/* ============================================
   爱智老师 — 宣传网站
   品牌视觉 v2.0 · 亮蓝 + 青色系
   主色 #2250EF · 辅色 #01C3F5 · 渐变 #2859F1→#498DFB
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
  /* ---- 基础 ---- */
  --font-sans: "Inter", "PingFang SC", "Source Han Sans SC", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
  --transition: 160ms ease-out;
  --container-max: 1200px;

  /* ---- 品牌主色 · 亮蓝 ---- */
  --primary: #2250EF;
  --primary-hover: #1D43D1;
  --primary-active: #1839B3;
  --primary-subtle: #E8EDFC;
  --primary-softer: #F0F4FE;
  --on-primary: #FFFFFF;

  /* ---- 品牌辅色 · 青色 ---- */
  --cyan: #01C3F5;
  --cyan-hover: #01A8D6;
  --cyan-subtle: #E0F7FE;
  --cyan-soft: #C8F1FD;

  /* ---- 品牌渐变 ---- */
  --gradient-brand: linear-gradient(135deg, #2859F1 0%, #498DFB 100%);
  --gradient-brand-soft: linear-gradient(135deg, #E8EDFC 0%, #E0F7FE 100%);
  --gradient-hero: linear-gradient(160deg, #1E2B8F 0%, #4052E8 45%, #7A5CF0 78%, #8B5CF6 100%);
  --gradient-deep: linear-gradient(160deg, #1E2B8F 0%, #312E81 55%, #4C1D95 100%);

  /* ---- CTA（用主色蓝，白字对比 5.5:1 过 AA） ---- */
  --cta: #2250EF;
  --cta-hover: #1D43D1;
  --cta-active: #1839B3;
  --cta-subtle: #E8EDFC;
  --cta-soft: #D3DFFA;

  /* ---- 文字 ---- */
  --text-1: #0F172A;
  --text-2: #475569;
  --text-3: #94A3B8;
  --text-on-dark: #F0F4FE;

  /* ---- 底/边 ---- */
  --bg-page: #F8FAFE;
  --bg-card: #FFFFFF;
  --bg-subtle: #F0F4FA;
  --bg-dark: #1E1B4B;
  --bg-deep: #312E81;
  --border: #CBD5E1;
  --border-light: #E2E8F0;
  --divider: #EDF1F7;

  /* ---- 语义色 ---- */
  --success: #10B981;
  --success-bg: #ECFDF5;
  --warning: #F59E0B;
  --warning-bg: #FFFBEB;
  --danger: #DC2626;
  --danger-bg: #FEF2F2;
  --info: #2250EF;
  --info-bg: #E8EDFC;

  /* ---- 暖色 CTA（与冷色主色形成强对比，用于关键行动按钮） ---- */
  --cta-warm: #F65314;
  --cta-warm-hover: #E04810;
  --cta-warm-soft: #FFE8DC;
  --gradient-warm: linear-gradient(135deg, #FF9A3D 0%, #F65314 100%);

  /* ---- 阴影（基于品牌蓝调） ---- */
  --shadow-sm: 0 1px 3px rgba(34, 80, 239, 0.06);
  --shadow-md: 0 4px 16px rgba(34, 80, 239, 0.09);
  --shadow-lg: 0 8px 32px rgba(34, 80, 239, 0.14);
  --focus-ring: 0 0 0 3px rgba(34, 80, 239, 0.18);
  --glow-cyan: 0 0 24px rgba(1, 195, 245, 0.25);

  /* ---- 排版 ---- */
  --text-xs: 12px;   --leading-xs: 18px;
  --text-sm: 14px;   --leading-sm: 22px;
  --text-base: 16px; --leading-base: 26px;
  --text-lg: 20px;   --leading-lg: 30px;
  --text-xl: 24px;   --leading-xl: 34px;
  --text-2xl: 30px;  --leading-2xl: 40px;
  --text-3xl: 36px;  --leading-3xl: 44px;
  --fw-regular: 400;
  --fw-medium: 500;
  --fw-semibold: 600;

  /* ---- 圆角（新品牌更圆润） ---- */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
  --radius-pill: 999px;

  /* ---- 间距 ---- */
  --space-1: 4px;  --space-2: 8px;  --space-3: 12px;
  --space-4: 16px; --space-5: 20px; --space-6: 24px;
  --space-8: 32px; --space-12: 48px; --space-16: 64px; --space-24: 96px;
}

/* ============ 全局重置 ============ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-base);
  color: var(--text-1);
  background: var(--bg-page);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button, input, select { font: inherit; }
::selection { background: var(--primary-subtle); }

/* ============ 容器 ============ */
.wrap { max-width: var(--container-max); margin: 0 auto; padding: 0 32px; }

/* ============ 按钮系统 ============ */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: 46px; padding: 0 26px; border-radius: var(--radius-md);
  font-family: inherit; font-size: var(--text-sm); font-weight: var(--fw-medium);
  line-height: 1; border: 1.5px solid transparent; cursor: pointer;
  transition: background var(--transition), box-shadow var(--transition),
              border-color var(--transition), color var(--transition),
              transform var(--transition);
  white-space: nowrap;
}
.btn:focus-visible { outline: none; box-shadow: var(--focus-ring); }
.btn:active { transform: scale(0.98); }

/* CTA 主按钮 — 品牌蓝 */
.btn-cta { background: var(--cta); color: #fff; }
.btn-cta:hover { background: var(--cta-hover); box-shadow: var(--shadow-md); }
.btn-cta:active { background: var(--cta-active); }

/* 暖色渐变 CTA（Hero 区用，冷色底上最醒目） */
.btn-cta-gradient {
  background: var(--gradient-warm); color: #fff;
  box-shadow: 0 4px 20px rgba(246, 83, 20, 0.35);
}
.btn-cta-gradient:hover {
  box-shadow: 0 6px 28px rgba(246, 83, 20, 0.45);
  transform: translateY(-1px);
}

/* 次按钮 */
.btn-sec { background: transparent; border-color: var(--primary); color: var(--primary); }
.btn-sec:hover { background: var(--primary-subtle); }

/* 文字按钮 */
.btn-txt { background: transparent; color: var(--primary); padding: 0 12px; border-color: transparent; }
.btn-txt:hover { background: var(--bg-subtle); }

/* 反色按钮（深底用） */
.btn-sec-inv { background: rgba(255,255,255,0.12); border-color: rgba(255,255,255,0.35); color: #fff; backdrop-filter: blur(4px); }
.btn-sec-inv:hover { background: rgba(255,255,255,0.2); }

/* 中大按钮 */
.btn-lg { height: 54px; padding: 0 34px; font-size: var(--text-base); border-radius: var(--radius-md); }
.btn-sm { height: 38px; padding: 0 18px; font-size: var(--text-xs); }

/* ============ 徽章 ============ */
.badge {
  display: inline-flex; align-items: center; height: 26px; padding: 0 12px;
  border-radius: var(--radius-pill); font-size: var(--text-xs); font-weight: var(--fw-medium);
  line-height: 1; white-space: nowrap;
}
.badge-blue { background: var(--primary-subtle); color: var(--primary); }
.badge-cyan { background: var(--cyan-subtle); color: #0284C7; }
.badge-gray { background: var(--bg-subtle); color: var(--text-2); }
.badge-gradient {
  background: var(--gradient-brand-soft);
  color: var(--primary);
  border: 1px solid var(--cta-soft);
}

/* ============ 区域通用 ============ */
.section { padding: 96px 0; }
.section-dark { background: var(--gradient-deep); color: var(--text-on-dark); }
.section-cta-soft { background: var(--gradient-brand-soft); }
.section-bg { background: var(--bg-subtle); }
.section-label {
  font-family: var(--font-mono); font-size: 12px; line-height: 18px;
  letter-spacing: 0.06em; text-transform: uppercase; color: var(--primary);
  font-weight: 600;
}
.section-heading {
  font-size: var(--text-2xl); line-height: var(--leading-2xl); font-weight: var(--fw-semibold);
  letter-spacing: -0.01em; margin: 12px 0 0;
}
.section-desc {
  margin-top: 12px; font-size: var(--text-base); line-height: var(--leading-base);
  color: var(--text-2); max-width: 680px;
}
.section-dark .section-heading { color: #fff; }
.section-dark .section-desc { color: rgba(255,255,255,0.75); }
.section-dark .section-label { color: var(--cyan); }

/* ============ 01 导航栏 ============ */
.site-header {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between;
  height: 68px; padding: 0 32px;
  background: rgba(255, 255, 255, 0.9); border-bottom: 1px solid var(--divider);
  backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px);
}
.header-brand {
  display: flex; align-items: center; gap: 12px; flex-shrink: 0;
}
.header-brand .logo-img { width: 40px; height: 40px; border-radius: 10px; }
.header-name {
  font-family: "Inter", "PingFang SC", system-ui, sans-serif;
  font-size: 19px; font-weight: var(--fw-semibold); letter-spacing: -0.01em;
  color: var(--text-1);
}

.nav-links { display: flex; align-items: center; gap: 36px; }
.nav-links a {
  position: relative; font-size: var(--text-sm); font-weight: var(--fw-medium);
  color: var(--text-2); padding: 8px 0; transition: color var(--transition);
}
.nav-links a:hover, .nav-links a.active { color: var(--primary); }
.nav-links a.active::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px;
  height: 2.5px; background: var(--gradient-brand); border-radius: 2px;
}

.header-actions { display: flex; align-items: center; gap: 12px; }
.btn-lang {
  display: inline-flex; align-items: center; justify-content: center;
  height: 38px; padding: 0 14px;
  border: 1.5px solid var(--border); border-radius: var(--radius-md);
  background: transparent; color: var(--text-2);
  font-size: var(--text-xs); font-weight: var(--fw-semibold);
  cursor: pointer; transition: all var(--transition);
  font-family: var(--font-mono); letter-spacing: 0.05em;
}
.btn-lang:hover {
  background: var(--bg-subtle); color: var(--text-1); border-color: var(--text-3);
}
.menu-toggle {
  display: none; flex-direction: column; justify-content: center; gap: 5px;
  width: 38px; height: 38px; padding: 8px; background: none; border: 0; cursor: pointer;
}
.menu-toggle span { display: block; height: 2px; background: var(--text-1); border-radius: 2px; transition: transform var(--transition), opacity var(--transition); }
.menu-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.menu-toggle.open span:nth-child(2) { opacity: 0; }
.menu-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ============ 02 Hero 区 ============ */
.hero {
  position: relative; overflow: hidden;
  background: var(--gradient-hero);
  color: #fff;
  padding: 104px 0 96px;
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(ellipse 60% 50% at 85% 20%, rgba(167, 139, 250, 0.25), transparent 60%),
    radial-gradient(ellipse 50% 60% at 10% 90%, rgba(99, 102, 241, 0.22), transparent 55%);
}
.hero::after {
  content: ""; position: absolute; inset: 0;
  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);
  background-size: 64px 64px;
  mask-image: linear-gradient(180deg, rgba(0,0,0,0.5), transparent 80%);
  -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,0.5), transparent 80%);
}
.hero-inner { position: relative; z-index: 1; }
.hero-content { max-width: 720px; }
.hero-badge {
  display: inline-flex; align-items: center; gap: 8px; height: 32px; padding: 0 16px;
  border-radius: var(--radius-pill); font-size: var(--text-xs); font-weight: var(--fw-medium);
  background: rgba(167, 139, 250, 0.16); color: #DDD6FE;
  border: 1px solid rgba(196, 181, 253, 0.3); margin-bottom: 36px;
  backdrop-filter: blur(4px);
}
.hero-badge::before {
  content: ""; width: 6px; height: 6px; border-radius: 50%;
  background: #C4B5FD; flex-shrink: 0;
  box-shadow: 0 0 8px rgba(167, 139, 250, 0.6);
}
.hero-title {
  font-size: clamp(38px, 5.5vw, 58px); line-height: 1.1; font-weight: var(--fw-semibold);
  letter-spacing: -0.02em;
}
.hero-title .accent {
  background: linear-gradient(90deg, #DDD6FE, #A78BFA);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-subtitle {
  margin-top: 18px; font-size: clamp(20px, 3vw, 28px); line-height: 1.4;
  color: rgba(255,255,255,0.92); font-weight: var(--fw-semibold); max-width: 600px;
}
.hero-desc {
  margin-top: 14px; font-size: clamp(14px, 1.6vw, 17px); line-height: 1.7;
  color: rgba(255,255,255,0.6); max-width: 560px;
}
.hero-cta { display: flex; gap: 16px; margin-top: 36px; flex-wrap: wrap; }
.hero-proof {
  display: flex; gap: 36px; margin-top: 52px; padding-top: 36px;
  border-top: 1px solid rgba(255,255,255,0.12); flex-wrap: wrap;
}
.hero-proof-value { font-size: 28px; font-weight: var(--fw-semibold); line-height: 1.2; }
.hero-proof-label { font-size: var(--text-sm); color: rgba(255,255,255,0.55); margin-top: 4px; }

/* Hero 装饰 Logo */
.hero-logo-decoration {
  position: absolute; right: -60px; bottom: -80px; z-index: 0;
  opacity: 0.12; pointer-events: none;
}
.hero-logo-decoration img { width: 440px; height: 440px; border-radius: 96px; }

/* ============ 使命与愿景 ============ */
.section-mission {
  padding: 80px 0;
  background: linear-gradient(180deg, var(--bg-deep) 0%, var(--bg-dark) 100%);
  color: var(--text-on-dark);
  border-top: 1px solid rgba(255,255,255,0.06);
}
.mission-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center;
}
.mission-badge {
  display: inline-flex; align-items: center; height: 38px; padding: 0 20px;
  border-radius: var(--radius-pill); font-size: var(--text-lg); font-weight: var(--fw-semibold);
  background: rgba(1, 195, 245, 0.12); color: #7FE3FF;
  border: 1px solid rgba(1, 195, 245, 0.25); margin-bottom: 24px;
}
.mission-slogan {
  font-size: var(--text-xl); line-height: var(--leading-xl); color: rgba(255,255,255,0.75);
}
.mission-slogan strong { color: #fff; font-weight: var(--fw-semibold); }
.mission-cards { display: grid; gap: 24px; }
.mission-card {
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-lg); padding: 28px;
  transition: background var(--transition), border-color var(--transition);
}
.mission-card:hover { background: rgba(255,255,255,0.08); border-color: rgba(1,195,245,0.25); }
.mission-card-icon {
  width: 46px; height: 46px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  background: rgba(1, 195, 245, 0.15); color: #7FE3FF;
  margin-bottom: 16px;
}
.mission-card h3 {
  font-size: var(--text-base); font-weight: var(--fw-semibold);
  color: #fff; margin-bottom: 6px;
}
.mission-card p {
  font-size: var(--text-sm); line-height: var(--leading-sm); color: rgba(255,255,255,0.6);
}

/* ============ 03 数据指标带 ============ */
.metrics-bar {
  background: #FFFFFF; color: var(--text-1); padding: 48px 0;
  position: relative;
  border-bottom: 1px solid var(--divider);
}
.metrics-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 48px;
  text-align: center; position: relative;
}
.metrics-grid > div { position: relative; }
.metrics-grid > div + div::before {
  content: ""; position: absolute; left: -24px; top: 50%; transform: translateY(-50%);
  width: 1px; height: 48px; background: var(--border-light);
}
.metric-value {
  font-size: 42px; line-height: 1.1; font-weight: var(--fw-semibold);
  font-feature-settings: "tnum"; font-variant-numeric: tabular-nums;
  color: var(--primary);
}
.metric-value .warm {
  background: var(--gradient-warm);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.metric-label { font-size: var(--text-sm); color: var(--text-3); margin-top: 8px; }

/* ============ 04 核心能力区 ============ */
.features-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 48px;
}
.feature-card {
  background: var(--bg-card); border: 1px solid var(--border-light); border-radius: var(--radius-lg);
  padding: 36px 28px; box-shadow: var(--shadow-sm);
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}
.feature-card:hover {
  transform: translateY(-3px); box-shadow: var(--shadow-md);
  border-color: var(--cta-soft);
}
.feature-icon {
  width: 52px; height: 52px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  background: var(--gradient-brand-soft); color: var(--primary); margin-bottom: 24px;
}
.feature-icon svg { width: 26px; height: 26px; }
.feature-card h3 {
  font-size: var(--text-lg); line-height: var(--leading-lg); font-weight: var(--fw-semibold);
  margin-bottom: 10px;
}
.feature-card p { font-size: var(--text-sm); line-height: var(--leading-sm); color: var(--text-2); }
/* 4 卡网格 */
.features-4 { grid-template-columns: repeat(2, 1fr); }
/* 高亮卡片 */
.feature-card.featured {
  border-color: var(--cyan-soft); background: linear-gradient(160deg, #F8FEFF 0%, #F0F4FE 100%);
}
.feature-card.featured .feature-icon { background: var(--cyan-subtle); color: #0284C7; }

/* ============ 为什么选择爱智老师 ============ */
.section-why {
  background: var(--bg-page);
  border-top: 1px solid var(--divider);
}
.why-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-top: 48px;
}
.why-card {
  display: flex; gap: 16px; padding: 26px;
  background: var(--bg-card); border: 1px solid var(--border-light);
  border-radius: var(--radius-lg); box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}
.why-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--cta-soft); }
.why-icon {
  width: 44px; height: 44px; border-radius: var(--radius-md); flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  background: var(--primary-subtle); color: var(--primary);
}
.why-content { flex: 1; min-width: 0; }
.why-content h4 {
  font-size: var(--text-base); font-weight: var(--fw-semibold);
  color: var(--text-1); margin-bottom: 6px; line-height: 1.5;
}
.why-content p {
  font-size: var(--text-sm); line-height: var(--leading-sm); color: var(--text-2);
}
.why-cta-card {
  background: var(--gradient-brand-soft); border-color: var(--cta-soft);
}
.why-cta-card .why-icon {
  background: #fff; color: var(--primary);
  box-shadow: var(--shadow-sm);
}
.why-cta-card .why-content h4 { color: var(--primary); }
.why-btn { margin-top: 12px; }

/* ============ 05 教学闭环 ============ */
.loop-visual { margin-top: 48px; }
.loop-ring {
  display: flex; align-items: center; justify-content: center;
  position: relative; width: 100%; max-width: 700px; margin: 0 auto;
  aspect-ratio: 1;
}
.loop-ring svg { width: 100%; height: 100%; }
.loop-center {
  position: absolute; text-align: center; top: 50%; left: 50%;
  transform: translate(-50%, -50%);
}
.loop-center-text {
  font-size: var(--text-lg); font-weight: var(--fw-semibold); color: #fff;
}
.loop-center-badge {
  font-size: var(--text-xs); color: rgba(255,255,255,0.45); margin-top: 6px;
  font-family: var(--font-mono); letter-spacing: 0.06em;
}

/* 替代方案：水平时间轴（小屏） */
.loop-timeline {
  display: none; flex-direction: column; gap: 0; margin-top: 48px;
}
.loop-step {
  display: flex; gap: 20px; position: relative; padding-bottom: 24px;
}
.loop-step::before {
  content: ""; position: absolute; left: 19px; top: 40px; bottom: 0;
  width: 2px; background: rgba(255,255,255,0.15);
}
.loop-step:last-child::before { display: none; }
.loop-step-num {
  width: 40px; height: 40px; border-radius: 50%; flex-shrink: 0;
  display: flex; align-items: center; justify-content: center;
  background: var(--gradient-brand); color: #fff; font-weight: var(--fw-semibold);
  font-size: var(--text-sm); position: relative; z-index: 1;
  box-shadow: 0 0 0 4px rgba(34,80,239,0.2);
}
.loop-step-content h4 { font-size: var(--text-base); font-weight: var(--fw-semibold); color: #fff; }
.loop-step-content p { font-size: var(--text-sm); color: rgba(255,255,255,0.6); margin-top: 4px; }

/* ============ 06 适用人群 ============ */
.roles-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 48px; }
.role-card {
  background: var(--bg-card); border: 1px solid var(--border-light); border-radius: var(--radius-lg);
  padding: 36px 28px; text-align: center; box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition), transform var(--transition), border-color var(--transition);
}
.role-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); border-color: var(--cta-soft); }
.role-avatar {
  width: 68px; height: 68px; border-radius: 50%; margin: 0 auto 20px;
  display: flex; align-items: center; justify-content: center;
  background: var(--gradient-brand); color: #fff;
  font-size: 26px; font-weight: var(--fw-semibold);
  box-shadow: 0 4px 12px rgba(34,80,239,0.25);
}
.role-card h3 { font-size: var(--text-lg); font-weight: var(--fw-semibold); margin-bottom: 8px; }
.role-card p { font-size: var(--text-sm); line-height: var(--leading-sm); color: var(--text-2); }

/* ============ 07 下载区 ============ */
.download-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; margin-top: 48px; }
.download-card {
  background: var(--bg-card); border: 1px solid var(--border-light); border-radius: var(--radius-lg);
  padding: 44px 28px; text-align: center; box-shadow: var(--shadow-sm);
  position: relative; overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
}
.download-card:hover { box-shadow: var(--shadow-md); transform: translateY(-2px); }
.download-card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 4px;
  background: var(--gradient-brand);
}
.download-icon {
  width: 60px; height: 60px; margin: 0 auto 20px;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-lg); background: var(--gradient-brand-soft);
  color: var(--primary);
}
.download-card h3 { font-size: var(--text-lg); font-weight: var(--fw-semibold); margin-bottom: 8px; }
.download-card .status {
  display: inline-flex; align-items: center; gap: 6px;
  font-size: var(--text-sm); color: var(--warning); margin-bottom: 16px;
}
.download-card .btn { width: 100%; }
.download-card .btn:disabled {
  opacity: 0.5; cursor: not-allowed; pointer-events: none;
}

/* 下载区 CTA 底部 */
.download-cta {
  text-align: center; margin-top: 48px; padding-top: 40px;
  border-top: 1px solid rgba(34,80,239,0.1);
}
.download-cta p {
  font-size: var(--text-lg); font-weight: var(--fw-medium);
  color: var(--text-1); margin-bottom: 18px;
}

/* ============ 路线图（深底） ============ */
.roadmap-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; margin-top: 48px; }
.roadmap-item {
  display: flex; gap: 20px; padding: 28px;
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1);
  border-radius: var(--radius-lg); transition: background var(--transition), border-color var(--transition);
}
.roadmap-item:hover { background: rgba(255,255,255,0.08); border-color: rgba(1,195,245,0.25); }
.roadmap-num {
  font-family: var(--font-mono); font-size: var(--text-lg); font-weight: var(--fw-semibold);
  color: #7FE3FF; flex-shrink: 0; width: 36px;
}
.roadmap-content h4 {
  font-size: var(--text-base); font-weight: var(--fw-semibold);
  color: #fff; margin-bottom: 4px;
}
.roadmap-content p {
  font-size: var(--text-sm); line-height: var(--leading-sm); color: rgba(255,255,255,0.6);
}

/* ============ 08 微信公众号 ============ */
.wechat-section {
  display: grid; grid-template-columns: auto 1fr; gap: 48px; align-items: center;
  margin-top: 48px; max-width: 640px; margin-left: auto; margin-right: auto;
  background: var(--bg-card); border: 1px solid var(--border-light); border-radius: var(--radius-lg);
  padding: 40px; box-shadow: var(--shadow-sm);
}
.wechat-qr {
  width: 140px; height: 140px; border: 1px solid var(--border-light); border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  background: var(--bg-subtle); flex-shrink: 0;
}
.wechat-qr svg { width: 96px; height: 96px; color: var(--text-3); }
.wechat-content h3 { font-size: var(--text-xl); font-weight: var(--fw-semibold); margin-bottom: 8px; }
.wechat-content p { font-size: var(--text-sm); color: var(--text-2); line-height: var(--leading-sm); }
.wechat-tips { display: flex; flex-direction: column; gap: 8px; margin-top: 16px; }
.wechat-tip {
  display: flex; align-items: center; gap: 8px;
  font-size: var(--text-sm); color: var(--text-2);
}
.wechat-tip::before {
  content: ""; width: 6px; height: 6px; border-radius: 50%;
  background: var(--success); flex-shrink: 0;
}

/* ============ 09 Footer ============ */
.site-footer {
  background: var(--bg-dark); color: rgba(255,255,255,0.55); padding: 64px 0 40px;
  position: relative; overflow: hidden;
}
.site-footer::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(1,195,245,0.4), transparent);
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr; gap: 48px;
  position: relative;
}
.footer-brand .logo-img { width: 36px; height: 36px; border-radius: 8px; margin-bottom: 12px; }
.footer-brand strong {
  display: block; font-size: var(--text-lg); font-weight: var(--fw-semibold);
  color: #fff; margin-bottom: 8px;
}
.footer-brand p { font-size: var(--text-sm); line-height: var(--leading-sm); }
.footer-col h4 {
  font-size: var(--text-sm); font-weight: var(--fw-semibold);
  color: #fff; margin-bottom: 20px;
}
.footer-col a {
  display: block; font-size: var(--text-sm); color: rgba(255,255,255,0.55);
  padding: 4px 0; transition: color var(--transition);
}
.footer-col a:hover { color: #7FE3FF; }
.footer-bottom {
  margin-top: 48px; padding-top: 24px; border-top: 1px solid rgba(255,255,255,0.08);
  display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap;
  font-size: var(--text-xs); line-height: var(--leading-xs);
  position: relative;
}
.footer-soul {
  font-family: var(--font-mono); letter-spacing: 0.06em;
  background: linear-gradient(90deg, #7FE3FF, #498DFB);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
  font-weight: 600;
}
.footer-icp {
  color: rgba(255,255,255,0.4);
  transition: color var(--transition);
}
.footer-icp:hover { color: rgba(255,255,255,0.7); }

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .features-4 { grid-template-columns: repeat(2, 1fr); }
  .why-grid { grid-template-columns: repeat(2, 1fr); }
  .loop-ring { display: none; }
  .loop-timeline { display: flex; }
  .roles-grid { grid-template-columns: 1fr 1fr; }
  .download-grid { grid-template-columns: 1fr 1fr; }
  .wechat-section { grid-template-columns: 1fr; text-align: center; }
  .wechat-qr { margin: 0 auto; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  .wrap { padding: 0 20px; }
  .site-header { padding: 0 20px; }
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; flex-direction: column; position: absolute; top: 68px; left: 0; right: 0;
    background: rgba(255,255,255,0.98); border-bottom: 1px solid var(--divider);
    padding: 16px 20px; gap: 0; backdrop-filter: blur(16px);
  }
  .nav-links.open a { padding: 14px 0; width: 100%; border-bottom: 1px solid var(--divider); }
  .nav-links.open a:last-child { border-bottom: none; }
  .menu-toggle { display: flex; }
  .hero { padding: 72px 0 64px; }
  .hero-cta { flex-direction: column; }
  .hero-proof { gap: 20px; }
  .metrics-grid { grid-template-columns: 1fr; gap: 32px; }
  .metrics-grid > div + div::before { display: none; }
  .features-grid { grid-template-columns: 1fr; }
  .features-4 { grid-template-columns: 1fr; }
  .why-grid { grid-template-columns: 1fr; }
  .roles-grid { grid-template-columns: 1fr; }
  .download-grid { grid-template-columns: 1fr; }
  .mission-grid { grid-template-columns: 1fr; gap: 32px; }
  .mission-slogan { font-size: var(--text-lg); }
  .roadmap-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .metric-value { font-size: 34px; }
  .section { padding: 64px 0; }
}