 2.22rem); line-height: 1.25; }
.feature-grid, .step-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 16px; margin-top: 24px; }
.feature-grid article { padding: clamp(16px, 2.5vw, 24px); border: 1px solid var(--line); border-radius: 14px; }
.section h3 { font-size: 1.12rem; line-height: 1.35; margin-bottom: 7px; }
.guide { background: var(--surface); }
.step-grid { margin-bottom: 0; padding-left: 1.45em; column-gap: 2.5em; }
.step-grid li { padding-inline-start: .22em; }
.step-grid li::marker { color: var(--accent); font-weight: 750; }
.faq-list { margin-top: 24px; border-block: 1px solid var(--line); }
.faq-list details + details { border-top: 1px solid var(--line); }
.faq-list summary { padding: 14px 2px; font-weight: 650; cursor: pointer; }
.faq-list summary::marker { color: var(--accent); }
.faq-list p { max-width: 70ch; padding: 0 10px 15px 20px; }
.callout {
    display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 16px 24px;
    margin-bottom: clamp(32px, 5vw, 64px); padding: clamp(20px, 4vw, 38px);
    border: 1px solid var(--line); border-radius: 16px; background: var(--surface);
}
.callout p { margin-top: 8px; }
.site-footer { border-top: 1px solid var(--line); }
.footer-inner { padding-block: 20px; }

@media (max-width: 760px) {
    .frame { width: calc(100% - 32px); }
    .header-inner, .account-links { gap: 8px 12px; }
    .header-inner .button { padding-inline: 10px; }
    .main-nav { order: 1; width: 100%; }
    .main-nav a, .plain-link { display: inline-flex; align-items: center; min-height: 44px; }
    .locale-options { inset-inline: 0 auto; }
    .hero-inner, .feature-grid, .step-grid { grid-template-columns: minmax(0, 1fr); }
}