/* ============================================
   震感实验室 (ShakeLab) — 全局样式
   暗色科幻主题 · 霓虹蓝绿点缀 · 儿童友好
   ============================================ */

/* ---------- 自定义属性（主题色） ---------- */
:root {
  --color-bg: #0b0e1a;
  --color-bg-card: #13182b;
  --color-bg-card-hover: #1a2140;
  --color-primary: #00e5ff;
  --color-secondary: #76ff03;
  --color-accent: #ff6d00;
  --color-danger: #ff1744;
  --color-text: #e0e6f0;
  --color-text-dim: #8892b0;
  --color-border: #1e2a4a;
  --color-glow: rgba(0, 229, 255, 0.15);
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
  --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", "Helvetica Neue", sans-serif;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-stack);
  background: linear-gradient(145deg, #0b0e1a 0%, #111830 50%, #0d1225 100%);
  color: var(--color-text);
  min-height: 100vh;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ---------- Typography ---------- */
h1, h2, h3, h4 {
  line-height: 1.3;
  font-weight: 700;
}

/* 渐变标题 */
.gradient-text {
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ---------- Layout ---------- */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ---------- Navigation ---------- */
.navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  background: rgba(11, 14, 26, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar .logo {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--color-primary);
  text-decoration: none;
  letter-spacing: 0.5px;
}

.navbar .logo:hover {
  text-shadow: 0 0 12px var(--color-glow);
}

.nav-links {
  display: flex;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  color: var(--color-text-dim);
  text-decoration: none;
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--color-primary);
  background: rgba(0, 229, 255, 0.08);
}

/* ---------- Cards ---------- */
.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 28px 24px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.card:hover {
  background: var(--color-bg-card-hover);
  border-color: rgba(0, 229, 255, 0.25);
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0, 229, 255, 0.1);
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
  margin: 32px 0;
}

/* ---------- Buttons ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 28px;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-stack);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  color: #fff;
}

.btn-primary {
  background: linear-gradient(135deg, var(--color-primary), #0091ea);
  color: #0b0e1a;
}

.btn-primary:hover {
  transform: scale(1.04);
  box-shadow: 0 0 20px rgba(0, 229, 255, 0.35);
}

.btn-primary:active {
  transform: scale(0.97);
}

.btn-secondary {
  background: rgba(0, 229, 255, 0.1);
  border: 1px solid var(--color-primary);
  color: var(--color-primary);
}

.btn-secondary:hover {
  background: rgba(0, 229, 255, 0.2);
  transform: scale(1.04);
}

.btn-danger {
  background: linear-gradient(135deg, var(--color-danger), #b71c1c);
}

.btn-danger:hover {
  transform: scale(1.04);
  box-shadow: 0 0 20px rgba(255, 23, 68, 0.35);
}

/* ---------- Slider (range input) ---------- */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 8px;
  border-radius: 4px;
  background: var(--color-border);
  outline: none;
  transition: var(--transition);
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  box-shadow: 0 0 12px rgba(0, 229, 255, 0.4);
  transition: var(--transition);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.15);
  box-shadow: 0 0 20px rgba(0, 229, 255, 0.6);
}

input[type="range"]::-moz-range-thumb {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  border: none;
  box-shadow: 0 0 12px rgba(0, 229, 255, 0.4);
}

/* ---------- Footer ---------- */
.footer {
  text-align: center;
  padding: 32px 20px;
  color: var(--color-text-dim);
  font-size: 0.85rem;
  border-top: 1px solid var(--color-border);
  margin-top: 48px;
}

/* ---------- Responsive ---------- */
@media (max-width: 768px) {
  .navbar {
    flex-direction: column;
    gap: 10px;
    padding: 12px 16px;
  }

  .nav-links {
    flex-wrap: wrap;
    justify-content: center;
  }

  .card-grid {
    grid-template-columns: 1fr;
  }

  .container {
    padding: 0 14px;
  }

  h1 {
    font-size: 1.6rem;
  }
}

/* ---------- Utility ---------- */
.text-center { text-align: center; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.mt-32 { margin-top: 32px; }
.mb-16 { margin-bottom: 16px; }
.mb-24 { margin-bottom: 24px; }