/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; }
body {
  font-family: 'Noto Sans JP', sans-serif;
  min-height: 100vh;
  overflow-x: hidden;
  color: #fff;
  background: #0a1a2e;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

/* ===== CSS VARIABLES ===== */
:root {
  --ocean-deep: #0a1a2e;
  --ocean-mid:  #0d2b4e;
  --ocean-light:#1565c0;
  --ocean-surf: #42a5f5;
  --coral:      #ff7043;
  --gold:       #ffd54f;
  --mint:       #4dd0e1;
  --white:      #ffffff;
  --glass:      rgba(255,255,255,0.08);
  --glass-border:rgba(255,255,255,0.15);
  --text-soft:  rgba(255,255,255,0.7);
  --radius:     16px;
  --radius-lg:  24px;
  --shadow:     0 8px 32px rgba(0,0,0,0.3);
  --header-h:   56px;
  --bg1: #0a1a2e;
  --bg2: #0d2b4e;
  --accent: #42a5f5;
}

/* ==============================
   TOPIC-BASED THEMES
============================== */
body[data-topic="Mind Cove"]       { --bg1:#050f1e; --bg2:#0c2040; --accent:#2471A3; }
body[data-topic="Evolution Bay"]   { --bg1:#041208; --bg2:#0a2e12; --accent:#1E8449; }
body[data-topic="Society Reef"]    { --bg1:#100618; --bg2:#210d36; --accent:#6C3483; }
body[data-topic="Language Lagoon"] { --bg1:#140e02; --bg2:#2e2004; --accent:#B7950B; }
body[data-topic="Heritage Harbour"]{ --bg1:#0c0e10; --bg2:#1c2028; --accent:#5D6D7E; }
body[data-topic="Eco Atoll"]       { --bg1:#041208; --bg2:#0c2a16; --accent:#148F77; }
body[data-topic="Tech Abyss"]      { --bg1:#140a02; --bg2:#2e1c06; --accent:#CA6F1E; }

/* ===== OCEAN BACKGROUND ===== */
#ocean-bg {
  position: fixed; inset: 0; z-index: 0;
  overflow: hidden;
}

.ocean-gradient {
  position: absolute; inset: 0;
  background: linear-gradient(180deg, var(--bg1) 0%, var(--bg2) 100%);
  transition: background 1.5s ease;
}

/* ===== CREATURE LAYER ===== */
.creatures-layer {
  position: absolute; inset: 0;
  pointer-events: none;
}
.creature {
  position: absolute;
  font-size: 32px;
  animation: creatureSwim linear infinite;
  opacity: 0.5;
  filter: drop-shadow(0 0 8px rgba(255,255,255,0.2));
  transition: opacity 1s;
}
.creature.large { font-size: 48px; opacity: 0.35; }
.creature.small  { font-size: 20px; opacity: 0.55; }

@keyframes creatureSwim {
  0%   { transform: translateX(-120px) scaleX(1); }
  49%  { transform: translateX(calc(100vw + 120px)) scaleX(1); opacity: 0.5; }
  50%  { transform: translateX(calc(100vw + 120px)) scaleX(-1); opacity: 0; }
  51%  { transform: translateX(calc(100vw + 120px)) scaleX(-1); opacity: 0.5; }
  100% { transform: translateX(-120px) scaleX(-1); }
}

/* ===== CORAL LAYER ===== */
.coral-layer {
  position: absolute; bottom: 0; left: 0; right: 0;
  height: 160px; pointer-events: none;
}
.coral {
  position: absolute; bottom: 0;
  font-size: 36px;
  animation: coralSway ease-in-out infinite;
  transform-origin: bottom center;
  filter: drop-shadow(0 4px 8px rgba(0,0,0,0.4));
  opacity: 0.6;
}
@keyframes coralSway {
  0%,100% { transform: rotate(-5deg) scale(1); }
  50%      { transform: rotate(5deg) scale(1.05); }
}

/* ===== PARTICLES & BUBBLES ===== */
.particles { position: absolute; inset: 0; pointer-events: none; }
.particle {
  position: absolute; width: 3px; height: 3px;
  border-radius: 50%; background: rgba(66,165,245,0.5);
  animation: particleDrift linear infinite;
  top: 100%;
}
@keyframes particleDrift {
  0%   { transform: translateY(0) translateX(0) scale(1); opacity: 0.4; }
  50%  { transform: translateY(-40vh) translateX(30px) scale(1.5); opacity: 0.7; }
  100% { transform: translateY(-100vh) translateX(-20px) scale(0.5); opacity: 0; }
}

.bubbles { position: absolute; inset: 0; pointer-events: none; }
.bubble {
  position: absolute; border-radius: 50%;
  background: radial-gradient(circle at 35% 35%, rgba(255,255,255,0.35), rgba(255,255,255,0.05));
  border: 1px solid rgba(255,255,255,0.2);
  animation: bubbleRise linear infinite;
}
@keyframes bubbleRise {
  0%   { transform: translateY(0) scale(1); opacity: 0.6; }
  80%  { opacity: 0.4; }
  100% { transform: translateY(-105vh) scale(1.3); opacity: 0; }
}

/* ===== WAVES ===== */
.wave {
  position: absolute; bottom: 0; left: 0; right: 0;
  height: 60px; pointer-events: none;
  background: linear-gradient(transparent, rgba(255,255,255,0.04));
  animation: wavePulse ease-in-out infinite;
}
.wave1 { animation-duration: 8s; }
.wave2 { animation-duration: 12s; animation-delay: -4s; opacity: 0.6; }
.wave3 { animation-duration: 16s; animation-delay: -8s; opacity: 0.4; }
@keyframes wavePulse {
  0%,100% { transform: scaleY(1) translateY(0); }
  50%      { transform: scaleY(1.3) translateY(-8px); }
}

/* ===== HEADER ===== */
#app-header {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--header-h); z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 16px;
  background: rgba(10,26,46,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(255,255,255,0.08);
}
.header-left { display: flex; align-items: center; gap: 8px; }
.logo-shark  { font-size: 24px; }
.logo-text   { font-family: 'Space Mono', monospace; font-size: 14px; font-weight: 700; color: var(--accent); letter-spacing: 2px; }
.header-stats { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--text-soft); font-family: 'Space Mono', monospace; }
.stat-sep    { opacity: 0.35; }

/* ===== SCREENS ===== */
.screen {
  position: relative; z-index: 10;
  min-height: 100vh;
  padding-top: calc(var(--header-h) + 12px);
  padding-bottom: 80px;
  display: none;
}
.screen.active { display: block; }

/* ===== SCREEN HEADER ===== */
.screen-header {
  display: flex; align-items: center; gap: 12px;
  padding: 12px 16px;
  background: rgba(255,255,255,0.04);
  border-bottom: 1px solid var(--glass-border);
  margin-bottom: 16px;
}
.screen-header h2 { font-size: 18px; font-weight: 700; flex: 1; }
.back-btn {
  background: var(--glass); border: 1px solid var(--glass-border);
  color: var(--text-soft); padding: 6px 12px; border-radius: 20px;
  font-size: 13px; cursor: pointer; white-space: nowrap;
}
.back-btn:hover { background: rgba(255,255,255,0.12); }

/* ===== HOME SCREEN ===== */
.home-hero {
  display: flex; flex-direction: column; align-items: center;
  padding: 20px 16px 10px;
  text-align: center; position: relative;
}
.shark-teacher { position: relative; margin-bottom: 12px; }
.shark-body    { font-size: 64px; filter: drop-shadow(0 0 20px var(--accent)); animation: sharkBob 3s ease-in-out infinite; }
@keyframes sharkBob {
  0%,100% { transform: translateY(0) rotate(-2deg); }
  50%      { transform: translateY(-8px) rotate(2deg); }
}
.shark-bubble {
  position: absolute; left: 50%; transform: translateX(-50%);
  top: -48px; white-space: nowrap; min-width: 200px; max-width: 280px; white-space: normal;
  background: rgba(255,255,255,0.12); border: 1px solid rgba(255,255,255,0.2);
  border-radius: 12px; padding: 8px 12px; font-size: 12px;
  text-align: center; backdrop-filter: blur(8px);
  animation: bubblePop 0.3s ease;
}
@keyframes bubblePop { from { opacity:0; transform: translateX(-50%) scale(0.8); } to { opacity:1; transform: translateX(-50%) scale(1); } }

.app-title {
  font-family: 'Playfair Display', serif;
  font-size: 42px; line-height: 1.1;
  background: linear-gradient(135deg, #fff 0%, var(--accent) 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  margin-bottom: 6px;
}
.app-sub { font-size: 13px; color: var(--text-soft); margin-bottom: 4px; }

/* ===== DAY STRIP ===== */
.day-progress-strip {
  padding: 12px 0;
  overflow: hidden;
  border-top: 1px solid var(--glass-border);
  border-bottom: 1px solid var(--glass-border);
  margin-bottom: 16px;
}
.day-scroll {
  display: flex; gap: 8px; padding: 0 16px;
  overflow-x: auto; scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.day-scroll::-webkit-scrollbar { display: none; }

.day-pill {
  flex: 0 0 72px; scroll-snap-align: center;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: 12px; padding: 8px 6px; text-align: center; cursor: pointer;
  transition: all 0.2s;
}
.day-pill:hover  { background: rgba(255,255,255,0.12); }
.day-pill.today  { background: var(--accent); border-color: var(--accent); box-shadow: 0 0 16px rgba(66,165,245,0.4); }
.day-pill.clear  { border-color: #4dd0e1; background: rgba(77,208,225,0.15); }
.day-pill.partial{ border-color: var(--gold); background: rgba(255,213,79,0.12); }
.day-num  { display: block; font-size: 11px; font-family: 'Space Mono', monospace; opacity: 0.8; }
.day-status { font-size: 15px; }

/* ===== HOME ACTIONS ===== */
.home-actions { display: flex; flex-direction: column; gap: 10px; padding: 0 16px 16px; }

.btn-primary {
  display: flex; align-items: center; gap: 12px;
  background: linear-gradient(135deg, var(--accent), #1565c0);
  border: none; border-radius: var(--radius); padding: 16px 20px;
  color: #fff; font-size: 16px; font-weight: 700; cursor: pointer;
  box-shadow: 0 4px 20px rgba(66,165,245,0.35);
  transition: transform 0.15s, box-shadow 0.15s;
}
.btn-primary:active { transform: scale(0.97); }
.btn-secondary {
  display: flex; align-items: center; gap: 12px;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 14px 20px;
  color: #fff; font-size: 15px; font-weight: 600; cursor: pointer;
  transition: background 0.2s;
}
.btn-secondary:hover { background: rgba(255,255,255,0.12); }
.btn-ghost {
  display: flex; align-items: center; gap: 12px;
  background: transparent; border: 1px solid rgba(255,255,255,0.2);
  border-radius: var(--radius); padding: 12px 20px;
  color: var(--text-soft); font-size: 14px; cursor: pointer;
  transition: all 0.2s;
}
.btn-ghost:hover { border-color: var(--accent); color: #fff; }
.btn-icon { font-size: 22px; }
.btn-text { flex: 1; text-align: left; }

/* ===== OVERALL PROGRESS ===== */
.overall-progress {
  margin: 0 16px; padding: 14px 16px;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius);
}
.prog-label { font-size: 11px; color: var(--text-soft); margin-bottom: 6px; font-family: 'Space Mono', monospace; text-transform: uppercase; letter-spacing: 1px; }
.prog-bar-wrap { height: 6px; background: rgba(255,255,255,0.1); border-radius: 3px; margin-bottom: 4px; overflow: hidden; }
.prog-bar { height: 100%; background: linear-gradient(90deg, var(--accent), #4dd0e1); border-radius: 3px; transition: width 0.5s ease; }
.prog-pct  { font-size: 12px; font-family: 'Space Mono', monospace; color: var(--accent); text-align: right; }

/* ===== TOPICS SCREEN ===== */
.topic-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 12px; padding: 0 16px;
}
.topic-card {
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg); padding: 16px 12px;
  text-align: center; cursor: pointer; transition: all 0.2s;
  background-color: var(--card-accent, transparent);
}
.topic-card:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,0.3); }
.topic-emoji    { font-size: 36px; margin-bottom: 6px; }
.topic-name     { font-size: 12px; font-weight: 700; margin-bottom: 2px; color: var(--accent); font-family: 'Space Mono', monospace; }
.topic-name-jp  { font-size: 11px; color: var(--text-soft); margin-bottom: 6px; }
.topic-count    { font-size: 11px; color: var(--text-soft); margin-bottom: 6px; }
.topic-mini-bar { height: 3px; background: rgba(255,255,255,0.1); border-radius: 2px; overflow: hidden; }
.topic-mini-fill{ height: 100%; border-radius: 2px; transition: width 0.5s; }

/* ===== TOPIC MODE MODAL ===== */
.modal-overlay {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(0,0,0,0.75); backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.modal-box {
  background: linear-gradient(160deg, #0a1a2e, #0d2b4e);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-lg); padding: 28px 20px;
  width: 100%; max-width: 360px; text-align: center;
}
.modal-topic-badge { display: inline-block; background: var(--accent); color: #fff; font-size: 12px; font-family: 'Space Mono', monospace; padding: 4px 12px; border-radius: 20px; margin-bottom: 12px; }
.modal-topic-creature { font-size: 56px; margin-bottom: 12px; }
.modal-title  { font-size: 16px; margin-bottom: 20px; color: var(--text-soft); }

.modal-btn {
  display: flex; align-items: center; gap: 14px;
  width: 100%; background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 14px 16px; margin-bottom: 10px;
  cursor: pointer; text-align: left; color: #fff; transition: all 0.2s;
}
.modal-btn:hover { background: rgba(255,255,255,0.12); }
.modal-btn.mode-full  { border-color: var(--accent); }
.modal-btn.mode-step  { border-color: var(--gold); }
.modal-btn-icon   { font-size: 28px; }
.modal-btn-content{ flex: 1; }
.modal-btn-title  { font-size: 15px; font-weight: 700; margin-bottom: 2px; }
.modal-btn-sub    { font-size: 12px; color: var(--text-soft); }
.modal-btn-count  { font-size: 13px; font-family: 'Space Mono', monospace; color: var(--accent); white-space: nowrap; }
.modal-cancel {
  background: transparent; border: none; color: var(--text-soft);
  font-size: 14px; cursor: pointer; margin-top: 6px; padding: 8px;
}
.modal-cancel:hover { color: #fff; }

/* ===== REVIEW SCREEN ===== */
.review-options  { padding: 0 16px; display: flex; flex-direction: column; gap: 10px; }
.review-btn {
  display: flex; align-items: center; gap: 14px;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 14px 16px; cursor: pointer;
  color: #fff; text-align: left; transition: all 0.2s; width: 100%;
}
.review-btn:hover { background: rgba(255,255,255,0.12); }
.r-icon  { font-size: 24px; }
.r-label { flex: 1; font-size: 15px; font-weight: 600; }
.r-count { font-size: 13px; font-family: 'Space Mono', monospace; color: var(--accent); }
.topic-review-list { display: flex; flex-direction: column; gap: 8px; margin-top: 8px; }

/* ===== FLASHCARD SCREEN ===== */
.flashcard-wrap {
  padding: 16px;
  display: flex; justify-content: center;
}

.flashcard {
  width: 100%; max-width: 460px;
  aspect-ratio: 5/7;
  perspective: 1000px;
  cursor: pointer;
  position: relative;
}
.card-front, .card-back {
  position: absolute; inset: 0;
  border-radius: var(--radius-lg);
  backface-visibility: hidden;
  transition: transform 0.55s cubic-bezier(0.4,0,0.2,1);
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  padding: 24px; gap: 10px;
  box-shadow: var(--shadow);
}
.card-front {
  background: linear-gradient(160deg, rgba(255,255,255,0.1), rgba(255,255,255,0.04));
  border: 1px solid rgba(255,255,255,0.15);
  transform: rotateY(0deg);
}
.card-back {
  background: linear-gradient(160deg, var(--bg2), var(--bg1));
  border: 1px solid var(--accent);
  transform: rotateY(180deg);
  justify-content: flex-start;
  align-items: flex-start;
  overflow-y: auto;
  gap: 8px;
}
.flashcard.flipped .card-front { transform: rotateY(-180deg); }
.flashcard.flipped .card-back  { transform: rotateY(0deg); }

.card-pos     { font-size: 12px; font-family: 'Space Mono', monospace; color: var(--accent); padding: 3px 10px; background: rgba(66,165,245,0.15); border-radius: 20px; }
.card-word    { font-family: 'Playfair Display', serif; font-size: 36px; font-weight: 700; text-align: center; line-height: 1.2; }
.card-hint    { font-size: 12px; color: var(--text-soft); margin-top: 8px; }
.card-meaning { font-size: 20px; font-weight: 700; color: var(--gold); }
.card-example, .card-translation { font-size: 13px; color: var(--text-soft); line-height: 1.6; }
.card-etymology  { font-size: 12px; color: #4dd0e1; border-top: 1px solid rgba(255,255,255,0.1); padding-top: 8px; width: 100%; }
.card-derivatives{ font-size: 12px; color: rgba(255,255,255,0.6); }

.fc-progress-info { flex: 1; text-align: center; font-size: 13px; color: var(--text-soft); font-family: 'Space Mono', monospace; }
.topic-badge { font-size: 11px; background: var(--accent); color: #fff; padding: 3px 10px; border-radius: 20px; font-family: 'Space Mono', monospace; white-space: nowrap; }

.fc-actions { display: flex; gap: 10px; padding: 0 16px 10px; }
.fc-nav     { display: flex; gap: 10px; padding: 0 16px 16px; }
.fc-btn {
  flex: 1; padding: 13px; border-radius: var(--radius);
  border: none; font-size: 14px; font-weight: 700; cursor: pointer;
  transition: all 0.15s;
}
.fc-skip  { background: var(--glass); border: 1px solid var(--glass-border); color: var(--text-soft); }
.fc-knew  { background: linear-gradient(135deg, var(--accent), #1565c0); color: #fff; }
.fc-btn-sm, .fc-btn-next {
  flex: 1; padding: 10px; border-radius: var(--radius);
  border: 1px solid var(--glass-border); background: var(--glass);
  color: var(--text-soft); font-size: 14px; cursor: pointer;
}
.fc-btn-next { border-color: var(--accent); color: var(--accent); }

/* ===== QUIZ SCREEN ===== */
.quiz-timer-wrap {
  display: flex; align-items: center; gap: 10px;
  padding: 0 16px 10px;
}
.quiz-timer-bar {
  flex: 1; height: 6px; background: rgba(255,255,255,0.1);
  border-radius: 3px; overflow: hidden; position: relative;
}
.quiz-timer-bar::after {
  content: ''; position: absolute; left: 0; top: 0; bottom: 0;
  width: var(--timer-pct, 100%);
  background: linear-gradient(90deg, var(--accent), #ff7043);
  border-radius: 3px; transition: width 0.9s linear;
}
.quiz-timer-text { font-size: 15px; font-family: 'Space Mono', monospace; color: var(--accent); min-width: 20px; text-align: center; }

.quiz-meta  { flex: 1; display: flex; align-items: center; gap: 8px; justify-content: center; }
.mode-badge { font-size: 11px; background: var(--accent); color: #fff; padding: 3px 10px; border-radius: 20px; font-family: 'Space Mono', monospace; }

.quiz-question-wrap { padding: 16px 20px; text-align: center; min-height: 80px; display: flex; flex-direction: column; align-items: center; gap: 8px; }
.quiz-word { font-family: 'Playfair Display', serif; font-size: 34px; font-weight: 700; line-height: 1.2; }
.quiz-listen-btn button { background: var(--glass); border: 1px solid var(--glass-border); color: #fff; padding: 8px 16px; border-radius: 20px; font-size: 13px; cursor: pointer; }

.quiz-choices { padding: 0 16px; display: flex; flex-direction: column; gap: 8px; }
.choice-btn {
  display: flex; align-items: center; gap: 12px;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 14px 16px;
  color: #fff; font-size: 14px; cursor: pointer; text-align: left;
  transition: all 0.15s; width: 100%;
}
.choice-btn:hover:not(.disabled) { background: rgba(255,255,255,0.12); border-color: var(--accent); }
.choice-btn.disabled { cursor: default; }
.choice-btn.correct  { background: rgba(77,208,225,0.2); border-color: #4dd0e1; }
.choice-btn.wrong    { background: rgba(255,112,67,0.2);  border-color: #ff7043; }
.choice-num { font-size: 12px; font-family: 'Space Mono', monospace; color: var(--accent); background: rgba(66,165,245,0.15); border-radius: 50%; width: 22px; height: 22px; display: flex; align-items: center; justify-content: center; flex-shrink: 0; }

.quiz-feedback {
  margin: 12px 16px 0;
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 14px 16px;
  animation: feedbackSlide 0.3s ease;
}
@keyframes feedbackSlide { from { opacity:0; transform: translateY(10px); } to { opacity:1; transform: translateY(0); } }
.feedback-header { display: flex; align-items: center; gap: 10px; margin-bottom: 8px; }
.feedback-icon   { font-size: 24px; }
.feedback-msg    { font-size: 14px; font-weight: 700; flex: 1; }
.feedback-correct{ font-size: 14px; color: var(--gold); font-weight: 700; margin-bottom: 8px; }
.feedback-hint   { border-top: 1px solid rgba(255,255,255,0.1); padding-top: 10px; display: flex; flex-direction: column; gap: 6px; }
.hint-etymology, .hint-derivatives, .hint-example { font-size: 12px; color: var(--text-soft); line-height: 1.5; }

/* ===== RESULTS SCREEN ===== */
.results-wrap {
  padding: 24px 20px;
  display: flex; flex-direction: column; align-items: center; gap: 16px;
  text-align: center; position: relative; z-index: 10;
}
.results-shark  { font-size: 72px; animation: sharkBob 3s ease-in-out infinite; }
.results-title  { font-family: 'Playfair Display', serif; font-size: 28px; }
.results-score  { font-family: 'Space Mono', monospace; font-size: 48px; color: var(--accent); }
.results-comment{ font-size: 14px; color: var(--text-soft); max-width: 280px; line-height: 1.6; }

.results-stats-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 10px; width: 100%; max-width: 320px;
}
.r-stat {
  background: var(--glass); border: 1px solid var(--glass-border);
  border-radius: var(--radius); padding: 14px 10px; text-align: center;
}
.r-stat-num   { font-family: 'Space Mono', monospace; font-size: 22px; color: var(--accent); margin-bottom: 4px; }
.r-stat-label { font-size: 11px; color: var(--text-soft); }

.results-actions { display: flex; flex-direction: column; gap: 10px; width: 100%; max-width: 320px; }

/* ===== CELEBRATIONS ===== */
.celebration { position: fixed; inset: 0; pointer-events: none; z-index: 150; }

.spark {
  position: absolute;
  animation: sparkFly ease-out forwards;
}
@keyframes sparkFly {
  0%   { transform: translate(0,0) scale(1); opacity: 1; }
  100% { transform: translate(var(--dx),var(--dy)) scale(0); opacity: 0; }
}

.fish-confetti {
  position: absolute;
  animation: fishFly ease-out forwards;
}
@keyframes fishFly {
  0%   { transform: translate(0,0) rotate(0); opacity: 1; }
  100% { transform: translate(var(--dx),var(--dy)) rotate(var(--dr)); opacity: 0; }
}

.correct-burst {
  position: fixed; inset: 0; z-index: 160;
  display: flex; align-items: center; justify-content: center;
  pointer-events: none;
}
.burst-content { font-size: 80px; animation: burstPop 0.65s ease-out forwards; }
@keyframes burstPop {
  0%   { transform: scale(0) rotate(-20deg); opacity: 1; }
  50%  { transform: scale(1.4) rotate(10deg); opacity: 1; }
  100% { transform: scale(2.0) rotate(5deg); opacity: 0; }
}

/* ===== SHARK OVERLAY ===== */
.shark-overlay {
  position: fixed; inset: 0; z-index: 300;
  background: rgba(0,0,0,0.75); backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
  padding: 20px;
}
.shark-msg-box {
  background: linear-gradient(160deg, #0a1a2e, #0d2b4e);
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: var(--radius-lg); padding: 32px 24px;
  text-align: center; max-width: 320px; width: 100%;
  display: flex; flex-direction: column; align-items: center; gap: 16px;
}
.shark-big   { font-size: 56px; }
.shark-msg-box p    { font-size: 16px; line-height: 1.6; }
.shark-msg-box button {
  background: linear-gradient(135deg, var(--accent), #1565c0);
  border: none; border-radius: var(--radius); padding: 12px 28px;
  color: #fff; font-size: 15px; font-weight: 700; cursor: pointer;
}

/* ===== RESPONSIVE / DESKTOP ===== */
@media (min-width: 480px) {
  .app-title { font-size: 52px; }
  .flashcard { max-width: 380px; }
  .quiz-word { font-size: 40px; }
  .home-actions { max-width: 420px; margin: 0 auto; }
  .overall-progress { max-width: 420px; margin: 0 auto 0; }
}

@media (min-width: 768px) {
  .topic-grid { grid-template-columns: repeat(3, 1fr); max-width: 600px; margin: 0 auto; }
  .review-options { max-width: 480px; margin: 0 auto; }
}