:root {
  --primary-color: #0052cc;
  --secondary-color: #00b8d9;
  --bg-color: #f1f5f9;
  --surface-color: rgba(255, 255, 255, 0.85);
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --border-color: rgba(0, 0, 0, 0.1);
  --success-color: #10b981;

  --font-main: 'Inter', system-ui, -apple-system, sans-serif;
  --transition-speed: 0.3s;
  --radius-lg: 16px;
  --radius-md: 12px;
  --radius-sm: 8px;

  /* Glassmorphism setup */
  --glass-bg: rgba(255, 255, 255, 0.7);
  --glass-border: rgba(255, 255, 255, 0.5);
  --glass-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.05);
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  /* Add a premium background gradient mesh */
  background-image: radial-gradient(at 0% 0%, hsla(253, 16%, 7%, 0) 0, transparent 50%), radial-gradient(at 50% 0%, hsla(225, 39%, 30%, 0.05) 0, transparent 50%), radial-gradient(at 100% 0%, hsla(339, 49%, 30%, 0) 0, transparent 50%);
  background-attachment: fixed;
}

/* Typography */
h1,
h2,
h3,
h4 {
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

p {
  color: var(--text-secondary);
}

/* Layout */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

header.page-header {
  text-align: center;
  margin-bottom: 3rem;
  padding: 2rem 0;
}

/* Breadcrumbs */
.breadcrumb {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
  padding: 1rem 1.5rem;
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-sm);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.02);
}

.breadcrumb a {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--transition-speed);
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
}

.breadcrumb a:hover {
  color: var(--secondary-color);
}

.breadcrumb .separator {
  color: var(--border-color);
  display: flex;
  align-items: center;
}

.breadcrumb .current {
  color: var(--text-primary);
  font-weight: 600;
}

/* Glass Card */
.glass-card {
  background: var(--glass-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
  border-radius: var(--radius-lg);
  padding: 2rem;
  transition: transform var(--transition-speed) ease, box-shadow var(--transition-speed) ease;
}

/* Grid Layouts */
.plan-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 2rem;
}

/* Plan Card specifically */
.plan-card {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
}

.plan-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.1);
}

.plan-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  opacity: 0;
  transition: opacity var(--transition-speed);
}

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

.plan-id-badge {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: var(--primary-color);
  color: white;
  padding: 0.25rem 0.75rem;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
}

.plan-title {
  font-size: 1.25rem;
  margin-top: 1rem;
  margin-bottom: 0.5rem;
}

.plan-card .arrow-icon {
  align-self: flex-end;
  color: var(--primary-color);
  margin-top: 1.5rem;
  transition: transform 0.2s;
}

.plan-card:hover .arrow-icon {
  transform: translateX(5px);
}

/* Form Elements */
.calc-form {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

@media (min-width: 768px) {
  .calc-form {
    grid-template-columns: 1fr 1fr;
  }
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.input-group label {
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text-primary);
}

.input-group input,
.input-group select {
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  background: white;
  font-family: inherit;
  font-size: 1rem;
  transition: border-color var(--transition-speed), box-shadow var(--transition-speed);
  outline: none;
}

.input-group input:focus,
.input-group select:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 82, 204, 0.1);
}

/* Button */
.btn-primary {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: white;
  border: none;
  padding: 1rem 2rem;
  border-radius: var(--radius-sm);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.1s, box-shadow var(--transition-speed);
  grid-column: 1 / -1;
  width: 100%;
}

.btn-primary:active {
  transform: scale(0.98);
}

.btn-primary:hover {
  box-shadow: 0 10px 20px rgba(0, 82, 204, 0.2);
}

/* Results Display */
.results-container {
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  display: none;
}

.results-container.active {
  display: block;
  animation: slideUp 0.4s ease forwards;
}

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.result-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 768px) {
  .result-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.result-box {
  background: white;
  padding: 1.5rem;
  border-radius: var(--radius-md);
  text-align: center;
  border: 1px solid var(--border-color);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.02);
}

.result-box.highlight {
  background: linear-gradient(135deg, #eff6ff, #e0f2fe);
  border-color: #bfdbfe;
}

.result-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 0.5rem;
  font-weight: 600;
}

.result-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--primary-color);
}

.result-box.highlight .result-value {
  color: var(--success-color);
  font-size: 1.75rem;
}

/* Utility */
.mb-1 {
  margin-bottom: 0.5rem;
}

.mb-2 {
  margin-bottom: 1rem;
}

.mb-3 {
  margin-bottom: 1.5rem;
}

.mb-4 {
  margin-bottom: 2rem;
}

.text-center {
  text-align: center;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 600;
  margin-bottom: 2rem;
  transition: color var(--transition-speed);
}

.back-link:hover {
  color: var(--primary-color);
}

/* --- Global Header --- */
.site-header {
  background: var(--surface-color);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  margin-bottom: 2rem;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 1.5rem;
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.25rem;
  transition: transform var(--transition-speed);
}

.logo:hover {
  transform: scale(1.02);
}

.main-nav ul {
  list-style: none;
  display: flex;
  gap: 1.5rem;
  margin: 0;
  padding: 0;
}

.main-nav a {
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 600;
  transition: color var(--transition-speed);
}

.main-nav a:hover {
  color: var(--primary-color);
}

/* --- Global Footer --- */
.site-footer {
  background: var(--surface-color);
  border-top: 1px solid var(--border-color);
  margin-top: 4rem;
  padding: 4rem 1rem 2rem;
}

.footer-container {
  max-width: 1200px;
  margin: 0 auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  margin-bottom: 3rem;
}

@media (min-width: 768px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr;
  }
}

.footer-about {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-top: 1rem;
  line-height: 1.6;
}

.footer-links h4 {
  color: var(--text-primary);
  margin-bottom: 1rem;
}

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

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

.footer-links a {
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-speed);
}

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

.footer-disclaimer {
  background: rgba(0, 0, 0, 0.03);
  padding: 1.5rem;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.85rem;
  margin-bottom: 2rem;
  line-height: 1.6;
}

.footer-bottom {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.9rem;
}

@media (min-width: 600px) {
  .footer-bottom {
    flex-direction: row;
    justify-content: space-between;
  }
}

.social-icons {
  display: flex;
  gap: 1rem;
}

.social-icons a {
  color: var(--text-secondary);
  transition: color var(--transition-speed);
}

.social-icons a:hover {
  color: var(--primary-color);
}