/* TiengTrungOnline.vn - Main CSS v1.0 */
:root {
  --tto-red: #C62828;
  --tto-red-light: #FFEBEE;
  --tto-red-dark: #B71C1C;
  --tto-blue: #1565C0;
  --tto-blue-light: #E3F2FD;
  --tto-green: #2E7D32;
  --tto-green-light: #E8F5E9;
  --tto-gold: #F9A825;
  --tto-bg: #f9f7f4;
  --tto-card: #ffffff;
  --tto-border: #e8e4de;
  --tto-text: #1a1a2e;
  --tto-muted: #666;
  --tto-radius: 12px;
  --tto-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

/* Reset */
.tto-wrap *, .tto-wrap *::before, .tto-wrap *::after { box-sizing: border-box; }
.tto-wrap { font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif; color: var(--tto-text); line-height: 1.6; }

/* --- VOCAB GRID --- */
.tto-vocab-wrap { padding: 1rem 0; }
.tto-search-bar { display: flex; gap: 10px; margin-bottom: 1rem; flex-wrap: wrap; align-items: center; }
.tto-search-bar input { flex: 1; min-width: 200px; padding: 10px 14px; border: 1px solid var(--tto-border); border-radius: 8px; font-size: 14px; }
.tto-hsk-filter { display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 1rem; }
.tto-hsk-filter button { padding: 5px 14px; border: 1px solid var(--tto-border); border-radius: 20px; background: #fff; cursor: pointer; font-size: 13px; transition: all .15s; }
.tto-hsk-filter button.active, .tto-hsk-filter button:hover { background: var(--tto-red); color: #fff; border-color: var(--tto-red); }
.tto-vocab-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 12px; }
.tto-word-card { background: var(--tto-card); border: 1px solid var(--tto-border); border-radius: var(--tto-radius); padding: 16px 12px; text-align: center; cursor: pointer; transition: all .2s; }
.tto-word-card:hover { border-color: var(--tto-red); transform: translateY(-2px); box-shadow: var(--tto-shadow); }
.tto-hanzi { font-size: 38px; color: var(--tto-red); margin-bottom: 6px; line-height: 1.2; }
.tto-pinyin { font-size: 14px; color: var(--tto-blue); font-style: italic; margin-bottom: 4px; }
.tto-meaning { font-size: 13px; color: var(--tto-muted); }
.tto-word-meta { margin-top: 8px; display: flex; gap: 4px; justify-content: center; flex-wrap: wrap; }
.tto-badge { display: inline-block; font-size: 10px; padding: 2px 8px; border-radius: 20px; font-weight: 600; }
.tto-badge-hsk1 { background: #E8F5E9; color: #1B5E20; }
.tto-badge-hsk2 { background: #E3F2FD; color: #0D47A1; }
.tto-badge-hsk3 { background: #FFF3E0; color: #BF360C; }
.tto-badge-hsk4 { background: #F3E5F5; color: #4A148C; }
.tto-badge-hsk5 { background: #FCE4EC; color: #880E4F; }
.tto-tag { font-size: 11px; padding: 2px 7px; background: #f5f3ef; border-radius: 20px; color: var(--tto-muted); }

/* Tone colors */
.t1 { color: #E53935; }
.t2 { color: #43A047; }
.t3 { color: #1565C0; }
.t4 { color: #6A1B9A; }
.t5 { color: #757575; }

/* --- FLASHCARD --- */
.tto-flashcard-wrap { max-width: 520px; margin: 0 auto; }
.tto-fc-progress { display: flex; align-items: center; gap: 10px; margin-bottom: 1rem; font-size: 13px; color: var(--tto-muted); }
.tto-progress-bar { flex: 1; height: 6px; background: #f0ede8; border-radius: 10px; overflow: hidden; }
.tto-progress-fill { height: 100%; background: var(--tto-red); border-radius: 10px; transition: width .4s ease; }
.tto-fc-card { background: var(--tto-card); border: 1px solid var(--tto-border); border-radius: 16px; min-height: 220px; display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 2rem; text-align: center; cursor: pointer; transition: box-shadow .2s; position: relative; margin-bottom: 1rem; }
.tto-fc-card:hover { box-shadow: var(--tto-shadow); }
.tto-fc-card.revealed { background: #fdfbf7; }
.tto-fc-hanzi { font-size: 60px; color: var(--tto-red); line-height: 1.1; margin-bottom: 8px; }
.tto-fc-pinyin { font-size: 20px; color: var(--tto-blue); font-style: italic; margin-bottom: 8px; }
.tto-fc-meaning { font-size: 18px; color: var(--tto-text); display: none; }
.revealed .tto-fc-meaning { display: block; }
.tto-fc-hint { position: absolute; bottom: 12px; font-size: 12px; color: #bbb; }
.tto-fc-tts { position: absolute; top: 12px; right: 12px; background: none; border: none; font-size: 22px; cursor: pointer; }
.tto-fc-hsk { position: absolute; top: 12px; left: 12px; }
.tto-fc-controls { display: flex; gap: 10px; justify-content: center; }
.tto-btn { display: inline-flex; align-items: center; gap: 6px; padding: 10px 20px; border: 1px solid var(--tto-border); border-radius: 8px; background: #fff; cursor: pointer; font-size: 14px; transition: all .15s; }
.tto-btn:hover { background: #f9f7f4; }
.tto-btn-wrong { border-color: #E53935; color: #E53935; }
.tto-btn-wrong:hover { background: var(--tto-red-light); }
.tto-btn-correct { border-color: #43A047; color: #43A047; }
.tto-btn-correct:hover { background: var(--tto-green-light); }
.tto-btn-primary { background: var(--tto-red); color: #fff; border-color: var(--tto-red); }
.tto-btn-primary:hover { background: var(--tto-red-dark); }

/* --- GRAMMAR --- */
.tto-grammar-wrap { }
.tto-grammar-item { background: var(--tto-card); border: 1px solid var(--tto-border); border-radius: var(--tto-radius); padding: 1rem 1.25rem; margin-bottom: 12px; }
.tto-grammar-pattern { font-size: 16px; font-weight: 600; color: var(--tto-red); margin-bottom: 6px; }
.tto-grammar-explanation { font-size: 14px; color: var(--tto-muted); margin-bottom: 10px; }
.tto-grammar-example { background: #faf9f6; border-left: 3px solid var(--tto-red); padding: 8px 12px; border-radius: 0 8px 8px 0; margin-bottom: 6px; }
.tto-grammar-example .zh { font-size: 16px; margin-bottom: 3px; }
.tto-grammar-example .py { font-size: 13px; color: var(--tto-blue); font-style: italic; }
.tto-grammar-example .vi { font-size: 13px; color: var(--tto-muted); }

/* --- DIALOGUE --- */
.tto-dialogue-wrap { }
.tto-dialogue-header { display: flex; align-items: center; gap: 10px; margin-bottom: 1rem; padding-bottom: 10px; border-bottom: 1px solid var(--tto-border); }
.tto-dialogue-title { font-size: 16px; font-weight: 600; }
.tto-dialogue-meta { font-size: 12px; color: var(--tto-muted); }
.tto-dialogue-line { padding: 10px 14px; border-radius: 0 10px 10px 0; margin-bottom: 10px; border-left: 3px solid var(--tto-red); background: #faf9f6; }
.tto-dialogue-line.student { border-left-color: var(--tto-blue); background: #f0f4ff; }
.tto-dialogue-speaker { font-size: 11px; color: var(--tto-muted); font-weight: 600; margin-bottom: 3px; text-transform: uppercase; letter-spacing: .5px; }
.tto-dialogue-zh { font-size: 16px; margin-bottom: 3px; }
.tto-dialogue-py { font-size: 13px; color: var(--tto-blue); font-style: italic; }
.tto-dialogue-vi { font-size: 13px; color: var(--tto-muted); }
.tto-tts-inline { background: none; border: none; cursor: pointer; font-size: 16px; vertical-align: middle; margin-left: 6px; }

/* --- STROKE WRITING --- */
.tto-write-wrap { }
.tto-char-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(56px, 1fr)); gap: 8px; margin-bottom: 1rem; }
.tto-char-btn { aspect-ratio: 1; border: 1px solid var(--tto-border); border-radius: 8px; background: #fff; font-size: 26px; cursor: pointer; display: flex; align-items: center; justify-content: center; color: var(--tto-muted); transition: all .15s; }
.tto-char-btn:hover, .tto-char-btn.active { border-color: var(--tto-red); color: var(--tto-red); background: var(--tto-red-light); }
.tto-stroke-canvas { background: #fff; border: 1px solid var(--tto-border); border-radius: var(--tto-radius); aspect-ratio: 1; max-width: 280px; margin: 0 auto 1rem; display: flex; align-items: center; justify-content: center; position: relative; overflow: hidden; }
.tto-stroke-guide { font-size: 140px; color: var(--tto-red); opacity: .9; user-select: none; }
.tto-stroke-bg { position: absolute; font-size: 140px; color: rgba(198,40,40,0.06); }
/* Grid lines for writing practice */
.tto-stroke-canvas::before, .tto-stroke-canvas::after { content: ''; position: absolute; background: #f0ede8; }
.tto-stroke-canvas::before { width: 1px; top: 0; bottom: 0; left: 50%; }
.tto-stroke-canvas::after { height: 1px; left: 0; right: 0; top: 50%; }
.tto-char-info { background: #faf9f6; border-radius: 8px; padding: 12px; font-size: 13px; margin-top: .5rem; }

/* --- QUIZ --- */
.tto-quiz-wrap { max-width: 600px; }
.tto-quiz-q { font-size: 18px; font-weight: 500; margin-bottom: 1rem; }
.tto-quiz-opts { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-bottom: 1rem; }
.tto-quiz-opt { padding: 12px; border: 1px solid var(--tto-border); border-radius: 8px; background: #fff; cursor: pointer; font-size: 14px; text-align: center; transition: all .15s; }
.tto-quiz-opt:hover { border-color: var(--tto-red); background: var(--tto-red-light); }
.tto-quiz-opt.correct { background: var(--tto-green-light); border-color: #43A047; color: #1B5E20; font-weight: 600; pointer-events: none; }
.tto-quiz-opt.wrong { background: var(--tto-red-light); border-color: var(--tto-red); color: var(--tto-red); pointer-events: none; }
.tto-quiz-feedback { padding: 12px; border-radius: 8px; font-size: 14px; margin-bottom: 1rem; }
.tto-quiz-feedback.correct { background: var(--tto-green-light); color: var(--tto-green); }
.tto-quiz-feedback.wrong { background: var(--tto-red-light); color: var(--tto-red); }

/* --- ANALYZE --- */
.tto-analyze-wrap textarea { width: 100%; padding: 12px; border: 1px solid var(--tto-border); border-radius: 8px; font-size: 16px; min-height: 80px; resize: vertical; margin-bottom: 10px; font-family: inherit; }
.tto-seg-result { line-height: 3; margin: 1rem 0; }
.tto-seg-word { display: inline-block; margin: 3px; padding: 3px 10px; border-radius: 20px; font-size: 15px; cursor: help; border: 1px solid; }
.tto-seg-noun { background: #E3F2FD; color: #0D47A1; border-color: #90CAF9; }
.tto-seg-verb { background: #E8F5E9; color: #1B5E20; border-color: #A5D6A7; }
.tto-seg-adjective { background: #FFF3E0; color: #BF360C; border-color: #FFCC80; }
.tto-seg-general { background: #F3E5F5; color: #4A148C; border-color: #CE93D8; }
.tto-seg-unknown { background: #F5F5F5; color: #666; border-color: #ddd; }
.tto-analyze-info { font-size: 13px; color: var(--tto-muted); border-top: 1px solid var(--tto-border); padding-top: 10px; margin-top: 10px; }

/* --- DASHBOARD --- */
.tto-stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 12px; margin-bottom: 1.5rem; }
.tto-stat-card { background: var(--tto-card); border: 1px solid var(--tto-border); border-radius: var(--tto-radius); padding: 1rem; text-align: center; }
.tto-stat-num { font-size: 28px; font-weight: 700; color: var(--tto-red); }
.tto-stat-label { font-size: 12px; color: var(--tto-muted); margin-top: 4px; }
.tto-hsk-progress { margin-bottom: 1.5rem; }
.tto-hsk-row { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; font-size: 13px; }
.tto-hsk-row label { width: 50px; color: var(--tto-muted); }
.tto-hsk-row .tto-progress-bar { flex: 1; height: 10px; }
.tto-hsk-row span { width: 60px; text-align: right; color: var(--tto-muted); font-size: 12px; }

/* --- RESPONSIVE --- */
@media (max-width: 600px) {
  .tto-vocab-grid { grid-template-columns: repeat(auto-fill, minmax(130px, 1fr)); }
  .tto-quiz-opts { grid-template-columns: 1fr; }
  .tto-fc-hanzi { font-size: 48px; }
  .tto-stats-grid { grid-template-columns: repeat(2, 1fr); }
}

/* --- LOADING SPINNER --- */
.tto-loading { display: flex; align-items: center; justify-content: center; padding: 2rem; }
.tto-spinner { width: 32px; height: 32px; border: 3px solid var(--tto-border); border-top-color: var(--tto-red); border-radius: 50%; animation: tto-spin .7s linear infinite; }
@keyframes tto-spin { to { transform: rotate(360deg); } }

/* --- NOTICE --- */
.tto-notice { padding: 10px 14px; border-radius: 8px; font-size: 13px; margin-bottom: 10px; }
.tto-notice-success { background: var(--tto-green-light); color: var(--tto-green); border: 1px solid #A5D6A7; }
.tto-notice-error { background: var(--tto-red-light); color: var(--tto-red); border: 1px solid #FFCDD2; }