/* ============================================================
   牛鼻子科技官网 — 全局设计系统
   Design System: Variables / Reset / Typography / Utilities
   ============================================================ */

/* ---------- 1. 设计令牌（CSS 变量） ---------- */
:root {
  /* 色彩 */
  --color-bg:          #0a0e1a;
  --color-bg-2:        #0d1424;
  --color-bg-card:     rgba(255, 255, 255, 0.04);
  --color-border:      rgba(79, 142, 247, 0.2);
  --color-border-hover:rgba(79, 142, 247, 0.6);

  --color-primary:     #4f8ef7;
  --color-primary-glow:rgba(79, 142, 247, 0.3);
  --color-accent:      #00d4ff;
  --color-accent-glow: rgba(0, 212, 255, 0.25);

  --color-text:        #e8eaf6;
  --color-text-sub:    #8892a4;
  --color-text-muted:  #4a5568;

  --color-success:     #38ef7d;
  --color-warning:     #f7b731;

  /* 字体 */
  --font-sans:    'Inter', 'Noto Sans SC', 'PingFang SC', system-ui, sans-serif;
  --font-mono:    'JetBrains Mono', 'Fira Code', monospace;

  /* 字号阶梯 */
  --text-xs:   0.75rem;
  --text-sm:   0.875rem;
  --text-base: 1rem;
  --text-lg:   1.125rem;
  --text-xl:   1.25rem;
  --text-2xl:  1.5rem;
  --text-3xl:  1.875rem;
  --text-4xl:  2.25rem;
  --text-5xl:  3rem;
  --text-6xl:  3.75rem;

  /* 间距 */
  --space-1:  0.25rem;
  --space-2:  0.5rem;
  --space-3:  0.75rem;
  --space-4:  1rem;
  --space-6:  1.5rem;
  --space-8:  2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --space-24: 6rem;

  /* 圆角 */
  --radius-sm:  6px;
  --radius-md:  12px;
  --radius-lg:  20px;
  --radius-xl:  32px;
  --radius-full:9999px;

  /* 阴影 / 发光 */
  --shadow-card:  0 4px 24px rgba(0,0,0,0.4);
  --glow-primary: 0 0 20px var(--color-primary-glow), 0 0 60px rgba(79,142,247,0.1);
  --glow-accent:  0 0 20px var(--color-accent-glow),  0 0 60px rgba(0,212,255,0.1);

  /* 动效 */
  --ease-out-cubic: cubic-bezier(0.33, 1, 0.68, 1);
  --transition-fast:  0.2s var(--ease-out-cubic);
  --transition-base:  0.35s var(--ease-out-cubic);
  --transition-slow:  0.6s  var(--ease-out-cubic);

  /* 布局 */
  --container-max: 1200px;
  --nav-height:    70px;
}

/* ---------- 1b. 亮色主题变量（覆盖暗色） ---------- */
[data-theme="light"] {
  --color-bg:           #f0f4ff;
  --color-bg-2:         #e8eef9;
  --color-bg-card:      rgba(255, 255, 255, 0.75);
  --color-border:       rgba(79, 142, 247, 0.18);
  --color-border-hover: rgba(79, 142, 247, 0.5);

  --color-primary:      #2d6ee0;
  --color-primary-glow: rgba(45, 110, 224, 0.25);
  --color-accent:       #0099cc;
  --color-accent-glow:  rgba(0, 153, 204, 0.2);

  --color-text:         #0f1829;
  --color-text-sub:     #4a5578;
  --color-text-muted:   #8898b0;

  --color-success:      #1db954;
  --color-warning:      #d4880e;

  --shadow-card:        0 4px 24px rgba(79, 142, 247, 0.1);
  --glow-primary:       0 0 20px var(--color-primary-glow), 0 0 60px rgba(45,110,224,0.08);
  --glow-accent:        0 0 20px var(--color-accent-glow),  0 0 60px rgba(0,153,204,0.08);
}

/* ---------- 1c. 全局颜色过渡（主题切换时平滑） ---------- */
html {
  transition:
    background-color 0.4s cubic-bezier(0.33,1,0.68,1),
    color            0.4s cubic-bezier(0.33,1,0.68,1);
}

/* ---------- 2. Reset ---------- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text);
  background-color: var(--color-bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul, ol { list-style: none; }
button { cursor: pointer; border: none; background: none; font-family: inherit; }
input, textarea { font-family: inherit; }

/* ---------- 3. 布局工具 ---------- */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-6);
}

.section {
  padding-block: var(--space-24);
}

.section--alt {
  background: var(--color-bg-2);
}

/* ---------- 4. 排版 ---------- */
.section-label {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.section-title {
  font-size: clamp(var(--text-2xl), 4vw, var(--text-4xl));
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: var(--space-4);
}

.section-title span {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-desc {
  font-size: var(--text-lg);
  color: var(--color-text-sub);
  max-width: 600px;
}

.text-center { text-align: center; }
.text-center .section-desc { margin-inline: auto; }

/* ---------- 5. 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-full);
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: var(--transition-base);
  white-space: nowrap;
}

.btn--primary {
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: #fff;
  box-shadow: 0 4px 24px var(--color-primary-glow);
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 32px var(--color-primary-glow), var(--glow-primary);
}

.btn--outline {
  border: 1px solid var(--color-border);
  color: var(--color-text);
  backdrop-filter: blur(8px);
}
.btn--outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: rgba(79,142,247,0.08);
}

/* ---------- 6. 毛玻璃卡片 ---------- */
.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: var(--transition-base);
}
.card:hover {
  border-color: var(--color-border-hover);
  box-shadow: var(--glow-primary), var(--shadow-card);
  transform: translateY(-4px);
}

/* ---------- 7. 网格 ---------- */
.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-8);
}
.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-6);
}

@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section { padding-block: var(--space-16); }
}

/* ---------- 8. 分割线装饰 ---------- */
.divider {
  width: 48px;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius-full);
  margin-block: var(--space-4);
}
.text-center .divider { margin-inline: auto; }

/* ---------- 9. 滚动条美化 ---------- */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--color-bg); }
::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}
::-webkit-scrollbar-thumb:hover { background: var(--color-primary); }

/* ---------- 10. 选中样式 ---------- */
::selection {
  background: var(--color-primary-glow);
  color: var(--color-text);
}

/* ---------- 11. 亮色模式补充覆盖 ---------- */

/* 亮色卡片：白底实感 */
[data-theme="light"] .card {
  background: rgba(255, 255, 255, 0.85);
  box-shadow: 0 2px 16px rgba(79, 142, 247, 0.08);
}
[data-theme="light"] .card:hover {
  box-shadow: var(--glow-primary), 0 8px 32px rgba(79,142,247,0.12);
}

/* 亮色滚动条 */
[data-theme="light"] ::-webkit-scrollbar-track  { background: var(--color-bg-2); }
[data-theme="light"] ::-webkit-scrollbar-thumb  { background: rgba(79,142,247,0.3); }

/* 亮色 section--alt */
[data-theme="light"] .section--alt { background: var(--color-bg-2); }

/* 亮色 stats 区 */
[data-theme="light"] .stats { background: var(--color-bg-2); }

/* 亮色 Hero 光晕 */
[data-theme="light"] .hero { background: linear-gradient(160deg, #deeaff 0%, #f0f4ff 60%, #e8eef9 100%); }
[data-theme="light"] .hero__glow-1 {
  background: radial-gradient(circle, rgba(45,110,224,0.18) 0%, transparent 70%);
}
[data-theme="light"] .hero__glow-2 {
  background: radial-gradient(circle, rgba(0,153,204,0.12) 0%, transparent 70%);
}

/* 亮色 footer */
[data-theme="light"] .footer { background: var(--color-bg-2); }

/* 亮色 mockup 屏幕 */
[data-theme="light"] .product-mockup__screen {
  background: rgba(255,255,255,0.95);
  border-color: rgba(79,142,247,0.2);
  box-shadow: 0 16px 48px rgba(79,142,247,0.15), 0 0 0 1px rgba(79,142,247,0.1);
}
[data-theme="light"] .mockup-header { background: rgba(79,142,247,0.05); }
[data-theme="light"] .mockup-row    { color: var(--color-text-sub); }
[data-theme="light"] .mockup-total  { color: var(--color-text); }

/* 亮色 CTA banner */
[data-theme="light"] .cta-banner::before {
  background: radial-gradient(ellipse 60% 80% at 50% 50%, rgba(45,110,224,0.07) 0%, transparent 70%);
}