/* ==========================================================================
   MYAI 优城市 (myai.city)
   主视觉样式表: 深邃暗黑极客科技风 (Linear / Vercel 质感规范)
   ========================================================================== */

:root {
  /* 强制暗黑极客色彩方案 */
  color-scheme: dark;

  /* 主题色系设计令牌 */
  --bg-primary: #06080F;
  --bg-surface: #0B1120;
  --bg-card: rgba(13, 19, 33, 0.72);
  --bg-card-hover: rgba(19, 28, 49, 0.88);
  --bg-glass: rgba(11, 17, 32, 0.65);

  /* 霓虹极光强调色 */
  --cyan-primary: #00F0FF;
  --cyan-glow: rgba(0, 240, 255, 0.35);
  --purple-primary: #A855F7;
  --purple-glow: rgba(168, 85, 247, 0.35);
  --emerald-primary: #00FFB2;
  --emerald-glow: rgba(0, 255, 178, 0.3);
  --blue-primary: #3B82F6;

  /* 文本灰阶 */
  --text-primary: #F8FAFC;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;
  --text-accent: #38BDF8;

  /* 边框与阴影 */
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-light: rgba(255, 255, 255, 0.15);
  --border-neon: rgba(0, 240, 255, 0.4);
  --shadow-subtle: 0 4px 20px rgba(0, 0, 0, 0.5);
  --shadow-card: 0 10px 30px -10px rgba(0, 0, 0, 0.7), 0 0 1px 1px rgba(255, 255, 255, 0.05);
  --shadow-neon: 0 0 35px rgba(0, 240, 255, 0.2);

  /* 布局与圆角 */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --container-max: 1280px;

  /* 字体族 */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', Menlo, Monaco, Consolas, monospace;

  /* 滚动条 */
  --scrollbar-thumb: rgba(0, 240, 255, 0.35);
  --scrollbar-track: #06080F;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
  scrollbar-width: thin;
}

/* 现代滚动条兼容回退 */
@supports not (scrollbar-color: auto) {
  ::-webkit-scrollbar {
    width: 8px;
    height: 8px;
  }
  ::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 4px;
  }
  ::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
  }
}

/* 基础重置 */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  line-height: 1.6;
}

body {
  min-height: 100vh;
  position: relative;
  overflow-x: hidden;
  background-color: var(--bg-primary);
  /* 极客网格微纹理 */
  background-image: 
    radial-gradient(circle at 50% 0%, rgba(0, 240, 255, 0.08) 0%, transparent 60%),
    radial-gradient(circle at 80% 40%, rgba(168, 85, 247, 0.06) 0%, transparent 50%),
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 100% 100%, 100% 100%, 60px 60px, 60px 60px;
}

/* 容器与版心 */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

@media (max-width: 640px) {
  .container {
    padding-left: 16px;
    padding-right: 16px;
  }
}

/* 章节通用排版 */
.section {
  padding: 110px 0;
  position: relative;
  z-index: 2;
}

@media (max-width: 768px) {
  .section {
    padding: 70px 0;
  }
}

.section-header {
  text-align: center;
  max-width: 780px;
  margin: 0 auto 60px auto;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  border-radius: var(--radius-full);
  background: rgba(0, 240, 255, 0.08);
  border: 1px solid rgba(0, 240, 255, 0.25);
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--cyan-primary);
  letter-spacing: 0.04em;
  margin-bottom: 16px;
  text-transform: uppercase;
}

.section-tag .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--cyan-primary);
  box-shadow: 0 0 10px var(--cyan-primary);
  animation: pulseDot 2s infinite ease-in-out;
}

@keyframes pulseDot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(0.8); }
}

.section-title {
  font-size: clamp(2rem, 3.8vw, 3rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 20px;
  color: #FFFFFF;
}

.section-title .gradient-text {
  background: linear-gradient(135deg, #FFFFFF 20%, #00F0FF 65%, #A855F7 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.section-description {
  font-size: 1.08rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* 通用渐变与发光特效 */
.glow-cyan {
  text-shadow: 0 0 20px rgba(0, 240, 255, 0.5);
}

.glow-purple {
  text-shadow: 0 0 20px rgba(168, 85, 247, 0.5);
}

/* 通用超链接 */
a {
  color: inherit;
  text-decoration: none;
  transition: all 0.25s ease;
}

/* 无障碍键盘聚焦环 */
:focus-visible {
  outline: 2px solid var(--cyan-primary);
  outline-offset: 3px;
}

/* 动效友好回退 */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}