:root {
    --paper: #f3ead8;
    --fiber: #e8dcc4;
    --ink: #2a2418;
    --mute: #6a5d4a;
    --seal: #b23a2f;
    --cinnabar: #d4543a;
    --line: #c9b89a;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
    font-family: "Songti SC", "STSong", "SimSun", "Noto Serif SC", serif;
    color: var(--ink);
    background-color: var(--paper);
    background-image:
        repeating-linear-gradient(0deg, transparent, transparent 27px, rgba(180,150,110,0.12) 28px),
        radial-gradient(circle at 12% 18%, rgba(90,70,40,0.05) 0 1px, transparent 2px),
        radial-gradient(circle at 68% 42%, rgba(90,70,40,0.04) 0 1px, transparent 2px),
        radial-gradient(circle at 34% 76%, rgba(140,90,50,0.05) 0 1px, transparent 2px);
    background-size: auto, 140px 90px, 180px 120px, 160px 100px;
    line-height: 1.75;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
.container { width: min(1080px, calc(100% - 40px)); margin: 0 auto; }

.paper-edge {
    height: 10px;
    background:
        linear-gradient(90deg, #c9b89a 0 8%, transparent 8% 14%, #d4c4a4 14% 22%, transparent 22% 30%, #c9b89a 30% 40%, transparent 40% 48%, #d4c4a4 48% 58%, transparent 58% 66%, #c9b89a 66% 78%, transparent 78% 86%, #d4c4a4 86% 100%);
    opacity: 0.7;
}

.site-nav {
    position: sticky;
    top: 0;
    z-index: 20;
    background: #efe4cc;
    border-bottom: 1px solid var(--line);
    box-shadow: 0 1px 0 #fff8ea inset;
}
.nav-wrap {
    display: flex;
    align-items: center;
    gap: 16px;
    min-height: 72px;
}
.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    letter-spacing: 0.12em;
}
.logo-mark {
    width: 34px;
    height: 34px;
    display: grid;
    place-items: center;
    border: 2px solid var(--seal);
    color: var(--seal);
    border-radius: 50%;
    font-size: 16px;
    box-shadow: 0 0 0 3px rgba(178,58,47,0.12);
}
.logo small { display: block; font-size: 10px; color: var(--mute); letter-spacing: 0.22em; }
.nav-toggle { display: none; }
.nav-burger {
    display: none;
    margin-left: auto;
    padding: 4px 12px;
    border: 1px solid var(--seal);
    color: var(--seal);
    font-size: 12px;
    letter-spacing: 0.16em;
}
.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(--seal);
    border-bottom: 1px solid var(--seal);
}
.nav-actions { display: flex; gap: 8px; }

.btn {
    display: inline-block;
    padding: 8px 16px;
    background: var(--seal);
    color: #f7efe0;
    font-size: 13px;
    letter-spacing: 0.08em;
    border: 1px solid #8d2a22;
}
.btn:hover { background: var(--cinnabar); }
.btn-lg { padding: 12px 22px; }
.btn-ghost {
    background: transparent;
    color: var(--ink);
    border: 1px solid var(--line);
}

.hero { padding: 52px 0 36px; }
.hero-grid {
    display: grid;
    grid-template-columns: 1.05fr 0.95fr;
    gap: 36px;
    align-items: center;
}
.hero-kicker {
    color: var(--seal);
    letter-spacing: 0.2em;
    font-size: 12px;
    margin-bottom: 12px;
}
.hero h1 {
    font-size: clamp(30px, 4.2vw, 44px);
    line-height: 1.28;
    font-weight: 700;
    margin-bottom: 14px;
}
.hero p { color: var(--mute); max-width: 38em; }
.hero-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 22px; }
.hero-visual {
    padding: 14px;
    background: #fff8ec;
    border: 1px solid var(--line);
    box-shadow: 8px 8px 0 rgba(42,36,24,0.06);
    position: relative;
}
.hero-visual::after {
    content: "";
    position: absolute;
    inset: 6px;
    border: 1px dashed rgba(178,58,47,0.25);
    pointer-events: none;
}
.hero-visual img { width: 100%; }

.data-band {
    background: #2a2418;
    color: #efe4cc;
}
.data-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.data-grid > div {
    padding: 22px 16px;
    border-right: 1px solid #4a4030;
}
.data-grid > div:last-child { border-right: 0; }
.data-num { font-size: 24px; color: #f3ead8; }
.data-label { color: #b8a888; font-size: 12px; letter-spacing: 0.12em; }

.section { padding: 52px 0; }
.section.alt { background: rgba(232,220,196,0.45); }
.section-head { margin-bottom: 22px; }
.section-head h2 {
    font-size: 26px;
    margin-bottom: 8px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--line);
    display: inline-block;
}
.section-head p { color: var(--mute); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
.card {
    padding: 20px 18px;
    background: #fff8ec;
    border: 1px solid var(--line);
    box-shadow: 0 1px 0 #fff inset;
}
.card.main { outline: 1px solid var(--seal); outline-offset: -5px; }
.card h3 { margin: 8px 0; font-size: 18px; }
.card p { color: var(--mute); font-size: 14px; }
.icon {
    width: 22px;
    height: 22px;
    border: 1px solid var(--seal);
    border-radius: 50%;
    position: relative;
}
.icon::after {
    content: "";
    position: absolute;
    inset: 6px;
    background: var(--seal);
    border-radius: 50%;
}
.solution-card { padding: 0; overflow: hidden; }
.solution-card img { height: 158px; width: 100%; object-fit: cover; }
.solution-card div { padding: 14px 16px 18px; }
.price { color: var(--seal); margin-bottom: 6px; letter-spacing: 0.08em; }

.cta {
    padding: 56px 0;
    text-align: center;
    background: #2a2418;
    color: #f3ead8;
}
.cta h2 { font-size: 28px; margin-bottom: 10px; }
.cta p { color: #c9b89a; margin-bottom: 20px; }
.cta-actions { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; }
.cta .btn { background: var(--seal); color: #fff8ec; }
.cta .btn-ghost { background: transparent; color: #f3ead8; border-color: #6a5d4a; }

.site-footer {
    padding: 36px 0 18px;
    background: #efe4cc;
    border-top: 1px solid var(--line);
}
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr 1fr; gap: 22px; }
.footer-grid h4 { color: var(--seal); margin-bottom: 10px; font-size: 13px; letter-spacing: 0.16em; }
.footer-grid a, .footer-grid p { display: block; color: var(--mute); margin-bottom: 6px; font-size: 13px; }
.footer-bottom {
    margin-top: 20px;
    padding-top: 12px;
    border-top: 1px dashed var(--line);
    color: #8a7a62;
    font-size: 12px;
}

.page-hero { padding: 40px 0 10px; }
.page-hero h1 { font-size: 32px; margin: 8px 0; }
.page-hero p { color: var(--mute); max-width: 44em; }
.dl-list, .help-list { display: grid; gap: 12px; }
.dl-item, .help-box {
    padding: 20px 22px;
    background: #fff8ec;
    border: 1px solid var(--line);
    border-left: 3px solid var(--seal);
}
.dl-item { display: flex; justify-content: space-between; gap: 18px; align-items: center; }
.dl-item.main { background: #fff3df; }
.specs { display: flex; gap: 14px; color: var(--seal); font-size: 12px; margin: 6px 0; letter-spacing: 0.08em; }
.shot {
    margin-top: 22px;
    padding: 10px;
    background: #fff8ec;
    border: 1px solid var(--line);
}
.shot img { width: 100%; }

@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: 14px;
    }
    .nav-wrap { flex-wrap: wrap; }
    .hero-grid, .grid-3, .data-grid, .footer-grid, .dl-item { grid-template-columns: 1fr; display: grid; }
    .data-grid > div { border-right: 0; border-bottom: 1px solid #4a4030; }
}