:root {
  --primary: #3498db;
  --secondary: #2ecc71;
  --accent: #f39c12;
  --light: #ecf0f1;
  --dark: #2c3e50;
  --success: #27ae60;
  --error: #e74c3c;
  --border-radius: 8px;
  --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
  --transition: all 0.3s ease;
  
  /* Light Theme */
  --bg-primary: #ffffff;
  --bg-secondary: var(--light);
  --text-primary: var(--dark);
  --text-secondary: #7f8c8d;
  --border-color: #dfe6e9;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #1a202c;
  --bg-secondary: #2d3748;
  --text-primary: #f7fafc;
  --text-secondary: #a0aec0;
  --border-color: #4a5568;
}

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

body {
  font-family: 'Open Sans', sans-serif;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  line-height: 1.6;
  transition: var(--transition);
}

h1, h2, h3, h4, h5, h6 {
  font-family: 'Montserrat', sans-serif;
  font-weight: 700;
  line-height: 1.2;
}

.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

header {
  background-color: var(--primary);
  color: white;
  padding: 2rem 0;
  box-shadow: var(--shadow);
}

.logo-container {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo {
  font-family: 'Montserrat', sans-serif;
  font-size: 2rem;
  font-weight: 700;
  color: white;
  background-color: var(--accent);
  width: 3rem;
  height: 3rem;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
}

.tagline {
  margin-top: 0.5rem;
  font-size: 1.1rem;
}

.calculator-section {
  padding: 3rem 0;
  background-color: var(--bg-secondary);
}

.calculator-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.tab-btn {
  padding: 0.75rem 1.25rem;
  background-color: var(--bg-primary);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition);
}

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

.calculator-content {
  background-color: var(--bg-primary);
  border-radius: var(--border-radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  display: none;
}

.calculator-content.active {
  display: block;
}

.form-group {
  margin-bottom: 1.5rem;
}

label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.currency-symbol {
  position: absolute;
  left: 1rem;
  font-weight: 600;
}

input {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  font-size: 1rem;
  transition: var(--transition);
  background-color: var(--bg-primary);
  color: var(--text-primary);
}

input[type="number"] {
  padding-left: 2rem;
}

input:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.25);
}

.tip-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.tip-btn {
  padding: 0.75rem 1.25rem;
  background-color: var(--bg-secondary);
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition);
  flex: 1;
  min-width: 60px;
  text-align: center;
}

.tip-btn.active, .tip-btn:hover {
  background-color: var(--primary);
  color: white;
}

.custom-tip-input {
  position: relative;
  flex: 1;
  min-width: 100px;
}

.custom-tip-input input {
  padding-right: 2rem;
}

.custom-tip-input span {
  position: absolute;
  right: 1rem;
  top: 50%;
  transform: translateY(-50%);
}

.results {
  margin-top: 2rem;
  padding: 1rem;
  background-color: var(--bg-secondary);
  border-radius: var(--border-radius);
}

.result-item {
  display: flex;
  justify-content: space-between;
  padding: 0.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

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

.result-item.total {
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--primary);
}

.content-section {
  padding: 4rem 0;
}

article {
  margin-bottom: 3rem;
}

article h2 {
  margin-bottom: 1rem;
  color: var(--primary);
}

article p, article ul {
  margin-bottom: 1rem;
}

article ul {
  padding-left: 1.5rem;
}

footer {
  background-color: var(--dark);
  color: white;
  padding: 3rem 0 1.5rem;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  margin-bottom: 2rem;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.footer-links, .social-links {
  display: flex;
  gap: 1.5rem;
}

.footer-links a, .social-links a {
  color: white;
  text-decoration: none;
  transition: var(--transition);
}

.footer-links a:hover, .social-links a:hover {
  color: var(--accent);
}

.copyright {
  text-align: center;
  padding-top: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}

/* Rating sliders for Custom Tip Calculator */
.rating-slider {
  width: 100%;
  margin: 10px 0;
}

.slider {
  -webkit-appearance: none;
  width: 100%;
  height: 10px;
  border-radius: 5px;
  background: var(--bg-secondary);
  outline: none;
  margin: 10px 0;
}

.slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
}

.slider::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--primary);
  cursor: pointer;
}

.rating-labels {
  display: flex;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* Dropdown selects for Delivery calculator */
select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  font-size: 1rem;
  transition: var(--transition);
  appearance: none;
  background-image: url("data:image/svg+xml;utf8,<svg fill='gray' height='24' viewBox='0 0 24 24' width='24' xmlns='http://www.w3.org/2000/svg'><path d='M7 10l5 5 5-5z'/><path d='M0 0h24v24H0z' fill='none'/></svg>");
  background-repeat: no-repeat;
  background-position: right 0.75rem center;
  background-size: 1.5rem;
}

select:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(52, 152, 219, 0.25);
}

/* Comparison Table Styles */
.comparison-results {
  padding: 0;
  background-color: transparent;
}

.comparison-header, .comparison-row {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  padding: 0.75rem;
  text-align: center;
}

.comparison-header {
  font-weight: 700;
  background-color: var(--bg-secondary);
  border-top-left-radius: var(--border-radius);
  border-top-right-radius: var(--border-radius);
}

.comparison-row {
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-primary);
}

.comparison-row:last-child {
  border-bottom: none;
  border-bottom-left-radius: var(--border-radius);
  border-bottom-right-radius: var(--border-radius);
}

.comparison-row.highlight {
  background-color: rgba(52, 152, 219, 0.1);
  font-weight: 600;
}

/* Responsive styles for comparison table */
@media (max-width: 480px) {
  .comparison-header div, .comparison-row div {
    font-size: 0.9rem;
    padding: 0.25rem;
  }
}

@media (max-width: 768px) {
  .calculator-tabs {
    overflow-x: auto;
    padding-bottom: 0.5rem;
  }
  
  .footer-content {
    flex-direction: column;
    gap: 1.5rem;
  }
  
  .footer-links, .social-links {
    justify-content: center;
  }
}