:root {
  --bg: #f7f8fa;
  --surface: #ffffff;
  --border: #e2e5ea;
  --text: #1a1d23;
  --text-muted: #6b7280;
  --accent: #2563eb;
  --accent-contrast: #ffffff;
  --warning-bg: #fffbeb;
  --warning-border: #fde68a;
  --warning-text: #92400e;
  --shadow: 0 1px 3px rgba(16, 24, 40, 0.06), 0 1px 2px rgba(16, 24, 40, 0.04);
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --surface: #1c1f26;
    --border: #2b2f38;
    --text: #e8eaed;
    --text-muted: #9aa1ac;
    --accent: #5b8def;
    --accent-contrast: #0b1220;
    --warning-bg: rgba(253, 230, 138, 0.08);
    --warning-border: rgba(253, 230, 138, 0.3);
    --warning-text: #fde68a;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4);
  }
}

* {
  box-sizing: border-box;
}

[hidden] {
  display: none !important;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.5;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 20px 60px;
}

.page-header {
  max-width: 720px;
  margin: 0 auto;
  padding: 40px 20px 8px;
}

.page-header h1 {
  margin: 0;
  font-size: 1.75rem;
  letter-spacing: -0.02em;
}

.subtitle {
  color: var(--text-muted);
  margin: 6px 0 24px;
}

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

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 24px;
  box-shadow: var(--shadow);
  margin-bottom: 20px;
}

textarea#text-input {
  width: 100%;
  padding: 14px;
  font-size: 1rem;
  font-family: inherit;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg);
  color: var(--text);
  resize: vertical;
  min-height: 160px;
}

textarea#text-input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.textarea-footer {
  display: flex;
  justify-content: flex-end;
  margin-top: 6px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.engine-selector {
  display: flex;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 14px;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.engine-selector label {
  display: flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
}

.engine-selector input[type="radio"] {
  width: 15px;
  height: 15px;
}

.controls-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: 16px;
  margin: 20px 0;
}

.api-key-label input {
  padding: 9px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.95rem;
}

.title-label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 14px;
}

.title-label input {
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.95rem;
}

.library-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-bottom: 14px;
}

.library-row select {
  flex: 1 1 200px;
  min-width: 0;
  padding: 9px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.95rem;
}

.library-row button {
  padding: 9px 16px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  color: var(--text);
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
}

.library-row button:hover {
  filter: brightness(1.08);
}

button.save-btn {
  display: block;
  width: 100%;
  padding: 12px 20px;
  margin-bottom: 14px;
  font-size: 1rem;
  font-weight: 600;
  border: 1px solid var(--accent);
  border-radius: 10px;
  background: var(--accent);
  color: var(--accent-contrast);
  cursor: pointer;
}

button.save-btn:hover {
  filter: brightness(1.08);
}

.token-details summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--text);
  margin-bottom: 10px;
}

.token-details .api-key-label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.hint {
  font-size: 0.8rem;
  color: var(--text-muted);
  margin: -10px 0 16px;
}

.controls-grid label {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.controls-grid select,
.controls-grid input[type="range"] {
  width: 100%;
}

.controls-grid select {
  padding: 9px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 0.95rem;
}

.button-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.button-row button {
  padding: 12px 20px;
  font-size: 1rem;
  font-weight: 600;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
}

.button-row button#speak-btn {
  background: var(--accent);
  color: var(--accent-contrast);
  border-color: var(--accent);
}

.button-row button:disabled {
  opacity: 0.45;
  cursor: default;
}

.button-row button:not(:disabled):hover {
  filter: brightness(1.08);
}

.status {
  min-height: 1.4em;
  color: var(--text-muted);
  font-size: 0.9rem;
  margin: 14px 0 0;
}

.card.warning {
  background: var(--warning-bg);
  border-color: var(--warning-border);
  color: var(--warning-text);
}

.hint-card h2 {
  margin-top: 0;
  font-size: 1.1rem;
}

.hint-card ul {
  margin: 0;
  padding-left: 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.7;
}

.hint-card strong {
  color: var(--text);
}

.page-footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 20px 20px 40px;
  color: var(--text-muted);
  font-size: 0.8rem;
  text-align: center;
}

@media (max-width: 560px) {
  .controls-grid {
    grid-template-columns: 1fr;
  }
}