/* Base styles for Chinese Radicals Learning Website */
:root {
  --primary: #4A90E2;
  --accent: #F5A623;
  --bg: #f8fafc;
  --text: #2D3748;
  --header-bg: rgba(255, 255, 255, 0.8);
  --footer-bg: #f1f1f1;
  --border: #E2E8F0;
  --card-bg: #ffffff;
  --radius: 12px;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --font-main: 'Segoe UI', 'Noto Sans SC', Arial, sans-serif;
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme='dark'] {
  --primary: #58a6ff;
  --accent: #f7b731;
  --bg: #0d1117;
  --text: #c9d1d9;
  --header-bg: rgba(13, 17, 23, 0.8);
  --footer-bg: #161b22;
  --border: #30363d;
  --card-bg: #161b22;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
}

html {
  font-size: 18px;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-main);
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

header {
  background: var(--header-bg);
  border-bottom: 1px solid var(--border);
  padding: 1.5rem 2vw;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

header h1 {
  margin: 0;
  font-size: 2.2rem;
  letter-spacing: 1px;
  background: linear-gradient(135deg, var(--primary), #6a11cb);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  transition: var(--transition);
}

header h1:hover {
  transform: scale(1.05);
}

nav ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  gap: 2.5rem;
}

nav a {
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 1.1rem;
  transition: var(--transition);
  position: relative;
}

nav a::after {
  content: '';
  position: absolute;
  width: 0;
  height: 2px;
  bottom: -4px;
  left: 0;
  background: linear-gradient(135deg, var(--primary), #6a11cb);
  transition: var(--transition);
}

nav a:hover::after, nav a:focus::after {
  width: 100%;
}

nav a:hover, nav a:focus {
  color: var(--primary);
  outline: none;
}

main {
  flex: 1;
  width: 100%;
  max-width: 1100px;
  margin: 2rem auto 0 auto;
  padding: 0 2vw;
}

section {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
  padding: 2rem;
  margin-bottom: 2rem;
}

.section-description {
  max-width: 800px;
  margin: 0 auto 2rem auto;
  text-align: center;
  color: var(--text-secondary, #555);
  line-height: 1.7;
}

/* Hero Section */
.hero {
  position: relative;
  background: linear-gradient(135deg, var(--primary), #6a11cb);
  color: #fff;
  text-align: center;
  padding: 4rem 2rem;
  border-radius: var(--radius);
  margin-bottom: 2rem;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.45);
  z-index: 1;
}

.hero-content {
    position: relative;
    z-index: 2;
}

.hero-content h2 {
  font-size: 2.5rem;
  margin-bottom: 1rem;
  color: #fff;
  text-shadow: 0 2px 8px rgba(0,0,0,0.25), 0 1px 0 #333;
}

.hero-content p {
  font-size: 1.2rem;
  max-width: 600px;
  margin: 0 auto 2rem auto;
  color: #f3f6fa;
  text-shadow: 0 1px 6px rgba(0,0,0,0.18);
}

.cta-button {
  background: var(--accent);
  color: white;
  padding: 0.8rem 2rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  transition: var(--transition);
}

.cta-button:hover {
  transform: translateY(-3px);
  box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}

.search-container {
  margin-bottom: 2rem;
  text-align: center;
}

input[type="search"] {
  width: 100%;
  max-width: 500px;
  padding: 0.8rem 1.2rem;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 1rem;
  transition: var(--transition);
}

input[type="search"]:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.3);
}

#radical-grid-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 1.5rem;
}

.radical-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);

/* Share Section */
.share-section {
  text-align: center;
  padding: 2rem;
  background: var(--card-bg);
  border-radius: var(--radius);
  margin-top: 2rem;
}

.share-buttons a {
  margin: 0 10px;
  display: inline-block;
  transition: transform 0.2s;
}

.share-buttons a:hover {
  transform: scale(1.1);
}

/* Tone Rules Section */
.tone-rules-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
  margin-top: 1.5rem;
}

.tone-rule-card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem;
  border-left: 5px solid var(--primary);
  transition: var(--transition);
}

.tone-rule-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
}

.tone-rule-card h5 {
  margin-top: 0;
  font-size: 1.2rem;
  color: var(--primary);
}

.tone-rule-example {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--border);
}

.tone-rule-example .audio-button {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  cursor: pointer;
  transition: var(--transition);
  font-size: 1rem;
}

.tone-rule-example .audio-button:hover {
  background: #3a7ac8;
}

.tone-rule-example p {
  margin: 0.5rem 0 0;
  font-style: italic;
  color: var(--text-secondary, #555);
}
  padding: 1.5rem 1rem;
  text-align: center;
  transition: var(--transition);
  cursor: pointer;
  text-decoration: none;
  color: var(--text);
}

/* Tones Page Specific Styles */
.tones-page main {
    max-width: 1200px;
}

.tones-hero {
    background: linear-gradient(135deg, var(--primary), #6a11cb);
    color: white;
    text-align: center;
    padding: 4rem 2rem;
    border-radius: var(--radius);
    margin-bottom: 3rem;
}

.tones-page .tones-hero h2 {
    font-size: 2.8rem;
    margin-bottom: 0.5rem;
}

.tone-chart-svg {
    max-width: 100%;
    height: auto;
    margin: 1rem auto;
    display: block;
    background: #fff;
    border-radius: var(--radius);
    padding: 1rem;
    box-shadow: var(--shadow);
}

.tone-combination-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 1rem;
    margin-top: 1rem;
}

.tone-combination-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 1rem;
    background: var(--bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.tone-combination-item .audio-button {
    font-size: 1.2rem;
    margin-bottom: 0.5rem;
}

.tone-combo-label {
    font-size: 0.9rem;
    color: var(--text-secondary, #555);
}

.tones-hero p {
    font-size: 1.3rem;
    max-width: 600px;
    margin: 0 auto;
    opacity: 0.9;
}

.tones-container-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(400px, 1fr));
    gap: 2rem;
}

.tone-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    padding: 2rem;
    transition: var(--transition);
}

.tone-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}

.tone-card h3 {
    font-size: 1.8rem;
    margin-top: 0;
    color: var(--primary);
}

/* Tone Tutorial Styles */
.tone-tutorial-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1.5rem;
}

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

.tone-mark {
    font-size: 1.8rem;
}

/* Tone Game Styles */
.game-card {
    background: linear-gradient(135deg, var(--bg-alt, #f0f4f8), var(--card-bg));
}

.character-container {
    margin: 2rem 0;
}

.character {
    font-size: 8rem;
    font-weight: bold;
    text-align: center;
}

.tone-options {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
}

.tone-options button {
    padding: 1rem;
    font-size: 1.1rem;
    font-weight: 600;
}

.feedback {
    min-height: 2em;
    font-size: 1.2rem;
    font-weight: bold;
}

.pinyin-reveal {
    font-size: 2rem;
    color: var(--accent);
    margin-top: 1rem;
    min-height: 2.5rem;
}

.radical-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 15px rgba(0,0,0,0.1);
}

.radical-card .symbol {
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.radical-card .pinyin {
  font-size: 0.9rem;
  color: var(--primary);
}

.radical-card .meaning {
  font-size: 0.9rem;
}

/* Back to Top Button */
#back-to-top {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(100px);
  transition: var(--transition);
  z-index: 1000;
}

#back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

#back-to-top:hover {
  background: var(--accent);
}

/* Theme Switcher */
.theme-switcher-container {
  position: absolute;
  top: 1.5rem;
  right: 2vw;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

#theme-switcher {
  opacity: 0;
  position: absolute;
}

.toggle-icon {
  width: 50px;
  height: 26px;
  background: #ccc;
  border-radius: 13px;
  cursor: pointer;
  position: relative;
  transition: var(--transition);
}

.toggle-icon::before {
  content: '';
  position: absolute;
  width: 22px;
  height: 22px;
  background: white;
  border-radius: 50%;
  top: 2px;
  left: 2px;
  transition: var(--transition);
}

#theme-switcher:checked + .toggle-icon {
  background: var(--primary);
}

#theme-switcher:checked + .toggle-icon::before {
  transform: translateX(24px);
}

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



.multiple-choice-game {
  text-align: center;
  padding: 2rem;
}

.multiple-choice-game .question {
  font-size: 1.5rem;
  margin-bottom: 2rem;
}

.multiple-choice-game .options {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  max-width: 600px;
  margin: 0 auto;
}

.multiple-choice-game .option {
  font-size: 2rem;
  padding: 1rem;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  background: white;
  cursor: pointer;
  transition: all 0.3s ease;
}

.multiple-choice-game .option:hover {
  border-color: var(--primary);
  transform: translateY(-2px);
}

.multiple-choice-game .correct-answer {
  background: #4CAF50;
  color: white;
  border-color: #4CAF50;
  animation: correct 0.5s ease;
}

.multiple-choice-game .incorrect-answer {
  background: #f44336;
  color: white;
  border-color: #f44336;
  animation: incorrect 0.5s ease;
}

.multiple-choice-game .result {
  margin-top: 2rem;
  font-size: 1.2rem;
}

.multiple-choice-game .result .correct {
  color: #4CAF50;
}

.multiple-choice-game .result .incorrect {
  color: #f44336;
}

@keyframes correct {
  0% { transform: scale(1); }
  50% { transform: scale(1.1); }
  100% { transform: scale(1); }
}

@keyframes incorrect {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-5px); }
  40%, 80% { transform: translateX(5px); }
}

.flashcard {
  background: white;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 2.5rem;
  max-width: 500px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  perspective: 1000px;
  transition: var(--transition);
}

.flashcard:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 12px -1px rgba(0, 0, 0, 0.15), 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.flashcard .srs-level {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: rgba(0,0,0,0.1);
  padding: 0.25rem 0.5rem;
  border-radius: 8px;
  font-size: 0.8rem;
}

.radical-symbol {
  font-size: 5rem;
  margin-bottom: 1.5rem;
  color: var(--text);
  font-weight: 500;
  line-height: 1.2;
  animation: fadeIn 0.5s ease-out;
}

.radical-pinyin {
  font-size: 1.5rem;
  color: var(--primary);
  margin-bottom: 2rem;
  font-weight: 500;
  animation: slideUp 0.5s ease-out;
}

.meaning-container {
  margin-bottom: 2rem;
}

.srs-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
}

.flashcard button {
  padding: 1rem 2rem;
  margin: 0;
  font-size: 1.1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

#show-meaning {
  background: var(--bg);
  color: var(--text);
  border: 2px solid var(--border);
  width: 100%;
  margin-bottom: 1rem;
}

#show-meaning:hover {
  background: var(--border);
  transform: translateY(-2px);
}

#meaning {
  font-size: 1.25rem;
  margin: 1.5rem 0;
  padding: 1rem;
  background: var(--bg);
  border-radius: var(--radius);
  color: var(--text);
  animation: fadeIn 0.3s ease-out;
}

#know, #dont-know {
  width: calc(50% - 1rem);
}

#know {
  background: #48BB78;
  color: white;
}

#know:hover {
  background: #38A169;
  transform: translateY(-2px);
}

#dont-know {
  background: #F56565;
  color: white;
}

#dont-know:hover {
  background: #E53E3E;
  transform: translateY(-2px);
}

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

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.flashcard.correct {
  animation: correct-swipe 0.5s forwards;
}

.flashcard.incorrect {
  animation: incorrect-shake 0.5s forwards;
}

@keyframes correct-swipe {
  to {
    opacity: 0;
    transform: translateX(100px) rotate(10deg);
  }
}

@keyframes incorrect-shake {
  0%, 100% { transform: translateX(0); }
  20%, 60% { transform: translateX(-10px); }
  40%, 80% { transform: translateX(10px); }
}

#gameSelection {
  text-align: center;
  margin: 0 auto 2.5rem;
  background: white;
  padding: 1rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  max-width: 400px;
}

#gameSelection button {
  padding: 1rem 2rem;
  margin: 0 0.75rem;
  font-size: 1.1rem;
  font-weight: 600;
  border: 2px solid var(--primary);
  border-radius: var(--radius);
  background: transparent;
  color: var(--primary);
  cursor: pointer;
  transition: var(--transition);
}

#gameSelection button:hover {
  background: var(--primary);
  color: white;
  transform: translateY(-2px);
}

#gameSelection button:active {
  transform: translateY(0);
}

th, td {
  padding: 0.75rem 0.5rem;
  text-align: left;
  border-bottom: 1px solid var(--border);
}

/* Character Gallery Styles */
#character-grid-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(100px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
}

.character-card {
  background: white;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1.5rem 1rem;
  text-align: center;
  transition: var(--transition);
  cursor: pointer;
  text-decoration: none;
  color: var(--text);
}

.character-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 8px 15px rgba(0,0,0,0.1);
  color: var(--primary);
}

.character-card .char-symbol {
  font-size: 2.5rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.character-card .char-pinyin {
  font-size: 0.9rem;
  color: #666;
}

.hidden {
    display: none;
}

/* Character Deconstruction Styles */
#deconstruct-form {
  max-width: 600px;
  margin: 0 auto 2rem;
  display: flex;
  gap: 1rem;
  align-items: center;
}

#char-input {
  font-size: 1.5rem;
  padding: 0.5rem;
  width: 4rem;
  text-align: center;
  border: 2px solid var(--border);
  border-radius: var(--radius);
  transition: var(--transition);
}

#char-input:focus {
  border-color: var(--primary);
  outline: none;
  box-shadow: 0 0 0 3px rgba(74, 144, 226, 0.2);
}

#deconstruct-form button {
  padding: 0.75rem 1.5rem;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: var(--transition);
}

#deconstruct-form button:hover {
  background: var(--accent);
  transform: translateY(-2px);
}

#deconstruction-container {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 2rem;
  margin-top: 2rem;
}

#deconstruction-visual {
  background: white;
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  min-height: 300px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

#deconstruction-details {
  background: white;
  padding: 2rem;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.radical-mini {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--bg);
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  margin: 0.25rem;
  font-size: 1.1rem;
  animation: fadeIn 0.3s ease-out;
}

.radical-mini span:first-child {
  font-weight: 600;
  color: var(--primary);
}

.char-deconstruct-card {
  margin-top: 1.5rem;
}

.char-deconstruct-card h3 {
  font-size: 3rem;
  margin: 0 0 1.5rem;
  color: var(--text);
  text-align: center;
}

.char-deconstruct-card > div {
  margin-bottom: 1.5rem;
}

.char-deconstruct-card strong {
  color: var(--primary);
  display: block;
  margin-bottom: 0.5rem;
}

.evolution-timeline {
  display: flex;
  align-items: center;
  gap: 1rem;
  overflow-x: auto;
  padding: 1rem 0;
}

.evolution-stage {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  min-width: 100px;
}

.evolution-stage img {
  height: 48px;
  width: auto;
}

.evolution-stage span {
  font-size: 0.9rem;
  color: var(--text);
  opacity: 0.8;
}

th {
  background: var(--bg);
  font-weight: 700;
}

tr:hover {
  background: #f5f7fa;
}

footer {
  background: var(--footer-bg);
  text-align: center;
  padding: 1rem 0;
  font-size: 0.95rem;
  color: #666;
  border-top: 1px solid var(--border);
}

/* Accessibility */
:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

@media (max-width: 700px) {
  main, section {
    padding: 1rem;
  }
  header {
    padding: 0.5rem 1vw;
  }
  nav ul {
    gap: 1rem;
  }
  th, td {
    padding: 0.5rem 0.25rem;
  }
}