/* ============================================================
   Mandarin Pronunciation Practice — Mobile-first stylesheet
   ============================================================ */

/* ── CSS Custom Properties ─────────────────────────────────── */
:root {
  --color-bg:          #1a1a2e;   /* deep navy background         */
  --color-surface:     #16213e;   /* card surface                 */
  --color-surface-alt: #0f3460;   /* elevated card / hover        */
  --color-accent:      #c0392b;   /* Chinese red — primary action */
  --color-accent-dark: #962d22;   /* pressed state                */
  --color-text:        #e8e8f0;   /* primary text                 */
  --color-text-muted:  #8888aa;   /* secondary / hint text        */
  --color-border:      #2a2a4a;   /* card borders                 */

  /* Diff colours */
  --color-correct:     #27ae60;   /* green  – character matched   */
  --color-wrong:       #e74c3c;   /* red    – wrong character     */
  --color-missing:     #636380;   /* grey   – not said            */
  --color-extra:       #e67e22;   /* orange – said but unexpected */

  --radius-card:  16px;
  --radius-btn:   50%;
  --radius-input: 12px;

  --font-zh: 'Noto Serif SC', 'SimSun', 'STSong', serif;
  --font-ui: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  --transition: 0.2s ease;
}

/* ── Reset / Base ──────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-ui);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 100dvh;            /* dynamic viewport height on mobile */
  line-height: 1.5;
}

/* ── App shell ─────────────────────────────────────────────── */
.app {
  display: flex;
  flex-direction: column;
  min-height: 100dvh;
  max-width: 540px;
  margin: 0 auto;
  padding: 0 16px 32px;
}

/* ── Header ────────────────────────────────────────────────── */
.header {
  text-align: center;
  padding: 32px 0 20px;
}

.header__zh {
  font-family: var(--font-zh);
  font-size: clamp(2rem, 8vw, 3rem);
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 0.08em;
  line-height: 1.1;
}

.header__en {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-top: 4px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* ── Main layout ───────────────────────────────────────────── */
.main {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

/* ── Cards ─────────────────────────────────────────────────── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-card);
  padding: 20px;
}

/* ── Form label ────────────────────────────────────────────── */
.label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 10px;
}

.label__hint {
  font-weight: 400;
  text-transform: none;
  letter-spacing: 0;
}

/* ── Text input ────────────────────────────────────────────── */
.input {
  width: 100%;
  background: var(--color-bg);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-input);
  color: var(--color-text);
  font-family: var(--font-zh);
  font-size: 1.4rem;
  padding: 12px 14px;
  outline: none;
  transition: border-color var(--transition);
  /* Prevent iOS zoom on focus (font-size >= 16px is sufficient) */
}

.input::placeholder {
  color: var(--color-text-muted);
  font-family: var(--font-ui);
  font-size: 0.95rem;
}

.input:focus {
  border-color: var(--color-accent);
}

.field-hint {
  font-size: 0.78rem;
  color: var(--color-text-muted);
  margin-top: 8px;
}

.detected-lang-row {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 6px;
  flex-wrap: wrap;
}

.detected-lang-label {
  font-size: 0.72rem;
  color: var(--color-text-muted);
}

.lang-chip {
  font-size: 0.72rem;
  color: var(--color-text-muted);
  background: var(--color-surface-alt);
  border: 1px solid transparent;
  padding: 2px 10px;
  border-radius: 12px;
  cursor: pointer;
  transition: all var(--transition);
  font-family: var(--font-ui);
}

.lang-chip:hover {
  color: var(--color-text);
  border-color: var(--color-text-muted);
}

.lang-chip.active {
  color: var(--color-text);
  background: var(--color-accent);
  border-color: var(--color-accent);
}

/* ── Input action row (holds convert + translate buttons) ────── */
.input-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

/* ── Convert-pinyin button ──────────────────────────────────── */
.btn-convert {
  display: inline-flex;
  align-items: center;
  margin-top: 10px;
  padding: 5px 14px;
  border: 1.5px solid var(--color-accent);
  border-radius: 99px;
  background: transparent;
  color: var(--color-accent);
  font-family: var(--font-ui);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  transition: background var(--transition), color var(--transition);
  animation: fade-in 0.2s ease;
}

.btn-convert:hover,
.btn-convert:active {
  background: var(--color-accent);
  color: #fff;
}

/* Translate button uses a blue tint to distinguish from pinyin convert */
.btn-convert--translate {
  border-color: #2980b9;
  color: #2980b9;
}

.btn-convert--translate:hover,
.btn-convert--translate:active {
  background: #2980b9;
  color: #fff;
}

.btn-convert:disabled {
  opacity: 0.55;
  cursor: wait;
}

/* ── Pronounce (TTS) button ────────────────────────────────── */
.btn-pronounce {
  display: inline-flex;
  align-items: center;
  margin-top: 10px;
  padding: 5px 14px;
  border: 1.5px solid #2980b9;
  border-radius: 99px;
  background: transparent;
  color: #2980b9;
  font-family: var(--font-ui);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  transition: background var(--transition), color var(--transition);
  animation: fade-in 0.2s ease;
}

.btn-pronounce:hover,
.btn-pronounce:active {
  background: #2980b9;
  color: #fff;
}

/* Active/speaking state */
.btn-pronounce--speaking {
  background: #2980b9;
  color: #fff;
}

/* ── Record section ────────────────────────────────────────── */
.record-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  padding: 8px 0;
}

/* ── Record button ─────────────────────────────────────────── */
.record-btn {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;

  width: 140px;
  height: 140px;
  border-radius: var(--radius-btn);
  border: none;
  cursor: pointer;

  background: var(--color-accent);
  color: #fff;
  box-shadow: 0 4px 24px rgba(192, 57, 43, 0.45);
  transition: background var(--transition), transform var(--transition), box-shadow var(--transition);

  /* Ensure large tap target */
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.record-btn:hover {
  background: var(--color-accent-dark);
}

.record-btn:active {
  transform: scale(0.94);
  box-shadow: 0 2px 12px rgba(192, 57, 43, 0.35);
}

/* Disabled while processing */
.record-btn:disabled {
  background: var(--color-surface-alt);
  box-shadow: none;
  cursor: not-allowed;
}

.record-btn__icon {
  font-size: 2.4rem;
  line-height: 1;
  pointer-events: none;
}

.record-btn__label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  pointer-events: none;
}

/* ── Pulsing ring (visible only while recording) ───────────── */
.record-btn__ring {
  display: none;                 /* hidden by default             */
  position: absolute;
  inset: -10px;
  border-radius: 50%;
  border: 3px solid var(--color-accent);
  animation: pulse-ring 1.2s ease-out infinite;
  pointer-events: none;
}

/* Recording state applied via JS */
.record-btn--recording {
  background: #8b0000;
  box-shadow: 0 4px 32px rgba(139, 0, 0, 0.65);
}

.record-btn--recording .record-btn__ring {
  display: block;
}

@keyframes pulse-ring {
  0%   { transform: scale(1);    opacity: 0.8; }
  100% { transform: scale(1.45); opacity: 0;   }
}

/* ── Status message ────────────────────────────────────────── */
.status {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  min-height: 1.2em;
  text-align: center;
}

/* ── Results card ──────────────────────────────────────────── */
.results {
  animation: fade-in 0.3s ease;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0);   }
}

.results__heading {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 16px;
}

/* ── Result rows ───────────────────────────────────────────── */
.result-row {
  margin-bottom: 16px;
}

.result-row__label {
  display: block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 4px;
}

.result-row__text {
  font-family: var(--font-zh);
  font-size: 1.5rem;
  line-height: 1.6;
  color: var(--color-text);
  word-break: break-all;
}

/* ── Transcription annotations (pinyin + English) ─────────── */
.result-row__annotation {
  margin-top: 5px;
  font-size: 0.9rem;
  line-height: 1.4;
  color: var(--color-text-muted);
  letter-spacing: 0.03em;
}

.result-row__annotation--pinyin {
  font-family: var(--font-ui);
  color: #7eb8d4;   /* soft blue — visually distinct from characters */
}

.result-row__annotation--english {
  font-style: italic;
  color: var(--color-text-muted);
}

.result-row__annotation--portuguese {
  font-style: italic;
  color: #9dbf8e;   /* soft green — distinct from the English muted grey */
}

/* ── Diff characters ───────────────────────────────────────── */
.diff-chars {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

/* Each character in the diff is wrapped in a <span> by JS */
.diff-chars .ch {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.2rem;
  height: 2.4rem;
  border-radius: 6px;
  font-family: var(--font-zh);
  font-size: 1.4rem;
  padding: 0 2px;
  line-height: 1;
}

/* Correct match — green */
.ch--correct {
  color: #fff;
  background: var(--color-correct);
}

/* Wrong character at this position — red */
.ch--wrong {
  color: #fff;
  background: var(--color-wrong);
}

/* Target character that was never said — grey, dashed border */
.ch--missing {
  color: var(--color-missing);
  background: transparent;
  border: 2px dashed var(--color-missing);
  text-decoration: line-through;
  text-decoration-color: var(--color-missing);
}

/* Character said beyond the length of the target — orange */
.ch--extra {
  color: #fff;
  background: var(--color-extra);
}

/* ── Legend ────────────────────────────────────────────────── */
.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 4px 0 20px;
}

.legend__item {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 99px;
}

.legend__item--correct { background: var(--color-correct); color: #fff; }
.legend__item--wrong   { background: var(--color-wrong);   color: #fff; }
.legend__item--missing { border: 2px dashed var(--color-missing); color: var(--color-missing); }
.legend__item--extra   { background: var(--color-extra);   color: #fff; }

/* ── Score ─────────────────────────────────────────────────── */
.score {
  text-align: center;
  padding: 20px 0 24px;
  border-top: 1px solid var(--color-border);
  margin-bottom: 20px;
}

.score__value {
  display: block;
  font-size: clamp(2.5rem, 12vw, 4rem);
  font-weight: 700;
  color: var(--color-accent);    /* default: red                */
  line-height: 1;
  transition: color 0.4s ease;   /* smooth colour change        */
}

/* Applied by JS when score >= 90 % */
.score__value--good {
  color: var(--color-correct);   /* green                       */
}

.score__label {
  display: block;
  font-size: 0.8rem;
  color: var(--color-text-muted);
  margin-top: 6px;
}

/* ── Secondary button (Try Again) ──────────────────────────── */
.btn-secondary {
  display: block;
  width: 100%;
  padding: 14px;
  border: 1.5px solid var(--color-accent);
  border-radius: var(--radius-input);
  background: transparent;
  color: var(--color-accent);
  font-family: var(--font-ui);
  font-size: 0.9rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  cursor: pointer;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  transition: background var(--transition), color var(--transition);
}

.btn-secondary:hover,
.btn-secondary:active {
  background: var(--color-accent);
  color: #fff;
}

/* ── Footer ────────────────────────────────────────────────── */
.footer {
  text-align: center;
  padding: 24px 0 8px;
  font-size: 0.72rem;
  color: var(--color-text-muted);
  letter-spacing: 0.03em;
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.footer__author {
  color: var(--color-text);
  font-weight: 600;
}

/* ── Utility ────────────────────────────────────────────────── */
[hidden] { display: none !important; }