:root {
    --ink: #1a1a1a;
    --paper: #f4f4f2;
    --mute: #5c5c5c;
    --line: #d5d5d0;
    --red: #c8102e;
    --blue: #003688;
    --yellow: #ffd329;
    --green: #007a53;
    --navy: #0019a8;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
    font-family: "Arial", "Helvetica Neue", "Microsoft YaHei", sans-serif;
    color: var(--ink);
    background: var(--paper);
    line-height: 1.7;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.container { width: min(1100px, calc(100% - 40px)); margin: 0 auto; }

.tube-bar {
    display: flex;
    justify-content: space-between;
    padding: 8px 20px;
    background: var(--ink);
    color: #fff;
    font-size: 11px;
    letter-spacing: 0.16em;
}
.tube-bar b {
    display: inline-block;
    width: 18px;
    height: 6px;
    margin-right: 4px;
    vertical-align: middle;
}
.tube-bar b:nth-child(1) { background: var(--red); }
.tube-bar b:nth-child(2) { background: var(--blue); }
.tube-bar b:nth-child(3) { background: var(--yellow); }

.site-nav {
    position: sticky;
    top: 0;
    z-index: 20;
    background: #fff;
    border-bottom: 6px solid var(--red);
}
.nav-wrap {
    display: flex;
    align-items: center;
    gap: 18px;
    min-height: 70px;
}
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
}
.logo-mark {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    border: 6px solid var(--red);
    display: grid;
    place-items: center;
    font-size: 12px;
    background: #fff;
}
.nav-toggle { display: none; }
.nav-burger {
    display: none;
    margin-left: auto;
    padding: 6px 10px;
    border: 1px solid var(--ink);
    font-size: 13px;
}
.nav-menu { display: flex; gap: 16px; flex: 1; font-size: 14px; }
.nav-menu a { color: var(--mute); }
.nav-menu a.active, .nav-menu a:hover { color: var(--red); }
.nav-actions { display: flex; gap: 10px; }

.btn {
    display: inline-block;
    padding: 10px 18px;
    background: var(--red);
    color: #fff;
    font-weight: 700;
}
.btn:hover { background: #a20d25; }
.btn-lg { padding: 14px 26px; }
.btn-ghost {
    background: transparent;
    color: var(--ink);
    border: 1px solid var(--ink);
}

.hero { padding: 56px 0 64px; background: #fff; }
.hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 36px;
    align-items: center;
}
.lines {
    display: flex;
    gap: 6px;
    margin-bottom: 14px;
}
.lines i { display: block; height: 8px; width: 48px; }
.lines i:nth-child(1) { background: var(--red); }
.lines i:nth-child(2) { background: var(--blue); }
.lines i:nth-child(3) { background: var(--yellow); }
.lines i:nth-child(4) { background: var(--green); }
.tag {
    display: inline-block;
    margin-bottom: 10px;
    color: var(--blue);
    letter-spacing: 0.12em;
    font-size: 12px;
    font-weight: 700;
}
.hero-kicker { color: var(--mute); margin-bottom: 8px; }
.hero h1 {
    font-size: clamp(28px, 4vw, 44px);
    line-height: 1.22;
    margin-bottom: 14px;
}
.hero p { color: var(--mute); max-width: 36em; }
.meta {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    margin-top: 16px;
    color: var(--mute);
    font-size: 13px;
}
.hero-visual img { width: 100%; border: 2px solid var(--ink); }

.data-band {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
}
.data-band > div {
    padding: 22px 12px;
    text-align: center;
    color: #fff;
}
.data-band > div:nth-child(1) { background: var(--red); }
.data-band > div:nth-child(2) { background: var(--blue); }
.data-band > div:nth-child(3) { background: var(--green); }
.data-band > div:nth-child(4) { background: var(--navy); }
.data-num { font-size: 26px; }
.data-label { font-size: 12px; letter-spacing: 0.1em; opacity: 0.9; }

.section { padding: 64px 0; }
.section.alt { background: #fff; }
.section-head { margin-bottom: 24px; }
.section-head h2 { font-size: 28px; margin-bottom: 8px; }
.section-head p { color: var(--mute); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card {
    padding: 20px;
    background: #fff;
    border-left: 8px solid var(--red);
}
.card:nth-child(2) { border-left-color: var(--blue); }
.card:nth-child(3) { border-left-color: var(--yellow); }
.card:nth-child(4) { border-left-color: var(--green); }
.card:nth-child(5) { border-left-color: var(--navy); }
.card:nth-child(6) { border-left-color: #9b0058; }
.card h3 { margin: 8px 0 8px; font-size: 19px; }
.card p { color: var(--mute); font-size: 14px; }
.card.main { outline: 2px solid var(--ink); }
.icon { font-size: 11px; font-weight: 700; letter-spacing: 0.1em; color: var(--mute); }
.solution-card { padding: 0; overflow: hidden; border-left-width: 8px; }
.solution-card img { height: 168px; width: 100%; object-fit: cover; }
.solution-card div { padding: 14px 16px 18px; }
.price { font-weight: 700; margin-bottom: 6px; }

.cta {
    padding: 64px 0;
    text-align: center;
    background: var(--ink);
    color: #fff;
}
.cta h2 { font-size: 30px; margin-bottom: 10px; }
.cta p { color: #c8c8c8; margin-bottom: 20px; }
.cta .btn { background: var(--yellow); color: var(--ink); }
.cta .btn-ghost { background: transparent; color: #fff; border-color: #fff; }
.cta-actions { display: flex; justify-content: center; gap: 12px; flex-wrap: wrap; }

.site-footer {
    padding: 40px 0 20px;
    background: #fff;
    border-top: 6px solid var(--blue);
}
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 24px; }
.footer-grid h4 { margin-bottom: 10px; }
.footer-grid a, .footer-grid p { display: block; color: var(--mute); margin-bottom: 6px; font-size: 14px; }
.footer-bottom {
    margin-top: 22px;
    padding-top: 12px;
    border-top: 1px solid var(--line);
    color: var(--mute);
    font-size: 12px;
}

.page-hero { padding: 48px 0 16px; }
.page-hero h1 { font-size: 34px; margin: 8px 0 10px; }
.page-hero p { color: var(--mute); max-width: 40em; }
.dl-list, .help-list { display: grid; gap: 12px; }
.dl-item, .help-box {
    padding: 18px 20px;
    background: #fff;
    border-left: 8px solid var(--blue);
}
.dl-item { display: flex; justify-content: space-between; gap: 20px; align-items: center; }
.dl-item.main { border-left-color: var(--red); }
.specs { display: flex; gap: 12px; font-size: 13px; margin: 6px 0; font-weight: 700; }
.shot { margin-top: 24px; }
.shot img { width: 100%; border: 2px solid var(--ink); }

@media (max-width: 900px) {
    .nav-burger { display: inline-block; }
    .nav-menu, .nav-actions { display: none; }
    .nav-toggle:checked ~ .nav-menu,
    .nav-toggle:checked ~ .nav-actions {
        display: flex;
        flex-direction: column;
        width: 100%;
        padding-bottom: 16px;
    }
    .nav-wrap { flex-wrap: wrap; }
    .hero-grid, .grid-3, .data-band, .footer-grid, .dl-item {
        grid-template-columns: 1fr;
        display: grid;
    }
}