/* ============================================
   E2EE Calls · 浅色系统一风格
   （设计语言参照 ai.igh.ink：白底 / 近黑主色 /
     蓝色交互色 / 细边框 + 柔和阴影 / 系统字体）
   ============================================ */
:root {
  --bg: #ffffff;
  --bg-2: #f5f5f7;
  --bg-3: #fafafa;
  --bg-4: #ebebee;
  --card: #ffffff;
  --border: rgba(0, 0, 0, 0.08);
  --border-2: rgba(0, 0, 0, 0.14);
  --text: #1d1d1f;
  --text-2: #6e6e73;
  --text-3: #86868b;
  --accent: #1d1d1f;
  --accent-dim: #0a84ff;
  --accent-dark: rgba(10, 132, 255, 0.35);
  --brand: #6c5ce7;
  --success: #1a7d3c;
  --green: #1a7d3c;
  --danger: #d70015;
  --red: #d70015;
  --warning: #c96800;
  --amber: #c96800;
  --info: #0a84ff;
  /* 兼容旧变量名 */
  --bg2: #ffffff;
  --bg3: #f5f5f7;
  --radius-sm: 10px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --shadow-1: 0 1px 3px rgba(0, 0, 0, 0.06), 0 0 0 1px rgba(0, 0, 0, 0.04);
  --shadow-2: 0 12px 32px rgba(0, 0, 0, 0.10), 0 0 0 1px rgba(0, 0, 0, 0.06);
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
.inner { position: relative; z-index: 1; max-width: 1040px; margin: 0 auto; padding: 0 24px; }

/* ─── 顶栏 ─── */
header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, 0.82);
  -webkit-backdrop-filter: saturate(180%) blur(18px);
  backdrop-filter: saturate(180%) blur(18px);
  border-bottom: 1px solid var(--border);
}
.hd { display: flex; align-items: center; gap: 12px; padding: 13px 0; }
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); flex: 1; }
.logo svg { width: 26px; height: 30px; }
.brand { font-size: 17px; font-weight: 700; letter-spacing: -0.02em; color: var(--text); line-height: 1.15; }
.brand small { display: block; font-size: 10px; color: var(--text-3); font-weight: 500; letter-spacing: .08em; text-transform: uppercase; }
nav { display: flex; align-items: center; }
nav a { color: var(--text-2); text-decoration: none; font-size: 13.5px; margin-left: 18px; transition: color .15s; }
nav a:hover { color: var(--text); }

/* ─── 按钮 ─── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  font-family: var(--font); font-size: 14px; font-weight: 500; letter-spacing: -0.01em;
  text-decoration: none; border: none; cursor: pointer; border-radius: 999px;
  padding: .72rem 1.45rem; transition: background .18s, transform .18s, box-shadow .18s, border-color .18s;
}
.btn-primary { background: var(--accent); color: #fff; box-shadow: 0 1px 2px rgba(0, 0, 0, 0.18); }
.btn-primary:hover { background: #3d3d41; transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }
.btn-ghost { background: #fff; color: var(--text); border: 1px solid var(--border-2); }
.btn-ghost:hover { background: var(--bg-2); transform: translateY(-1px); }

/* ─── 首屏 ─── */
.hero { position: relative; text-align: center; padding: 92px 0 82px; overflow: hidden; background: linear-gradient(180deg, var(--bg-3) 0%, var(--bg) 100%); }
.hero-deco { position: absolute; inset: 0; pointer-events: none; }
.hero-deco::before {
  content: ''; position: absolute; inset: 0;
  background-image: linear-gradient(rgba(0, 0, 0, 0.04) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(0, 0, 0, 0.04) 1px, transparent 1px);
  background-size: 52px 52px;
  -webkit-mask-image: radial-gradient(ellipse 80% 70% at 50% 35%, #000 20%, transparent 72%);
  mask-image: radial-gradient(ellipse 80% 70% at 50% 35%, #000 20%, transparent 72%);
}
.orb { position: absolute; border-radius: 50%; filter: blur(70px); opacity: .6; }
.orb-a { width: 340px; height: 340px; left: 6%; top: -100px; background: radial-gradient(circle, rgba(10, 132, 255, 0.32), transparent 70%); }
.orb-b { width: 380px; height: 380px; right: 4%; top: -70px; background: radial-gradient(circle, rgba(108, 92, 231, 0.30), transparent 70%); }
.orb-c { width: 260px; height: 260px; left: 44%; top: 130px; background: radial-gradient(circle, rgba(26, 125, 60, 0.20), transparent 70%); }
.hero > *:not(.hero-deco) { position: relative; z-index: 1; }
.eyebrow {
  display: inline-flex; align-items: center; gap: 9px;
  font-size: 13px; color: var(--text-2); background: #fff;
  border: 1px solid var(--border); border-radius: 999px;
  padding: 7px 16px; margin-bottom: 26px;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.04);
}
.eyebrow::before {
  content: ''; width: 7px; height: 7px; border-radius: 50%;
  background: var(--green); box-shadow: 0 0 0 4px rgba(26, 125, 60, 0.15);
}
h1 { font-size: clamp(34px, 6vw, 56px); line-height: 1.08; letter-spacing: -0.03em; font-weight: 700; margin-bottom: 20px; }
h1 em {
  font-style: normal;
  background: linear-gradient(90deg, #0a84ff 0%, #6c5ce7 100%);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: #0a84ff;
}
.sub { color: var(--text-2); font-size: clamp(15px, 2.2vw, 17px); max-width: 620px; margin: 0 auto 34px; line-height: 1.7; }
.cta-row { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }
.fine { margin-top: 20px; font-size: 12.5px; color: var(--text-3); letter-spacing: .02em; }

/* ─── 页脚 ─── */
footer {
  padding: 38px 0 48px; text-align: center; font-size: 12.5px; color: var(--text-3);
  border-top: 1px solid var(--border); background: var(--bg-3);
}
footer a { color: var(--text-2); text-decoration: none; }
footer a:hover { color: var(--text); }

@media (max-width: 720px) {
  nav { display: none; }
  .hero { padding: 64px 0 56px; }
}

/* ═══════════ 深色模式（跟随系统 prefers-color-scheme）═══════════ */
@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #0b0b0d;
    --bg-2: #17171a;
    --bg-3: #101013;
    --bg-4: #1e1e22;
    --bg2: #17171a;
    --bg3: #101013;
    --card: #17171a;
    --border: rgba(255, 255, 255, 0.10);
    --border-2: rgba(255, 255, 255, 0.16);
    --text: #f2f2f4;
    --text-2: #a1a1a6;
    --text-3: #8e8e93;
    --accent: #f2f2f4;
    --accent-dim: #0a84ff;
    --green: #4ade80;
    --danger: #ff6961;
    --red: #ff6961;
    --warning: #fbbf24;
    --amber: #fbbf24;
    --shadow-1: 0 1px 3px rgba(0, 0, 0, 0.5), 0 0 0 1px rgba(255, 255, 255, 0.06);
    --shadow-2: 0 12px 32px rgba(0, 0, 0, 0.6), 0 0 0 1px rgba(255, 255, 255, 0.08);
  }
  header { background: rgba(16, 16, 19, 0.86); }
  .eyebrow { background: #17171a; }
  .btn-ghost { background: #17171a; }
  .hero-deco::before {
    background-image: linear-gradient(rgba(255, 255, 255, 0.05) 1px, transparent 1px),
                      linear-gradient(90deg, rgba(255, 255, 255, 0.05) 1px, transparent 1px);
  }
}