/* Reset and Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-primary: #0070f3;
  --color-primary-dark: #0051cc;
  --color-secondary: #10b981;
  --color-accent: #f59e0b;
  --color-background: #ffffff;
  --color-surface: #f8fafc;
  --color-border: #e2e8f0;
  --color-text: #1e293b;
  --color-text-muted: #64748b;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --color-error: #ef4444;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
}

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background-color: var(--color-background);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header Styles */
.site-header {
  background: var(--color-background);
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--color-text);
  text-decoration: none;
}

.logo svg {
  flex-shrink: 0;
}

.nav-menu {
  display: flex;
  gap: 2rem;
}

.nav-link {
  color: var(--color-text-muted);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

.mobile-menu-toggle {
  display: none;
  flex-direction: column;
  gap: 0.25rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.mobile-menu-toggle span {
  width: 1.5rem;
  height: 2px;
  background: var(--color-text);
  transition: all 0.3s;
}

/* Hero Section */
.hero-section {
  background: linear-gradient(135deg, #0070f3 0%, #00c2ff 100%);
  color: white;
  padding: 4rem 0;
  text-align: center;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero-section h1 {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  line-height: 1.2;
}

.hero-subtitle {
  font-size: 1.25rem;
  margin-bottom: 2rem;
  opacity: 0.95;
}

.search-bar {
  display: flex;
  align-items: center;
  background: white;
  border-radius: var(--radius-xl);
  padding: 0.75rem 1.5rem;
  box-shadow: var(--shadow-xl);
  max-width: 600px;
  margin: 0 auto;
}

.search-icon {
  color: var(--color-text-muted);
  flex-shrink: 0;
  margin-right: 0.75rem;
}

.search-input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1rem;
  color: var(--color-text);
}

.search-input::placeholder {
  color: var(--color-text-muted);
}

/* Section Styles */
.featured-section,
.all-calculators-section,
.features-section,
.how-it-works-section {
  padding: 4rem 0;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 700;
  text-align: center;
  margin-bottom: 3rem;
  color: var(--color-text);
}

/* Featured Calculators */
.featured-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 2rem;
  margin-bottom: 2rem;
}

.calculator-card {
  background: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 2rem;
  text-decoration: none;
  color: var(--color-text);
  transition: all 0.3s;
  position: relative;
  overflow: hidden;
}

.calculator-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-4px);
  border-color: var(--color-primary);
}

.calculator-card.featured {
  border-color: var(--color-primary);
  border-width: 2px;
}

.card-icon {
  width: 56px;
  height: 56px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1rem;
  color: white;
}

.calculator-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.calculator-card p {
  color: var(--color-text-muted);
  line-height: 1.6;
}

.card-tag {
  display: inline-block;
  background: var(--color-primary);
  color: white;
  padding: 0.25rem 0.75rem;
  border-radius: var(--radius-md);
  font-size: 0.75rem;
  font-weight: 600;
  margin-top: 1rem;
}

/* Filter Tabs */
.filter-tabs {
  display: flex;
  gap: 1rem;
  margin-bottom: 2rem;
  justify-content: center;
  flex-wrap: wrap;
}

.filter-tab {
  padding: 0.75rem 1.5rem;
  border: 2px solid var(--color-border);
  background: var(--color-background);
  border-radius: var(--radius-lg);
  color: var(--color-text-muted);
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.filter-tab:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.filter-tab.active {
  background: var(--color-primary);
  color: white;
  border-color: var(--color-primary);
}

/* Calculators Grid */
.calculators-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
}

.calculator-card.hidden {
  display: none;
}

/* Features Section */
.features-section {
  background: var(--color-surface);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

.feature-card {
  text-align: center;
  padding: 2rem;
}

.feature-icon {
  width: 64px;
  height: 64px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
  border-radius: var(--radius-xl);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 1rem;
  color: white;
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}

.feature-card p {
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* How It Works Section */
.steps-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 2rem;
}

.step-card {
  text-align: center;
  padding: 2rem;
}

.step-number {
  width: 56px;
  height: 56px;
  background: var(--color-primary);
  color: white;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 auto 1rem;
}

.step-card h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.step-card p {
  color: var(--color-text-muted);
}

/* Footer */
.site-footer {
  background: var(--color-text);
  color: white;
  padding: 3rem 0 1.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(4, 1fr);
  gap: 2rem;
  margin-bottom: 2rem;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-weight: 700;
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.footer-description {
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.6;
}

.footer-column h4 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.footer-column ul {
  list-style: none;
}

.footer-column ul li {
  margin-bottom: 0.5rem;
}

.footer-column ul li a {
  color: rgba(255, 255, 255, 0.7);
  text-decoration: none;
  transition: color 0.2s;
}

.footer-column ul li a:hover {
  color: white;
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  color: rgba(255, 255, 255, 0.5);
}

/* Responsive Design */
@media (max-width: 768px) {
  .nav-menu {
    display: none;
  }

  .mobile-menu-toggle {
    display: flex;
  }

  .hero-section h1 {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .section-title {
    font-size: 1.75rem;
  }

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

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

  .filter-tabs {
    justify-content: flex-start;
    overflow-x: auto;
    padding-bottom: 0.5rem;
  }

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

@media (max-width: 480px) {
  .container {
    padding: 0 1rem;
  }

  .search-bar {
    padding: 0.5rem 1rem;
  }

  .calculator-card {
    padding: 1.5rem;
  }
}