/* ============================================================
   landing.css — 营销落地页样式（B2）
   ============================================================ */
.site-header {
  position: sticky; top: 0; z-index: 50; height: var(--header-h);
  display: flex; align-items: center; backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--bg-elevated) 80%, transparent);
  border-bottom: 1px solid var(--border);
}
.site-header .container { display: flex; align-items: center; justify-content: space-between; gap: var(--sp-4); }
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: var(--fs-18); }
.brand .logo { width: 30px; height: 30px; border-radius: 8px; background: linear-gradient(135deg, var(--c-primary), var(--c-accent)); }
.nav { display: flex; align-items: center; gap: var(--sp-5); }
.nav a { color: var(--text-2); font-weight: 600; font-size: var(--fs-14); }
.nav a:hover { color: var(--text); }
.header-actions { display: flex; align-items: center; gap: var(--sp-3); }

.hero { position: relative; overflow: hidden; background: var(--hero-grad); }
.hero .container { padding: var(--sp-8) var(--sp-5); text-align: center; }
.hero h1 { font-size: var(--fs-40); line-height: 1.2; font-weight: 800; letter-spacing: -0.5px; }
.hero h1 .grad { background: linear-gradient(120deg, var(--c-primary), var(--c-accent)); -webkit-background-clip: text; background-clip: text; color: transparent; }
.hero p.sub { max-width: 720px; margin: var(--sp-4) auto var(--sp-6); color: var(--text-2); font-size: var(--fs-18); }
.hero .cta { display: flex; gap: var(--sp-3); justify-content: center; flex-wrap: wrap; }

.badges { display: flex; gap: var(--sp-3); justify-content: center; flex-wrap: wrap; margin-top: var(--sp-6); }
.badges .tag { font-size: var(--fs-13); padding: 6px 14px; }

.section-head { text-align: center; max-width: 760px; margin: 0 auto var(--sp-6); }
.section-head h2 { font-size: var(--fs-28); font-weight: 800; margin-bottom: var(--sp-2); }
.section-head p { color: var(--text-2); }

/* 九大壁垒网格 */
.barriers { grid-template-columns: repeat(3, 1fr); }
.barrier { position: relative; overflow: hidden; }
.barrier .b-ico { font-size: 26px; margin-bottom: var(--sp-2); }
.barrier h3 { font-size: var(--fs-16); margin-bottom: 6px; }
.barrier p { color: var(--text-2); font-size: var(--fs-13); }
.barrier::after { content: ""; position: absolute; inset: 0; border-radius: var(--r-lg); pointer-events: none;
  background: radial-gradient(400px 200px at var(--mx,50%) var(--my,0%), color-mix(in srgb, var(--c-primary) 12%, transparent), transparent 70%); opacity: 0; transition: opacity .3s; }
.barrier:hover::after { opacity: 1; }

/* 能力矩阵 */
.matrix { grid-template-columns: repeat(3, 1fr); }
.matrix .card { display: flex; flex-direction: column; gap: 6px; }
.matrix .num { font-size: var(--fs-28); font-weight: 800; color: var(--c-primary); }

/* 信任数据 */
.trust { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-4); text-align: center; }
.trust .big { font-size: var(--fs-40); font-weight: 800; color: var(--c-accent); }

/* FAQ + 表单 */
.faq-grid { grid-template-columns: 1.2fr 1fr; align-items: start; }
.faq-item { border-bottom: 1px solid var(--border); padding: var(--sp-3) 0; }
.faq-item summary { cursor: pointer; font-weight: 600; list-style: none; display: flex; justify-content: space-between; }
.faq-item summary::after { content: "+"; color: var(--c-primary); font-weight: 800; }
.faq-item[open] summary::after { content: "−"; }
.form-card { position: sticky; top: calc(var(--header-h) + 16px); }

.site-footer { border-top: 1px solid var(--border); padding: var(--sp-6) 0; color: var(--text-3); font-size: var(--fs-13); }
.site-footer .container { display: flex; justify-content: space-between; flex-wrap: wrap; gap: var(--sp-3); }

@media (max-width: 900px) {
  .barriers, .matrix { grid-template-columns: repeat(2, 1fr); }
  .trust { grid-template-columns: repeat(2, 1fr); }
  .faq-grid { grid-template-columns: 1fr; }
}
@media (max-width: 600px) {
  .barriers, .matrix { grid-template-columns: 1fr; }
  .nav .nav-links { display: none; }
}