/* ========== Base & Theme ========== */
:root{
  --bg: #ffffff;
  --text: #1f2937;        /* slate-800 */
  --muted: #6b7280;       /* slate-500 */
  --card: #ffffff;
  --border: #e5e7eb;      /* gray-200 */
  --primary: #0ea5e9;     /* sky-500 */
  --primary-600:#0284c7;  /* sky-600 */
  --accent: #111827;      /* slate-900 for brand */
  --radius: 14px;
  --shadow: 0 8px 24px rgba(2, 8, 23, .06);
}

@media (prefers-color-scheme: dark){
  :root{
    --bg:#0b1220;
    --text:#e5e7eb;
    --muted:#94a3b8;
    --card:#0f172a;
    --border:#1f2a44;
    --primary:#38bdf8;
    --primary-600:#0ea5e9;
    --accent:#e2e8f0;
    --shadow: 0 8px 24px rgba(0,0,0,.35);
  }
}

*{ box-sizing: border-box; }
html,body{ height:100%; }
body{
  margin:0;
  font-family: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI",
               Roboto, "Helvetica Neue", Arial, "Apple Color Emoji","Segoe UI Emoji";
  line-height:1.6;
  color:var(--text);
  background:var(--bg);
}

/* Utilities */
.container{
  width:min(1100px, 92%);
  margin-inline:auto;
}
.center{ text-align:center; }
.muted{ color:var(--muted); }
.badge{
  display:inline-block; padding:.25rem .5rem; border-radius:999px;
  font-size:.75rem; background:rgba(14,165,233,.1); color:var(--primary-600);
}

/* ========== Nav ========== */
.nav{
  position:sticky; top:0; z-index:40;
  backdrop-filter: saturate(180%) blur(10px);
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  border-bottom:1px solid var(--border);
}
.nav__inner{
  display:flex; align-items:center; justify-content:space-between;
  padding: .8rem 0;
}
.nav__brand{
  color:var(--accent); font-weight:800; letter-spacing:.3px; text-decoration:none;
  font-size:1.15rem;
}
.nav__menu a{
  color:var(--text); text-decoration:none; margin-left:1rem; font-weight:600;
  padding:.4rem .6rem; border-radius:10px; transition: all .16s ease;
}
.nav__menu a:hover{ background:var(--border); }

/* ========== Hero ========== */
.hero{ padding: 56px 0 28px; }
.hero__inner{
  display:grid; gap:32px; align-items:center;
  grid-template-columns: 1.2fr .8fr;
}
.hero__text h1{
  margin:0 0 .4rem; line-height:1.15; font-size: clamp(2rem, 4vw, 3rem);
}
.hero__subtitle{ color:var(--muted); font-size:1.05rem; max-width:55ch; }
.hero__cta{ margin:1.2rem 0 .8rem; display:flex; gap:.75rem; flex-wrap:wrap; }
.hero__social{ color:var(--muted); display:flex; gap:.5rem; align-items:center; }
.hero__social a{ color:inherit; text-decoration:none; font-weight:600; }
.hero__media{ display:flex; justify-content:center; }
.hero__avatar{
  width:min(220px, 60vw); aspect-ratio:1/1; object-fit:cover;
  border-radius:24px; box-shadow: var(--shadow); border: 1px solid var(--border);
}

/* Buttons */
.btn{
  display:inline-block; border-radius:12px; padding:.7rem 1rem; font-weight:700;
  text-decoration:none; transition: transform .12s ease, background .2s ease, color .2s ease;
  border:1px solid transparent; cursor:pointer;
}
.btn--primary{ background:var(--primary); color:#fff; }
.btn--primary:hover{ background:var(--primary-600); transform: translateY(-1px); }
.btn--ghost{ background:transparent; color:var(--text); border-color:var(--border); }
.btn--ghost:hover{ background:var(--border); }

/* ========== Sections / Cards / Grid ========== */
section{ padding: 48px 0; }
h2{ font-size: clamp(1.4rem, 2.4vw, 2rem); margin:0 0 1rem; }
.grid{ display:grid; gap:20px; }
.grid--2{ grid-template-columns: repeat(2, minmax(0,1fr)); }
.grid--3{ grid-template-columns: repeat(3, minmax(0,1fr)); }

.card{
  background:var(--card); border:1px solid var(--border); border-radius: var(--radius);
  padding: 18px; box-shadow: var(--shadow); text-decoration:none; color:inherit;
  transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease;
}
.card:hover{ transform: translateY(-3px); box-shadow: 0 14px 36px rgba(2,8,23,.10); border-color: color-mix(in srgb, var(--border) 60%, var(--primary) 40%); }
.card h3{ margin:.1rem 0 .3rem; }
.card--product{ display:flex; align-items:flex-start; justify-content:space-between; gap:12px; }

/* Pillars */
.pillars .card p{ color:var(--muted); }

/* ========== Newsletter ========== */
.newsletter{
  background: linear-gradient(180deg, color-mix(in srgb, var(--primary) 8%, var(--bg)) 0%, transparent 100%);
  border-top:1px solid var(--border); border-bottom:1px solid var(--border);
}
.newsletter__inner{
  display:grid; gap:18px; align-items:center; grid-template-columns: 1.2fr 1fr;
}
.newsletter__form{
  display:flex; gap:10px; flex-wrap:wrap; align-items:center;
}
.newsletter__form input[type="email"]{
  flex:1 1 220px; min-width: 220px;
  padding:.75rem .9rem; border-radius:12px; border:1px solid var(--border);
  background:var(--card); color:var(--text); outline:none;
}
.newsletter__form input:focus{ border-color: var(--primary); box-shadow: 0 0 0 4px color-mix(in srgb, var(--primary) 25%, transparent); }

/* ========== Video (16:9) ========== */
.video__frame{
  position:relative; width:100%; padding-bottom:56.25%; border-radius:16px; overflow:hidden;
  border:1px solid var(--border); box-shadow: var(--shadow); background:#000;
}
.video__frame iframe{
  position:absolute; inset:0; width:100%; height:100%; border:0;
}

/* ========== Blog Cards ========== */
.post.card p{ color:var(--muted); margin:.3rem 0 .6rem; }
.post__meta{ color:var(--muted); font-size:.9rem; }

/* ========== Testimonials ========== */
.quote{ font-style:italic; }
.quote cite{ display:block; margin-top:.4rem; color:var(--muted); font-style:normal; }

/* ========== Footer ========== */
.footer{
  border-top:1px solid var(--border); padding-top:28px; padding-bottom:36px;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
}
.footer__inner{
  display:flex; align-items:center; justify-content:space-between; gap:16px; margin-bottom:12px;
}
.footer__links a{ color:var(--muted); text-decoration:none; margin-left:14px; }
.footer__links a:hover{ color:var(--text); }

/* ========== Links ========== */
a{ color:var(--primary-600); }
a:hover{ color:var(--primary); }

/* ========== Responsive ========== */
@media (max-width: 960px){
  .hero__inner{ grid-template-columns: 1fr; text-align:center; }
  .hero__media{ order:-1; }
  .newsletter__inner{ grid-template-columns: 1fr; text-align:center; }
  .grid--3{ grid-template-columns: 1fr 1fr; }
  .footer__inner{ flex-direction:column; }
}
@media (max-width: 640px){
  .grid--2, .grid--3{ grid-template-columns: 1fr; }
  .nav__menu{ display:none; } /* 小屏隐藏顶部菜单，保持简洁 */
}