/* KnitCalc Pro - Main Stylesheet */

/* CSS Variables for Consistent Theming */
:root {
  --color-dark: #111827;
  --color-light: #F3F4F6;
  --color-accent: #D1FAE5;
  --color-neutral: #E5E7EB;
  --font-stack: system-ui, -apple-system, 'Segoe UI', Roboto, Inter, Arial, sans-serif;
  --container-max: 1200px;
  --border-radius: 8px;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --transition: all 0.2s ease-in-out;
}

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

body {
  font-family: var(--font-stack);
  line-height: 1.6;
  color: var(--color-dark);
  background-color: var(--color-light);
}

/* Container and Layout */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 1rem;
}

.grid {
  display: grid;
  gap: 2rem;
}

.grid-2 {
  grid-template-columns: 1fr 1fr;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

/* Header */
.header {
  background: white;
  box-shadow: var(--shadow);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
}

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

.logo img {
  height: 32px;
  margin-right: 0.5rem;
}

/* Navigation */
.nav {
  display: flex;
  list-style: none;
  gap: 2rem;
}

.nav-item {
  position: relative;
}

.nav-link {
  text-decoration: none;
  color: var(--color-dark);
  font-weight: 500;
  padding: 0.5rem 1rem;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.nav-link:hover {
  background-color: var(--color-accent);
}

/* Mega Menu */
.mega-menu {
  position: absolute;
  top: 100%;
  left: 0;
  min-width: 280px;
  background: white;
  box-shadow: var(--shadow);
  border-radius: var(--border-radius);
  padding: 1rem;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-10px);
  transition: var(--transition);
  z-index: 200;
}

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

.mega-menu-link {
  display: block;
  text-decoration: none;
  color: var(--color-dark);
  padding: 0.5rem;
  border-radius: var(--border-radius);
  transition: var(--transition);
}

.mega-menu-link:hover {
  background-color: var(--color-accent);
}

/* Mobile Navigation */
.mobile-menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
}

/* Main Content */
.main {
  min-height: calc(100vh - 200px);
  padding: 2rem 0;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 4rem 0;
  background: linear-gradient(135deg, var(--color-accent) 0%, white 100%);
  border-radius: var(--border-radius);
  margin-bottom: 3rem;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  margin-bottom: 1rem;
  color: var(--color-dark);
}

.hero p {
  font-size: 1.25rem;
  margin-bottom: 2rem;
  color: #4B5563;
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  border-radius: var(--border-radius);
  text-decoration: none;
  font-weight: 600;
  text-align: center;
  transition: var(--transition);
  border: none;
  cursor: pointer;
  font-size: 1rem;
}

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

.btn-primary:hover {
  background-color: #1F2937;
  transform: translateY(-2px);
}

.btn-secondary {
  background-color: white;
  color: var(--color-dark);
  border: 2px solid var(--color-dark);
}

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

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* Cards */
.card {
  background: white;
  border-radius: var(--border-radius);
  padding: 2rem;
  box-shadow: var(--shadow);
  transition: var(--transition);
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 25px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

.card h3 {
  margin-bottom: 1rem;
  color: var(--color-dark);
}

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

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

.form-input {
  width: 100%;
  padding: 0.75rem;
  border: 2px solid var(--color-neutral);
  border-radius: var(--border-radius);
  font-size: 1rem;
  transition: var(--transition);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-dark);
  box-shadow: 0 0 0 3px rgba(17, 24, 39, 0.1);
}

.form-input.error {
  border-color: #EF4444;
}

.form-error {
  color: #EF4444;
  font-size: 0.875rem;
  margin-top: 0.25rem;
}

.form-help {
  color: #6B7280;
  font-size: 0.875rem;
  margin-top: 0.25rem;
}

/* Calculator Specific Styles */
.calculator-container {
  display: grid;
  grid-template-columns: 2fr 1fr;
  gap: 2rem;
  align-items: start;
}

.calculator-form {
  background: white;
  padding: 2rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
}

.calculator-sidebar {
  background: white;
  padding: 2rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
  position: sticky;
  top: 100px;
}

.mode-tabs {
  display: flex;
  background: var(--color-neutral);
  border-radius: var(--border-radius);
  padding: 0.25rem;
  margin-bottom: 2rem;
}

.mode-tab {
  flex: 1;
  background: none;
  border: none;
  padding: 0.75rem 1rem;
  border-radius: calc(var(--border-radius) - 2px);
  cursor: pointer;
  transition: var(--transition);
  font-weight: 500;
}

.mode-tab.active {
  background: white;
  color: var(--color-dark);
  box-shadow: var(--shadow);
}

.mode-tab:not(.active) {
  color: #6B7280;
}

.mode-tab:hover:not(.active) {
  background: rgba(255, 255, 255, 0.5);
}

/* Results */
.results {
  background: var(--color-accent);
  border-radius: var(--border-radius);
  padding: 2rem;
  margin-top: 2rem;
}

.results h3 {
  margin-bottom: 1rem;
  color: var(--color-dark);
}

.result-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 0;
  border-bottom: 1px solid rgba(17, 24, 39, 0.1);
}

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

.result-label {
  font-weight: 500;
  color: var(--color-dark);
}

.result-value {
  font-weight: 700;
  color: var(--color-dark);
  font-size: 1.125rem;
}

/* Table */
.table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 1rem;
}

.table th,
.table td {
  padding: 0.75rem;
  text-align: left;
  border-bottom: 1px solid var(--color-neutral);
}

.table th {
  background: var(--color-accent);
  font-weight: 600;
  color: var(--color-dark);
}

.table tr:hover {
  background: rgba(209, 250, 229, 0.3);
}

/* Tips Sidebar */
.tips {
  background: #FEF3C7;
  border-radius: var(--border-radius);
  padding: 1.5rem;
  margin-bottom: 2rem;
}

.tips h4 {
  margin-bottom: 1rem;
  color: #92400E;
}

.tips ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.tips li {
  margin-bottom: 0.5rem;
  padding-left: 1.5rem;
  position: relative;
  color: #92400E;
}

.tips li::before {
  content: "💡";
  position: absolute;
  left: 0;
}

/* Footer */
.footer {
  background: var(--color-dark);
  color: var(--color-light);
  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-column h4 {
  margin-bottom: 1rem;
  color: white;
}

.footer-link {
  display: block;
  color: var(--color-light);
  text-decoration: none;
  padding: 0.25rem 0;
  transition: var(--transition);
}

.footer-link:hover {
  color: var(--color-accent);
}

.footer-bottom {
  text-align: center;
  padding-top: 2rem;
  border-top: 1px solid #374151;
  color: #9CA3AF;
}

/* Accessibility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus styles */
*:focus {
  outline: 2px solid var(--color-dark);
  outline-offset: 2px;
}

/* Live region for screen readers */
.live-region {
  position: absolute;
  left: -10000px;
  width: 1px;
  height: 1px;
  overflow: hidden;
}

/* Print Styles */
@media print {
  .header,
  .footer,
  .calculator-sidebar,
  .btn,
  .mobile-menu-toggle {
    display: none !important;
  }
  
  .calculator-container {
    grid-template-columns: 1fr;
  }
  
  .results {
    background: white !important;
    border: 2px solid var(--color-dark);
  }
}

/* Responsive Design */
@media (max-width: 768px) {
  .container {
    padding: 0 0.5rem;
  }
  
  .hero h1 {
    font-size: 2rem;
  }
  
  .hero p {
    font-size: 1rem;
  }
  
  .nav {
    display: none;
  }
  
  .mobile-menu-toggle {
    display: block;
  }
  
  .calculator-container {
    grid-template-columns: 1fr;
  }
  
  .calculator-sidebar {
    position: static;
    order: -1;
  }
  
  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr;
  }
  
  .hero-cta {
    flex-direction: column;
    align-items: center;
  }
  
  .mode-tabs {
    flex-direction: column;
  }
  
  .card {
    padding: 1rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding: 2rem 0;
  }
  
  .hero h1 {
    font-size: 1.75rem;
  }
  
  .calculator-form,
  .calculator-sidebar {
    padding: 1rem;
  }
  
  .btn {
    width: 100%;
  }
}

/* Animation for loading states */
@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

.loading {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* Custom scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-light);
}

::-webkit-scrollbar-thumb {
  background: var(--color-neutral);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-dark);
}