:root {
    color-scheme: light;
    --ink: #172033;
    --muted: #5f6b7c;
    --line: #dfe4ec;
    --surface: #fff;
    --brand: #6857d9;
    --brand-dark: #4c3bb9;
    --accent: #e9e5ff;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
    margin: 0;
    color: var(--ink);
    background: radial-gradient(circle at 90% 4%, rgba(104, 87, 217, .14), transparent 30rem), linear-gradient(180deg, #fbfbfe, #f4f6fa);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
    line-height: 1.65;
}

a { color: var(--brand-dark); }
.landing-shell { width: min(1120px, calc(100% - 40px)); margin: 0 auto; }

.landing-header,
.landing-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.landing-header { padding: 24px 0; }
.landing-brand { color: var(--ink); font-weight: 800; letter-spacing: -.02em; text-decoration: none; }
.landing-nav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px 18px; font-size: 14px; }
.landing-nav a { color: var(--muted); text-decoration: none; }
.landing-nav a[aria-current="page"], .landing-nav a:hover { color: var(--brand-dark); }

.landing-hero {
    display: grid;
    grid-template-columns: minmax(0, 1.3fr) minmax(300px, .7fr);
    gap: 54px;
    align-items: center;
    padding: 76px 0 70px;
}

.landing-eyebrow {
    display: inline-flex;
    margin-bottom: 18px;
    padding: 6px 12px;
    color: var(--brand-dark);
    background: var(--accent);
    border-radius: 999px;
    font-size: 13px;
    font-weight: 750;
}

.landing-hero h1 {
    max-width: 820px;
    margin: 0;
    font-size: clamp(40px, 6vw, 68px);
    line-height: 1.06;
    letter-spacing: -.045em;
}

.landing-lead { max-width: 720px; margin: 24px 0 0; color: var(--muted); font-size: clamp(18px, 2vw, 21px); }
.landing-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }

.landing-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 0 20px;
    color: #fff;
    background: var(--brand);
    border: 1px solid var(--brand);
    border-radius: 10px;
    font-weight: 750;
    text-decoration: none;
    box-shadow: 0 12px 28px rgba(76, 59, 185, .2);
}

.landing-button:hover { background: var(--brand-dark); }
.landing-button.secondary { color: var(--ink); background: var(--surface); border-color: var(--line); box-shadow: none; }

.format-card {
    padding: 20px;
    background: rgba(255, 255, 255, .92);
    border: 1px solid rgba(223, 228, 236, .9);
    border-radius: 18px;
    box-shadow: 0 26px 60px rgba(47, 39, 101, .14);
}

.format-card-header { display: flex; align-items: center; gap: 8px; padding-bottom: 16px; color: var(--muted); font-size: 13px; font-weight: 700; }
.format-dot { width: 9px; height: 9px; border-radius: 50%; background: #f87171; }
.format-dot:nth-child(2) { background: #fbbf24; }
.format-dot:nth-child(3) { background: #4ade80; }

.format-card pre {
    overflow: auto;
    margin: 0;
    padding: 20px;
    color: #dbeafe;
    background: #172033;
    border-radius: 12px;
    font: 14px/1.7 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
    white-space: pre-wrap;
}

.landing-section { padding: 68px 0; }
.landing-section h2 { max-width: 760px; margin: 0 0 18px; font-size: clamp(29px, 4vw, 42px); line-height: 1.15; letter-spacing: -.03em; }
.section-intro { max-width: 760px; margin: 0 0 32px; color: var(--muted); font-size: 18px; }
.feature-grid, .step-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 18px; }

.feature-card,
.step-card {
    padding: 26px;
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: 14px;
}

.feature-card h3, .step-card h3 { margin: 0 0 9px; font-size: 18px; }
.feature-card p, .step-card p { margin: 0; color: var(--muted); }

.step-number {
    display: inline-grid;
    width: 34px;
    height: 34px;
    margin-bottom: 16px;
    place-items: center;
    color: #fff;
    background: var(--brand);
    border-radius: 50%;
    font-weight: 800;
}

.limit-box { padding: 28px 30px; color: #493c22; background: #fffbeb; border: 1px solid #fde68a; border-radius: 14px; }
.limit-box h2 { margin-bottom: 12px; font-size: 24px; }
.limit-box ul { margin: 0; padding-left: 22px; }
.faq-list { display: grid; gap: 12px; max-width: 860px; }
.faq-list details { padding: 20px 22px; background: var(--surface); border: 1px solid var(--line); border-radius: 12px; }
.faq-list summary { cursor: pointer; font-weight: 750; }
.faq-list p { margin: 12px 0 0; color: var(--muted); }

.landing-cta { margin: 60px auto; padding: 48px; text-align: center; color: #fff; background: #17162f; border-radius: 20px; }
.landing-cta h2 { margin: 0; font-size: clamp(30px, 4vw, 44px); }
.landing-cta p { margin: 12px auto 24px; color: #c7c7dc; }
.landing-footer { padding: 30px 0 44px; color: var(--muted); border-top: 1px solid var(--line); font-size: 14px; }

@media (max-width: 820px) {
    .landing-header, .landing-footer { align-items: flex-start; flex-direction: column; }
    .landing-nav { justify-content: flex-start; }
    .landing-hero { grid-template-columns: 1fr; padding-top: 48px; }
    .feature-grid, .step-grid { grid-template-columns: 1fr; }
    .landing-cta { padding: 36px 22px; }
}