/* 
 * ConvertTudo - Main Stylesheet
 * A responsive and accessible converter application
 */

:root {
  /* Color Palette */
  --color-white: #FFFFFF;
  --color-light-gray: #F8F9FA;
  --color-medium-gray: #E9ECEF;
  --color-dark-gray: #DEE2E6;
  --color-dark: #212529;
  
  /* Theme Colors - Light */
  --background-primary: var(--color-white);
  --background-secondary: var(--color-light-gray);
  --background-tertiary: var(--color-medium-gray);
  --text-primary: var(--color-dark);
  --text-secondary: #495057;
  --border-color: var(--color-dark-gray);
  --accent-color: #4361ee;
  --accent-hover: #3a56d4;
  --error-color: #e63946;
  --success-color: #2a9d8f;
  --warning-color: #f9c74f;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  
  /* Typography */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-md: 1rem;
  --font-size-lg: 1.25rem;
  --font-size-xl: 1.5rem;
  --font-size-xxl: 2rem;
  
  /* Border Radius */
  --border-radius-sm: 4px;
  --border-radius-md: 8px;
  --border-radius-lg: 12px;
  
  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
  
  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 300ms ease;
  --transition-slow: 500ms ease;
  
  /* Z-index layers */
  --z-index-base: 1;
  --z-index-dropdown: 10;
  --z-index-sticky: 20;
  --z-index-fixed: 30;
  --z-index-modal: 40;
  --z-index-popover: 50;
  --z-index-toast: 60;
  --z-index-tooltip: 70;
}

/* Dark Theme Variables */
.dark-theme {
  --background-primary: #121212;
  --background-secondary: #1e1e1e;
  --background-tertiary: #2d2d2d;
  --text-primary: #f8f9fa;
  --text-secondary: #ced4da;
  --border-color: #495057;
  --accent-color: #4cc9f0;
  --accent-hover: #4361ee;
}

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

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

body {
  font-family: var(--font-family);
  background-color: var(--background-primary);
  color: var(--text-primary);
  line-height: 1.5;
  min-height: 100vh;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--spacing-md);
}

h1 {
  font-size: var(--font-size-xxl);
}

h2 {
  font-size: var(--font-size-xl);
}

h3 {
  font-size: var(--font-size-lg);
}

p {
  margin-bottom: var(--spacing-md);
}

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

a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

/* Layout */
.app-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: var(--spacing-md);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

main {
  flex: 1;
  margin-bottom: var(--spacing-lg);
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--spacing-md) 0;
  margin-bottom: var(--spacing-lg);
  border-bottom: 1px solid var(--border-color);
}

.logo-container {
  display: flex;
  flex-direction: column;
}

.app-title {
  font-size: var(--font-size-xxl);
  font-weight: 700;
  color: var(--accent-color);
  margin-bottom: var(--spacing-xs);
}

.app-subtitle {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin: 0;
}

.header-controls {
  display: flex;
  gap: var(--spacing-sm);
}

/* Buttons */
button {
  cursor: pointer;
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  border: none;
  background: none;
  transition: all var(--transition-fast);
}

.icon-button {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: var(--background-secondary);
  color: var(--text-primary);
}

.icon-button:hover {
  background-color: var(--background-tertiary);
  transform: translateY(-2px);
}

.action-button {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  background-color: var(--accent-color);
  color: white;
  font-weight: 500;
}

.action-button:hover {
  background-color: var(--accent-hover);
  transform: translateY(-2px);
}

.back-button {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  background-color: var(--background-secondary);
  color: var(--text-primary);
}

.back-button:hover {
  background-color: var(--background-tertiary);
}

.danger-button {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  background-color: var(--error-color);
  color: white;
  font-weight: 500;
}

.danger-button:hover {
  background-color: #d32f2f;
}

.settings-button {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-md);
  border-radius: var(--border-radius-md);
  background-color: var(--background-secondary);
  color: var(--text-primary);
  width: 100%;
}

.settings-button:hover {
  background-color: var(--background-tertiary);
}

.settings-button.danger {
  background-color: rgba(230, 57, 70, 0.1);
  color: var(--error-color);
}

.settings-button.danger:hover {
  background-color: rgba(230, 57, 70, 0.2);
}

/* Form Controls */
.form-control {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  background-color: var(--background-primary);
  color: var(--text-primary);
  font-family: var(--font-family);
  font-size: var(--font-size-md);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-control:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 2px rgba(67, 97, 238, 0.3);
}

.select-wrapper {
  position: relative;
  width: 100%;
}

.select-wrapper select {
  appearance: none;
  padding-right: 2.5rem;
}

.select-arrow {
  position: absolute;
  right: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-secondary);
  pointer-events: none;
}

/* Converter Section */
.converter-section {
  background-color: var(--background-secondary);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
  margin-bottom: var(--spacing-lg);
}

.category-selector {
  display: flex;
  flex-direction: column;
  margin-bottom: var(--spacing-lg);
}

.category-selector label {
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
}

.conversion-container {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

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

.input-group label {
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
}

.units-container {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
}

.unit-selector {
  flex: 1;
  display: flex;
  flex-direction: column;
}

.unit-selector label {
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
}

.swap-button {
  margin-top: 1.5rem;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: var(--background-tertiary);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
}

.swap-button:hover {
  background-color: var(--accent-color);
  color: white;
  transform: rotate(180deg);
}

.result-container {
  background-color: var(--background-tertiary);
  border-radius: var(--border-radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.result-label {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
}

.result-value {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--spacing-md);
  word-break: break-word;
}

.result-actions {
  display: flex;
  gap: var(--spacing-md);
}

.formula-display {
  background-color: var(--background-primary);
  border-radius: var(--border-radius-md);
  padding: var(--spacing-md);
  border: 1px solid var(--border-color);
}

.formula-title {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  margin-bottom: var(--spacing-xs);
}

.formula-text {
  font-family: monospace;
  font-size: var(--font-size-md);
}

/* Settings Section */
.settings-section {
  background-color: var(--background-secondary);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
}

.section-title {
  margin-bottom: var(--spacing-lg);
  padding-bottom: var(--spacing-sm);
  border-bottom: 1px solid var(--border-color);
}

.settings-group {
  margin-bottom: var(--spacing-lg);
}

.settings-group h3 {
  font-size: var(--font-size-md);
  margin-bottom: var(--spacing-md);
  color: var(--accent-color);
}

.setting-item {
  margin-bottom: var(--spacing-md);
}

.setting-item label {
  display: block;
  margin-bottom: var(--spacing-sm);
}

.checkbox-item {
  display: flex;
  align-items: center;
}

.checkbox-item label {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: 0;
  cursor: pointer;
}

.checkbox-item input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--accent-color);
}

.settings-actions {
  display: flex;
  justify-content: flex-end;
  margin-top: var(--spacing-lg);
}

/* History Section */
.history-section {
  background-color: var(--background-secondary);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
}

.history-filters {
  margin-bottom: var(--spacing-lg);
}

.filter-item {
  display: flex;
  flex-direction: column;
}

.filter-item label {
  margin-bottom: var(--spacing-sm);
}

.history-items {
  max-height: 400px;
  overflow-y: auto;
  margin-bottom: var(--spacing-lg);
  border-radius: var(--border-radius-md);
  background-color: var(--background-primary);
  border: 1px solid var(--border-color);
}

.history-item {
  padding: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

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

.history-details {
  flex: 1;
}

.history-formula {
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
}

.history-meta {
  display: flex;
  gap: var(--spacing-md);
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
}

.history-actions {
  display: flex;
  justify-content: space-between;
  margin-top: var(--spacing-lg);
}

.empty-history {
  padding: var(--spacing-lg);
  text-align: center;
  color: var(--text-secondary);
}

/* About Section */
.about-section {
  background-color: var(--background-secondary);
  border-radius: var(--border-radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-md);
}

.about-content {
  margin-bottom: var(--spacing-lg);
}

.instructions-list {
  margin-left: var(--spacing-lg);
  margin-bottom: var(--spacing-lg);
}

.instructions-list li {
  margin-bottom: var(--spacing-sm);
}

.faq-item {
  margin-bottom: var(--spacing-md);
}

.faq-question {
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
}

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

.credits {
  margin-bottom: var(--spacing-lg);
}

.credits-list {
  list-style: none;
  margin-left: var(--spacing-md);
}

.credits-list li {
  margin-bottom: var(--spacing-xs);
}

.about-actions {
  display: flex;
  justify-content: flex-end;
}

/* Footer */
.app-footer {
  margin-top: auto;
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  text-align: center;
  color: var(--text-secondary);
  font-size: var(--font-size-sm);
}

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

.footer-separator {
  margin: 0 var(--spacing-sm);
}

.footer-copyright {
  font-size: var(--font-size-xs);
}

/* Loading Overlay */
.loading-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.7);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  z-index: var(--z-index-modal);
  color: white;
}

.loader {
  border: 5px solid var(--color-dark-gray);
  border-top: 5px solid var(--accent-color);
  border-radius: 50%;
  width: 50px;
  height: 50px;
  animation: spin 1s linear infinite;
  margin-bottom: var(--spacing-md);
}

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

/* Responsive Styles */
@media (max-width: 768px) {
  :root {
    --font-size-xxl: 1.75rem;
    --font-size-xl: 1.25rem;
    --font-size-lg: 1.125rem;
  }
  
  .app-container {
    padding: var(--spacing-sm);
  }
  
  .units-container {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .swap-button {
    margin: var(--spacing-sm) 0;
    align-self: center;
    transform: rotate(90deg);
  }
  
  .swap-button:hover {
    transform: rotate(270deg);
  }
  
  .result-actions {
    flex-direction: column;
    gap: var(--spacing-sm);
  }
  
  .action-button {
    width: 100%;
  }
  
  .history-item {
    flex-direction: column;
    align-items: flex-start;
  }
  
  .history-meta {
    margin-top: var(--spacing-xs);
    flex-direction: column;
    gap: var(--spacing-xs);
  }
  
  .history-actions {
    flex-direction: column-reverse;
    gap: var(--spacing-md);
  }
  
  .history-actions button {
    width: 100%;
  }
}

@media (max-width: 480px) {
  .app-header {
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
  }
  
  .logo-container {
    text-align: center;
  }
  
  .converter-section,
  .settings-section,
  .history-section,
  .about-section {
    padding: var(--spacing-md);
  }
}

/* Animations */
.fade-in {
  animation: fadeIn 0.5s ease-in;
}

.fade-out {
  animation: fadeOut 0.5s ease-out;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeOut {
  from { opacity: 1; }
  to { opacity: 0; }
}

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

button:focus,
input:focus,
select:focus,
a:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

/* Skip to content link for keyboard users */
.skip-link {
  background: var(--accent-color);
  color: white;
  font-weight: 700;
  left: 50%;
  padding: 4px;
  position: absolute;
  transform: translateY(-100%);
  transition: transform 0.3s;
}

.skip-link:focus {
  transform: translateY(0%);
}

/* Focus visible utility */
.focus-visible:focus {
  outline: 2px solid var(--accent-color);
  outline-offset: 2px;
}

/* Print styles */
@media print {
  .app-container {
    padding: 0;
  }
  
  .header-controls,
  .result-actions,
  .settings-actions,
  .history-actions,
  .about-actions {
    display: none;
  }
  
  .app-footer {
    position: fixed;
    bottom: 0;
    width: 100%;
  }
}