*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg: #0a0a1a;
  --card-bg: rgba(255,255,255,0.04);
  --card-border: rgba(255,255,255,0.08);
  --text-primary: #f0f0ff;
  --text-secondary: #9999cc;
  --accent: #7c6fff;
  --accent2: #ff6fa8;
  --accent3: #6fdfff;
  --vowel-color: #ff6fa8;
  --consonant-color: #7c6fff;
  --diph-color: #a78bfa;
  --radius: 20px;
  --radius-sm: 12px;
}

html { scroll-behavior: smooth; }
body {
  font-family: 'Outfit', sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
}

/* ── ORBS ── */
.bg-orbs { position: fixed; inset: 0; pointer-events: none; z-index: 0; overflow: hidden; }
.orb { position: absolute; border-radius: 50%; filter: blur(80px); opacity: 0.16; animation: float 12s ease-in-out infinite; }
.orb-1 { width: 500px; height: 500px; background: radial-gradient(circle,#7c6fff,transparent); top:-100px; left:-100px; }
.orb-2 { width: 400px; height: 400px; background: radial-gradient(circle,#ff6fa8,transparent); top:40%; right:-80px; animation-delay:4s; }
.orb-3 { width: 350px; height: 350px; background: radial-gradient(circle,#6fdfff,transparent); bottom:-80px; left:40%; animation-delay:8s; }
@keyframes float { 0%,100%{transform:translateY(0) scale(1)} 50%{transform:translateY(-30px) scale(1.05)} }

/* ── HERO ── */
.hero { position:relative; z-index:1; padding:52px 20px 20px; text-align:center; }
.hero-content { max-width:700px; margin:0 auto; }
.badge {
  display:inline-block; background:rgba(124,111,255,0.18); border:1px solid rgba(124,111,255,0.4);
  color:#b0a0ff; font-size:0.82rem; font-weight:600; padding:5px 16px;
  border-radius:50px; letter-spacing:0.5px; margin-bottom:16px;
}
h1 {
  font-family:'Baloo 2',cursive; font-size:clamp(2rem,5.5vw,3.6rem); font-weight:800;
  line-height:1.1; margin-bottom:10px; letter-spacing:-1px;
}
.gradient-text {
  background:linear-gradient(135deg,#7c6fff,#ff6fa8,#6fdfff);
  -webkit-background-clip:text; -webkit-text-fill-color:transparent; background-clip:text;
  animation:gradShift 4s ease infinite; background-size:200% 200%;
}
@keyframes gradShift { 0%{background-position:0% 50%} 50%{background-position:100% 50%} 100%{background-position:0% 50%} }
.subtitle { color:var(--text-secondary); font-size:1rem; margin-bottom:0; }

/* ── TAB BAR ── */
.tab-bar {
  position:relative; z-index:1; display:flex; justify-content:center; gap:12px;
  padding:24px 20px 0; flex-wrap:wrap;
}
.tab-btn {
  display:flex; align-items:center; gap:8px;
  background:rgba(255,255,255,0.05); border:1px solid rgba(255,255,255,0.1);
  color:var(--text-secondary); padding:11px 28px;
  border-radius:50px; cursor:pointer; font-family:'Outfit',sans-serif;
  font-size:1rem; font-weight:700; transition:all 0.3s ease;
}
.tab-btn .tab-icon { font-size:1.1rem; }
.tab-btn:hover { border-color:var(--accent); color:var(--text-primary); }
.tab-btn.active {
  background:linear-gradient(135deg,var(--accent),var(--accent2));
  border-color:transparent; color:#fff;
  box-shadow:0 4px 24px rgba(124,111,255,0.45);
}

/* ── MAIN ── */
main { position:relative; z-index:1; padding:20px 16px 60px; max-width:1200px; margin:0 auto; }
.panel { }
.hidden { display:none !important; }

/* ── FILTER BAR ── */
.filter-bar, .phoneme-filter-bar {
  display:flex; gap:10px; justify-content:center; flex-wrap:wrap; margin-bottom:28px;
}
.filter-btn {
  background:rgba(255,255,255,0.05); border:1px solid rgba(255,255,255,0.1);
  color:var(--text-secondary); padding:9px 20px; border-radius:50px;
  cursor:pointer; font-family:'Outfit',sans-serif; font-size:0.9rem; font-weight:600;
  transition:all 0.3s ease;
}
.filter-btn:hover { border-color:var(--accent); color:var(--text-primary); }
.filter-btn.active {
  background:linear-gradient(135deg,var(--accent),var(--accent2));
  border-color:transparent; color:#fff; box-shadow:0 4px 16px rgba(124,111,255,0.38);
}

/* ────────────────────────────────── */
/*  26 CHỮ CÁI                        */
/* ────────────────────────────────── */
.alphabet-grid {
  display:grid; grid-template-columns:repeat(auto-fill,minmax(155px,1fr)); gap:14px;
}
.letter-card {
  background:var(--card-bg); border:1px solid var(--card-border); border-radius:var(--radius);
  padding:22px 14px 14px; text-align:center; position:relative; cursor:pointer;
  transition:all 0.35s cubic-bezier(0.34,1.56,0.64,1); backdrop-filter:blur(10px);
  overflow:hidden; animation:cardIn 0.4s ease both;
}
@keyframes cardIn { from{opacity:0;transform:translateY(20px) scale(0.95)} to{opacity:1;transform:none} }
.letter-card:hover { transform:translateY(-7px) scale(1.04); border-color:rgba(124,111,255,0.5); box-shadow:0 14px 36px rgba(0,0,0,0.5); }
.letter-card.vowel-card:hover { border-color:rgba(255,111,168,0.5); }

.card-type-badge {
  position:absolute; top:9px; left:11px; font-size:0.58rem; font-weight:700;
  letter-spacing:0.4px; padding:2px 7px; border-radius:50px; text-transform:uppercase;
}
.vowel-badge { background:rgba(255,111,168,0.18); color:#ff6fa8; border:1px solid rgba(255,111,168,0.3); }
.consonant-badge { background:rgba(124,111,255,0.18); color:#b0a0ff; border:1px solid rgba(124,111,255,0.3); }

.letter-upper {
  font-family:'Baloo 2',cursive; font-size:3.4rem; font-weight:800; line-height:1;
  background:linear-gradient(135deg,#fff,rgba(255,255,255,0.55));
  -webkit-background-clip:text; -webkit-text-fill-color:transparent; background-clip:text; display:block;
}
.letter-lower {
  font-family:'Baloo 2',cursive; font-size:1.9rem; font-weight:600;
  color:var(--text-secondary); display:block; margin-top:-4px;
}
.letter-phonetic { font-size:0.76rem; color:var(--accent3); margin:7px 0 3px; font-weight:500; letter-spacing:0.4px; }
.letter-reading { font-size:0.7rem; color:var(--text-secondary); margin-bottom:9px; }

/* ────────────────────────────────── */
/*  44 ÂM VỊ                          */
/* ────────────────────────────────── */
.phoneme-section-title {
  font-family:'Baloo 2',cursive; font-size:1.1rem; font-weight:800;
  color:var(--text-secondary); letter-spacing:0.5px; text-transform:uppercase;
  margin:28px 0 14px 4px; display:flex; align-items:center; gap:10px;
}
.phoneme-section-title::after {
  content:''; flex:1; height:1px; background:rgba(255,255,255,0.08);
}

.phoneme-grid {
  display:grid; grid-template-columns:repeat(auto-fill,minmax(170px,1fr)); gap:13px;
}

.phoneme-card {
  background:var(--card-bg); border:1px solid var(--card-border);
  border-radius:var(--radius); padding:20px 14px 13px;
  position:relative; cursor:default; transition:all 0.3s ease;
  backdrop-filter:blur(10px); animation:cardIn 0.4s ease both; overflow:hidden;
}
.phoneme-card:hover { transform:translateY(-5px); box-shadow:0 12px 30px rgba(0,0,0,0.45); }

/* accent strip trên cùng */
.phoneme-card::before {
  content:''; position:absolute; top:0; left:0; right:0; height:3px; border-radius:var(--radius) var(--radius) 0 0;
}
.phoneme-card.mono::before  { background:linear-gradient(90deg,#6fdfff,#3bb8f5); }
.phoneme-card.diph::before  { background:linear-gradient(90deg,#a78bfa,#ff6fa8); }
.phoneme-card.conso::before { background:linear-gradient(90deg,#7c6fff,#a78bfa); }

.phoneme-card.mono:hover  { border-color:rgba(111,223,255,0.4); }
.phoneme-card.diph:hover  { border-color:rgba(167,139,250,0.4); }
.phoneme-card.conso:hover { border-color:rgba(124,111,255,0.4); }

.ph-badge {
  position:absolute; top:10px; right:11px; font-size:0.56rem; font-weight:700;
  letter-spacing:0.4px; padding:2px 7px; border-radius:50px; text-transform:uppercase;
}
.ph-badge.mono  { background:rgba(111,223,255,0.15); color:#6fdfff;  border:1px solid rgba(111,223,255,0.3); }
.ph-badge.diph  { background:rgba(167,139,250,0.15); color:#a78bfa;  border:1px solid rgba(167,139,250,0.3); }
.ph-badge.conso { background:rgba(124,111,255,0.15); color:#b0a0ff;  border:1px solid rgba(124,111,255,0.3); }

.ph-symbol {
  font-family:'Baloo 2',cursive; font-size:2.6rem; font-weight:800; line-height:1;
  display:block; margin-top:4px; margin-bottom:6px;
}
.ph-symbol.mono  { color:#6fdfff; }
.ph-symbol.diph  { color:#c4b5fd; }
.ph-symbol.conso { background:linear-gradient(135deg,#fff,rgba(255,255,255,0.6)); -webkit-background-clip:text; -webkit-text-fill-color:transparent; background-clip:text; }

.ph-viet { font-size:0.78rem; font-weight:700; color:#ffd580; margin-bottom:3px; }
.ph-desc { font-size:0.7rem; color:var(--text-secondary); margin-bottom:4px; line-height:1.4; }
.ph-examples {
  font-size:0.68rem; color:rgba(255,255,255,0.45);
  border-top:1px solid rgba(255,255,255,0.06); padding-top:5px; margin-top:4px;
  line-height:1.5;
}
.ph-examples em { color:rgba(255,255,255,0.7); font-style:normal; font-weight:600; }

/* ── SPEAK BTN (dùng chung) ── */
.speak-btn {
  display:flex; align-items:center; justify-content:center; gap:5px;
  width:100%; background:rgba(255,255,255,0.06); border:1px solid rgba(255,255,255,0.12);
  color:var(--text-primary); border-radius:10px; padding:7px 10px;
  cursor:pointer; font-family:'Outfit',sans-serif; font-size:0.78rem; font-weight:600;
  transition:all 0.3s ease; margin-top:8px;
}
.speak-btn:hover { background:linear-gradient(135deg,rgba(124,111,255,0.28),rgba(255,111,168,0.18)); border-color:rgba(124,111,255,0.4); }
.speak-btn:active { transform:scale(0.96); }
.speak-btn.speaking { background:linear-gradient(135deg,rgba(124,111,255,0.4),rgba(255,111,168,0.3)); border-color:rgba(124,111,255,0.6); animation:speakPulse 0.7s ease infinite; }
@keyframes speakPulse { 0%,100%{box-shadow:0 0 0 0 rgba(124,111,255,0.4)} 50%{box-shadow:0 0 0 7px rgba(124,111,255,0)} }
.speak-icon { font-size:0.95rem; }

/* ── MODAL ── */
.modal-overlay {
  position:fixed; inset:0; z-index:100; background:rgba(0,0,0,0.75);
  backdrop-filter:blur(8px); display:flex; align-items:center; justify-content:center;
  padding:20px; opacity:0; pointer-events:none; transition:opacity 0.3s ease;
}
.modal-overlay.open { opacity:1; pointer-events:all; }
.modal-card {
  background:linear-gradient(135deg,rgba(20,20,40,0.98),rgba(30,15,50,0.98));
  border:1px solid rgba(124,111,255,0.3); border-radius:28px; padding:38px 30px 30px;
  max-width:370px; width:100%; text-align:center; position:relative;
  box-shadow:0 32px 80px rgba(0,0,0,0.6);
  transform:scale(0.85) translateY(20px); transition:transform 0.35s cubic-bezier(0.34,1.56,0.64,1);
}
.modal-overlay.open .modal-card { transform:scale(1) translateY(0); }
.modal-close {
  position:absolute; top:13px; right:13px; background:rgba(255,255,255,0.08);
  border:1px solid rgba(255,255,255,0.12); color:var(--text-secondary); width:30px; height:30px;
  border-radius:50%; cursor:pointer; font-size:0.82rem; display:flex; align-items:center; justify-content:center; transition:all 0.2s;
}
.modal-close:hover { background:rgba(255,80,80,0.2); color:#ff6060; }
.modal-letter-display { display:flex; align-items:baseline; justify-content:center; gap:14px; margin-bottom:10px; }
.modal-letter-upper { font-family:'Baloo 2',cursive; font-size:5.5rem; font-weight:800; line-height:1; background:linear-gradient(135deg,#fff 30%,#a0a0ff); -webkit-background-clip:text; -webkit-text-fill-color:transparent; background-clip:text; }
.modal-letter-lower { font-family:'Baloo 2',cursive; font-size:3.2rem; font-weight:600; color:var(--text-secondary); }
.modal-name { font-size:1.05rem; font-weight:700; color:var(--text-primary); margin-bottom:5px; }
.modal-phonetic { font-size:1.3rem; color:var(--accent3); font-weight:600; background:rgba(111,223,255,0.1); border:1px solid rgba(111,223,255,0.2); display:inline-block; padding:3px 14px; border-radius:8px; margin:5px 0; }
.modal-reading { font-size:0.95rem; color:#ffd580; font-weight:600; margin:7px 0; }
.modal-type { display:inline-block; font-size:0.72rem; font-weight:700; padding:3px 13px; border-radius:50px; margin:7px 0 14px; letter-spacing:0.5px; text-transform:uppercase; }
.modal-type.vowel { background:rgba(255,111,168,0.15); color:#ff6fa8; border:1px solid rgba(255,111,168,0.3); }
.modal-type.consonant { background:rgba(124,111,255,0.15); color:#b0a0ff; border:1px solid rgba(124,111,255,0.3); }
.modal-example { background:rgba(255,255,255,0.04); border:1px solid rgba(255,255,255,0.08); border-radius:11px; padding:10px 14px; margin-bottom:18px; text-align:left; }
.example-label { font-size:0.72rem; color:var(--text-secondary); font-weight:600; text-transform:uppercase; letter-spacing:0.5px; display:block; margin-bottom:3px; }
.example-words { font-size:0.9rem; color:var(--text-primary); font-weight:500; }
.modal-speak-btn {
  display:flex; align-items:center; justify-content:center; gap:10px; width:100%;
  background:linear-gradient(135deg,var(--accent),var(--accent2)); border:none; color:#fff;
  border-radius:13px; padding:13px 22px; cursor:pointer; font-family:'Outfit',sans-serif;
  font-size:0.97rem; font-weight:700; transition:all 0.3s ease; box-shadow:0 8px 22px rgba(124,111,255,0.38);
}
.modal-speak-btn:hover { transform:translateY(-2px); box-shadow:0 12px 30px rgba(124,111,255,0.5); }
.modal-speak-btn:active { transform:scale(0.97); }
.modal-speak-btn.speaking { animation:speakPulse 0.7s ease infinite; }
.modal-speak-btn .speak-icon { font-size:1.1rem; }

/* ── FOOTER ── */
footer { position:relative; z-index:1; text-align:center; padding:22px 20px; color:rgba(255,255,255,0.22); font-size:0.82rem; border-top:1px solid rgba(255,255,255,0.05); }

/* ── RESPONSIVE ── */
@media(max-width:640px){
  .alphabet-grid { grid-template-columns:repeat(3,1fr); gap:9px; }
  .phoneme-grid  { grid-template-columns:repeat(2,1fr); gap:9px; }
  .letter-upper  { font-size:2.7rem; }
  .letter-lower  { font-size:1.6rem; }
  h1 { font-size:2rem; }
  .tab-btn { padding:9px 18px; font-size:0.9rem; }
}
@media(max-width:380px){
  .alphabet-grid { grid-template-columns:repeat(2,1fr); }
  .phoneme-grid  { grid-template-columns:1fr 1fr; }
}

/* ══════════════════════════════════════════════
   QUY TẮC PHÁT ÂM — RULES TAB
══════════════════════════════════════════════ */

.rules-filter-bar {
  display:flex; gap:10px; justify-content:center; flex-wrap:wrap; margin-bottom:28px;
}

/* ── GROUP SECTION ── */
.rule-group {
  margin-bottom: 36px;
}
.rule-group-title {
  font-family: "Baloo 2", cursive;
  font-size: 1.15rem; font-weight: 800;
  color: var(--text-secondary); letter-spacing: 0.5px;
  display: flex; align-items: center; gap: 10px;
  margin-bottom: 16px; padding-bottom: 8px;
  border-bottom: 1px solid rgba(255,255,255,0.07);
}
.rule-group-title::after { content:""; flex:1; height:1px; background:rgba(255,255,255,0.05); }

/* ── LETTER RULE BLOCK ── */
.rule-letter-block {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 18px; overflow: hidden;
  margin-bottom: 14px;
  animation: cardIn 0.4s ease both;
}

.rule-letter-header {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.rule-letter-symbol {
  font-family: "Baloo 2", cursive;
  font-size: 2rem; font-weight: 800; line-height: 1;
  min-width: 44px; text-align: center;
}
.rule-letter-block.vowel   .rule-letter-symbol { color: #ff6fa8; }
.rule-letter-block.consonant .rule-letter-symbol { color: #b0a0ff; }
.rule-letter-block.digraph .rule-letter-symbol { color: #c4b5fd; font-size: 1.4rem; }
.rule-letter-block.silent  .rule-letter-symbol { color: #888; }

.rule-letter-name {
  font-size: 0.82rem; font-weight: 600;
  color: var(--text-secondary); text-transform: uppercase; letter-spacing: 0.6px;
}
.rule-letter-tag {
  margin-left: auto; font-size: 0.6rem; font-weight: 700; padding: 3px 10px;
  border-radius: 50px; text-transform: uppercase; letter-spacing: 0.5px;
}
.tag-vowel    { background: rgba(255,111,168,0.15); color: #ff6fa8; border: 1px solid rgba(255,111,168,0.3); }
.tag-consonant{ background: rgba(124,111,255,0.15); color: #b0a0ff; border: 1px solid rgba(124,111,255,0.3); }
.tag-digraph  { background: rgba(167,139,250,0.15); color: #c4b5fd; border: 1px solid rgba(167,139,250,0.3); }
.tag-silent   { background: rgba(120,120,120,0.15); color: #999;    border: 1px solid rgba(120,120,120,0.3); }

/* ── RULE CASES ── */
.rule-cases { padding: 6px 0; }

.rule-case {
  display: grid;
  grid-template-columns: 1fr auto auto;
  align-items: start;
  gap: 10px;
  padding: 12px 20px;
  border-bottom: 1px solid rgba(255,255,255,0.04);
  transition: background 0.2s;
}
.rule-case:last-child { border-bottom: none; }
.rule-case:hover { background: rgba(255,255,255,0.02); }

.rule-case-info { flex: 1; }
.rule-case-when {
  font-size: 0.82rem; color: var(--text-secondary); font-weight: 500;
  margin-bottom: 3px;
}
.rule-case-when strong { color: var(--text-primary); font-weight: 700; }

.rule-case-sound-row {
  display: flex; align-items: center; gap: 8px; margin-bottom: 5px;
}
.rule-sound-badge {
  font-size: 1rem; font-weight: 700; color: var(--accent3);
  background: rgba(111,223,255,0.1); border: 1px solid rgba(111,223,255,0.2);
  padding: 1px 10px; border-radius: 6px; font-family: monospace; letter-spacing: 0.5px;
}
.rule-sound-badge.silent { color: #888; background: rgba(128,128,128,0.1); border-color: rgba(128,128,128,0.2); }
.rule-viet { font-size: 0.78rem; color: #ffd580; font-weight: 600; }
.rule-tip { font-size: 0.7rem; color: rgba(255,255,255,0.35); margin-top: 1px; font-style: italic; }

/* ── EXAMPLE WORD BUTTONS ── */
.rule-examples {
  display: flex; flex-wrap: wrap; gap: 6px;
  grid-column: 1 / -1; margin-top: 6px;
}
.ex-word-btn {
  background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-primary); font-family: "Outfit", sans-serif;
  font-size: 0.78rem; font-weight: 600;
  padding: 4px 12px; border-radius: 8px; cursor: pointer;
  transition: all 0.25s ease; display: flex; align-items: center; gap: 4px;
}
.ex-word-btn:hover {
  background: rgba(124,111,255,0.2); border-color: rgba(124,111,255,0.4);
  transform: translateY(-1px);
}
.ex-word-btn:active { transform: scale(0.95); }
.ex-word-btn.speaking {
  background: linear-gradient(135deg, rgba(124,111,255,0.4), rgba(255,111,168,0.3));
  border-color: rgba(124,111,255,0.6);
  animation: speakPulse 0.7s ease infinite;
}
.ex-word-icon { font-size: 0.75rem; opacity: 0.7; }

/* highlight chữ cái trong từ ví dụ */
.ex-highlight { color: #ffd580; }

/* responsive */
@media(max-width:640px) {
  .rule-case {
    grid-template-columns: 1fr;
  }
  .rule-letter-header { padding: 12px 14px; gap: 10px; }
  .rule-cases { padding: 4px 0; }
  .rule-case { padding: 10px 14px; }
}

/* ══════════════════════════════════════════════
   TỪ VỰNG THI — VOCAB TAB
══════════════════════════════════════════════ */

/* ── EXAM SUBTAB ── */
.exam-subtabs {
  display: flex; justify-content: center; gap: 12px;
  margin-bottom: 20px; flex-wrap: wrap;
}
.exam-tab {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 28px; border-radius: 50px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 1rem; font-weight: 700;
  border: 2px solid transparent; transition: all 0.3s ease;
}
.exam-tab.pte {
  background: rgba(99,102,241,0.1); border-color: rgba(99,102,241,0.3); color: #818cf8;
}
.exam-tab.pte:hover, .exam-tab.pte.active {
  background: linear-gradient(135deg,#6366f1,#8b5cf6);
  border-color: transparent; color: #fff;
  box-shadow: 0 4px 24px rgba(99,102,241,0.45);
}
.exam-tab.ielts {
  background: rgba(16,185,129,0.1); border-color: rgba(16,185,129,0.3); color: #34d399;
}
.exam-tab.ielts:hover, .exam-tab.ielts.active {
  background: linear-gradient(135deg,#10b981,#059669);
  border-color: transparent; color: #fff;
  box-shadow: 0 4px 24px rgba(16,185,129,0.45);
}

/* ── SCORE / BAND SELECTOR ── */
.score-selector {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 16px; padding: 18px 20px; margin-bottom: 20px;
}
.score-selector-title {
  font-size: 0.82rem; font-weight: 700; color: var(--text-secondary);
  text-transform: uppercase; letter-spacing: 0.6px; margin-bottom: 12px;
}
.score-presets {
  display: flex; flex-wrap: wrap; gap: 8px; align-items: center;
}
.score-preset-btn {
  padding: 7px 18px; border-radius: 50px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 0.85rem; font-weight: 700;
  border: 1px solid rgba(255,255,255,0.12); background: rgba(255,255,255,0.05);
  color: var(--text-secondary); transition: all 0.25s ease;
}
.score-preset-btn:hover { border-color: rgba(99,102,241,0.5); color: #a5b4fc; }
.score-preset-btn.active.pte-active {
  background: linear-gradient(135deg,#6366f1,#8b5cf6);
  border-color: transparent; color: #fff;
  box-shadow: 0 3px 12px rgba(99,102,241,0.4);
}
.score-preset-btn.active.ielts-active {
  background: linear-gradient(135deg,#10b981,#059669);
  border-color: transparent; color: #fff;
  box-shadow: 0 3px 12px rgba(16,185,129,0.4);
}
.score-divider { width: 1px; height: 28px; background: rgba(255,255,255,0.1); margin: 0 4px; }

.custom-score-wrap {
  display: flex; align-items: center; gap: 8px; margin-top: 12px;
}
.custom-score-wrap label { font-size: 0.8rem; color: var(--text-secondary); font-weight: 600; white-space: nowrap; }
.custom-score-input {
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.12);
  color: var(--text-primary); font-family: "Outfit", sans-serif;
  font-size: 0.9rem; font-weight: 700; padding: 6px 12px;
  border-radius: 8px; width: 80px; text-align: center; outline: none;
  transition: border-color 0.2s;
}
.custom-score-input:focus { border-color: rgba(99,102,241,0.5); }
.custom-score-btn {
  padding: 6px 16px; border-radius: 8px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 0.82rem; font-weight: 700;
  background: rgba(99,102,241,0.2); border: 1px solid rgba(99,102,241,0.4);
  color: #a5b4fc; transition: all 0.2s;
}
.custom-score-btn.ielts-btn { background: rgba(16,185,129,0.2); border-color: rgba(16,185,129,0.4); color: #6ee7b7; }
.custom-score-btn:hover { transform: translateY(-1px); }

/* ── TOPIC FILTER ── */
.topic-filter {
  display: flex; gap: 7px; flex-wrap: wrap; margin-bottom: 20px;
}
.topic-btn {
  padding: 5px 14px; border-radius: 50px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 0.78rem; font-weight: 600;
  background: rgba(255,255,255,0.04); border: 1px solid rgba(255,255,255,0.09);
  color: var(--text-secondary); transition: all 0.2s;
}
.topic-btn:hover { border-color: rgba(255,255,255,0.2); color: var(--text-primary); }
.topic-btn.active {
  background: rgba(255,255,255,0.1); border-color: rgba(255,255,255,0.25);
  color: var(--text-primary);
}

/* ── VOCAB STATS BAR ── */
.vocab-stats {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  margin-bottom: 20px; padding: 12px 18px;
  background: rgba(255,255,255,0.03); border: 1px solid rgba(255,255,255,0.06);
  border-radius: 12px;
}
.vocab-count {
  font-size: 0.85rem; color: var(--text-secondary); font-weight: 600;
}
.vocab-count strong { color: var(--text-primary); font-size: 1rem; }
.vocab-search {
  margin-left: auto;
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-primary); font-family: "Outfit", sans-serif;
  font-size: 0.85rem; padding: 7px 14px; border-radius: 8px;
  outline: none; width: 200px; transition: border-color 0.2s;
}
.vocab-search::placeholder { color: rgba(255,255,255,0.3); }
.vocab-search:focus { border-color: rgba(99,102,241,0.4); }

/* ── VOCAB GRID ── */
.vocab-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 14px;
}

/* ── VOCAB CARD ── */
.vocab-card {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 18px; padding: 18px 18px 14px;
  position: relative; overflow: hidden;
  transition: all 0.3s ease; animation: cardIn 0.4s ease both;
}
.vocab-card::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 3px;
  border-radius: 18px 18px 0 0;
}
.vocab-card.pte-card::before  { background: linear-gradient(90deg,#6366f1,#8b5cf6); }
.vocab-card.ielts-card::before { background: linear-gradient(90deg,#10b981,#059669); }
.vocab-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 12px 32px rgba(0,0,0,0.4);
}
.vocab-card.pte-card:hover  { border-color: rgba(99,102,241,0.35); }
.vocab-card.ielts-card:hover { border-color: rgba(16,185,129,0.35); }

/* Header row */
.vocab-card-top {
  display: flex; align-items: flex-start; justify-content: space-between;
  margin-bottom: 8px;
}
.vocab-word {
  font-family: "Baloo 2", cursive;
  font-size: 1.6rem; font-weight: 800; line-height: 1.1;
  color: var(--text-primary);
}
.vocab-badges { display: flex; flex-direction: column; align-items: flex-end; gap: 4px; }

/* ============================================================
   WORD TYPE BADGES — Compact professional
   ============================================================ */
.rv-type-badge,
.vocab-type-badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 0.62rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 2px 8px 2px 6px;
  border-radius: 20px;
  white-space: nowrap;
  font-family: "Outfit", sans-serif;
  transition: opacity 0.2s;
}
.rv-type-badge::before,
.vocab-type-badge::before {
  content: "";
  display: inline-block;
  width: 5px; height: 5px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* Danh từ — Amber */
.badge-noun {
  background: rgba(251,191,36,0.1);
  color: #d4a017;
  border: 1px solid rgba(251,191,36,0.25);
}
.badge-noun::before { background: #fbbf24; box-shadow: 0 0 4px #fbbf24; }

/* Động từ — Blue */
.badge-verb {
  background: rgba(99,102,241,0.1);
  color: #7eb3fa;
  border: 1px solid rgba(99,102,241,0.28);
}
.badge-verb::before { background: #6366f1; box-shadow: 0 0 4px #6366f1; }

/* Tính từ — Violet */
.badge-adj {
  background: rgba(139,92,246,0.1);
  color: #b39dfc;
  border: 1px solid rgba(139,92,246,0.28);
}
.badge-adj::before { background: #8b5cf6; box-shadow: 0 0 4px #8b5cf6; }

/* Trạng từ — Teal */
.badge-adv {
  background: rgba(20,184,166,0.1);
  color: #5eead4;
  border: 1px solid rgba(20,184,166,0.28);
}
.badge-adv::before { background: #14b8a6; box-shadow: 0 0 4px #14b8a6; }

/* Liên từ — Rose */
.badge-conj {
  background: rgba(244,114,182,0.1);
  color: #f472b6;
  border: 1px solid rgba(244,114,182,0.28);
}
.badge-conj::before { background: #f472b6; box-shadow: 0 0 4px #f472b6; }

/* Giới từ — Amber */
.badge-prep {
  background: rgba(245,158,11,0.1);
  color: #fbbf24;
  border: 1px solid rgba(245,158,11,0.28);
}
.badge-prep::before { background: #f59e0b; box-shadow: 0 0 4px #f59e0b; }

/* Mạo từ — Cyan */
.badge-art {
  background: rgba(6,182,212,0.1);
  color: #67e8f9;
  border: 1px solid rgba(6,182,212,0.28);
}
.badge-art::before { background: #06b6d4; box-shadow: 0 0 4px #06b6d4; }

/* Đại từ — Emerald */
.badge-pron {
  background: rgba(16,185,129,0.1);
  color: #6ee7b7;
  border: 1px solid rgba(16,185,129,0.28);
}
.badge-pron::before { background: #10b981; box-shadow: 0 0 4px #10b981; }

.rv-type-badge:hover, .vocab-type-badge:hover { opacity: 0.8; }


.vocab-level-badge {
  font-size: 0.62rem; font-weight: 800; padding: 2px 9px;
  border-radius: 50px; letter-spacing: 0.3px;
}
.vocab-level-badge.pte  { background: rgba(99,102,241,0.2); color: #a5b4fc; border: 1px solid rgba(99,102,241,0.35); }
.vocab-level-badge.ielts { background: rgba(16,185,129,0.2); color: #6ee7b7; border: 1px solid rgba(16,185,129,0.35); }

/* Phonetic */
.vocab-phonetic {
  font-size: 0.8rem; color: var(--accent3); font-weight: 500;
  letter-spacing: 0.3px; margin-bottom: 8px;
}

/* Meaning */
.vocab-meaning {
  font-size: 1rem; font-weight: 700; color: #ffd580;
  margin-bottom: 6px;
}

/* Example */
.vocab-example {
  font-size: 0.78rem; color: rgba(255,255,255,0.45);
  line-height: 1.5; margin-bottom: 10px; font-style: italic;
  border-left: 2px solid rgba(255,255,255,0.1); padding-left: 8px;
}

/* Topic tag */
.vocab-topic {
  display: inline-block; font-size: 0.6rem; font-weight: 700;
  padding: 2px 8px; border-radius: 50px; text-transform: uppercase;
  letter-spacing: 0.4px; background: rgba(255,255,255,0.06);
  color: rgba(255,255,255,0.4); border: 1px solid rgba(255,255,255,0.08);
  margin-bottom: 10px;
}

/* Bottom row */
.vocab-card-bottom {
  display: flex; align-items: center; gap: 8px;
}
.vocab-speak-btn {
  display: flex; align-items: center; gap: 5px;
  flex: 1; background: rgba(255,255,255,0.05);
  border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-primary); border-radius: 9px;
  padding: 7px 12px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 0.78rem; font-weight: 600;
  transition: all 0.25s ease;
}
.vocab-speak-btn:hover { background: rgba(99,102,241,0.2); border-color: rgba(99,102,241,0.4); }
.vocab-speak-btn.ielts:hover { background: rgba(16,185,129,0.2); border-color: rgba(16,185,129,0.4); }
.vocab-speak-btn.speaking { animation: speakPulse 0.7s ease infinite; }

/* Empty state */
.vocab-empty {
  text-align: center; padding: 60px 20px; color: var(--text-secondary);
}
.vocab-empty-icon { font-size: 3rem; margin-bottom: 12px; }
.vocab-empty-text { font-size: 1.1rem; font-weight: 600; }
.vocab-empty-sub { font-size: 0.85rem; margin-top: 6px; opacity: 0.6; }

@media(max-width:640px) {
  .vocab-grid { grid-template-columns: 1fr; }
  .vocab-search { width: 100%; }
  .vocab-stats { flex-direction: column; align-items: flex-start; }
  .score-presets { gap: 6px; }
  .score-preset-btn { padding: 6px 13px; font-size: 0.8rem; }
}

/* ══════════════════════════════════════════════
   RULES + VOCAB MERGED — rv-* styles
══════════════════════════════════════════════ */

/* ── Vocab Controls Bar ── */
.rv-controls {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.07);
  border-radius: 16px; padding: 14px 18px;
  margin-bottom: 20px; display: flex; flex-direction: column; gap: 10px;
}
.rv-row {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
}
.rv-label {
  font-size: 0.82rem; font-weight: 700; color: var(--text-secondary);
  white-space: nowrap;
}
.rv-sublabel {
  font-size: 0.78rem; font-weight: 600; color: rgba(255,255,255,0.4);
  white-space: nowrap; min-width: 90px;
}

/* Exam buttons */
.rv-exam-group, .rv-level-group { display: flex; gap: 6px; flex-wrap: wrap; }
.rv-exam-btn {
  padding: 5px 16px; border-radius: 50px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 0.8rem; font-weight: 700;
  background: rgba(255,255,255,0.05); border: 1px solid rgba(255,255,255,0.1);
  color: var(--text-secondary); transition: all 0.25s;
}
.rv-exam-btn:hover { border-color: rgba(255,255,255,0.25); color: var(--text-primary); }
.rv-exam-btn.active {
  background: linear-gradient(135deg,#6366f1,#8b5cf6);
  border-color: transparent; color: #fff;
  box-shadow: 0 3px 12px rgba(99,102,241,0.4);
}

/* Level buttons */
.rv-level-btn {
  padding: 4px 13px; border-radius: 50px; cursor: pointer;
  font-family: "Outfit", sans-serif; font-size: 0.78rem; font-weight: 700;
  background: rgba(255,255,255,0.04); border: 1px solid rgba(255,255,255,0.09);
  color: rgba(255,255,255,0.45); transition: all 0.2s;
}
.rv-level-btn:hover { border-color: rgba(255,255,255,0.2); color: var(--text-primary); }
.rv-level-btn.active.pte-lb  { background: rgba(99,102,241,0.25); border-color: rgba(99,102,241,0.5); color: #a5b4fc; }
.rv-level-btn.active.ielts-lb { background: rgba(16,185,129,0.25); border-color: rgba(16,185,129,0.5); color: #6ee7b7; }

/* ── Vocab Section inside Letter Block ── */
.rv-vocab-section {
  border-top: 1px solid rgba(255,255,255,0.06);
  padding: 12px 20px 14px;
  background: rgba(0,0,0,0.1);
}
.rv-vocab-title {
  font-size: 0.75rem; font-weight: 700; color: var(--text-secondary);
  text-transform: uppercase; letter-spacing: 0.5px;
  margin-bottom: 10px; display: flex; align-items: center; gap: 6px;
}
.rv-vocab-title strong { color: var(--accent3); }
.rv-vocab-count {
  font-size: 0.65rem; background: rgba(255,255,255,0.07);
  padding: 1px 7px; border-radius: 50px; color: rgba(255,255,255,0.4);
  font-weight: 600; font-style: normal;
}

/* Each word row */
.rv-word-item {
  display: grid;
  grid-template-columns: 130px 110px 60px 1fr auto auto;
  align-items: center; gap: 8px;
  padding: 7px 0;
  border-bottom: 1px solid rgba(255,255,255,0.04);
  transition: background 0.2s;
}
.rv-word-item:last-child { border-bottom: none; }
.rv-word-item:hover { background: rgba(255,255,255,0.02); border-radius: 8px; padding-left:6px; }

.rv-word-text {
  font-family: "Baloo 2", cursive; font-size: 0.98rem; font-weight: 800;
  color: var(--text-primary);
}
.rv-word-phonetic {
  font-size: 0.72rem; color: var(--accent3); font-family: monospace;
}
.rv-word-type {
  font-size: 0.58rem; font-weight: 700; padding: 2px 6px;
  border-radius: 50px; text-transform: uppercase; text-align: center;
}
.rv-word-meaning {
  font-size: 0.8rem; color: #ffd580; font-weight: 600;
}
.rv-word-badge {
  font-size: 0.6rem; font-weight: 800; padding: 2px 8px;
  border-radius: 50px; white-space: nowrap;
}
.rv-word-badge.pte   { background: rgba(99,102,241,0.2); color: #a5b4fc; border: 1px solid rgba(99,102,241,0.35); }
.rv-word-badge.ielts { background: rgba(16,185,129,0.2); color: #6ee7b7; border: 1px solid rgba(16,185,129,0.35); }

.rv-speak-btn {
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.1);
  border-radius: 7px; padding: 4px 10px; cursor: pointer; font-size: 0.8rem;
  transition: all 0.2s; color: var(--text-primary);
}
.rv-speak-btn:hover { background: rgba(124,111,255,0.2); border-color: rgba(124,111,255,0.4); }
.rv-speak-btn.speaking { animation: speakPulse 0.7s ease infinite; }

@media(max-width:700px) {
  .rv-word-item {
    grid-template-columns: 1fr auto;
    grid-template-rows: auto auto;
  }
  .rv-word-text    { grid-column: 1; grid-row: 1; font-size: 1rem; }
  .rv-speak-btn    { grid-column: 2; grid-row: 1 / 3; }
  .rv-word-phonetic,.rv-word-type,.rv-word-meaning,.rv-word-badge {
    grid-column: 1; font-size: 0.72rem;
  }
  .rv-vocab-section { padding: 10px 14px 12px; }
}

/* ══════════════════════════════════════════════
   VOCAB 2-COLUMN CARD GRID
══════════════════════════════════════════════ */
.rv-words-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 4px;
}

/* Word card */
.rv-word-card {
  background: rgba(255,255,255,0.04);
  border: 1px solid rgba(255,255,255,0.08);
  border-radius: 14px;
  padding: 14px 14px 11px 16px;
  display: flex; flex-direction: column; gap: 5px;
  position: relative; overflow: hidden;
  transition: transform 0.22s, box-shadow 0.22s, border-color 0.22s;
  cursor: default;
}

.rv-word-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 28px rgba(0,0,0,0.4);
}
.rv-word-card.exam-pte:hover   { border-color: rgba(99,102,241,0.45); }
.rv-word-card.exam-ielts:hover { border-color: rgba(16,185,129,0.45); }

/* ── Badge: absolute top-right corner ── */
.rv-exam-badge {
  position: absolute;
  top: 10px; right: 12px;
  font-size: 0.68rem; font-weight: 800;
  letter-spacing: 0.04em;
  padding: 3px 9px;
  border-radius: 20px;
  line-height: 1;
  white-space: nowrap;
  font-family: "Outfit", sans-serif;
  pointer-events: none;
  box-shadow: 0 2px 8px rgba(0,0,0,0.3);
}
.badge-pte {
  background: linear-gradient(135deg, #4f46e5, #7c3aed);
  color: #fff;
  border: 1px solid rgba(139,92,246,0.4);
}
.badge-ielts {
  background: linear-gradient(135deg, #059669, #0d9488);
  color: #fff;
  border: 1px solid rgba(16,185,129,0.4);
}
.badge-ielts2 {
  background: linear-gradient(135deg, #ec4899, #8b5cf6);
  color: #fff;
  border: 1px solid rgba(236,72,153,0.4);
}

/* Word name — leave space for the badge on the right */
.rv-word-name {
  font-family: "Baloo 2", cursive;
  font-size: 1.12rem; font-weight: 800;
  color: var(--text-primary);
  line-height: 1.2;
  padding-right: 72px; /* room for badge */
  word-break: break-word;
}

/* Phonetic */
.rv-wc-phonetic {
  font-size: 0.72rem; color: var(--accent3);
  font-family: monospace; letter-spacing: 0.3px;
}

/* Meaning */
.rv-wc-meaning {
  font-size: 0.82rem; font-weight: 700; color: #ffd580;
  line-height: 1.3;
}

/* Footer: type badge + speak btn */
.rv-wc-footer {
  display: flex; align-items: center; justify-content: space-between;
  margin-top: 2px;
}
.rv-speak-btn {
  background: rgba(255,255,255,0.06); border: 1px solid rgba(255,255,255,0.1);
  border-radius: 7px; padding: 4px 11px; cursor: pointer;
  font-size: 0.75rem; font-weight: 600; color: var(--text-primary);
  transition: all 0.2s; white-space: nowrap; font-family: "Outfit", sans-serif;
}
.rv-speak-btn:hover { background: rgba(124,111,255,0.2); border-color: rgba(124,111,255,0.4); }
.rv-speak-btn.speaking { animation: speakPulse 0.7s ease infinite; }

@media(max-width:780px) {
  .rv-words-grid { grid-template-columns: 1fr; }
}
@media(min-width:1400px) {
  .rv-words-grid { grid-template-columns: 1fr 1fr 1fr; }
}

/* ============================================================
   VOCAB TAB — A-Z Letter Bar
   ============================================================ */
.vocab-letter-bar {
  display: flex; flex-wrap: wrap; gap: 6px;
  padding: 14px 20px; background: rgba(255,255,255,0.03);
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.vocab-letter-btn {
  min-width: 36px; height: 36px; padding: 0 10px;
  border-radius: 8px; border: 1px solid rgba(255,255,255,0.1);
  background: rgba(255,255,255,0.04); color: var(--text-secondary);
  font-size: 0.8rem; font-weight: 700; cursor: pointer;
  transition: all 0.18s; font-family: "Outfit", sans-serif;
}
.vocab-letter-btn:hover { background: rgba(124,111,255,0.15); color: var(--text-primary); }
.vocab-letter-btn.active {
  background: linear-gradient(135deg, #7c6fff, #5e9fff);
  color: #fff; border-color: transparent;
  box-shadow: 0 2px 10px rgba(124,111,255,0.4);
}

/* ============================================================
   VOCAB TAB — Topic Filter
   ============================================================ */
.rv-topic-group {
  display: flex; flex-wrap: wrap; gap: 6px;
}
.rv-topic-btn {
  padding: 4px 14px; border-radius: 20px;
  border: 1px solid rgba(255,255,255,0.12);
  background: rgba(255,255,255,0.05); color: var(--text-secondary);
  font-size: 0.78rem; font-weight: 600; cursor: pointer;
  transition: all 0.18s; font-family: "Outfit", sans-serif;
}
.rv-topic-btn:hover { background: rgba(124,111,255,0.15); color: var(--text-primary); }
.rv-topic-btn.active {
  background: rgba(124,111,255,0.25); color: #b3aaff;
  border-color: rgba(124,111,255,0.5);
}

/* ============================================================
   VOCAB TAB — Search
   ============================================================ */
.rv-search-wrap {
  position: relative; display: flex; align-items: center; flex: 1; max-width: 360px;
}
.rv-search {
  width: 100%; padding: 8px 36px 8px 14px;
  background: rgba(255,255,255,0.07); border: 1px solid rgba(255,255,255,0.12);
  border-radius: 10px; color: var(--text-primary); font-family: "Outfit", sans-serif;
  font-size: 0.9rem; outline: none; transition: all 0.2s;
}
.rv-search::placeholder { color: var(--text-muted, #666); }
.rv-search:focus { border-color: rgba(124,111,255,0.5); background: rgba(255,255,255,0.1); }
.rv-search-clear {
  position: absolute; right: 8px; top: 50%; transform: translateY(-50%);
  background: none; border: none; color: var(--text-secondary); cursor: pointer;
  font-size: 0.9rem; padding: 2px 6px; display: none;
  align-items: center; justify-content: center; border-radius: 4px;
}
.rv-search-clear:hover { color: var(--text-primary); background: rgba(255,255,255,0.1); }

/* ============================================================
   VOCAB TAB — Stats bar
   ============================================================ */
.vocab-stats {
  padding: 10px 20px; font-size: 0.85rem;
  color: var(--text-secondary); font-weight: 600;
  letter-spacing: 0.02em;
}

/* ============================================================
   VOCAB TAB — Letter sections
   ============================================================ */
.vocab-grid-container { padding: 0 20px 40px; }
.vocab-letter-section { margin-bottom: 32px; }
.vocab-letter-heading {
  display: flex; align-items: baseline; gap: 12px;
  padding: 10px 0 8px; margin-bottom: 14px;
  border-bottom: 2px solid rgba(124,111,255,0.25);
}
.vocab-letter-char {
  font-size: 2rem; font-weight: 900; line-height: 1;
  background: linear-gradient(135deg, #7c6fff, #5e9fff);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.vocab-letter-count {
  font-size: 0.8rem; color: var(--text-secondary); font-weight: 600;
}

/* ============================================================
   VOCAB TAB — Card improvements for standalone view
   ============================================================ */
.rv-word-card .rv-word-topic {
  font-size: 0.7rem; color: var(--text-muted, #666);
  background: rgba(255,255,255,0.05); border-radius: 4px;
  padding: 2px 7px; border: 1px solid rgba(255,255,255,0.07);
  margin-left: auto;
}
.rv-word-card .rv-word-meta {
  display: flex; align-items: center; gap: 8px; flex-wrap: wrap;
}
.rv-word-card .rv-word-example {
  font-size: 0.75rem; color: var(--text-secondary);
  font-style: italic; padding-top: 4px;
  border-top: 1px solid rgba(255,255,255,0.05);
  margin-top: 6px;
}

/* Empty state */
.vocab-empty {
  text-align: center; padding: 60px 20px;
  color: var(--text-secondary); font-size: 1rem;
}

/* ============================================================
   MOBILE OPTIMIZATION & PERFORMANCE (Sleek & Ultra-Fast)
   ============================================================ */
body, main {
  overflow-x: hidden;
}

/* Hardware acceleration & contain layout for performance */
.letter-card, .phoneme-card, .rule-card, .rv-word-card {
  contain: content;
  will-change: transform;
}

/* Hide scrollbars on horizontal filter groups for native feel */
.rv-level-group::-webkit-scrollbar,
.vocab-letter-bar::-webkit-scrollbar,
.rv-topic-group::-webkit-scrollbar,
.phoneme-filter-bar::-webkit-scrollbar,
.rules-filter-bar::-webkit-scrollbar,
.filter-bar::-webkit-scrollbar {
  display: none;
}

.rv-level-group,
.vocab-letter-bar,
.rv-topic-group,
.phoneme-filter-bar,
.rules-filter-bar,
.filter-bar {
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}

/* Mobile adjustments (<= 768px) */
@media (max-width: 768px) {
  body {
    padding: 0;
  }
  
  .hero {
    padding: 24px 16px 16px;
  }
  
  .hero h1 {
    font-size: 2.2rem;
  }
  
  .subtitle {
    font-size: 0.9rem;
  }

  /* Sticky Glassmorphism Tab Bar on mobile */
  .tab-bar {
    position: sticky;
    top: 0;
    z-index: 99;
    background: rgba(18, 18, 30, 0.88);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    padding: 8px 12px;
    margin-bottom: 16px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

  .tab-btn {
    padding: 8px 14px;
    font-size: 0.85rem;
    min-height: 42px;
  }

  .filter-bar, .phoneme-filter-bar, .rules-filter-bar {
    padding: 6px 12px;
    gap: 8px;
    flex-wrap: nowrap;
    overflow-x: auto;
  }

  .filter-btn {
    white-space: nowrap;
    padding: 8px 14px;
    font-size: 0.82rem;
    min-height: 40px;
  }

  .rv-controls {
    padding: 14px 12px;
  }

  .rv-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }

  .rv-level-group, .rv-exam-group, .rv-topic-group {
    width: 100%;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .rv-level-btn, .rv-exam-btn, .rv-topic-btn {
    white-space: nowrap;
    min-height: 38px;
    padding: 6px 14px;
    font-size: 0.82rem;
  }

  .rv-search-wrap {
    max-width: 100%;
    width: 100%;
  }

  .rv-search {
    font-size: 16px; /* Prevents iOS auto-zoom on focus */
    padding: 10px 36px 10px 14px;
  }

  .vocab-letter-bar {
    padding: 10px 12px;
    flex-wrap: nowrap;
    overflow-x: auto;
  }

  .vocab-letter-btn {
    min-width: 38px;
    height: 38px;
    font-size: 0.85rem;
  }

  .vocab-grid-container {
    padding: 0 12px 30px;
  }

  .alphabet-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 12px;
    padding: 0 12px 30px;
  }

  .phoneme-grid {
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 12px;
  }

  .rv-words-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .rv-word-card {
    padding: 14px;
  }

  .rv-word-name {
    font-size: 1.15rem;
  }

  .modal-card {
    width: 92%;
    padding: 24px 18px;
  }
}