:root {
  --bg-primary: #fff;
  --bg-secondary: #f5f5f5;
  --bg-tooltip: #f0f0f0;
  --text-primary: #000;
  --text-secondary: #666;
  --border-color: #ddd;
  --border-color-light: #ccc;
  --highlight-bg: #FFD700;
  --highlight-text: #000;
  --button-bg: #666;
  --button-bg-hover: #555;
  --button-bg-active: #444;
  --button-text: #fff;
  --input-bg: #fff;
  --input-text: #000;
  --input-border: #ccc;
  --error-color: #d32f2f;
  --link-color: #5a7fa7;
  --link-hover-color: #4a6f97;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2a2a2a;
    --bg-tooltip: #333;
    --text-primary: #e0e0e0;
    --text-secondary: #b0b0b0;
    --border-color: #444;
    --border-color-light: #555;
    --highlight-bg: #B8860B;
    --highlight-text: #fff;
    --button-bg: #555;
    --button-bg-hover: #666;
    --button-bg-active: #777;
    --button-text: #fff;
    --input-bg: #2a2a2a;
    --input-text: #e0e0e0;
    --input-border: #555;
    --error-color: #ef5350;
    --link-color: #8ab4d4;
    --link-hover-color: #a0c4e4;
  }
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text-primary);
  background-color: var(--bg-primary);
}

a {
  color: var(--link-color);
  text-decoration: none;
}

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

#loading, #error {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100vh;
  font-size: 16px;
  color: var(--text-secondary);
}

#error { color: var(--error-color); }

.hidden { display: none !important; }

#app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  background-color: var(--bg-primary);
}

#top-bar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  padding: 10px;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  gap: 10px;
}

#top-bar > div {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  grid-column: 2;
}

#help-button {
  grid-column: 1;
  justify-self: start;
}

#toggle-chinese {
  grid-column: 3;
  justify-self: end;
}
#toggle-chinese.inactive {
  opacity: 0.4;
}

#paste-input {
  padding: 8px 12px;
  border: 1px solid var(--input-border);
  border-radius: 6px;
  width: 85px;
  font-size: 14px;
  background-color: var(--input-bg);
  color: var(--input-text);
}

#reader {
  flex: 1;
  padding: 20px;
  position: relative;
  overflow-y: auto;
}

#text-display {
  font-size: 18px;
  line-height: 28px;
  white-space: pre-wrap;
  word-wrap: break-word;
  color: var(--text-primary);
}

.highlight {
  background-color: var(--highlight-bg);
  color: var(--highlight-text);
}

#tooltip {
  position: absolute;
  left: 0;
  right: 0;
  margin: 10px;
  padding: 12px;
  background-color: var(--bg-tooltip);
  border: 1px solid var(--border-color-light);
  border-radius: 6px;
  color: var(--text-primary);
  z-index: 10;
}

#tooltip .word {
  font-weight: bold;
  margin-bottom: 8px;
}

#bottom-bar {
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 16px;
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  gap: 20px;
}

#nav-left, #nav-right, #nav-within-left, #nav-within-right {
  font-size: 24px;
  font-weight: 600;
  width: 65px;
  height: 50px;
}

button {
  background-color: var(--button-bg);
  color: var(--button-text);
  padding: 10px 16px;
  border: none;
  border-radius: 6px;
  font-size: 14px;
  cursor: pointer;
  touch-action: manipulation;
}

button:hover { background-color: var(--button-bg-hover); }
button:active { background-color: var(--button-bg-active); }

#help-content h1 {
  font-size: 24px;
}

#help-content h2 {
  font-size: 18px;
}

#help-content ul {
  margin: 0 0 16px 0;
  padding-left: 20px;
}

#help-content li {
  line-height: 1.7;
}