:root {
    --primary: rgb(70,139,223);
    --primary-dark: #245caa;
    --primary-soft: #eaf4ff;
    --ink: #102033;
    --muted: #637083;
    --line: #dce8f7;
    --card: rgba(255,255,255,0.86);
    --bg: #f7fbff;
    --radius: 22px;
    --shadow: 0 18px 55px rgba(33, 86, 150, 0.10);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
    color: var(--ink);
    background:
        radial-gradient(circle at 10% 0%, rgba(70,139,223,0.16), transparent 32rem),
        linear-gradient(180deg, #f4f9ff 0%, #ffffff 42%, #f8fbff 100%);
    line-height: 1.72;
    overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.container { width: min(1120px, calc(100% - 36px)); margin: 0 auto; }
.section { padding: 56px 0; }
.section-sm { padding: 34px 0; }
.section-head { max-width: 720px; margin-bottom: 26px; }
.section-head.center { text-align: center; margin-left: auto; margin-right: auto; }
.eyebrow, .badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 7px 12px;
    color: var(--primary-dark);
    background: rgba(70,139,223,0.11);
    border: 1px solid rgba(70,139,223,0.18);
    border-radius: 999px;
    font-size: 13px;
    font-weight: 700;
}
h1, h2, h3 { line-height: 1.22; letter-spacing: -0.02em; margin: 0 0 14px; }
h1 { font-size: clamp(34px, 8vw, 66px); }
h2 { font-size: clamp(26px, 5vw, 42px); }
h3 { font-size: 20px; }
p { margin: 0 0 14px; color: var(--muted); }

/* header / logo / responsive nav / mobile nav / desktop nav */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(248, 252, 255, 0.86);
    backdrop-filter: blur(18px);
    border-bottom: 1px solid rgba(201, 221, 245, 0.8);
}
.nav-wrap { min-height: 72px; display: flex; align-items: center; justify-content: space-between; gap: 18px; }
.brand, .footer-brand { display: inline-flex; align-items: center; gap: 10px; font-weight: 800; color: var(--ink); }
.logo { width: 38px; height: 38px; border-radius: 12px; box-shadow: 0 8px 24px rgba(70,139,223,0.22); }
.site-nav { display: none; }
.site-nav a { color: #435168; font-size: 15px; font-weight: 650; padding: 10px 12px; border-radius: 999px; }
.site-nav a:hover, .site-nav a.active { color: var(--primary-dark); background: rgba(70,139,223,0.10); }
.nav-toggle { position: absolute; opacity: 0; pointer-events: none; }
.nav-toggle-label { display: grid; gap: 5px; padding: 9px; border-radius: 12px; border: 1px solid var(--line); background: white; cursor: pointer; }
.nav-toggle-label span { width: 22px; height: 2px; border-radius: 2px; background: var(--ink); }
.nav-toggle:checked ~ .site-nav {
    display: grid;
    position: absolute;
    top: 72px;
    left: 18px;
    right: 18px;
    padding: 14px;
    background: rgba(255,255,255,0.96);
    border: 1px solid var(--line);
    border-radius: 18px;
    box-shadow: var(--shadow);
}

/* hero banner / gradient background */
.hero-banner { padding: 64px 0 34px; }
.hero-layout {
    display: grid;
    gap: 34px;
    align-items: center;
    min-height: 620px;
}
.hero-copy { max-width: 650px; }
.hero-copy p { font-size: 18px; }
.hero-tags, .tag-row { display: flex; flex-wrap: wrap; gap: 10px; margin: 18px 0 24px; }
.safe-tag, .mini-tag {
    display: inline-flex;
    align-items: center;
    padding: 8px 12px;
    background: rgba(255,255,255,0.8);
    color: #2b587f;
    border: 1px solid var(--line);
    border-radius: 999px;
    font-weight: 650;
    font-size: 13px;
}
.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 24px;
    border-radius: 999px;
    background: rgb(70,139,223);
    color: #fff;
    font-weight: 800;
    border: 0;
    box-shadow: 0 14px 30px rgba(70,139,223,0.26);
    transition: transform .18s ease, box-shadow .18s ease;
}
.download-btn:hover { transform: translateY(-2px); box-shadow: 0 18px 38px rgba(70,139,223,0.32); }
.hero-visual {
    position: relative;
    padding: 18px;
    border-radius: 32px;
    background: linear-gradient(135deg, rgba(255,255,255,0.92), rgba(231,244,255,0.92));
    border: 1px solid rgba(207,226,247,0.95);
    box-shadow: var(--shadow);
    overflow: hidden;
}
.hero-visual::before {
    content: "";
    position: absolute;
    inset: 8% auto auto 5%;
    width: 78%;
    height: 42%;
    background: radial-gradient(circle, rgba(70,139,223,0.18), transparent 65%);
}
.phone-card {
    position: relative;
    width: min(300px, 78vw);
    margin: 0 auto;
    padding: 18px;
    border-radius: 34px;
    background: linear-gradient(180deg, #ffffff, #eaf5ff);
    border: 1px solid var(--line);
}
.phone-card img { border-radius: 26px; box-shadow: 0 28px 70px rgba(19, 71, 128, 0.18); }
.float-card {
    position: relative;
    margin: 12px auto 0;
    width: 100%;
    padding: 13px 14px;
    border-radius: 18px;
    background: rgba(255,255,255,0.90);
    border: 1px solid var(--line);
    box-shadow: 0 10px 30px rgba(42, 91, 154, 0.08);
    font-size: 13px;
    color: #35506e;
}
.float-card strong { display: block; color: var(--ink); font-size: 14px; }
.status-card { border-left: 4px solid var(--primary); }
.visual-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }

/* trust data */
.trust-strip {
    display: grid;
    gap: 14px;
    grid-template-columns: 1fr;
    padding: 16px;
    border-radius: 24px;
    background: rgba(255,255,255,0.78);
    border: 1px solid var(--line);
    box-shadow: 0 12px 32px rgba(70,139,223,0.08);
}
.trust-item { padding: 16px; border-radius: 18px; background: #f7fbff; border: 1px solid #e7f0fb; }
.trust-item strong { display: block; font-size: 18px; margin-bottom: 6px; }

/* section content container */
.panel {
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}
.panel.pad { padding: 24px; }
.lead { font-size: 18px; color: #4d5d72; }

/* category nav / category card */
.category-grid, .feature-grid, .scenario-grid, .related-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
}
.category-card, .feature-card, .scenario-card, .faq-item, .note-card, .doc-card {
    background: rgba(255,255,255,0.86);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 22px;
    box-shadow: 0 10px 34px rgba(70,139,223,0.07);
}
.category-card { min-height: 180px; display: flex; flex-direction: column; justify-content: space-between; }
.category-card a, .scenario-card a, .inline-link { color: var(--primary-dark); font-weight: 800; }
.category-card:hover, .feature-card:hover, .scenario-card:hover { transform: translateY(-2px); transition: transform .18s ease; }

/* feature grid */
.feature-card.big { background: linear-gradient(135deg, #ffffff 0%, #edf6ff 100%); }
.feature-icon {
    width: 42px;
    height: 42px;
    display: grid;
    place-items: center;
    border-radius: 15px;
    background: rgba(70,139,223,0.12);
    color: var(--primary-dark);
    font-weight: 900;
    margin-bottom: 14px;
}

/* security panel */
.security-layout {
    display: grid;
    grid-template-columns: 1fr;
    gap: 22px;
    align-items: start;
}
.security-panel {
    padding: 22px;
    border-radius: 26px;
    border: 1px solid var(--line);
    background: linear-gradient(180deg, #ffffff 0%, #f0f7ff 100%);
    box-shadow: var(--shadow);
}
.principle-list { display: grid; gap: 12px; margin: 0; padding: 0; list-style: none; }
.principle-list li {
    padding: 14px;
    background: rgba(255,255,255,0.82);
    border: 1px solid var(--line);
    border-radius: 16px;
    color: #41516a;
}

/* process steps */
.steps {
    display: grid;
    grid-template-columns: 1fr;
    gap: 14px;
    counter-reset: step;
}
.step-card {
    position: relative;
    padding: 22px;
    border-radius: 22px;
    background: rgba(255,255,255,0.88);
    border: 1px solid var(--line);
    box-shadow: 0 10px 28px rgba(70,139,223,0.07);
}
.step-no {
    width: 34px;
    height: 34px;
    display: inline-grid;
    place-items: center;
    border-radius: 12px;
    background: rgb(70,139,223);
    color: #fff;
    font-weight: 900;
    margin-bottom: 12px;
}

/* FAQ item */
.faq-list { display: grid; gap: 14px; }
.faq-item h3 { margin-bottom: 8px; }
.faq-item p { margin-bottom: 0; }

/* page documents */
.page-hero { padding: 58px 0 30px; }
.page-hero .doc-title { max-width: 820px; }
.doc-layout { display: grid; grid-template-columns: 1fr; gap: 22px; align-items: start; }
.article-body { max-width: 780px; }
.article-body .panel, .article-body .doc-card { margin: 18px 0; }
.content-list { margin: 0; padding-left: 20px; color: var(--muted); }
.content-list li { margin-bottom: 10px; }
.check-grid { display: grid; gap: 12px; grid-template-columns: 1fr; }
.check-item { padding: 15px; border-radius: 16px; background: #f7fbff; border: 1px solid var(--line); }
.cta-inline { margin-top: 26px; }

/* cta-section */
.cta-section {
    text-align: center;
    padding: 44px 22px;
    border-radius: 30px;
    background:
      radial-gradient(circle at 50% 0%, rgba(70,139,223,0.18), transparent 32rem),
      linear-gradient(135deg, #ffffff 0%, #eaf5ff 100%);
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}
.cta-section p { max-width: 680px; margin-left: auto; margin-right: auto; }

/* footer */
.site-footer { margin-top: 48px; padding: 44px 0 24px; background: #f0f6fd; border-top: 1px solid var(--line); }
.footer-grid { display: grid; gap: 24px; grid-template-columns: 1fr; }
.footer-grid h3 { font-size: 16px; margin-bottom: 10px; }
.footer-grid a { display: block; color: #536278; margin: 7px 0; }
.footer-brand img { width: 34px; height: 34px; border-radius: 10px; }
.footer-bottom { margin-top: 28px; padding-top: 18px; border-top: 1px solid #d9e8f8; display: flex; flex-direction: column; gap: 8px; color: #6b7787; font-size: 13px; }

@media (min-width: 680px) {
    .container { width: min(1120px, calc(100% - 56px)); }
    .trust-strip { grid-template-columns: repeat(2, 1fr); }
    .category-grid, .feature-grid, .scenario-grid, .related-grid { grid-template-columns: repeat(2, 1fr); }
    .check-grid { grid-template-columns: repeat(2, 1fr); }
    .steps { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1fr; }
}
@media (min-width: 920px) {
    .nav-toggle-label { display: none; }
    .site-nav { display: flex; align-items: center; gap: 3px; }
    .hero-layout { grid-template-columns: 1.02fr .98fr; gap: 46px; }
    .hero-visual { min-height: 560px; display: flex; align-items: center; justify-content: center; }
    .float-card { position: absolute; max-width: 210px; margin: 0; }
    .float-card.one { left: 22px; top: 52px; }
    .float-card.two { right: 22px; top: 126px; }
    .float-card.three { left: 28px; bottom: 90px; }
    .float-card.four { right: 28px; bottom: 44px; }
    .visual-tags { position: absolute; left: 26px; right: 26px; bottom: 22px; justify-content: center; }
    .trust-strip { grid-template-columns: repeat(4, 1fr); }
    .category-grid { grid-template-columns: repeat(3, 1fr); }
    .feature-grid { grid-template-columns: repeat(3, 1fr); }
    .feature-card.big { grid-column: span 2; }
    .security-layout { grid-template-columns: 1fr .9fr; gap: 34px; }
    .steps { grid-template-columns: repeat(4, 1fr); }
    .scenario-grid { grid-template-columns: repeat(3, 1fr); }
    .doc-layout { grid-template-columns: minmax(0, 760px) 320px; }
    .footer-bottom { flex-direction: row; justify-content: space-between; }
}
@media (min-width: 1120px) {
    .category-card.featured { grid-column: span 2; }
}