:root {
  --bg-color: #0f172a;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --card-bg: rgba(30, 41, 59, 0.7);
  --card-border: rgba(255, 255, 255, 0.1);
  --card-hover-border: rgba(56, 189, 248, 0.5);
  --accent-color: #38bdf8;
  --accent-glow: rgba(56, 189, 248, 0.2);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  min-height: 100vh;
  background-image: 
    radial-gradient(at 0% 0%, rgba(15, 23, 42, 1) 0, transparent 50%),
    radial-gradient(at 50% 0%, rgba(30, 58, 138, 0.4) 0, transparent 50%),
    radial-gradient(at 100% 0%, rgba(15, 23, 42, 1) 0, transparent 50%);
  background-attachment: fixed;
  line-height: 1.5;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 4rem 2rem;
}

header {
  text-align: center;
  margin-bottom: 4rem;
}

h1 {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  background: linear-gradient(to right, #e2e8f0, #38bdf8);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.025em;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 1.25rem;
}

/* 导航网格 */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 2rem;
}

/* 卡片 */
.tool-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 1rem;
  padding: 2rem;
  text-decoration: none;
  color: inherit;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.tool-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 50% 0%, var(--accent-glow) 0%, transparent 70%);
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
}

.tool-card:hover {
  transform: translateY(-4px);
  border-color: var(--card-hover-border);
  box-shadow: 0 10px 30px -10px rgba(0, 0, 0, 0.5), 0 0 20px var(--accent-glow);
}

.tool-card:hover::before {
  opacity: 1;
}

.card-icon {
  font-size: 2.5rem;
  margin-bottom: 1.25rem;
  display: inline-block;
  transition: transform 0.3s ease;
}

.tool-card:hover .card-icon {
  transform: scale(1.1) rotate(5deg);
}

.card-title {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--text-primary);
}

.card-desc {
  color: var(--text-secondary);
  font-size: 0.95rem;
  flex-grow: 1;
}

/* 标签 */
.card-badge {
  position: absolute;
  top: 1.5rem;
  right: 1.5rem;
  font-size: 0.75rem;
  padding: 0.25rem 0.75rem;
  border-radius: 9999px;
  font-weight: 500;
  border: 1px solid rgba(255,255,255,0.1);
}

.badge-internal {
  background: rgba(16, 185, 129, 0.1);
  color: #34d399;
  border-color: rgba(16, 185, 129, 0.2);
}

.badge-external {
  background: rgba(99, 102, 241, 0.1);
  color: #818cf8;
  border-color: rgba(99, 102, 241, 0.2);
}

@media (max-width: 768px) {
  .tools-grid {
    grid-template-columns: 1fr;
  }
  .container {
    padding: 2rem 1.5rem;
  }
}