:root {
  --primary: #4A90E2;
  --secondary: #50E3C2;
  --bg: #F5F7FA;
  --text: #333333;
  --card-bg: #FFFFFF;
  --muted: #777777;
  --radius: 8px;
  --transition: all 0.2s ease;
  --font: 'Inter', sans-serif;
}

[data-theme="dark"] {
  --bg: #2B2D42;
  --text: #EDF2F4;
  --card-bg: #3F4159;
  --muted: #A8AAB3;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  margin: 0;
  padding: 0;
}

.container {
  max-width: 900px;
  margin: auto;
  padding: 1.5rem;
}

.header {
  text-align: center;
  margin-bottom: 2rem;
  position: relative;
}

#themeLogo {
  width: 120px;
  margin-bottom: 1rem;
}

.theme-toggle {
  position: absolute;
  right: 1rem;
  top: 1rem;
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--text);
}

.subtitle {
  color: var(--muted);
  font-weight: 300;
  margin-top: 0.5rem;
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
}

.tool-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
  text-align: center;
  padding: 1.5rem;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.tool-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.08);
}

.tool-icon {
  font-size: 2.5rem;
  margin-bottom: 1rem;
}

.tool-card h3 {
  margin: 0.5rem 0;
  font-size: 1.25rem;
  color: var(--primary);
}

.tool-card p {
  color: var(--muted);
  font-size: 0.95rem;
  margin-bottom: 1rem;
}

.calculate-btn {
  background: var(--primary);
  color: #fff;
  padding: 0.65rem 1.2rem;
  border: none;
  border-radius: var(--radius);
  font-size: 0.95rem;
  cursor: pointer;
  text-decoration: none;
  display: inline-block;
  transition: var(--transition);
}

.calculate-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.08);
}

.footer {
  text-align: center;
  margin-top: 3rem;
  padding: 2rem 0;
  color: var(--muted);
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 1rem;
}

.footer-links a {
  text-decoration: none;
  color: var(--text);
  transition: color 0.2s ease;
}

.footer-links a:hover {
  color: var(--primary);
}