/* ============ 基础变量与重置 ============ */
:root {
    --c-bg: #0A1628;
    --c-bg-2: #0F1E36;
    --c-bg-3: #162843;
    --c-cyan: #00D4FF;
    --c-cyan-dim: #0099BB;
    --c-silver: #8B9DC3;
    --c-orange: #FF6B35;
    --c-white: #FFFFFF;
    --c-text: #E8EEF7;
    --c-text-dim: #9FB0CC;
    --c-border: rgba(139, 157, 195, 0.18);
    --c-card: rgba(22, 40, 67, 0.6);
    --c-card-hover: rgba(0, 212, 255, 0.08);
    --shadow-glow: 0 0 30px rgba(0, 212, 255, 0.25);
    --shadow-card: 0 12px 40px rgba(0, 0, 0, 0.4);
    --radius: 6px;
    --radius-lg: 12px;
    --container: 1200px;
    --font-sans: "PingFang SC", "Source Han Sans SC", "Noto Sans CJK SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
    --font-num: "DIN Alternate", "Helvetica Neue", Arial, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
    font-family: var(--font-sans);
    background: var(--c-bg);
    color: var(--c-text);
    line-height: 1.7;
    font-size: 15px;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; transition: color .25s ease; }
img { max-width: 100%; display: block; }
ul { list-style: none; }
button { font-family: inherit; cursor: pointer; border: none; background: none; color: inherit; }

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 24px; }

/* ============ 顶部导航 ============ */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    background: rgba(10, 22, 40, 0.75);
    backdrop-filter: blur(20px) saturate(160%);
    -webkit-backdrop-filter: blur(20px) saturate(160%);
    border-bottom: 1px solid var(--c-border);
    transition: background .3s ease, box-shadow .3s ease;
}
.navbar.scrolled {
    background: rgba(10, 22, 40, 0.92);
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}
.nav-container {
    display: flex; align-items: center; justify-content: space-between;
    height: 72px;
}

/* Logo */
.logo {
    display: flex; align-items: baseline; gap: 8px;
    font-weight: 700; letter-spacing: 0.5px;
}
.logo-text { font-size: 22px; color: var(--c-white); }
.logo-reg {
    font-size: 11px; color: var(--c-cyan);
    border: 1px solid var(--c-cyan); border-radius: 50%;
    width: 14px; height: 14px; display: inline-flex;
    align-items: center; justify-content: center;
    line-height: 1; margin-left: 2px;
    transform: translateY(-6px);
}
.logo-divider { color: var(--c-silver); font-weight: 300; opacity: .6; }
.logo-sub { font-size: 18px; color: var(--c-cyan); letter-spacing: 2px; }

/* Nav menu */
.nav-menu { display: flex; gap: 4px; }
.nav-link {
    padding: 8px 16px; font-size: 15px; color: var(--c-text-dim);
    border-radius: var(--radius); position: relative;
}
.nav-link::after {
    content: ""; position: absolute; bottom: 2px; left: 50%;
    width: 0; height: 2px; background: var(--c-cyan);
    transition: width .3s ease, left .3s ease;
}
.nav-link:hover, .nav-link.active { color: var(--c-white); }
.nav-link:hover::after, .nav-link.active::after { width: 24px; left: calc(50% - 12px); }

.nav-cta {
    display: flex; align-items: center; gap: 8px;
    padding: 9px 18px; background: linear-gradient(135deg, var(--c-orange), #E84A12);
    color: var(--c-white); border-radius: var(--radius);
    font-weight: 600; font-size: 14px;
    box-shadow: 0 4px 16px rgba(255, 107, 53, 0.35);
    transition: transform .25s ease, box-shadow .25s ease;
}
.nav-cta:hover { transform: translateY(-2px); box-shadow: 0 6px 22px rgba(255, 107, 53, 0.5); }
.cta-icon { font-size: 16px; }

.nav-toggle {
    display: none; flex-direction: column; gap: 5px; padding: 6px;
}
.nav-toggle span {
    width: 24px; height: 2px; background: var(--c-white);
    transition: transform .3s ease, opacity .3s ease;
}
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============ Hero 区 ============ */
.hero {
    position: relative; min-height: 100vh;
    background: radial-gradient(ellipse at top right, #142A4D 0%, var(--c-bg) 55%, #060F1E 100%);
    overflow: hidden; padding-top: 72px;
}
.hero-grid {
    position: absolute; inset: 0;
    background-image:
        linear-gradient(rgba(0, 212, 255, 0.06) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 212, 255, 0.06) 1px, transparent 1px);
    background-size: 56px 56px;
    mask-image: radial-gradient(ellipse at 70% 40%, #000 0%, transparent 75%);
    -webkit-mask-image: radial-gradient(ellipse at 70% 40%, #000 0%, transparent 75%);
    animation: gridShift 24s linear infinite;
}
@keyframes gridShift {
    from { background-position: 0 0, 0 0; }
    to { background-position: 56px 56px, 56px 56px; }
}
.hero::before {
    content: ""; position: absolute; top: -200px; right: -150px;
    width: 600px; height: 600px; border-radius: 50%;
    background: radial-gradient(circle, rgba(0, 212, 255, 0.18), transparent 70%);
    filter: blur(40px); animation: float 12s ease-in-out infinite;
}
.hero::after {
    content: ""; position: absolute; bottom: -200px; left: -150px;
    width: 500px; height: 500px; border-radius: 50%;
    background: radial-gradient(circle, rgba(255, 107, 53, 0.12), transparent 70%);
    filter: blur(50px); animation: float 14s ease-in-out infinite reverse;
}
@keyframes float {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(30px, -30px); }
}

.hero-content { position: relative; z-index: 2; padding: 80px 0 60px; }
.hero-inner { max-width: 820px; }
.hero-tag {
    display: inline-block; padding: 6px 16px;
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.3);
    color: var(--c-cyan); border-radius: 20px;
    font-size: 13px; letter-spacing: 1px;
    margin-bottom: 28px;
    animation: fadeUp .8s ease both;
}
.hero-title {
    font-size: 52px; font-weight: 800; line-height: 1.2;
    color: var(--c-white); margin-bottom: 28px;
    letter-spacing: 1px;
    animation: fadeUp .8s ease .1s both;
}
.title-accent {
    background: linear-gradient(120deg, var(--c-cyan), var(--c-silver));
    -webkit-background-clip: text; background-clip: text;
    -webkit-text-fill-color: transparent;
}
.hero-desc {
    font-size: 17px; color: var(--c-text-dim); line-height: 1.9;
    margin-bottom: 40px; max-width: 720px;
    animation: fadeUp .8s ease .2s both;
}
.hero-actions { display: flex; gap: 16px; margin-bottom: 56px; animation: fadeUp .8s ease .3s both; }

.btn {
    display: inline-flex; align-items: center; justify-content: center;
    padding: 15px 34px; border-radius: var(--radius);
    font-size: 16px; font-weight: 600; letter-spacing: 1px;
    transition: transform .25s ease, box-shadow .25s ease, background .25s ease;
}
.btn-primary {
    background: linear-gradient(135deg, var(--c-orange), #E84A12);
    color: var(--c-white);
    box-shadow: 0 6px 24px rgba(255, 107, 53, 0.4);
}
.btn-primary:hover { transform: translateY(-3px); box-shadow: 0 10px 32px rgba(255, 107, 53, 0.55); }
.btn-ghost {
    background: transparent; color: var(--c-cyan);
    border: 1px solid rgba(0, 212, 255, 0.5);
}
.btn-ghost:hover { background: rgba(0, 212, 255, 0.1); border-color: var(--c-cyan); }

.hero-points {
    display: flex; gap: 48px; flex-wrap: wrap;
    animation: fadeUp .8s ease .4s both;
}
.hero-points li { display: flex; flex-direction: column; }
.hero-points strong {
    font-family: var(--font-num); font-size: 38px; font-weight: 700;
    color: var(--c-cyan); line-height: 1; margin-bottom: 6px;
}
.hero-points span { font-size: 13px; color: var(--c-text-dim); letter-spacing: 1px; }

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ============ 通用 Section ============ */
.section { padding: 96px 0; position: relative; }
.section-head { text-align: center; max-width: 760px; margin: 0 auto 64px; }
.section-label {
    display: inline-block; font-family: var(--font-num);
    font-size: 13px; letter-spacing: 4px; color: var(--c-cyan);
    margin-bottom: 12px; padding: 0 14px; position: relative;
}
.section-label::before, .section-label::after {
    content: ""; position: absolute; top: 50%; width: 32px; height: 1px;
    background: linear-gradient(90deg, transparent, var(--c-cyan));
}
.section-label::before { right: 100%; transform: scaleX(-1); }
.section-label::after { left: 100%; }
.section-title {
    font-size: 36px; font-weight: 800; color: var(--c-white);
    letter-spacing: 2px; margin-bottom: 16px;
}
.section-sub { font-size: 16px; color: var(--c-text-dim); }

/* ============ 主营业务 ============ */
.business { background: var(--c-bg-2); }
.business-grid {
    display: grid; grid-template-columns: repeat(4, 1fr);
    gap: 20px;
}
.biz-card {
    background: var(--c-card); border: 1px solid var(--c-border);
    border-radius: var(--radius-lg); padding: 32px 24px;
    position: relative; overflow: hidden;
    transition: transform .35s ease, border-color .35s ease, background .35s ease;
}
.biz-card::before {
    content: ""; position: absolute; top: 0; left: 0; right: 0; height: 2px;
    background: linear-gradient(90deg, transparent, var(--c-cyan), transparent);
    transform: scaleX(0); transition: transform .4s ease;
}
.biz-card:hover, .biz-card.active {
    transform: translateY(-6px);
    border-color: rgba(0, 212, 255, 0.5);
    background: var(--c-card-hover);
}
.biz-card:hover::before, .biz-card.active::before { transform: scaleX(1); }
.biz-card.active { box-shadow: var(--shadow-glow); }

.biz-icon {
    width: 52px; height: 52px; margin-bottom: 20px;
    border-radius: var(--radius);
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.15), rgba(0, 212, 255, 0.04));
    border: 1px solid rgba(0, 212, 255, 0.25);
    position: relative;
}
.biz-icon::after {
    content: ""; position: absolute; inset: 12px;
    background: var(--c-cyan); opacity: .85;
    -webkit-mask: var(--icon-svg) center/contain no-repeat;
    mask: var(--icon-svg) center/contain no-repeat;
}
.biz-icon[data-icon="industry"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M2 20h20v-9l-6 4V7l-6 4V3H2z'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="gear"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M12 8a4 4 0 1 0 0 8 4 4 0 0 0 0-8m9 4-2.1.6-1.2-2 1.2-2L21 12m-9 9 .6-2.1-2-1.2-2 1.2L9 21m-6-9 2.1-.6 1.2 2-1.2 2L3 12m9-9-.6 2.1 2 1.2 2-1.2L15 3'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="box"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M12 2 2 7v10l10 5 10-5V7zm0 2.2 7.5 3.8L12 11.8 4.5 8zM4 9.5l7 3.5v7.4l-7-3.5zm9 10.9V13l7-3.5v7.4z'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="shield"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M12 2 4 5v6c0 5 3.5 9.5 8 11 4.5-1.5 8-6 8-11V5zm0 5 4 1.5V12c0 3-1.5 5.5-4 6.5-2.5-1-4-3.5-4-6.5V8.5z'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="gift"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M20 12v8H4v-8M2 7h20v5H2zm10 0c0-2.2-1.8-4-4-4S4 4.8 4 7m8 0c0-2.2 1.8-4 4-4s4 1.8 4 4'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="cube"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='m12 2 9 5v10l-9 5-9-5V7zm0 2.3L4.8 8.5 12 12l7.2-3.5zM11 13.7l-6-3v6.6l6 3zm2 6.6 6-3v-6.6l-6 3z'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="scan"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M3 3h6v2H5v4H3zm12 0h6v6h-2V5h-4zM3 15h2v4h4v2H3zm16 0h2v6h-6v-2h4zM7 11h10v2H7z'/%3E%3C/svg%3E"); }
.biz-icon[data-icon="printer"] { --icon-svg: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath fill='%2300D4FF' d='M6 9V2h12v7M6 18H4a2 2 0 0 1-2-2v-4a2 2 0 0 1 2-2h16a2 2 0 0 1 2 2v4a2 2 0 0 1-2 2h-2m-6 4H6v-7h12zM8 11h8'/%3E%3C/svg%3E"); }

.biz-card h3 {
    font-size: 19px; font-weight: 700; color: var(--c-white);
    margin-bottom: 10px; letter-spacing: 1px;
}
.biz-card p { font-size: 13px; color: var(--c-text-dim); line-height: 1.7; margin-bottom: 18px; }
.biz-arrow {
    font-size: 13px; color: var(--c-cyan); font-weight: 600;
    display: inline-flex; align-items: center; gap: 4px;
    transition: gap .25s ease;
}
.biz-card:hover .biz-arrow { gap: 10px; }

/* ============ 案例展示 ============ */
.cases { background: var(--c-bg); }
.cases-grid {
    display: grid; grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}
.case-card {
    background: var(--c-card); border: 1px solid var(--c-border);
    border-radius: var(--radius-lg); overflow: hidden;
    cursor: pointer; position: relative;
    transition: transform .4s ease, border-color .4s ease, box-shadow .4s ease;
}
.case-card:hover {
    transform: translateY(-6px);
    border-color: rgba(0, 212, 255, 0.5);
    box-shadow: var(--shadow-card);
}
.case-img {
    position: relative; overflow: hidden; aspect-ratio: 4/3;
    background: #0a1426;
}
.case-img img {
    width: 100%; height: 100%; object-fit: cover;
    transition: transform .6s ease;
}
.case-card:hover .case-img img { transform: scale(1.08); }
.case-img::after {
    content: ""; position: absolute; inset: 0;
    background: linear-gradient(to top, rgba(10,22,40,.6), transparent 50%);
    opacity: 0; transition: opacity .4s ease;
}
.case-card:hover .case-img::after { opacity: 1; }
.case-card figcaption { padding: 20px 22px 24px; }
.case-card h3 {
    font-size: 17px; font-weight: 700; color: var(--c-white);
    margin-bottom: 8px; letter-spacing: .5px;
}
.case-card p { font-size: 13px; color: var(--c-text-dim); line-height: 1.6; }

/* ============ FAQ ============ */
.faq { background: var(--c-bg-2); }
.faq-grid {
    display: grid; grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}
.faq-item {
    background: var(--c-card); border: 1px solid var(--c-border);
    border-radius: var(--radius-lg); overflow: hidden;
    transition: border-color .3s ease, background .3s ease;
}
.faq-item.open {
    border-color: rgba(0, 212, 255, 0.45);
    background: var(--c-card-hover);
}
.faq-q {
    width: 100%; display: flex; align-items: center; gap: 14px;
    padding: 20px 22px; text-align: left;
    font-size: 15px; font-weight: 600; color: var(--c-white);
    line-height: 1.5;
}
.faq-num {
    font-family: var(--font-num); font-size: 14px; font-weight: 700;
    color: var(--c-cyan); flex-shrink: 0;
    width: 30px; height: 30px; border-radius: 50%;
    background: rgba(0, 212, 255, 0.1);
    border: 1px solid rgba(0, 212, 255, 0.3);
    display: flex; align-items: center; justify-content: center;
}
.faq-q span:nth-child(2) { flex: 1; }
.faq-plus {
    flex-shrink: 0; width: 16px; height: 16px; position: relative;
    transition: transform .3s ease;
}
.faq-plus::before, .faq-plus::after {
    content: ""; position: absolute; background: var(--c-cyan);
    transition: opacity .3s ease;
}
.faq-plus::before { top: 50%; left: 0; right: 0; height: 2px; transform: translateY(-50%); }
.faq-plus::after { left: 50%; top: 0; bottom: 0; width: 2px; transform: translateX(-50%); }
.faq-item.open .faq-plus { transform: rotate(180deg); }
.faq-item.open .faq-plus::after { opacity: 0; }

.faq-a {
    max-height: 0; overflow: hidden;
    transition: max-height .4s ease, padding .4s ease;
    padding: 0 22px;
}
.faq-item.open .faq-a { max-height: 320px; padding: 0 22px 22px 66px; }
.faq-a p { font-size: 14px; color: var(--c-text-dim); line-height: 1.8; }

/* ============ 关于我们 ============ */
.about { background: var(--c-bg); }
.about-body {
    display: grid; grid-template-columns: 1.1fr 1.4fr;
    gap: 56px; align-items: center;
}
.about-media { position: relative; }
.about-media img {
    width: 100%; height: 380px; object-fit: cover;
    border-radius: var(--radius-lg);
    border: 1px solid var(--c-border);
}
.about-badge {
    position: absolute; top: 20px; left: 20px;
    padding: 8px 16px; background: rgba(0, 212, 255, 0.15);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(0, 212, 255, 0.4);
    color: var(--c-cyan); border-radius: 20px;
    font-size: 13px; font-weight: 600; letter-spacing: 1px;
}
.about-text { color: var(--c-text-dim); }
.about-lead {
    font-size: 16px; color: var(--c-text); line-height: 1.9;
    margin-bottom: 20px; font-weight: 500;
}
.about-text p { font-size: 14px; line-height: 1.9; margin-bottom: 28px; }
.about-stats {
    display: grid; grid-template-columns: repeat(4, 1fr);
    gap: 20px; padding: 28px 0;
    border-top: 1px solid var(--c-border);
    border-bottom: 1px solid var(--c-border);
}
.stat { display: flex; flex-direction: column; align-items: flex-start; }
.stat-num {
    font-family: var(--font-num); font-size: 36px; font-weight: 700;
    color: var(--c-cyan); line-height: 1;
}
.stat-plus { font-size: 24px; color: var(--c-cyan); font-weight: 700; line-height: 1; margin-top: -4px; }
.stat-label { font-size: 12px; color: var(--c-text-dim); margin-top: 8px; letter-spacing: 1px; }

/* ============ 联系我们 ============ */
.contact { background: linear-gradient(180deg, var(--c-bg-2), #060F1E); }
.contact-body {
    display: grid; grid-template-columns: 1.3fr 1fr;
    gap: 48px; align-items: stretch;
}
.contact-info { display: flex; flex-direction: column; gap: 16px; }
.contact-item {
    display: flex; align-items: center; gap: 18px;
    padding: 22px 24px; background: var(--c-card);
    border: 1px solid var(--c-border); border-radius: var(--radius-lg);
    transition: border-color .3s ease, transform .3s ease, background .3s ease;
}
.contact-item:hover {
    border-color: rgba(0, 212, 255, 0.4);
    transform: translateX(6px); background: var(--c-card-hover);
}
.ci-icon {
    width: 46px; height: 46px; flex-shrink: 0;
    border-radius: 50%; display: flex; align-items: center; justify-content: center;
    background: linear-gradient(135deg, rgba(0, 212, 255, 0.15), rgba(0, 212, 255, 0.04));
    border: 1px solid rgba(0, 212, 255, 0.3);
    color: var(--c-cyan); font-size: 20px;
}
.ci-label { display: block; font-size: 12px; color: var(--c-text-dim); margin-bottom: 4px; letter-spacing: 1px; }
.ci-value { display: block; font-size: 16px; color: var(--c-white); font-weight: 600; }

.contact-qr { display: flex; gap: 20px; justify-content: center; align-items: center; }
.qr-card {
    background: var(--c-card); border: 1px solid var(--c-border);
    border-radius: var(--radius-lg); padding: 24px;
    display: flex; flex-direction: column; align-items: center; gap: 14px;
    flex: 1; transition: transform .3s ease, border-color .3s ease;
}
.qr-card:hover { transform: translateY(-4px); border-color: rgba(0, 212, 255, 0.4); }
.qr-card img {
    width: 180px; height: 180px; object-fit: cover;
    border-radius: var(--radius); background: var(--c-white);
    padding: 8px;
}
.qr-label { font-size: 14px; color: var(--c-cyan); font-weight: 600; letter-spacing: 1px; }

/* ============ 底部 ============ */
.footer { background: #060F1E; padding: 64px 0 0; border-top: 1px solid var(--c-border); }
.footer-top {
    display: grid; grid-template-columns: 1.6fr 1fr 1fr 1.4fr;
    gap: 40px; padding-bottom: 48px;
    border-bottom: 1px solid var(--c-border);
}
.footer-logo { display: flex; align-items: baseline; gap: 8px; margin-bottom: 18px; }
.footer-desc { font-size: 13px; color: var(--c-text-dim); line-height: 1.8; max-width: 320px; }
.footer-col h4 {
    font-size: 15px; color: var(--c-white); font-weight: 700;
    margin-bottom: 18px; letter-spacing: 1px;
    position: relative; padding-left: 14px;
}
.footer-col h4::before {
    content: ""; position: absolute; left: 0; top: 50%;
    width: 4px; height: 14px; background: var(--c-cyan);
    transform: translateY(-50%); border-radius: 2px;
}
.footer-col ul li { margin-bottom: 10px; }
.footer-col ul li a, .footer-col ul li {
    font-size: 13px; color: var(--c-text-dim);
    transition: color .25s ease;
}
.footer-col ul li a:hover { color: var(--c-cyan); }
.footer-bottom { padding: 22px 0; text-align: center; }
.footer-bottom p { font-size: 12px; color: var(--c-text-dim); line-height: 1.8; }
.footer-bottom a { color: var(--c-cyan); }
.footer-bottom a:hover { text-decoration: underline; }

/* ============ 灯箱 ============ */
.lightbox {
    position: fixed; inset: 0; z-index: 1000;
    background: rgba(6, 15, 30, 0.92); backdrop-filter: blur(8px);
    display: none; align-items: center; justify-content: center;
    padding: 60px;
}
.lightbox.open { display: flex; }
.lightbox-content {
    max-width: 900px; max-height: 80vh; text-align: center;
}
.lightbox-content img {
    max-width: 100%; max-height: 70vh; object-fit: contain;
    border-radius: var(--radius); border: 1px solid var(--c-border);
}
#lightboxCaption {
    margin-top: 18px; color: var(--c-white); font-size: 15px;
}
#lightboxCaption h3 { font-size: 18px; margin-bottom: 6px; color: var(--c-cyan); }
#lightboxCaption p { font-size: 14px; color: var(--c-text-dim); }
.lightbox-close, .lightbox-prev, .lightbox-next {
    position: absolute; color: var(--c-white);
    width: 52px; height: 52px; border-radius: 50%;
    background: rgba(0, 212, 255, 0.1); border: 1px solid var(--c-border);
    font-size: 28px; display: flex; align-items: center; justify-content: center;
    transition: background .25s ease, transform .25s ease;
}
.lightbox-close:hover, .lightbox-prev:hover, .lightbox-next:hover {
    background: rgba(0, 212, 255, 0.25); transform: scale(1.08);
}
.lightbox-close { top: 24px; right: 24px; }
.lightbox-prev { left: 24px; top: 50%; transform: translateY(-50%); }
.lightbox-next { right: 24px; top: 50%; transform: translateY(-50%); }
.lightbox-prev:hover { transform: translateY(-50%) scale(1.08); }
.lightbox-next:hover { transform: translateY(-50%) scale(1.08); }

/* ============ 返回顶部 ============ */
.back-top {
    position: fixed; right: 28px; bottom: 28px; z-index: 90;
    width: 48px; height: 48px; border-radius: 50%;
    background: linear-gradient(135deg, var(--c-cyan), var(--c-cyan-dim));
    color: var(--c-bg); font-size: 22px; font-weight: 700;
    box-shadow: 0 6px 20px rgba(0, 212, 255, 0.4);
    opacity: 0; visibility: hidden; transform: translateY(20px);
    transition: opacity .3s ease, transform .3s ease, visibility .3s ease;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { transform: translateY(-3px); }

/* ============ 响应式 ============ */
@media (max-width: 1199px) {
    .hero-title { font-size: 44px; }
    .business-grid { grid-template-columns: repeat(2, 1fr); }
    .cases-grid { grid-template-columns: repeat(2, 1fr); }
    .about-body { grid-template-columns: 1fr; gap: 36px; }
    .about-stats { grid-template-columns: repeat(4, 1fr); }
    .footer-top { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
    .container { padding: 0 16px; }
    .nav-menu, .nav-cta { display: none; }
    .nav-toggle { display: flex; }
    .nav-menu.open {
        display: flex; flex-direction: column;
        position: fixed; top: 72px; left: 0; right: 0;
        background: rgba(10, 22, 40, 0.98);
        padding: 16px; gap: 0;
        border-bottom: 1px solid var(--c-border);
    }
    .nav-menu.open .nav-link { padding: 14px 16px; border-bottom: 1px solid var(--c-border); }
    .hero { min-height: auto; padding-top: 72px; }
    .hero-content { padding: 56px 0 48px; }
    .hero-title { font-size: 32px; }
    .hero-desc { font-size: 15px; }
    .hero-points { gap: 28px; }
    .hero-points strong { font-size: 28px; }
    .hero-actions { flex-wrap: wrap; }
    .btn { padding: 13px 26px; font-size: 14px; }
    .section { padding: 64px 0; }
    .section-title { font-size: 26px; }
    .section-head { margin-bottom: 40px; }
    .business-grid { grid-template-columns: 1fr; }
    .biz-card { padding: 24px 20px; }
    .cases-grid { grid-template-columns: 1fr; }
    .faq-grid { grid-template-columns: 1fr; }
    .faq-item.open .faq-a { padding: 0 18px 18px 18px; }
    .about-stats { grid-template-columns: repeat(2, 1fr); gap: 24px; }
    .about-media img { height: 260px; }
    .contact-body { grid-template-columns: 1fr; gap: 32px; }
    .contact-qr { flex-wrap: wrap; }
    .qr-card img { width: 150px; height: 150px; }
    .footer-top { grid-template-columns: 1fr; gap: 32px; padding-bottom: 36px; }
    .footer { padding: 48px 0 0; }
    .lightbox { padding: 20px; }
    .lightbox-close { top: 16px; right: 16px; }
    .lightbox-prev { left: 12px; }
    .lightbox-next { right: 12px; }
    .back-top { right: 16px; bottom: 16px; width: 42px; height: 42px; }
}