/* CSS Custom Properties (Variables) */
:root {
  --color-bg-light: #ffffff;
  --color-bg-dark: #121212;
  --color-text-light: #000000;
  --color-text-dark: #ffffff;
  --color-accent-light: #f9f9f9;
  --color-accent-dark: #1f1f1f;
  --color-gray: #666;
  --color-gray-dark: #aaa;
  --color-button-bg: #000000;
  --color-button-text: #ffffff;
  --color-button-hover: #333;
  --font-primary: 'SF Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
  --border-radius: 5px;
  --transition-speed: 0.3s;
  --max-width-content: 800px;
  --spacing-small: 10px;
  --spacing-medium: 20px;
  --spacing-large: 40px;
}

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

/* General Body Styling */
body {
  font-family: var(--font-primary);
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background-color: var(--color-bg-light);
  color: var(--color-text-light);
  transition: background-color var(--transition-speed) ease, 
              color var(--transition-speed) ease;
}

/* Skip Link for Accessibility */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-button-bg);
  color: var(--color-button-text);
  padding: 8px 16px;
  text-decoration: none;
  z-index: 100;
  border-radius: 0 0 var(--border-radius) 0;
}

.skip-link:focus {
  top: 0;
}

/* Visually Hidden (for screen readers only) */
.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;
}

/* Header and Footer Styling */
header, footer {
  padding: var(--spacing-small) var(--spacing-medium);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--color-accent-light);
  transition: background-color var(--transition-speed) ease, 
              color var(--transition-speed) ease;
}

header h1 {
  margin: 0;
  color: var(--color-text-light);
}

footer {
  font-size: 14px;
  background-color: var(--color-button-bg);
  color: var(--color-button-text);
  text-align: center;
  padding: var(--spacing-small);
  flex-shrink: 0;
  margin-top: auto;
  border-top: 1px solid #333;
}

/* Navigation Styling */
nav {
  position: relative;
  padding-bottom: 5px;
  transition: border-color var(--transition-speed) ease;
}

nav a {
  margin: 0 var(--spacing-small);
  text-decoration: none;
  color: var(--color-text-light);
  font-weight: bold;
  transition: color var(--transition-speed) ease;
}

nav a:visited {
  color: inherit;
}

nav a:hover {
  text-decoration: underline;
}

#logo {
  text-decoration: none;
  color: var(--color-text-light);
  font-weight: bold;
}

#logo:hover {
  opacity: 0.8;
}

/* Focus Styles for Accessibility */
*:focus {
  outline: 2px solid #0066cc;
  outline-offset: 2px;
}

*:focus:not(:focus-visible) {
  outline: none;
}

*:focus-visible {
  outline: 2px solid #0066cc;
  outline-offset: 2px;
}

/* Dark Mode Styling */
body.dark-mode {
  background-color: var(--color-bg-dark);
  color: var(--color-text-dark);
}

body.dark-mode header, 
body.dark-mode footer {
  background-color: var(--color-accent-dark);
}

body.dark-mode header h1 {
  color: var(--color-text-dark);
}

body.dark-mode nav a {
  color: var(--color-text-dark);
}

body.dark-mode nav a:hover {
  color: #ccc;
}

body.dark-mode #logo {
  color: var(--color-text-dark);
}

/* Dark Mode Toggle Button */
#darkModeToggle {
  background-color: var(--color-button-bg);
  color: var(--color-button-text);
  border: none;
  padding: var(--spacing-small) var(--spacing-medium);
  cursor: pointer;
  border-radius: var(--border-radius);
  transition: background-color var(--transition-speed) ease, 
              color var(--transition-speed) ease;
}

#darkModeToggle:hover {
  background-color: var(--color-button-hover);
}

body.dark-mode #darkModeToggle {
  background-color: var(--color-button-text);
  color: var(--color-button-bg);
}

body.dark-mode #darkModeToggle:hover {
  background-color: #ddd;
}

/* Main Content Styling */
main {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: var(--spacing-large) var(--spacing-medium);
  text-align: center;
}

/* Output Box */
.output-box {
  border: 3px solid var(--color-text-light);
  padding: var(--spacing-medium);
  margin: var(--spacing-medium) auto;
  width: fit-content;
  min-width: 300px;
  text-align: center;
  font-size: 24px;
  border-radius: var(--border-radius);
  animation: fadeIn 0.5s ease-in-out;
}

body.dark-mode .output-box {
  border-color: var(--color-text-dark);
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Input Styling */
.input-container {
  position: relative;
  max-width: 500px;
  width: 100%;
  margin: var(--spacing-medium) auto;
}

.input-container input {
  width: 100%;
  padding: var(--spacing-small);
  font-size: 24px;
  border: 2px solid var(--color-text-light);
  border-radius: var(--border-radius);
  text-align: center;
  padding-right: 40px;
  box-sizing: border-box;
  transition: border-color var(--transition-speed) ease;
}

.input-container input:focus {
  border-color: #0066cc;
}

body.dark-mode .input-container input {
  background-color: var(--color-accent-dark);
  color: var(--color-text-dark);
  border-color: var(--color-text-dark);
}

.input-container input:focus + .clear-icon,
.input-container input:not(:placeholder-shown) + .clear-icon {
  visibility: visible;
}

.clear-icon {
  position: absolute;
  top: 50%;
  right: var(--spacing-small);
  transform: translateY(-50%);
  background: none;
  border: none;
  font-size: 22px;
  cursor: pointer;
  color: var(--color-text-light);
  visibility: hidden;
  transition: color var(--transition-speed) ease;
  padding: 5px;
}

.clear-icon:hover {
  color: var(--color-button-hover);
}

body.dark-mode .clear-icon {
  color: var(--color-text-dark);
}

/* Button Group */
.button-group {
  display: flex;
  gap: var(--spacing-small);
  flex-wrap: wrap;
  justify-content: center;
  margin: var(--spacing-medium) 0;
}

/* General Button Styling */
button:not(#darkModeToggle):not(.clear-icon) {
  margin: 1px;
  padding: 8px 18px;
  min-height: 44px;
  font-size: 18px;
  background-color: var(--color-button-bg);
  color: var(--color-button-text);
  border: none;
  cursor: pointer;
  border-radius: var(--border-radius);
  transition: background-color var(--transition-speed) ease, 
              color var(--transition-speed) ease,
              transform 0.1s ease;
}

button:not(#darkModeToggle):not(.clear-icon):hover {
  background-color: var(--color-button-hover);
  transform: translateY(-1px);
}

button:not(#darkModeToggle):not(.clear-icon):active {
  transform: translateY(0);
}

body.dark-mode button:not(#darkModeToggle):not(.clear-icon) {
  background-color: var(--color-button-text);
  color: var(--color-button-bg);
}

body.dark-mode button:not(#darkModeToggle):not(.clear-icon):hover {
  background-color: #ddd;
}

/* History Section */
.history {
  margin-top: var(--spacing-large);
  max-width: var(--max-width-content);
  width: 100%;
}

.history h3 {
  margin-bottom: var(--spacing-medium);
}

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

.history li {
  padding: var(--spacing-small);
  margin: 5px 0;
  background-color: var(--color-accent-light);
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: background-color var(--transition-speed) ease;
}

.history li:hover {
  background-color: #e0e0e0;
}

body.dark-mode .history li {
  background-color: var(--color-accent-dark);
}

body.dark-mode .history li:hover {
  background-color: #2a2a2a;
}

/* About Page Styling */
.description, .socials {
  font-size: 20px;
  text-align: center;
  margin: var(--spacing-large) auto;
  max-width: var(--max-width-content);
  line-height: 1.6;
  transition: color var(--transition-speed) ease;
}

.description p {
  margin-bottom: var(--spacing-medium);
}

.socials {
  font-style: italic;
  color: var(--color-gray);
}

body.dark-mode .socials {
  color: var(--color-gray-dark);
}

/* Contact Form Styles */
.contact-form {
  margin: 50px auto;
  width: 90%;
  max-width: 500px;
  text-align: left;
}

.form-group {
  margin-bottom: var(--spacing-medium);
}

.form-group label {
  display: block;
  margin-bottom: 5px;
  font-weight: bold;
}

.contact-form input,
.contact-form textarea {
  width: 100%;
  padding: var(--spacing-small);
  font-size: 16px;
  font-family: var(--font-primary);
  border: 2px solid var(--color-text-light);
  border-radius: var(--border-radius);
  transition: border-color var(--transition-speed) ease;
}

.contact-form input:focus,
.contact-form textarea:focus {
  border-color: #0066cc;
}

.contact-form textarea {
  resize: vertical;
  min-height: 120px;
}

.contact-form button {
  width: 100%;
  margin-top: var(--spacing-small);
}

body.dark-mode .contact-form input,
body.dark-mode .contact-form textarea {
  background-color: var(--color-accent-dark);
  color: var(--color-text-dark);
  border-color: var(--color-text-dark);
}

/* Copy Notification */
#copyNotification {
  position: fixed;
  top: 60px;
  right: var(--spacing-medium);
  background-color: #333;
  color: #fff;
  padding: var(--spacing-small) 15px;
  border-radius: var(--border-radius);
  font-size: 14px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.3);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-speed) ease, 
              visibility var(--transition-speed) ease;
  z-index: 1000;
}

#copyNotification.visible {
  opacity: 1;
  visibility: visible;
}

body.dark-mode #copyNotification {
  background-color: #fff;
  color: #000;
  box-shadow: 0 2px 5px rgba(255, 255, 255, 0.3);
}

/* Mobile Responsive Design */
@media (max-width: 768px) {
  header {
    flex-wrap: wrap;
    gap: var(--spacing-small);
  }

  nav {
    order: 2;
    width: 100%;
    text-align: center;
  }

  #darkModeToggle {
    order: 3;
  }

  .input-container input {
    font-size: 16px; /* Prevents iOS zoom on focus */
  }

  .output-box {
    font-size: 20px;
    min-width: 250px;
  }

  button:not(#darkModeToggle):not(.clear-icon) {
    min-height: 44px; /* iOS minimum touch target */
    padding: 12px 20px;
  }
}

@media (max-width: 480px) {
  header {
    flex-direction: column;
  }

  nav a {
    display: inline-block;
    padding: var(--spacing-small);
  }

  .button-group {
    flex-direction: column;
    width: 100%;
    max-width: 300px;
  }

  .button-group button {
    width: 100%;
  }

  .description, .socials {
    font-size: 18px;
  }
}

/* Print Styles */
@media print {
  header, footer, button, nav, #darkModeToggle, .clear-icon, #copyNotification {
    display: none;
  }

  body {
    background: white;
    color: black;
  }

  .output-box {
    border-color: black;
  }
}