/* Frecotoken - Physics Calculators - Main Styles */

/* CSS Variables for theming */
:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --secondary-color: #64748b;
  --background: #ffffff;
  --surface: #f8fafc;
  --text-primary: #1e293b;
  --text-secondary: #64748b;
  --border-color: #e2e8f0;
  --shadow: rgba(0, 0, 0, 0.1);
  --success: #10b981;
  --error: #ef4444;
  --warning: #f59e0b;
}

[data-theme="dark"] {
  --primary-color: #3b82f6;
  --primary-hover: #2563eb;
  --secondary-color: #94a3b8;
  --background: #0f172a;
  --surface: #1e293b;
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --border-color: #334155;
  --shadow: rgba(0, 0, 0, 0.3);
}

/* Reset & Base Styles */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--text-primary);
  background-color: var(--background);
  transition: background-color 0.3s ease, color 0.3s ease;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1rem;
  color: var(--text-primary);
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }

p {
  margin-bottom: 1rem;
}

a {
  color: var(--primary-color);
  text-decoration: none;
  transition: color 0.3s ease;
}

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

ul, ol {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
}

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

/* Header & Navigation */
.header {
  background: var(--surface);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 1000;
  box-shadow: 0 2px 4px var(--shadow);
}

.nav {
  padding: 1rem 0;
}

.nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
}

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

.logo-icon {
  width: 32px;
  height: 32px;
  stroke: var(--primary-color);
  stroke-width: 2;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  width: 24px;
  height: 2px;
  background: var(--text-primary);
  transition: 0.3s;
}

.nav-menu {
  display: flex;
  list-style: none;
  gap: 2rem;
  margin: 0;
}

.nav-menu a {
  color: var(--text-primary);
  font-weight: 500;
  padding: 0.5rem 0;
  transition: color 0.3s ease;
}

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

/* Dropdown Menu */
.dropdown {
  position: relative;
}

.dropdown-toggle::after {
  content: ' ▾';
  font-size: 0.8em;
}

.dropdown-menu {
  position: absolute;
  top: 100%;
  left: 0;
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  box-shadow: 0 4px 12px var(--shadow);
  min-width: 200px;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: all 0.3s ease;
  list-style: none;
  padding: 0.5rem 0;
  margin: 0;
}

.dropdown:hover .dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.dropdown-menu li {
  margin: 0;
}

.dropdown-menu a {
  display: block;
  padding: 0.75rem 1.5rem;
  color: var(--text-primary);
  transition: background 0.3s ease;
}

.dropdown-menu a:hover {
  background: var(--background);
}

/* Theme Toggle */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.theme-toggle svg {
  width: 24px;
  height: 24px;
  stroke: currentColor;
  stroke-width: 2;
  fill: none;
}

.sun-icon {
  display: block;
}

.moon-icon {
  display: none;
}

[data-theme="dark"] .sun-icon {
  display: none;
}

[data-theme="dark"] .moon-icon {
  display: block;
}

/* Hero Section */
.hero {
  background: linear-gradient(135deg, var(--primary-color), #7c3aed);
  color: white;
  padding: 4rem 0;
  text-align: center;
}

.hero h1 {
  color: white;
  font-size: 3rem;
  margin-bottom: 1rem;
}

.hero-subtitle {
  font-size: 1.25rem;
  margin-bottom: 2rem;
  opacity: 0.9;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: all 0.3s ease;
  text-decoration: none;
}

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

.btn-primary:hover {
  background: var(--primary-hover);
  transform: translateY(-2px);
  box-shadow: 0 4px 12px var(--shadow);
}

.btn-secondary {
  background: var(--surface);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

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

/* Sections */
section {
  padding: 4rem 0;
}

.page-section {
  min-height: 60vh;
}

/* Tools Grid */
.tools-section {
  background: var(--surface);
}

.tools-section h2 {
  text-align: center;
  margin-bottom: 3rem;
}

.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 2rem;
}

.tool-card {
  background: var(--background);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  text-align: center;
  transition: all 0.3s ease;
}

.tool-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 24px var(--shadow);
}

.tool-icon {
  width: 64px;
  height: 64px;
  margin: 0 auto 1.5rem;
}

.tool-icon svg {
  width: 100%;
  height: 100%;
  stroke: var(--primary-color);
  stroke-width: 2;
  fill: none;
}

.tool-card h3 {
  margin-bottom: 1rem;
}

.tool-card p {
  color: var(--text-secondary);
  margin-bottom: 1.5rem;
}

/* Calculator Card */
.calculator-card {
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  margin-bottom: 2rem;
}

.calculator-form {
  max-width: 600px;
}

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

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

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

.input-group input,
.input-group select,
input[type="text"],
input[type="email"],
input[type="number"],
textarea,
select {
  flex: 1;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  background: var(--background);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color 0.3s ease;
}

input:focus,
textarea:focus,
select:focus {
  outline: none;
  border-color: var(--primary-color);
}

textarea {
  width: 100%;
  resize: vertical;
}

.form-actions {
  display: flex;
  gap: 1rem;
  margin-top: 1.5rem;
}

/* Results */
.results {
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  margin-top: 2rem;
}

.results h3 {
  margin-bottom: 1rem;
}

#results-content {
  background: var(--background);
  padding: 1.5rem;
  border-radius: 8px;
  margin-bottom: 1rem;
  font-family: 'Courier New', monospace;
}

.results-actions {
  display: flex;
  gap: 1rem;
}

/* Info & Example Cards */
.info-card,
.examples-card {
  background: var(--surface);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 2rem;
  margin-bottom: 2rem;
}

.examples-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.example {
  background: var(--background);
  padding: 1.5rem;
  border-radius: 8px;
  border: 1px solid var(--border-color);
}

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

.example p {
  margin-bottom: 0.5rem;
}

/* Article & FAQ Sections */
.article-section,
.faq-section {
  margin-top: 3rem;
}

.article-content,
.faq-content {
  background: var(--surface);
  padding: 2rem;
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.faq-item {
  margin-bottom: 2rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border-color);
}

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

.faq-question {
  font-weight: 600;
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: var(--primary-color);
}

.faq-answer {
  color: var(--text-secondary);
}

/* Content Sections */
.content-section {
  margin-bottom: 2rem;
}

.content-section h2 {
  margin-top: 2rem;
  margin-bottom: 1rem;
}

.content-section h3 {
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

.content-section ul,
.content-section ol {
  margin-bottom: 1rem;
}

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

/* Footer */
.footer {
  background: var(--surface);
  border-top: 1px solid var(--border-color);
  padding: 3rem 0 1rem;
  margin-top: 4rem;
}

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

.footer-section h4 {
  margin-bottom: 1rem;
}

.footer-section ul {
  list-style: none;
  margin: 0;
}

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

.footer-section a {
  color: var(--text-secondary);
}

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

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
}

/* Responsive Design */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }
  
  .nav-menu {
    display: none;
    width: 100%;
    flex-direction: column;
    margin-top: 1rem;
  }
  
  .nav-menu.active {
    display: flex;
  }
  
  .dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    box-shadow: none;
    border: none;
    margin-left: 1rem;
  }
  
  .hero h1 {
    font-size: 2rem;
  }
  
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  
  .form-actions {
    flex-direction: column;
  }
  
  .results-actions {
    flex-direction: column;
  }
}

/* Print Styles */
@media print {
  .header,
  .footer,
  .nav,
  .btn,
  .calculator-card,
  .theme-toggle {
    display: none;
  }
  
  .article-content,
  .faq-content {
    border: none;
    box-shadow: none;
  }
}

/* Utility Classes */
.text-center { text-align: center; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }

/* Model Selector (for Wave Energy) */
.model-selector {
  margin-bottom: 2rem;
  padding: 1rem;
  background: var(--background);
  border-radius: 8px;
}

.radio-group {
  display: flex;
  gap: 2rem;
  margin-top: 0.5rem;
}

.radio-group label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
}

.info-text {
  color: var(--text-secondary);
  font-size: 0.9rem;
  margin-bottom: 1rem;
}

/* Contact Form */
.contact-form-container {
  max-width: 600px;
  margin: 2rem auto;
}

.form-message {
  padding: 1rem;
  border-radius: 8px;
  margin-top: 1rem;
}

.form-message.success {
  background: var(--success);
  color: white;
}

.form-message.error {
  background: var(--error);
  color: white;
}

/* Loading Spinner */
.spinner {
  border: 3px solid var(--border-color);
  border-top: 3px solid var(--primary-color);
  border-radius: 50%;
  width: 40px;
  height: 40px;
  animation: spin 1s linear infinite;
  margin: 2rem auto;
}

@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}