@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap');

:root {
  /* Light Mode Colors */
  --bg-light: #f8fafc;
  --text-light: #0f172a;
  --card-light: #ffffff;
  --card-border-light: #e2e8f0;
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --secondary: #f1f5f9;
  --secondary-hover: #e2e8f0;
  --accent: #10b981;
  --error: #ef4444;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
  --result-bg: #eef2ff;
  --result-text: #3730a3;
  --result-border: #c7d2fe;

  --bg-color: var(--bg-light);
  --text-color: var(--text-light);
  --card-bg: var(--card-light);
  --card-border: var(--card-border-light);
  --input-bg: #ffffff;
  --input-border: #cbd5e1;
  --input-text: #0f172a;
  --stepper-bg: var(--secondary);
  --stepper-text: #475569;
  --stepper-hover: var(--secondary-hover);

  --ad-bg: #f1f5f9;
  --ad-text: #94a3b8;
  --ad-border: #cbd5e1;

  --transition: all 0.3s ease;
}

body.dark {
  /* Dark Mode Colors */
  --bg-dark: #0f172a;
  --text-dark: #f8fafc;
  --card-dark: #1e293b;
  --card-border-dark: #334155;

  --bg-color: var(--bg-dark);
  --text-color: var(--text-dark);
  --card-bg: var(--card-dark);
  --card-border: var(--card-border-dark);
  --input-bg: #0f172a;
  --input-border: #475569;
  --input-text: #f8fafc;
  --stepper-bg: #334155;
  --stepper-text: #cbd5e1;
  --stepper-hover: #475569;

  --result-bg: #1e1b4b;
  --result-text: #c7d2fe;
  --result-border: #3730a3;

  --ad-bg: #1e293b;
  --ad-text: #64748b;
  --ad-border: #334155;
}

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

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  transition: var(--transition);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header & Navigation */
header {
  background-color: var(--card-bg);
  border-bottom: 1px solid var(--card-border);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: 700;
  text-decoration: none;
  color: var(--text-color);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

nav {
  display: flex;
  gap: 1.5rem;
  align-items: center;
}

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

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

/* Dark Mode Toggle Switch */
.theme-switch-wrapper {
  display: flex;
  align-items: center;
}

.theme-switch {
  display: inline-block;
  height: 24px;
  position: relative;
  width: 48px;
}

.theme-switch input {
  display: none;
}

.slider {
  background-color: #cbd5e1;
  bottom: 0;
  cursor: pointer;
  left: 0;
  position: absolute;
  right: 0;
  top: 0;
  transition: .4s;
  border-radius: 24px;
}

.slider:before {
  background-color: #fff;
  bottom: 4px;
  content: "";
  height: 16px;
  left: 4px;
  position: absolute;
  transition: .4s;
  width: 16px;
  border-radius: 50%;
}

input:checked + .slider {
  background-color: var(--primary);
}

input:checked + .slider:before {
  transform: translateX(24px);
}

/* Main Content Area */
main {
  flex: 1;
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1rem;
  width: 100%;
}

/* Calculator Card */
.calculator-card {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 1rem;
  padding: 2rem;
  box-shadow: var(--shadow-md);
  margin-bottom: 2rem;
  transition: var(--transition);
}

.calculator-card.compact {
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
}

.calculator-card h1 {
  font-size: 1.8rem;
  text-align: center;
  margin-bottom: 1.5rem;
  font-weight: 700;
}

.calculator-card.compact h2 {
  font-size: 1.4rem;
  text-align: center;
  margin-bottom: 1rem;
}

/* Form Inputs */
.input-group {
  margin-bottom: 1.25rem;
}

.input-group label {
  display: block;
  font-weight: 600;
  margin-bottom: 0.5rem;
  font-size: 0.95rem;
}

.input-wrapper {
  display: flex;
  align-items: stretch;
  border: 1px solid var(--input-border);
  border-radius: 0.5rem;
  overflow: hidden;
  background-color: var(--input-bg);
  transition: border-color 0.2s;
}

.input-wrapper:focus-within {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.2);
}

.input-wrapper select,
.input-wrapper input {
  flex: 1;
  border: none;
  padding: 0.75rem 1rem;
  font-size: 1rem;
  background: transparent;
  color: var(--input-text);
  outline: none;
  font-family: inherit;
}

.stepper-btn {
  background-color: var(--stepper-bg);
  color: var(--stepper-text);
  border: none;
  padding: 0 1rem;
  font-size: 1.25rem;
  cursor: pointer;
  transition: background-color 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
  user-select: none;
}

.stepper-btn:hover {
  background-color: var(--stepper-hover);
}

/* Calculate Button */
.btn-calculate {
  background-color: var(--primary);
  color: #fff;
  border: none;
  border-radius: 0.5rem;
  padding: 1rem;
  width: 100%;
  font-size: 1.1rem;
  font-weight: 600;
  cursor: pointer;
  margin-top: 1rem;
  transition: background-color 0.2s;
}

.btn-calculate:hover {
  background-color: var(--primary-hover);
}

/* Results Card */
.result-card {
  display: none; /* Hidden by default */
  margin-top: 2rem;
  padding: 1.5rem;
  background-color: var(--result-bg);
  border: 2px solid var(--result-border);
  border-radius: 0.75rem;
  color: var(--result-text);
  box-shadow: var(--shadow-md);
  animation: fadeInDown 0.4s ease-out;
}

.result-card.active {
  display: block;
}

.result-card h3 {
  font-size: 1.25rem;
  margin-bottom: 1rem;
  text-align: center;
  font-weight: 700;
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}

.result-item {
  background: rgba(255, 255, 255, 0.5);
  padding: 1rem;
  border-radius: 0.5rem;
  text-align: center;
}

.dark .result-item {
  background: rgba(0, 0, 0, 0.2);
}

.result-label {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  opacity: 0.8;
  margin-bottom: 0.25rem;
}

.result-value {
  font-size: 1.5rem;
  font-weight: 700;
}

.result-yearly {
  grid-column: span 2;
  font-size: 2rem;
  color: var(--primary);
}
.dark .result-yearly {
  color: #a5b4fc;
}

/* Ad Placeholder */
.ad-placeholder {
  width: 100%;
  height: auto;
  min-height: 90px;
  aspect-ratio: 728 / 90;
  background-color: var(--ad-bg);
  border: 1px dashed var(--ad-border);
  border-radius: 0.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--ad-text);
  font-size: 0.875rem;
  margin: 2rem 0;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

@media (max-width: 768px) {
  .ad-placeholder {
    aspect-ratio: 320 / 50;
    min-height: 50px;
  }
}

.ad-placeholder.large {
  aspect-ratio: 300 / 250;
  min-height: 250px;
}

/* Content Formatting */
.content-section {
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 1rem;
  padding: 2rem;
  margin-top: 2rem;
  box-shadow: var(--shadow-sm);
}

.content-section h2, .article-content h2 {
  font-size: 1.75rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
  color: var(--text-color);
}

.content-section h3, .article-content h3 {
  font-size: 1.25rem;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

.content-section p, .article-content p {
  margin-bottom: 1.25rem;
  color: var(--text-color);
  opacity: 0.9;
}

.content-section ul, .article-content ul {
  margin-bottom: 1.5rem;
  padding-left: 1.5rem;
}

.content-section li, .article-content li {
  margin-bottom: 0.5rem;
}

/* Article Styles */
.article-header {
  margin-bottom: 2rem;
  text-align: center;
}

.article-header h1 {
  font-size: 2.5rem;
  line-height: 1.2;
  margin-bottom: 1rem;
}

.tldr-box {
  background-color: var(--result-bg);
  border-left: 4px solid var(--primary);
  padding: 1.5rem;
  border-radius: 0 0.5rem 0.5rem 0;
  margin: 2rem 0;
  font-weight: 500;
}

/* Tables */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 2rem 0;
  background-color: var(--card-bg);
  border-radius: 0.5rem;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

th, td {
  padding: 1rem;
  text-align: left;
  border-bottom: 1px solid var(--card-border);
}

th {
  background-color: var(--secondary);
  font-weight: 600;
}

.dark th {
  background-color: #334155;
}

tr:last-child td {
  border-bottom: none;
}

/* FAQ */
.faq-item {
  margin-bottom: 1.5rem;
  border-bottom: 1px solid var(--card-border);
  padding-bottom: 1.5rem;
}

.faq-question {
  font-weight: 700;
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

/* Footer */
footer {
  background-color: var(--card-bg);
  border-top: 1px solid var(--card-border);
  padding: 2rem;
  margin-top: auto;
}

.footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  justify-content: center;
}

.footer-links a {
  text-decoration: none;
  color: var(--text-color);
  opacity: 0.8;
  font-size: 0.9rem;
}

.footer-links a:hover {
  opacity: 1;
  color: var(--primary);
}

.copyright {
  font-size: 0.85rem;
  opacity: 0.6;
}

/* Article List */
.article-list {
  list-style: none;
  padding: 0;
}

.article-list li {
  margin-bottom: 1rem;
}

.article-list a {
  display: block;
  padding: 1.5rem;
  background-color: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 0.5rem;
  text-decoration: none;
  color: var(--text-color);
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.article-list a:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}

.article-list h3 {
  margin-top: 0;
  color: var(--primary);
}

/* Animations */
@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Responsive */
@media (max-width: 768px) {
  .header-container {
    flex-direction: column;
    gap: 1rem;
  }

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

  .result-yearly {
    grid-column: span 1;
  }
}