/* ═══════════════════════════════════════════════
   aibuild.work — Design System v2
   深色科技风 · 玻璃拟态 · 粒子网络 · 3D 倾斜
   ═══════════════════════════════════════════════ */

/* ── 字体 ── */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

/* ── 设计变量 ── */
:root {
  --bg: #070b1a;
  --bg2: #0b122e;
  --bg3: #0f1838;
  --card: rgba(255, 255, 255, 0.04);
  --card-hover: rgba(255, 255, 255, 0.08);
  --card-border: rgba(120, 160, 255, 0.12);
  --card-border-hover: rgba(91, 141, 239, 0.4);
  --glass: rgba(255, 255, 255, 0.03);
  --glass-border: rgba(255, 255, 255, 0.06);
  --txt: #e8edff;
  --txt-secondary: #94a3c8;
  --txt-tertiary: #6b7fa0;
  --accent: #5b8def;
  --accent-hover: #7aa3ff;
  --accent2: #4ecdc4;
  --accent3: #8aa6ff;
  --purple: #a78bfa;
  --success: #4ecdc4;
  --warn: #fbbf24;
  --danger: #f87171;
  --glow: rgba(91, 141, 239, 0.25);
  --glow2: rgba(78, 205, 196, 0.2);
  --glow3: rgba(167, 139, 250, 0.15);
  --radius: 16px;
  --radius-sm: 10px;
  --radius-xs: 8px;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.4);
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
  --font: 'Inter', -apple-system, BlinkMacSystemFont, 'PingFang SC', 'Microsoft YaHei', sans-serif;
}

/* ── 基础重置 ── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 80px; }
body {
  font-family: var(--font); background: var(--bg); color: var(--txt);
  line-height: 1.65; overflow-x: hidden; -webkit-font-smoothing: antialiased;
}

/* ── Canvas 粒子层 ── */
#particle-canvas {
  position: fixed; inset: 0; z-index: -1;
  pointer-events: none;
}

/* ── 背景网格 (3D 透视) ── */
.bg-grid {
  position: fixed; inset: 0; z-index: -2;
  background-image:
    linear-gradient(rgba(91, 141, 239, 0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(91, 141, 239, 0.04) 1px, transparent 1px);
  background-size: 60px 60px;
  mask-image: radial-gradient(ellipse 70% 50% at 50% 0%, #000 25%, transparent 100%);
  -webkit-mask-image: radial-gradient(ellipse 70% 50% at 50% 0%, #000 25%, transparent 100%);
  perspective: 600px;
  transform: rotateX(4deg);
  transform-origin: 50% 0%;
}

/* ── 动态极光 ── */
.bg-aurora {
  position: fixed; inset: 0; z-index: -1; pointer-events: none;
  overflow: hidden;
}
.bg-aurora .aurora {
  position: absolute; border-radius: 50%;
  filter: blur(100px); opacity: 0.2;
  animation: auroraMove 25s ease-in-out infinite alternate;
}
.bg-aurora .aurora:nth-child(1) {
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(91,141,239,0.2), transparent);
  top: -15%; left: -10%;
  animation-duration: 25s;
}
.bg-aurora .aurora:nth-child(2) {
  width: 450px; height: 450px;
  background: radial-gradient(circle, rgba(78,205,196,0.15), transparent);
  bottom: -10%; right: -8%;
  animation-duration: 30s; animation-delay: -10s;
}
.bg-aurora .aurora:nth-child(3) {
  width: 350px; height: 350px;
  background: radial-gradient(circle, rgba(167,139,250,0.12), transparent);
  top: 30%; left: 40%;
  animation-duration: 20s; animation-delay: -5s;
}
@keyframes auroraMove {
  0% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(40px, -50px) scale(1.15); }
  66% { transform: translate(-30px, 30px) scale(0.9); }
  100% { transform: translate(50px, 20px) scale(1.05); }
}

/* ── 扫描线 (超微) ── */
.scanlines {
  position: fixed; inset: 0; z-index: 0; pointer-events: none;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(255,255,255,0.008) 2px,
    rgba(255,255,255,0.008) 4px
  );
}

/* ── 容器 ── */
.wrap { max-width: 1040px; margin: 0 auto; padding: 0 22px; }
.wrap-narrow { max-width: 800px; margin: 0 auto; padding: 0 22px; }

/* ── 导航栏 ── */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 0 22px;
  background: rgba(7, 11, 26, 0.5);
  backdrop-filter: blur(24px) saturate(1.4);
  -webkit-backdrop-filter: blur(24px) saturate(1.4);
  border-bottom: 1px solid rgba(120, 160, 255, 0.06);
  transition: var(--transition);
}
.navbar.scrolled {
  background: rgba(7, 11, 26, 0.82);
  border-bottom-color: rgba(120, 160, 255, 0.12);
  box-shadow: 0 4px 30px rgba(0, 0, 0, 0.25);
}
.navbar-inner {
  max-width: 1040px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  height: 64px;
}
.navbar-brand {
  display: flex; align-items: center; gap: 10px;
  font-weight: 800; font-size: 16px; color: var(--txt);
  text-decoration: none; letter-spacing: -0.3px;
}
.navbar-brand .logo-dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  box-shadow: 0 0 16px var(--glow);
  animation: pulse-dot 2s ease-in-out infinite;
}
@keyframes pulse-dot {
  0%, 100% { box-shadow: 0 0 16px var(--glow); }
  50% { box-shadow: 0 0 24px var(--glow), 0 0 40px var(--glow2); }
}
.navbar-links { display: flex; align-items: center; gap: 4px; }
.navbar-links a {
  color: var(--txt-secondary); text-decoration: none;
  font-size: 14px; font-weight: 500;
  padding: 8px 14px; border-radius: var(--radius-xs);
  transition: var(--transition); position: relative;
}
.navbar-links a:hover { color: var(--txt); background: rgba(255,255,255,0.04); }
.navbar-links a::after {
  content: ''; position: absolute; bottom: 2px; left: 50%;
  width: 0; height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  border-radius: 2px; transition: var(--transition); transform: translateX(-50%);
}
.navbar-links a:hover::after { width: 60%; }

/* ── 通用卡片 (玻璃拟态 + 渐变边框) ── */
.card {
  position: relative;
  background: linear-gradient(135deg, rgba(255,255,255,0.04), rgba(255,255,255,0.01));
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  backdrop-filter: blur(16px) saturate(1.2);
  -webkit-backdrop-filter: blur(16px) saturate(1.2);
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1),
              border-color 0.35s ease,
              box-shadow 0.35s ease;
  overflow: hidden;
  transform-style: preserve-3d;
  will-change: transform;
}

/* 渐变边框光晕 (悬停) */
.card::before {
  content: '';
  position: absolute; inset: -1px;
  border-radius: inherit;
  background: linear-gradient(135deg, var(--accent), var(--accent2), var(--purple), var(--accent));
  background-size: 300% 300%;
  opacity: 0;
  transition: opacity 0.4s ease;
  z-index: -1;
  animation: borderGlow 4s ease-in-out infinite;
}
.card:hover::before { opacity: 1; }

@keyframes borderGlow {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

.card:hover {
  transform: translateY(-4px) scale(1.01);
  border-color: transparent;
  box-shadow: 0 16px 48px rgba(0,0,0,0.3), 0 0 40px rgba(91,141,239,0.08);
}

/* 卡片内部光晕 */
.card::after {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
  opacity: 0; transition: opacity 0.4s ease;
}
.card:hover::after { opacity: 1; }

/* ── 渐变文字 ── */
.grad {
  background: linear-gradient(100deg, var(--accent), var(--accent2) 55%, var(--accent3));
  -webkit-background-clip: text; background-clip: text; color: transparent;
  background-size: 200% 200%;
  animation: gradShift 4s ease-in-out infinite;
}
@keyframes gradShift {
  0% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
  100% { background-position: 0% 50%; }
}

/* ── 按钮 (磁吸效果基座) ── */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 24px; border-radius: var(--radius-sm);
  font-weight: 600; font-size: 14.5px;
  cursor: pointer; border: none; text-decoration: none;
  transition: transform 0.25s ease, box-shadow 0.25s ease, background 0.25s ease;
  font-family: var(--font); position: relative; overflow: hidden;
}
.btn::before {
  content: ''; position: absolute; inset: 0;
  border-radius: inherit; opacity: 0;
  transition: opacity 0.3s ease;
}
.btn-primary {
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  color: #070b1a; box-shadow: 0 4px 20px var(--glow);
}
.btn-primary:hover {
  transform: translateY(-2px) scale(1.02);
  box-shadow: 0 8px 30px var(--glow);
}
.btn-secondary {
  background: var(--card); border: 1px solid var(--card-border); color: var(--txt);
}
.btn-secondary:hover {
  background: var(--card-hover); border-color: var(--accent);
  transform: translateY(-2px) scale(1.02);
}
.btn-ghost {
  background: transparent; border: 1px solid var(--card-border); color: var(--txt-secondary);
}
.btn-ghost:hover {
  border-color: var(--accent); color: var(--txt); background: rgba(91,141,239,0.05);
}

/* ── 徽章 ── */
.badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px; border: 1px solid var(--card-border);
  border-radius: 30px; font-size: 12.5px; color: var(--accent2);
  background: var(--card); backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px); font-weight: 500; letter-spacing: 0.3px;
}
.badge .dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--accent2); box-shadow: 0 0 8px var(--accent2);
  animation: pulse-dot 2s ease-in-out infinite;
}

/* ── 区块 ── */
section { padding: 80px 0; }
.sec-head { text-align: center; margin-bottom: 48px; }
.sec-head .k {
  font-size: 11px; letter-spacing: 3px; color: var(--accent);
  text-transform: uppercase; font-weight: 600; margin-bottom: 10px;
}
.sec-head h2 {
  font-size: clamp(24px, 3.6vw, 34px); font-weight: 800;
  letter-spacing: -0.5px; line-height: 1.2;
}
.sec-head p {
  color: var(--txt-secondary); margin-top: 12px;
  max-width: 600px; margin-inline: auto; font-size: 15px; line-height: 1.6;
}

/* ── 滚动动画 ── */
.anim-fade { opacity: 0; transform: translateY(24px); transition: opacity 0.6s ease, transform 0.6s ease; }
.anim-fade.visible { opacity: 1; transform: translateY(0); }
.anim-fade-up { opacity: 0; transform: translateY(40px); transition: opacity 0.7s ease, transform 0.7s ease; }
.anim-fade-up.visible { opacity: 1; transform: translateY(0); }
.anim-scale { opacity: 0; transform: scale(0.92); transition: opacity 0.6s ease, transform 0.6s ease; }
.anim-scale.visible { opacity: 1; transform: scale(1); }

/* stagger children */
.anim-stagger > * {
  opacity: 0; transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.anim-stagger.visible > *:nth-child(1) { transition-delay: 0s; }
.anim-stagger.visible > *:nth-child(2) { transition-delay: 0.07s; }
.anim-stagger.visible > *:nth-child(3) { transition-delay: 0.14s; }
.anim-stagger.visible > *:nth-child(4) { transition-delay: 0.21s; }
.anim-stagger.visible > *:nth-child(5) { transition-delay: 0.28s; }
.anim-stagger.visible > *:nth-child(6) { transition-delay: 0.35s; }
.anim-stagger.visible > *:nth-child(7) { transition-delay: 0.42s; }
.anim-stagger.visible > *:nth-child(8) { transition-delay: 0.49s; }
.anim-stagger.visible > *:nth-child(9) { transition-delay: 0.56s; }
.anim-stagger.visible > *:nth-child(10) { transition-delay: 0.63s; }
.anim-stagger.visible > * { opacity: 1; transform: translateY(0); }

/* ── 分隔线 ── */
.divider { height: 1px; background: linear-gradient(90deg, transparent, var(--card-border), transparent); margin: 0 auto; max-width: 600px; }

/* ── 页脚 ── */
footer {
  text-align: center; padding: 48px 0 56px;
  color: var(--txt-tertiary); font-size: 13px;
  border-top: 1px solid var(--card-border); margin-top: 20px;
}
footer a { color: var(--accent); text-decoration: none; transition: var(--transition); }
footer a:hover { color: var(--accent-hover); text-decoration: underline; }

/* ── 响应式 ── */
@media (max-width: 768px) {
  .navbar-links a { font-size: 13px; padding: 6px 10px; }
  section { padding: 56px 0; }
  .wrap { padding: 0 16px; }
}
@media (max-width: 480px) {
  .navbar-links a:not(.nav-keep) { display: none; }
  .navbar-links a.nav-keep { display: inline-flex; }
}