* {
    box-sizing: border-box;
}

:root {
    --primary: rgb(70,139,223);
    --primary-dark: #1e5fa8;
    --primary-soft: #eaf4ff;
    --ink: #12233f;
    --muted: #63708a;
    --line: #dbe7f5;
    --bg: #f7fbff;
    --card: #ffffff;
    --shadow: 0 18px 45px rgba(38, 88, 150, 0.12);
    --radius: 22px;
}

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: linear-gradient(180deg, #f5faff 0%, #ffffff 38%, #f8fbff 100%);
    line-height: 1.75;
    overflow-x: hidden;
}

img {
    max-width: 100%;
    display: block;
}

a {
    color: inherit;
    text-decoration: none;
}

.container {
    width: min(100% - 32px, 1160px);
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 30;
    background: rgba(255,255,255,0.9);
    border-bottom: 1px solid rgba(219, 231, 245, 0.9);
    backdrop-filter: blur(16px);
}

.header-inner {
    min-height: 68px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.logo, .footer-logo {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    letter-spacing: 0.02em;
    color: var(--primary-dark);
}

.logo img, .footer-logo img {
    width: 36px;
    height: 36px;
    border-radius: 12px;
}

.nav-toggle {
    border: 1px solid var(--line);
    background: #fff;
    color: var(--ink);
    width: 42px;
    height: 42px;
    border-radius: 14px;
    font-size: 20px;
}

.main-nav {
    display: none;
    position: absolute;
    left: 16px;
    right: 16px;
    top: 74px;
    padding: 12px;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 18px;
    box-shadow: var(--shadow);
}

.main-nav.open {
    display: grid;
    gap: 6px;
}

.main-nav a {
    padding: 10px 12px;
    border-radius: 12px;
    color: #41506a;
    font-size: 15px;
}

.main-nav a:hover, .main-nav a.active {
    background: var(--primary-soft);
    color: var(--primary-dark);
}

.section {
    padding: 64px 0;
}

.section-sm {
    padding: 42px 0;
}

.hero {
    padding: 54px 0 48px;
    background:
        radial-gradient(circle at top left, rgba(70,139,223,0.18), transparent 36%),
        linear-gradient(135deg, #ffffff 0%, #edf7ff 100%);
}

.hero-layout {
    display: grid;
    gap: 32px;
    align-items: center;
}

.eyebrow, .badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    width: fit-content;
    padding: 7px 12px;
    border-radius: 999px;
    color: var(--primary-dark);
    background: rgba(70,139,223,0.11);
    border: 1px solid rgba(70,139,223,0.18);
    font-size: 13px;
    font-weight: 700;
}

h1, h2, h3 {
    line-height: 1.25;
    margin: 0 0 14px;
}

h1 {
    font-size: clamp(34px, 7vw, 58px);
    letter-spacing: -0.04em;
}

h2 {
    font-size: clamp(26px, 4vw, 38px);
    letter-spacing: -0.03em;
}

h3 {
    font-size: 19px;
}

.lead {
    font-size: 17px;
    color: var(--muted);
    margin: 0 0 24px;
}

.hero-tags, .tag-row {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 22px 0 28px;
}

.hero-tags span, .tag-row span {
    padding: 8px 11px;
    border-radius: 999px;
    background: #fff;
    border: 1px solid var(--line);
    color: #40506c;
    font-size: 13px;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 48px;
    padding: 13px 24px;
    border-radius: 999px;
    color: #fff;
    background: linear-gradient(135deg, var(--primary), #2f78d3);
    box-shadow: 0 12px 28px rgba(70,139,223,0.28);
    font-weight: 800;
    border: none;
    cursor: pointer;
    transition: transform .2s ease, box-shadow .2s ease;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 16px 32px rgba(70,139,223,0.32);
}

.hero-visual {
    position: relative;
    min-height: 430px;
    border-radius: 30px;
    padding: 22px;
    background: linear-gradient(150deg, rgba(255,255,255,0.92), rgba(232,244,255,0.9));
    border: 1px solid rgba(70,139,223,0.14);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.app-shell {
    width: min(250px, 75%);
    margin: 8px auto 0;
    padding: 12px;
    border-radius: 34px;
    background: #101a2d;
    box-shadow: 0 24px 60px rgba(20, 48, 87, .24);
}

.app-shell img {
    border-radius: 24px;
}

.float-card {
    position: absolute;
    display: grid;
    gap: 4px;
    width: 180px;
    padding: 14px;
    border-radius: 18px;
    background: rgba(255,255,255,0.88);
    border: 1px solid rgba(219,231,245,0.85);
    box-shadow: 0 15px 36px rgba(32,74,126,.14);
    backdrop-filter: blur(14px);
    font-size: 13px;
}

.float-card strong {
    color: var(--primary-dark);
}

.float-card.one { left: 14px; top: 26px; }
.float-card.two { right: 12px; top: 86px; }
.float-card.three { left: 22px; bottom: 28px; }
.float-card.four { right: 18px; bottom: 44px; }

.stats-strip {
    display: grid;
    gap: 14px;
    padding: 18px;
    border-radius: var(--radius);
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.stat-item {
    padding: 16px;
    border-radius: 18px;
    background: linear-gradient(180deg, #f6fbff, #ffffff);
    border: 1px solid var(--line);
}

.stat-item strong {
    display: block;
    color: var(--primary-dark);
    font-size: 18px;
    margin-bottom: 4px;
}

.section-head {
    max-width: 780px;
    margin-bottom: 28px;
}

.section-head.center {
    text-align: center;
    margin-left: auto;
    margin-right: auto;
}

.grid, .feature-grid, .category-grid, .scenario-grid, .article-grid, .faq-grid {
    display: grid;
    gap: 18px;
}

.card, .category-card, .feature-card, .scenario-card, .faq-item, .note-card, .step-card {
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 22px;
    box-shadow: 0 14px 34px rgba(30, 82, 145, 0.08);
}

.category-card, .feature-card, .scenario-card {
    transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.category-card:hover, .feature-card:hover, .scenario-card:hover {
    transform: translateY(-3px);
    border-color: rgba(70,139,223,0.35);
    box-shadow: var(--shadow);
}

.card-icon {
    width: 42px;
    height: 42px;
    display: grid;
    place-items: center;
    margin-bottom: 12px;
    color: var(--primary-dark);
    border-radius: 15px;
    background: var(--primary-soft);
    font-weight: 800;
}

.steps {
    display: grid;
    gap: 16px;
    counter-reset: step;
}

.step-card {
    position: relative;
    overflow: hidden;
}

.step-card:before {
    counter-increment: step;
    content: counter(step);
    width: 34px;
    height: 34px;
    display: grid;
    place-items: center;
    margin-bottom: 12px;
    color: #fff;
    border-radius: 12px;
    background: var(--primary);
    font-weight: 800;
}

.security-layout, .split-layout {
    display: grid;
    gap: 24px;
    align-items: center;
}

.security-panel {
    position: relative;
    padding: 24px;
    border-radius: 28px;
    background: linear-gradient(135deg, #ffffff, #edf7ff);
    border: 1px solid rgba(70,139,223,0.18);
    box-shadow: var(--shadow);
}

.security-row {
    display: flex;
    justify-content: space-between;
    gap: 14px;
    padding: 14px 0;
    border-bottom: 1px solid var(--line);
}

.security-row:last-child {
    border-bottom: 0;
}

.security-row span {
    color: var(--muted);
}

.cta-section {
    padding: 48px 22px;
    text-align: center;
    border-radius: 30px;
    background: linear-gradient(135deg, rgba(70,139,223,0.12), rgba(255,255,255,0.95));
    border: 1px solid rgba(70,139,223,0.18);
}

.page-hero {
    padding: 54px 0 34px;
    background: radial-gradient(circle at top right, rgba(70,139,223,0.16), transparent 35%), linear-gradient(180deg, #ffffff, #f2f8ff);
}

.page-hero .container {
    max-width: 920px;
}

.content-layout {
    display: grid;
    gap: 22px;
    align-items: start;
}

.article-body {
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 26px;
    padding: 24px;
    box-shadow: var(--shadow);
}

.article-body p {
    color: #46536b;
    margin: 0 0 16px;
}

.article-body ul, .article-body ol {
    padding-left: 22px;
    color: #46536b;
}

.tip-box {
    padding: 18px;
    border-radius: 20px;
    background: #f1f8ff;
    border: 1px solid rgba(70,139,223,0.18);
    color: #354762;
}

.info-list {
    display: grid;
    gap: 12px;
    margin: 18px 0;
}

.info-list div {
    padding: 14px 16px;
    border-radius: 16px;
    background: #f7fbff;
    border: 1px solid var(--line);
}

.faq-item details {
    cursor: pointer;
}

.faq-item summary {
    font-weight: 800;
    color: var(--ink);
}

.faq-item p {
    color: var(--muted);
    margin-bottom: 0;
}

.site-footer {
    margin-top: 50px;
    background: #0f2747;
    color: #dce9f8;
    padding: 46px 0 24px;
}

.footer-grid {
    display: grid;
    gap: 24px;
}

.site-footer h3 {
    color: #fff;
    font-size: 16px;
}

.site-footer a {
    display: block;
    color: #c6d8ee;
    margin: 8px 0;
    font-size: 14px;
}

.footer-bottom {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding-top: 22px;
    margin-top: 28px;
    border-top: 1px solid rgba(255,255,255,0.12);
    font-size: 13px;
    color: #aac0da;
}

@media (min-width: 640px) {
    .stats-strip, .category-grid, .feature-grid, .scenario-grid, .faq-grid, .article-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
    .steps {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (min-width: 920px) {
    .container { width: min(100% - 56px, 1160px); }
    .nav-toggle { display: none; }
    .main-nav {
        display: flex;
        position: static;
        padding: 0;
        border: 0;
        box-shadow: none;
        background: transparent;
        align-items: center;
        gap: 2px;
    }
    .hero { padding: 78px 0 70px; }
    .hero-layout, .security-layout, .split-layout {
        grid-template-columns: 1.02fr .98fr;
    }
    .category-grid, .feature-grid, .scenario-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
    .stats-strip {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }
    .steps {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
    .content-layout {
        grid-template-columns: minmax(0, 1fr) 330px;
    }
    .footer-grid {
        grid-template-columns: 1.4fr repeat(3, 1fr);
    }
    .footer-bottom {
        flex-direction: row;
        justify-content: space-between;
    }
    .article-body { padding: 34px; }
}

@media (max-width: 420px) {
    .float-card {
        position: static;
        width: 100%;
        margin-top: 10px;
    }
    .hero-visual {
        min-height: auto;
    }
    .app-shell {
        width: min(230px, 86%);
    }
}