/* Tech Performance Lab - Main Stylesheet */
/* ======================================== */

/* CSS Variables for Theming */
:root {
  /* Light Theme (Default) */
  --bg-primary: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --text-primary: #111827;
  --text-secondary: #4b5563;
  --text-muted: #6b7280;
  --border-color: #e5e7eb;
  --card-bg: #ffffff;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --card-shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  --header-bg: rgba(255, 255, 255, 0.95);
  --header-border: #e5e7eb;
  --input-bg: #ffffff;
  --input-border: #d1d5db;
  --input-focus: #3b82f6;
  
  /* Primary Colors */
  --primary-500: #3b82f6;
  --primary-600: #2563eb;
  --primary-700: #1d4ed8;
  --accent-gradient: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --success: #10b981;
  --warning: #f59e0b;
  --error: #ef4444;
  
  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;
  --space-4xl: 6rem;
  
  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  
  /* Border Radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 250ms ease;
  --transition-slow: 350ms ease;
}

/* Dark Theme */
[data-theme="dark"] {
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --text-primary: #e5e7eb;
  --text-secondary: #9ca3af;
  --text-muted: #6b7280;
  --border-color: #374151;
  --card-bg: #1e293b;
  --card-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
  --card-shadow-hover: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.4);
  --header-bg: rgba(15, 23, 42, 0.95);
  --header-border: #374151;
  --input-bg: #1e293b;
  --input-border: #4b5563;
  --input-focus: #60a5fa;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  transition: background-color var(--transition-base), color var(--transition-base);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--primary-500);
  text-decoration: none;
  transition: color var(--transition-fast);
}

a:hover {
  color: var(--primary-600);
}

[data-theme="dark"] a:hover {
  color: var(--input-focus);
}

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

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

p {
  margin-bottom: var(--space-md);
  color: var(--text-secondary);
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Header & Navigation */
.header {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: var(--header-bg);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--header-border);
  transition: background-color var(--transition-base), border-color var(--transition-base);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: var(--accent-gradient);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-weight: 700;
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-xl);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  list-style: none;
}

.nav-link {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  padding: var(--space-sm) 0;
  position: relative;
}

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

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--accent-gradient);
  transition: width var(--transition-base);
}

.nav-link:hover::after {
  width: 100%;
}

.nav-link.active {
  color: var(--primary-500);
}

.nav-link.active::after {
  width: 100%;
}

/* Theme Toggle */
.theme-toggle {
  background: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-full);
  width: 48px;
  height: 26px;
  position: relative;
  cursor: pointer;
  transition: background-color var(--transition-fast);
}

.theme-toggle::after {
  content: '';
  position: absolute;
  top: 2px;
  left: 2px;
  width: 20px;
  height: 20px;
  background: white;
  border-radius: 50%;
  transition: transform var(--transition-base);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2);
}

[data-theme="dark"] .theme-toggle::after {
  transform: translateX(22px);
}

.theme-toggle-icon {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  font-size: 12px;
}

.theme-toggle-icon.sun {
  left: 6px;
}

.theme-toggle-icon.moon {
  right: 6px;
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
}

.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background-color: var(--text-primary);
  transition: transform var(--transition-base), opacity var(--transition-base);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-xl);
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--radius-lg);
  border: none;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
}

.btn-primary {
  background: var(--accent-gradient);
  color: white;
  box-shadow: 0 4px 14px rgba(59, 130, 246, 0.4);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(59, 130, 246, 0.5);
  color: white;
}

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

.btn-secondary:hover {
  background-color: var(--border-color);
  color: var(--text-primary);
}

.btn-outline {
  background-color: transparent;
  color: var(--text-primary);
  border: 2px solid var(--border-color);
}

.btn-outline:hover {
  border-color: var(--primary-500);
  color: var(--primary-500);
}

.btn-sm {
  padding: var(--space-sm) var(--space-md);
  font-size: 0.875rem;
}

.btn-lg {
  padding: var(--space-lg) var(--space-2xl);
  font-size: 1.125rem;
}

/* Hero Section */
.hero {
  padding: var(--space-4xl) 0;
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  text-align: center;
}

.hero-content {
  max-width: 800px;
  margin: 0 auto;
}

.hero-title {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: var(--space-lg);
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-description {
  font-size: 1.25rem;
  color: var(--text-secondary);
  margin-bottom: var(--space-2xl);
  max-width: 600px;
  margin-left: auto;
  margin-right: auto;
}

.hero-buttons {
  display: flex;
  gap: var(--space-md);
  justify-content: center;
  flex-wrap: wrap;
}

/* Section Styles */
.section {
  padding: var(--space-4xl) 0;
}

.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto var(--space-3xl);
}

.section-title {
  font-size: 2.25rem;
  margin-bottom: var(--space-md);
}

.section-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
}

/* Cards */
.card {
  background-color: var(--card-bg);
  border-radius: var(--radius-lg);
  padding: var(--space-xl);
  box-shadow: var(--card-shadow);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  border: 1px solid var(--border-color);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--card-shadow-hover);
}

.card-icon {
  width: 56px;
  height: 56px;
  background: var(--accent-gradient);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: var(--space-lg);
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: var(--space-sm);
}

.card-description {
  color: var(--text-secondary);
  margin-bottom: var(--space-lg);
  line-height: 1.6;
}

/* Grid Layouts */
.grid {
  display: grid;
  gap: var(--space-xl);
}

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

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

.grid-4 {
  grid-template-columns: repeat(4, 1fr);
}

/* Tool Cards */
.tool-card {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.tool-card .card-content {
  flex: 1;
}

.tool-card .card-footer {
  margin-top: auto;
  padding-top: var(--space-lg);
}

/* Blog Cards */
.blog-card {
  overflow: hidden;
}

.blog-card-image {
  width: 100%;
  height: 200px;
  background: var(--bg-tertiary);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 3rem;
}

.blog-card-meta {
  display: flex;
  gap: var(--space-md);
  margin-bottom: var(--space-sm);
  font-size: 0.875rem;
  color: var(--text-muted);
}

/* Forms */
.form-group {
  margin-bottom: var(--space-lg);
}

.form-label {
  display: block;
  margin-bottom: var(--space-sm);
  font-weight: 500;
  color: var(--text-primary);
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--space-md);
  background-color: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 1rem;
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--input-focus);
  box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

.form-error {
  color: var(--error);
  font-size: 0.875rem;
  margin-top: var(--space-xs);
}

/* Calculator Styles */
.calculator-container {
  background-color: var(--card-bg);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  box-shadow: var(--card-shadow);
  border: 1px solid var(--border-color);
  margin-bottom: var(--space-2xl);
}

.calculator-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--space-lg);
  margin-bottom: var(--space-xl);
}

.calculator-result {
  background: var(--accent-gradient);
  color: white;
  padding: var(--space-xl);
  border-radius: var(--radius-lg);
  text-align: center;
}

.calculator-result-label {
  font-size: 0.875rem;
  opacity: 0.9;
  margin-bottom: var(--space-sm);
}

.calculator-result-value {
  font-size: 2.5rem;
  font-weight: 700;
}

/* FAQ Styles */
.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  border-bottom: 1px solid var(--border-color);
  padding: var(--space-lg) 0;
}

.faq-question {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-sm);
}

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

/* Tables */
.table-container {
  overflow-x: auto;
  margin-bottom: var(--space-xl);
}

.table {
  width: 100%;
  border-collapse: collapse;
}

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

.table th {
  font-weight: 600;
  color: var(--text-primary);
  background-color: var(--bg-secondary);
}

.table tr:hover {
  background-color: var(--bg-secondary);
}

/* Footer */
.footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: var(--space-3xl) 0 var(--space-xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-2xl);
  margin-bottom: var(--space-2xl);
}

.footer-brand {
  max-width: 300px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: var(--space-md);
}

.footer-description {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.footer-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-lg);
}

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

.footer-links li {
  margin-bottom: var(--space-sm);
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

.footer-links a:hover {
  color: var(--primary-500);
}

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: var(--space-xl);
  text-align: center;
  color: var(--text-muted);
  font-size: 0.875rem;
}

/* Breadcrumb */
.breadcrumb {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-xl);
  font-size: 0.875rem;
}

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

.breadcrumb a:hover {
  color: var(--primary-500);
}

.breadcrumb-separator {
  color: var(--text-muted);
}

.breadcrumb-current {
  color: var(--text-primary);
  font-weight: 500;
}

/* Page Header */
.page-header {
  background: linear-gradient(180deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
  padding: var(--space-3xl) 0 var(--space-2xl);
  text-align: center;
}

.page-title {
  font-size: 2.5rem;
  margin-bottom: var(--space-md);
}

.page-description {
  font-size: 1.125rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* Content Styles */
.content {
  max-width: 800px;
  margin: 0 auto;
}

.content h2 {
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-md);
}

.content h3 {
  margin-top: var(--space-xl);
  margin-bottom: var(--space-sm);
}

.content p {
  margin-bottom: var(--space-md);
}

.content ul,
.content ol {
  margin-bottom: var(--space-md);
  padding-left: var(--space-xl);
}

.content li {
  margin-bottom: var(--space-sm);
  color: var(--text-secondary);
}

/* Tags */
.tag {
  display: inline-flex;
  align-items: center;
  padding: var(--space-xs) var(--space-md);
  background-color: var(--bg-tertiary);
  border-radius: var(--radius-full);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.tag-primary {
  background: var(--accent-gradient);
  color: white;
}

/* Alert/Notice */
.alert {
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  margin-bottom: var(--space-lg);
}

.alert-info {
  background-color: rgba(59, 130, 246, 0.1);
  border-left: 4px solid var(--primary-500);
}

.alert-success {
  background-color: rgba(16, 185, 129, 0.1);
  border-left: 4px solid var(--success);
}

.alert-warning {
  background-color: rgba(245, 158, 11, 0.1);
  border-left: 4px solid var(--warning);
}

/* Loading Spinner */
.spinner {
  width: 40px;
  height: 40px;
  border: 3px solid var(--border-color);
  border-top-color: var(--primary-500);
  border-radius: 50%;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Utility Classes */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-0 { margin-top: 0; }
.mb-0 { margin-bottom: 0; }
.my-0 { margin-top: 0; margin-bottom: 0; }

.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;
}

/* Responsive Design */
@media (max-width: 1024px) {
  .grid-4 {
    grid-template-columns: repeat(3, 1fr);
  }
  
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 768px) {
  h1 { font-size: 2rem; }
  h2 { font-size: 1.75rem; }
  h3 { font-size: 1.25rem; }
  
  .hero {
    padding: var(--space-3xl) 0;
  }
  
  .hero-title {
    font-size: 2rem;
  }
  
  .hero-description {
    font-size: 1.125rem;
  }
  
  .section {
    padding: var(--space-3xl) 0;
  }
  
  .section-title {
    font-size: 1.75rem;
  }
  
  .grid-2,
  .grid-3,
  .grid-4 {
    grid-template-columns: 1fr;
  }
  
  .nav-links {
    display: none;
    position: absolute;
    top: 72px;
    left: 0;
    right: 0;
    background-color: var(--header-bg);
    flex-direction: column;
    padding: var(--space-lg);
    border-bottom: 1px solid var(--header-border);
    gap: var(--space-md);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .menu-toggle {
    display: flex;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-xl);
  }
  
  .calculator-grid {
    grid-template-columns: 1fr;
  }
  
  .page-title {
    font-size: 1.75rem;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 var(--space-md);
  }
  
  .hero-buttons {
    flex-direction: column;
    width: 100%;
  }
  
  .hero-buttons .btn {
    width: 100%;
  }
  
  .card {
    padding: var(--space-lg);
  }
  
  .calculator-container {
    padding: var(--space-lg);
  }
}

/* Print Styles */
@media print {
  .header,
  .footer,
  .theme-toggle,
  .menu-toggle {
    display: none;
  }
  
  body {
    background: white;
    color: black;
  }
  
  .card {
    box-shadow: none;
    border: 1px solid #ccc;
  }
}