:root {
  --bg: #1a1a1a;
  --card-bg: #2a2a2a;
  --text: #ffffff;
  --text-muted: #888;
  --accent: #70b5f9;
  --border: #333;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  min-height: 100vh;
}

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

a { color: var(--accent); text-decoration: none; }

/* Header */
header {
  background: rgba(0,0,0,0.8);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

nav {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 1.5rem;
}

.logo {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text);
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.nav-links a:hover { color: var(--text); }

/* Main */
main {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* Search Bar Style */
.search-box {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.search-box h1 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.search-box p {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
}

/* Form */
.calc-form {
  background: var(--card-bg);
  border-radius: 12px;
  padding: 2rem;
}

.form-group { margin-bottom: 1.25rem; }

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.form-group input, .form-group select {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 1rem;
  background: var(--bg);
  color: var(--text);
}

.form-group input:focus {
  outline: none;
  border-color: var(--accent);
}

.btn {
  display: block;
  width: 100%;
  padding: 0.875rem;
  background: var(--accent);
  color: #000;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
}

.btn:hover { opacity: 0.9; }

.btn-secondary {
  background: var(--border);
  color: var(--text);
  margin-top: 0.75rem;
}

/* Results */
.results {
  margin-top: 1.5rem;
  padding: 1.5rem;
  background: var(--bg);
  border-radius: 12px;
  border: 1px solid var(--border);
}

.results h3 {
  color: var(--accent);
  margin-bottom: 1rem;
  font-size: 1.1rem;
}

.result-item {
  display: flex;
  justify-content: space-between;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border);
}

.result-item:last-child { border-bottom: none; }

.result-label { color: var(--text-muted); }
.result-value { font-weight: 600; }

/* Features Section */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}

.feature-card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.5rem;
  text-align: center;
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
}

.feature-card h4 {
  margin-bottom: 0.5rem;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Footer */
footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
}

/* Mobile */
@media (max-width: 600px) {
  .search-box h1 { font-size: 1.5rem; }
  .nav-links { gap: 1rem; }
}