/* ============================================================
   秒速排 · 黑帽SEO技术矩阵 · 高级版样式
   深色科技风 + 玻璃拟态 + 霓虹渐变
   ============================================================ */
:root {
    --bg: #05070d;
    --bg-2: #0a0e18;
    --bg-3: #0d1322;
    --card: rgba(255, 255, 255, .035);
    --card-hover: rgba(255, 255, 255, .06);
    --line: rgba(255, 255, 255, .08);
    --line-strong: rgba(255, 255, 255, .16);
    --txt: #e9eef8;
    --txt-dim: #9aa6bd;
    --txt-faint: #66728c;
    --cyan: #22d3ee;
    --blue: #4f7dff;
    --purple: #9a6bff;
    --grad: linear-gradient(120deg, var(--cyan), var(--blue) 55%, var(--purple));
    --grad-soft: linear-gradient(120deg, rgba(34, 211, 238, .14), rgba(79, 125, 255, .14));
    --glow: rgba(34, 211, 238, .35);
    --radius: 18px;
    --radius-lg: 26px;
    --maxw: 1180px;
    --header-h: 70px;
    --shadow: 0 24px 60px rgba(0, 0, 0, .5);
}

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

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

body {
    background: var(--bg);
    color: var(--txt);
    font-family: "Inter", "PingFang SC", "HarmonyOS Sans SC", "Microsoft YaHei", sans-serif;
    line-height: 1.72;
    overflow-x: hidden;
}

img, svg { max-width: 100%; vertical-align: middle; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }
em { font-style: normal; }
strong { color: var(--cyan); font-weight: 700; }

.container {
    width: 100%;
    max-width: var(--maxw);
    margin: 0 auto;
    padding: 0 24px;
}
.container-narrow { max-width: 860px; }

/* ---------- 通用按钮 ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 13px 28px;
    font-size: 15px;
    font-weight: 700;
    border-radius: 14px;
    border: none;
    cursor: pointer;
    transition: transform .22s, box-shadow .22s, background .22s, border-color .22s;
}
.btn-sm { padding: 9px 18px; font-size: 13.5px; border-radius: 11px; }
.btn-lg { padding: 16px 40px; font-size: 16px; }
.btn-glow {
    color: #fff;
    background: var(--grad);
    box-shadow: 0 10px 30px var(--glow);
    position: relative;
    overflow: hidden;
}
.btn-glow::after {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(120deg, transparent 30%, rgba(255,255,255,.25) 50%, transparent 70%);
    transform: translateX(-120%);
    transition: transform .6s;
}
.btn-glow:hover { transform: translateY(-3px); box-shadow: 0 16px 44px var(--glow); }
.btn-glow:hover::after { transform: translateX(120%); }
.btn-ghost {
    color: var(--txt);
    background: rgba(255, 255, 255, .04);
    border: 1px solid var(--line-strong);
}
.btn-ghost:hover { transform: translateY(-3px); border-color: var(--cyan); color: var(--cyan); }

/* ---------- Header ---------- */
.site-header {
    position: fixed;
    top: 0; left: 0; right: 0;
    height: var(--header-h);
    z-index: 200;
    background: rgba(5, 7, 13, .6);
    backdrop-filter: blur(18px);
    -webkit-backdrop-filter: blur(18px);
    border-bottom: 1px solid transparent;
    transition: background .3s, border-color .3s, box-shadow .3s;
}
.site-header.scrolled {
    background: rgba(5, 7, 13, .85);
    border-bottom-color: var(--line);
    box-shadow: 0 12px 34px rgba(0, 0, 0, .4);
}
.header-inner {
    max-width: var(--maxw);
    height: 100%;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-mark {
    width: 38px; height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    border-radius: 12px;
    background: var(--grad);
    box-shadow: 0 6px 20px var(--glow);
}
.brand-name { font-size: 19px; font-weight: 800; letter-spacing: .5px; color: #fff; }
.brand-name em {
    margin-left: 5px;
    font-size: 13px;
    font-weight: 700;
    color: var(--cyan);
    background: rgba(34, 211, 238, .12);
    border: 1px solid rgba(34, 211, 238, .3);
    padding: 2px 8px;
    border-radius: 999px;
    vertical-align: 2px;
}
.site-nav { display: flex; align-items: center; gap: 6px; }
.site-nav a {
    padding: 8px 15px;
    font-size: 14.5px;
    color: var(--txt-dim);
    border-radius: 10px;
    transition: color .2s, background .2s;
}
.site-nav a:hover { color: #fff; background: rgba(255, 255, 255, .06); }
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    width: 42px; height: 42px;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, .06);
    border: 1px solid var(--line);
    border-radius: 10px;
    cursor: pointer;
}
.nav-toggle span { width: 18px; height: 2px; background: #fff; border-radius: 2px; transition: transform .3s, opacity .3s; }
.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 ---------- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: calc(var(--header-h) + 56px) 0 90px;
    overflow: hidden;
    background: var(--bg);
}
.hero-bg { position: absolute; inset: 0; pointer-events: none; }
.orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(90px);
    opacity: .5;
}
.orb-1 { width: 520px; height: 520px; top: -180px; right: -120px; background: radial-gradient(circle, rgba(79,125,255,.5), transparent 70%); animation: float 10s ease-in-out infinite; }
.orb-2 { width: 420px; height: 420px; bottom: -160px; left: -120px; background: radial-gradient(circle, rgba(34,211,238,.42), transparent 70%); animation: float 13s ease-in-out infinite reverse; }
.orb-3 { width: 300px; height: 300px; top: 30%; left: 45%; background: radial-gradient(circle, rgba(154,107,255,.35), transparent 70%); animation: float 15s ease-in-out infinite; }
@keyframes float { 0%, 100% { transform: translate(0, 0) scale(1); } 50% { transform: translate(24px, -28px) scale(1.06); } }
.grid-lines {
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(255,255,255,.035) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,.035) 1px, transparent 1px);
    background-size: 56px 56px;
    mask-image: radial-gradient(ellipse at center, #000 30%, transparent 75%);
    -webkit-mask-image: radial-gradient(ellipse at center, #000 30%, transparent 75%);
}
.noise {
    position: absolute;
    inset: 0;
    opacity: .35;
    background-image: radial-gradient(rgba(255,255,255,.05) 1px, transparent 1px);
    background-size: 22px 22px;
}

.hero-grid {
    position: relative;
    z-index: 2;
    display: grid;
    grid-template-columns: 1.08fr .92fr;
    align-items: center;
    gap: 60px;
}
.hero-chip {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    padding: 8px 18px;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: .4px;
    color: var(--cyan);
    background: rgba(34, 211, 238, .08);
    border: 1px solid rgba(34, 211, 238, .28);
    border-radius: 999px;
    margin-bottom: 26px;
    backdrop-filter: blur(6px);
}
.chip-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--cyan); box-shadow: 0 0 12px var(--glow); animation: pulse 1.8s ease-in-out infinite; }
@keyframes pulse { 0%,100% { opacity: 1; transform: scale(1); } 50% { opacity: .4; transform: scale(.8); } }

.hero h1 {
    font-size: clamp(34px, 5vw, 58px);
    line-height: 1.2;
    font-weight: 800;
    letter-spacing: -1.2px;
    margin-bottom: 22px;
    color: #fff;
}
.grad-text {
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}
.hero-lead { font-size: 17px; color: var(--txt-dim); margin-bottom: 32px; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 30px; }
.hero-badges { display: flex; flex-wrap: wrap; gap: 16px; }
.hero-badges li {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 13.5px;
    color: var(--txt-dim);
}
.hero-badges svg { color: var(--cyan); }

/* ---------- Hero 可视化 ---------- */
.hero-visual { position: relative; }
.dash-card {
    position: relative;
    background: linear-gradient(160deg, rgba(255,255,255,.07), rgba(255,255,255,.02));
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-lg);
    padding: 22px 24px;
    backdrop-filter: blur(12px);
    box-shadow: var(--shadow);
    z-index: 2;
    transform: rotate(-1.5deg);
    animation: floatCard 9s ease-in-out infinite;
}
@keyframes floatCard { 0%,100% { transform: rotate(-1.5deg) translateY(0); } 50% { transform: rotate(-1.5deg) translateY(-14px); } }
.dash-head { display: flex; align-items: center; gap: 7px; margin-bottom: 18px; }
.dash-dot { width: 11px; height: 11px; border-radius: 50%; }
.dash-dot.r { background: #ff5f57; } .dash-dot.y { background: #febc2e; } .dash-dot.g { background: #28c840; }
.dash-title { margin-left: 8px; font-size: 13px; font-weight: 600; color: var(--txt-dim); }
.dash-row { display: grid; grid-template-columns: 58px 1fr 30px; align-items: center; gap: 12px; padding: 8px 0; }
.dash-kw { font-size: 13px; color: var(--txt-dim); }
.dash-bar { height: 9px; background: rgba(255,255,255,.08); border-radius: 999px; overflow: hidden; }
.dash-bar i { display: block; height: 100%; border-radius: 999px; background: var(--grad); box-shadow: 0 0 14px var(--glow); }
.dash-row b { font-size: 13px; font-weight: 800; color: var(--cyan); text-align: right; }
.dash-foot { display: flex; justify-content: space-between; margin-top: 14px; padding-top: 14px; border-top: 1px solid var(--line); }
.dash-foot span { font-size: 12.5px; color: var(--txt-faint); }
.dash-foot b { color: var(--cyan); margin-left: 4px; }

.dash-card-2 { margin-top: -8px; margin-left: 46px; transform: rotate(1.5deg); animation: floatCard2 11s ease-in-out infinite; z-index: 1; }
@keyframes floatCard2 { 0%,100% { transform: rotate(1.5deg) translateY(0); } 50% { transform: rotate(1.5deg) translateY(-10px); } }
.dash-chart { width: 100%; height: 74px; }
.chart-line { fill: none; stroke: url(#lg); stroke-width: 2.4; stroke-linecap: round; }
.chart-area { fill: rgba(34, 211, 238, .12); }

.float-chip {
    position: absolute;
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 10px 16px;
    font-size: 13px;
    font-weight: 600;
    color: #fff;
    background: rgba(13, 19, 34, .85);
    border: 1px solid var(--line-strong);
    border-radius: 12px;
    backdrop-filter: blur(10px);
    box-shadow: 0 12px 30px rgba(0,0,0,.4);
    z-index: 3;
}
.float-chip svg { color: var(--cyan); }
.chip-a { top: -18px; right: 4%; animation: floatChip 6s ease-in-out infinite; }
.chip-b { bottom: -16px; left: 2%; animation: floatChip 7s ease-in-out infinite reverse; }
@keyframes floatChip { 0%,100% { transform: translateY(0); } 50% { transform: translateY(-10px); } }

/* ---------- 数据统计 ---------- */
.stats {
    position: relative;
    padding: 54px 0;
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
    background: linear-gradient(180deg, var(--bg), var(--bg-2));
}
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    text-align: center;
}
.stat b {
    display: block;
    font-size: clamp(30px, 3.6vw, 44px);
    font-weight: 800;
    background: var(--grad);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    line-height: 1.2;
}
.stat span { font-size: 13.5px; color: var(--txt-dim); }

/* ---------- Section 通用 ---------- */
.section { padding: 100px 0; }
.section-dark { background: linear-gradient(180deg, var(--bg), var(--bg-3)); }
.section-alt { background: linear-gradient(180deg, var(--bg-2), var(--bg)); }

.section-head { text-align: center; max-width: 700px; margin: 0 auto 60px; }
.tag {
    display: inline-block;
    padding: 7px 18px;
    font-size: 12.5px;
    font-weight: 700;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--cyan);
    background: rgba(34, 211, 238, .09);
    border: 1px solid rgba(34, 211, 238, .28);
    border-radius: 999px;
    margin-bottom: 18px;
}
.tag-alt { color: var(--purple); background: rgba(154, 107, 255, .1); border-color: rgba(154, 107, 255, .3); }
.section-head h2 {
    font-size: clamp(26px, 3.4vw, 40px);
    font-weight: 800;
    line-height: 1.28;
    letter-spacing: -.6px;
    color: #fff;
    margin-bottom: 14px;
}
.section-head p { font-size: 16px; color: var(--txt-dim); }

/* ---------- 技术矩阵卡片 ---------- */
.tech-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }
.tech-card {
    position: relative;
    padding: 30px 28px;
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    backdrop-filter: blur(8px);
    transition: transform .28s, border-color .28s, box-shadow .28s, background .28s;
    overflow: hidden;
}
.tech-card::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 3px;
    background: var(--grad);
    opacity: 0;
    transition: opacity .28s;
}
.tech-card:hover {
    transform: translateY(-8px);
    border-color: rgba(34, 211, 238, .4);
    background: var(--card-hover);
    box-shadow: 0 26px 60px rgba(0, 0, 0, .45);
}
.tech-card:hover::before { opacity: 1; }
.tech-top { display: flex; align-items: flex-start; justify-content: space-between; margin-bottom: 20px; }
.tech-ico {
    width: 58px; height: 58px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 16px;
    background: var(--grad-soft);
    border: 1px solid var(--line-strong);
}
.tech-ico svg { width: 28px; height: 28px; color: var(--cyan); }
.tech-ico.i2 svg { color: var(--blue); }
.tech-ico.i3 svg { color: var(--purple); }
.tech-ico.i4 svg { color: var(--cyan); }
.tech-ico.i5 svg { color: var(--blue); }
.tech-ico.i6 svg { color: var(--purple); }
.tech-no {
    font-size: 30px;
    font-weight: 800;
    line-height: 1;
    background: linear-gradient(120deg, rgba(34,211,238,.35), rgba(154,107,255,.35));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
}
.tech-card h3 { font-size: 19px; font-weight: 700; color: #fff; margin-bottom: 10px; }
.tech-card p { font-size: 14.5px; color: var(--txt-dim); margin-bottom: 18px; }
.tech-tag {
    display: inline-block;
    padding: 5px 14px;
    font-size: 12px;
    font-weight: 600;
    color: var(--cyan);
    background: rgba(34, 211, 238, .1);
    border-radius: 999px;
}

/* ---------- 协同引擎 ---------- */
.synergy-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.synergy-card {
    padding: 30px 26px;
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    transition: transform .28s, border-color .28s, background .28s;
}
.synergy-card:hover { transform: translateY(-6px); border-color: rgba(154, 107, 255, .4); background: var(--card-hover); }
.synergy-num {
    font-size: 36px;
    font-weight: 800;
    line-height: 1;
    background: linear-gradient(120deg, var(--purple), var(--blue));
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    color: transparent;
    margin-bottom: 16px;
}
.synergy-card h3 { font-size: 17px; font-weight: 700; color: #fff; margin-bottom: 8px; }
.synergy-card p { font-size: 14px; color: var(--txt-dim); }

/* ---------- 服务流程 ---------- */
.steps-row {
    display: flex;
    align-items: flex-start;
    justify-content: center;
    gap: 24px;
    max-width: 920px;
    margin: 0 auto;
}
.step { flex: 1; text-align: center; padding: 10px; }
.step-circle {
    width: 68px; height: 68px;
    margin: 0 auto 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    font-weight: 800;
    color: #fff;
    border-radius: 50%;
    background: var(--grad);
    box-shadow: 0 12px 30px var(--glow);
    position: relative;
}
.step-circle::after {
    content: "";
    position: absolute;
    inset: -8px;
    border-radius: 50%;
    border: 1px dashed rgba(34, 211, 238, .5);
    animation: spin 14s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.step h3 { font-size: 18px; font-weight: 700; color: #fff; margin-bottom: 8px; }
.step p { font-size: 14px; color: var(--txt-dim); }
.step-line {
    flex: 0 0 70px;
    height: 2px;
    align-self: center;
    background: linear-gradient(90deg, var(--cyan), var(--purple));
    opacity: .55;
    position: relative;
    top: -28px;
}

/* ---------- 优势 ---------- */
.advantage-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.adv-card {
    padding: 32px 26px;
    text-align: center;
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius-lg);
    transition: transform .28s, border-color .28s, background .28s;
}
.adv-card:hover { transform: translateY(-6px); border-color: rgba(34, 211, 238, .4); background: var(--card-hover); }
.adv-ico {
    width: 56px; height: 56px;
    margin: 0 auto 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--grad-soft);
    border: 1px solid var(--line-strong);
}
.adv-ico svg { width: 26px; height: 26px; color: var(--cyan); }
.adv-card h3 { font-size: 17px; font-weight: 700; color: #fff; margin-bottom: 8px; }
.adv-card p { font-size: 14px; color: var(--txt-dim); }

/* ---------- FAQ ---------- */
.faq-list { display: flex; flex-direction: column; gap: 14px; }
.faq-item {
    background: var(--card);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    overflow: hidden;
    transition: border-color .25s, background .25s;
}
.faq-item.open { border-color: rgba(34, 211, 238, .38); background: var(--card-hover); }
.faq-q {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 20px 24px;
    font-size: 16px;
    font-weight: 600;
    color: var(--txt);
    background: transparent;
    border: none;
    cursor: pointer;
    text-align: left;
    transition: color .2s;
}
.faq-q:hover { color: var(--cyan); }
.faq-plus { position: relative; flex-shrink: 0; width: 18px; height: 18px; }
.faq-plus::before, .faq-plus::after {
    content: "";
    position: absolute;
    top: 50%; left: 50%;
    width: 14px; height: 2px;
    background: var(--txt-dim);
    border-radius: 2px;
    transform: translate(-50%, -50%);
    transition: background .25s, transform .3s;
}
.faq-plus::after { transform: translate(-50%, -50%) rotate(90deg); }
.faq-item.open .faq-plus::before, .faq-item.open .faq-plus::after { background: var(--cyan); }
.faq-item.open .faq-plus::after { transform: translate(-50%, -50%) rotate(0deg); }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .38s ease; }
.faq-a p { padding: 0 24px 22px; font-size: 14.5px; color: var(--txt-dim); }

/* ---------- CTA ---------- */
.cta {
    position: relative;
    padding: 96px 0;
    text-align: center;
    overflow: hidden;
    background:
        radial-gradient(720px 360px at 50% -30%, rgba(34, 211, 238, .16), transparent 60%),
        radial-gradient(720px 360px at 50% 140%, rgba(154, 107, 255, .18), transparent 60%),
        var(--bg-2);
    border-top: 1px solid var(--line);
    border-bottom: 1px solid var(--line);
}
.cta h2 {
    font-size: clamp(26px, 3.4vw, 40px);
    font-weight: 800;
    color: #fff;
    margin-bottom: 12px;
}
.cta p { font-size: 16px; color: var(--txt-dim); margin-bottom: 34px; }

/* ---------- 联系 ---------- */
.contact-card {
    max-width: 500px;
    margin: 0 auto;
    padding: 36px 36px 32px;
    background: var(--card);
    border: 1px solid var(--line-strong);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow);
    backdrop-filter: blur(10px);
}
.contact-card h3 { font-size: 20px; font-weight: 700; color: #fff; margin-bottom: 20px; text-align: center; }
.contact-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 15px 20px;
    background: var(--bg-2);
    border: 1px solid var(--line);
    border-radius: 13px;
    font-size: 16px;
    margin-bottom: 12px;
    transition: border-color .25s;
}
.contact-row:hover { border-color: rgba(34, 211, 238, .4); }
.contact-label { font-size: 13px; font-weight: 700; color: var(--cyan); }
.contact-value { font-weight: 800; color: #fff; letter-spacing: .5px; }
.contact-note { margin-top: 14px; font-size: 13px; color: var(--txt-faint); text-align: center; }

/* ---------- Footer ---------- */
.site-footer {
    padding: 38px 0;
    border-top: 1px solid var(--line);
    background: var(--bg);
    text-align: center;
}
.site-footer p { font-size: 13px; color: var(--txt-faint); }
.site-footer .footer-kw { margin-top: 6px; font-size: 12px; color: var(--txt-faint); letter-spacing: .3px; }

/* ---------- 滚动显示 ---------- */
.js-anim .reveal { opacity: 0; transform: translateY(30px); transition: opacity .8s ease, transform .8s ease; }
.js-anim .reveal.visible { opacity: 1; transform: none; }
.js-anim .reveal.d1 { transition-delay: .08s; }
.js-anim .reveal.d2 { transition-delay: .16s; }
.js-anim .reveal.d3 { transition-delay: .24s; }

/* ---------- 响应式 ---------- */
@media (max-width: 1080px) {
    .tech-grid { grid-template-columns: repeat(2, 1fr); }
    .synergy-grid, .advantage-grid { grid-template-columns: repeat(2, 1fr); }
    .stats-grid { grid-template-columns: repeat(2, 1fr); row-gap: 28px; }
}
@media (max-width: 900px) {
    .hero-grid { grid-template-columns: 1fr; gap: 56px; }
    .hero-visual { max-width: 500px; }
    .site-nav {
        position: fixed;
        top: var(--header-h);
        left: 0; right: 0;
        flex-direction: column;
        align-items: stretch;
        background: rgba(5, 7, 13, .97);
        border-bottom: 1px solid var(--line);
        padding: 14px 24px 20px;
        gap: 4px;
        transform: translateY(-12px);
        opacity: 0;
        visibility: hidden;
        transition: transform .3s, opacity .3s, visibility .3s;
    }
    .site-nav.open { transform: none; opacity: 1; visibility: visible; }
    .site-nav a { padding: 13px 12px; font-size: 16px; }
    .nav-toggle { display: flex; }
    .header-inner .btn { display: none; }
    .section { padding: 76px 0; }
}
@media (max-width: 640px) {
    .tech-grid, .synergy-grid, .advantage-grid { grid-template-columns: 1fr; }
    .steps-row { flex-direction: column; align-items: center; gap: 30px; }
    .step-line { width: 2px; height: 30px; flex: 0 0 auto; top: 0; }
    .dash-card-2 { margin-left: 0; }
    .float-chip.chip-b { bottom: -30px; }
    .hero { padding-top: calc(var(--header-h) + 30px); }
}