.welcome-banner { text-align:center; margin:24px 0 20px; }
.welcome-banner h1 { font-size:26px; background:var(--grad); -webkit-background-clip:text; -webkit-text-fill-color:transparent; }
.welcome-banner p { font-size:16px; color:var(--text-light); margin-top:6px; }

#units-grid { display:grid; grid-template-columns:1fr; gap:16px; margin-bottom:32px; }
.unit-card { border-radius:var(--radius); padding:20px; color:#fff; cursor:pointer; transition:transform .2s,box-shadow .2s; box-shadow:0 4px 12px rgba(0,0,0,.1); animation:fadeIn .4s; }
.unit-card:hover { transform:translateY(-4px); box-shadow:0 8px 24px rgba(0,0,0,.2); }
.unit-card h2 { font-size:20px; margin-bottom:6px; }
.unit-card .unit-icon { font-size:40px; margin-bottom:10px; }
.unit-card .unit-progress { margin-top:14px; background:rgba(255,255,255,.2); border-radius:8px; padding:4px; }
.unit-card .progress-bar { background:#fff; border-radius:6px; height:8px; transition:width .5s; }
.unit-card .progress-text { font-size:12px; margin-top:6px; opacity:.9; }
.unit-card .chapters-preview { margin-top:10px; font-size:13px; opacity:.85; line-height:1.4; }

#sections-grid { display:grid; grid-template-columns:1fr; gap:14px; }
.section-card { background:var(--card); border-radius:var(--radius); padding:18px; box-shadow:0 2px 8px rgba(0,0,0,.08); cursor:pointer; transition:transform .2s; border:3px solid transparent; animation:fadeIn .4s; }
.section-card:hover { transform:translateY(-3px); border-color:var(--primary); }
.section-card.completed { border-color:var(--success); }
.section-card .section-code { font-size:13px; color:var(--text-light); font-weight:600; }
.section-card .section-name { font-size:18px; font-weight:700; margin:6px 0; }
.section-card .section-meta { display:flex; gap:6px; flex-wrap:wrap; margin-top:10px; }
.section-card .meta-badge { padding:4px 10px; border-radius:12px; font-size:11px; font-weight:600; }
.meta-badge.done { background:#e8f5e9; color:var(--success); }
.meta-badge.todo { background:#fff3e0; color:var(--warning); }
.meta-badge.exp { background:#e3f2fd; color:var(--info); }
.section-card .section-progress-ring { width:48px; height:48px; float:right; }

#activities-list { display:flex; flex-direction:column; gap:12px; max-width:700px; margin:0 auto; }
.activity-card { background:var(--card); border-radius:var(--radius); padding:16px 18px; box-shadow:0 2px 8px rgba(0,0,0,.08); cursor:pointer; transition:transform .1s; display:flex; align-items:center; gap:12px; animation:slideIn .3s; }
.activity-card:hover { transform:translateX(4px); }
.activity-card.done { border-left:6px solid var(--success); }
.activity-card .act-icon { font-size:30px; flex-shrink:0; }
.activity-card .act-info { flex:1; min-width:0; }
.activity-card .act-title { font-size:16px; font-weight:700; }
.activity-card .act-type { font-size:12px; color:var(--text-light); }
.activity-card .act-points { font-size:13px; font-weight:700; color:var(--warning); flex-shrink:0; }
.activity-card .checkmark { font-size:28px; color:var(--success); }

#activity-container, #experiment-container { max-width:700px; margin:0 auto; }
.activity-header { text-align:center; margin-bottom:20px; }
.activity-header h2 { font-size:24px; }
.activity-header .act-type-label { font-size:13px; color:var(--text-light); text-transform:uppercase; letter-spacing:1px; }

.flashcard-stage { perspective:1000px; margin:0 auto; width:100%; max-width:400px; height:260px; }
.flashcard { width:100%; height:100%; position:relative; transform-style:preserve-3d; transition:transform .6s; cursor:pointer; }
.flashcard.flipped { transform:rotateY(180deg); }
.flashcard-face { position:absolute; inset:0; backface-visibility:hidden; border-radius:20px; display:flex; flex-direction:column; align-items:center; justify-content:center; padding:20px; text-align:center; }
.flashcard-front { background:var(--grad); color:#fff; }
.flashcard-back { background:#fff; border:3px solid var(--primary); transform:rotateY(180deg); color:var(--text); }
.flashcard-back h3 { font-size:20px; }
.flashcard-img { width:64px; height:64px; object-fit:contain; margin-bottom:12px; }
.flashcard-nav { display:flex; justify-content:center; gap:12px; margin-top:20px; align-items:center; }
.flashcard-counter { font-size:15px; font-weight:600; color:var(--text-light); }

.quiz-question { background:var(--card); border-radius:var(--radius); padding:18px; margin-bottom:14px; box-shadow:0 2px 8px rgba(0,0,0,.06); }
.quiz-question .q-text { font-size:17px; font-weight:600; margin-bottom:14px; }
.quiz-question .q-image { max-width:100px; max-height:100px; object-fit:contain; border-radius:12px; margin-bottom:10px; }
.quiz-options { display:grid; gap:8px; }
.quiz-option { padding:14px; border:2px solid var(--border); border-radius:12px; cursor:pointer; font-size:15px; transition:all .2s; background:#fff; }
.quiz-option:hover { border-color:var(--primary); background:#f0f4ff; }
.quiz-option.selected { border-color:var(--primary); background:#e8eaff; }
.quiz-option.correct { border-color:var(--success); background:#e8f5e9; }
.quiz-option.wrong { border-color:var(--danger); background:#fce8e8; }
.quiz-explanation { margin-top:10px; padding:10px; border-radius:8px; font-size:13px; display:none; }
.quiz-explanation.show { display:block; animation:fadeIn .3s; }
.quiz-explanation.correct { background:#e8f5e9; color:var(--success); }
.quiz-explanation.wrong { background:#fce8e8; color:var(--danger); }

.tf-question { background:var(--card); border-radius:var(--radius); padding:18px; margin-bottom:14px; box-shadow:0 2px 8px rgba(0,0,0,.06); }
.tf-question .q-text { font-size:17px; font-weight:600; margin-bottom:14px; }
.tf-buttons { display:flex; gap:10px; }
.tf-btn { flex:1; padding:14px; border:2px solid var(--border); border-radius:12px; cursor:pointer; font-size:16px; font-weight:700; transition:all .2s; background:#fff; }
.tf-btn:hover { transform:scale(1.02); }
.tf-btn.true-btn:hover { border-color:var(--success); background:#e8f5e9; }
.tf-btn.false-btn:hover { border-color:var(--danger); background:#fce8e8; }
.tf-btn.correct { border-color:var(--success); background:#c8e6c9; }
.tf-btn.wrong { border-color:var(--danger); background:#ffcdd2; }

.match-board { display:flex; gap:16px; justify-content:center; }
.match-col { display:flex; flex-direction:column; gap:10px; flex:1; max-width:200px; }
.match-card { padding:14px 16px; background:var(--card); border:3px solid var(--border); border-radius:14px; cursor:pointer; font-weight:600; font-size:15px; text-align:center; transition:all .15s; box-shadow:0 2px 6px rgba(0,0,0,.06); }
.match-card:hover { border-color:var(--primary); transform:translateY(-2px); }
.match-card.selected { border-color:var(--warning); background:#FFF3E0; box-shadow:0 4px 12px rgba(255,152,0,.3); }
.match-card.matched { border-color:var(--success); background:#C8E6C9; color:var(--success); pointer-events:none; }

.sort-categories { display:grid; gap:12px; margin-bottom:20px; }
.sort-category { background:#f0f4ff; border-radius:var(--radius); padding:14px; min-height:100px; }
.sort-category h4 { margin-bottom:10px; font-size:15px; }
.sort-items { display:flex; flex-wrap:wrap; gap:8px; }
.sort-item { padding:10px 14px; background:var(--card); border-radius:10px; cursor:grab; font-weight:600; box-shadow:0 2px 4px rgba(0,0,0,.08); transition:transform .1s; user-select:none; font-size:14px; }
.sort-item:hover { transform:scale(1.05); }
.sort-item.dragging { opacity:.5; }
.sort-item.placed { cursor:pointer; }

.memory-grid { display:grid; grid-template-columns:repeat(2,1fr); gap:10px; max-width:500px; margin:0 auto; }
.memory-card { aspect-ratio:1; border-radius:12px; cursor:pointer; display:flex; align-items:center; justify-content:center; font-weight:700; transition:transform .3s; transform-style:preserve-3d; position:relative; }
.memory-card.flipped { transform:rotateY(180deg); }
.memory-card-face { position:absolute; inset:0; backface-visibility:hidden; border-radius:12px; display:flex; align-items:center; justify-content:center; padding:6px; text-align:center; }
.memory-front { background:var(--grad); color:#fff; font-size:28px; }
.memory-back { background:#fff; border:2px solid var(--primary); transform:rotateY(180deg); font-size:12px; }
.memory-card.matched .memory-back { background:#c8e6c9; border-color:var(--success); }
.memory-card.matched { animation:glow 1s; }

.label-stage { position:relative; max-width:500px; margin:0 auto; }
.label-img { width:100%; border-radius:16px; }
.label-slot { position:absolute; transform:translate(-50%,-50%); background:#fff; border:3px solid var(--primary); border-radius:8px; padding:4px 10px; font-size:12px; font-weight:600; cursor:pointer; min-width:70px; text-align:center; }
.label-slot.answered { background:var(--success); color:#fff; border-color:var(--success); }
.label-options { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; margin-top:20px; }
.label-option { padding:10px 14px; background:var(--card); border:2px solid var(--border); border-radius:10px; cursor:pointer; font-weight:600; font-size:14px; }
.label-option.used { opacity:.3; pointer-events:none; }

.experiment-step { background:var(--card); border-radius:var(--radius); padding:18px; margin-bottom:14px; box-shadow:0 2px 8px rgba(0,0,0,.06); animation:fadeIn .4s; }
.experiment-step .step-num { display:inline-flex; align-items:center; justify-content:center; width:32px; height:32px; background:var(--primary); color:#fff; border-radius:50%; font-weight:700; margin-right:10px; flex-shrink:0; }
.experiment-step .step-text { font-size:16px; }
.experiment-step img { max-width:130px; border-radius:12px; margin-top:10px; }
.experiment-answer-input { margin-top:10px; padding:12px; border:2px solid var(--border); border-radius:8px; font-size:15px; width:100%; }
.experiment-conclusion { background:linear-gradient(135deg,#C8E6C9,#A5D6A7); border-radius:var(--radius); padding:20px; margin-top:14px; text-align:center; }
.experiment-conclusion h3 { color:var(--success); margin-bottom:8px; }

.exp-intro { background:linear-gradient(135deg,#E0F7FA,#B2EBF2); border-radius:16px; padding:20px; margin-bottom:16px; }
.exp-intro p { font-size:17px; }
.exp-progress-bar { width:100%; height:8px; background:#E0E0E0; border-radius:4px; overflow:hidden; margin-bottom:16px; }
.exp-progress-fill { height:100%; background:var(--grad); border-radius:4px; transition:width .4s; width:0%; }
.exp-prediction { margin-top:14px; padding:14px; background:#FFF8E1; border-radius:12px; }
.exp-prediction-label { font-weight:700; font-size:16px; margin-bottom:10px; color:var(--text); }
.exp-choices { display:flex; flex-direction:column; gap:8px; }
.exp-choice { padding:14px; background:var(--card); border:3px solid var(--warning); border-radius:12px; cursor:pointer; font-weight:600; font-size:15px; text-align:center; transition:all .15s; }
.exp-choice:hover { background:#FFF3E0; transform:scale(1.02); }
.exp-observe { display:flex; flex-direction:column; gap:8px; }
.exp-check { display:flex; align-items:center; gap:8px; padding:12px; background:var(--card); border-radius:10px; cursor:pointer; font-size:15px; }
.exp-check input { width:20px; height:20px; cursor:pointer; }

.btn-primary { padding:14px 28px; background:var(--grad); color:#fff; border:none; border-radius:12px; font-size:16px; font-weight:700; cursor:pointer; transition:transform .1s; }
.btn-primary:hover { transform:scale(1.02); }
.btn-primary:active { transform:scale(.98); }
.btn-primary:disabled { opacity:.5; cursor:not-allowed; }

.result-screen { text-align:center; padding:32px 20px; }
.result-screen .score-circle { width:100px; height:100px; border-radius:50%; display:flex; align-items:center; justify-content:center; margin:0 auto 20px; font-size:32px; font-weight:800; }
.result-screen .score-circle.good { background:#c8e6c9; color:var(--success); }
.result-screen .score-circle.mid { background:#fff3e0; color:var(--warning); }
.result-screen .score-circle.low { background:#fce8e8; color:var(--danger); }
.result-screen h2 { font-size:24px; margin-bottom:8px; }
.result-screen .points-earned { font-size:22px; color:var(--warning); font-weight:700; margin:14px 0; }

.badge-popup { text-align:center; }
.badge-popup .badge-icon { font-size:64px; margin-bottom:12px; animation:pop .5s; }
.badge-popup h2 { font-size:22px; margin-bottom:8px; }
.badge-popup p { color:var(--text-light); }

#confetti-canvas { position:fixed; inset:0; pointer-events:none; z-index:999; }
.confetti-piece { position:absolute; width:10px; height:10px; animation:confetti-fall 3s linear forwards; }
@keyframes confetti-fall { to { transform:translateY(100vh) rotate(720deg); opacity:0; } }

.puzzle-board { display:flex; flex-wrap:wrap; border-radius:12px; overflow:hidden; box-shadow:0 4px 12px rgba(0,0,0,.15); }
.puzzle-tile { background-repeat:no-repeat; cursor:pointer; transition:transform .15s; border:1px solid rgba(255,255,255,.3); }
.puzzle-tile:hover { transform:scale(.95); z-index:1; }
.puzzle-empty { background:rgba(0,0,0,.1) !important; cursor:default; border:1px solid rgba(0,0,0,.1); }

.dp-board { display:flex; flex-wrap:wrap; border-radius:12px; overflow:hidden; box-shadow:0 4px 16px rgba(0,0,0,.15); margin:0 auto; background:#f5f7fa; }
.dp-slot { border:2px dashed #ccc; transition:border-color .2s; }
.dp-slot.dp-empty { background:rgba(0,0,0,.03); }
.dp-slot.dp-filled { border:1px solid rgba(255,255,255,.5); background-repeat:no-repeat; }
.dp-tray { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; padding:16px; margin-top:16px; background:#f0f4ff; border-radius:16px; min-height:80px; }
.dp-piece { border-radius:8px; border:2px solid var(--primary); background-repeat:no-repeat; cursor:grab; transition:transform .1s; touch-action:none; box-shadow:0 2px 6px rgba(0,0,0,.15); }
.dp-piece:hover { transform:scale(1.08); z-index:2; }
.dp-piece.dp-dragging { opacity:.8; cursor:grabbing; transform:scale(1.1); }
.dp-piece.dp-selected { border-color:var(--warning); box-shadow:0 0 12px rgba(255,152,0,.5); transform:scale(1.08); }

.ws-hint { background:#E8F5E9; border-radius:12px; padding:12px 16px; margin-bottom:16px; text-align:center; }
.ws-hint p { font-size:14px; color:var(--text); }
.ws-words { display:flex; flex-wrap:wrap; gap:6px; justify-content:center; margin-bottom:16px; }
.ws-word { padding:4px 12px; background:#E0F7FA; border-radius:8px; font-weight:700; font-size:13px; color:var(--secondary); }
.ws-word.found { background:#C8E6C9; color:var(--success); text-decoration:line-through; }
.ws-grid { display:grid; gap:2px; max-width:360px; margin:0 auto; touch-action:none; user-select:none; }
.ws-cell { aspect-ratio:1; display:flex; align-items:center; justify-content:center; font-size:13px; font-weight:700; background:#fff; border-radius:4px; cursor:pointer; transition:background .1s; }
.ws-cell:hover { background:#E0F7FA; }
.ws-cell.dragging { background:var(--secondary); color:#fff; transform:scale(1.1); }
.ws-cell.found { background:#C8E6C9; color:var(--success); }

.scramble-arranged { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; min-height:50px; padding:16px; background:#f0f4ff; border-radius:12px; margin-bottom:16px; align-items:center; }
.scramble-available { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; padding:16px; background:var(--card); border-radius:12px; box-shadow:0 2px 8px rgba(0,0,0,.06); }
.scramble-letter { display:inline-flex; align-items:center; justify-content:center; width:40px; height:40px; background:var(--card); border:2px solid var(--primary); border-radius:8px; font-size:20px; font-weight:700; cursor:pointer; transition:transform .1s; }
.scramble-letter:hover { transform:scale(1.1); }
.scramble-letter.arranged { background:var(--primary); color:#fff; }

.fb-sentence { background:var(--card); border-radius:12px; padding:14px; box-shadow:0 2px 4px rgba(0,0,0,.04); }
.fb-blank { display:inline-block; min-width:60px; padding:2px 10px; background:#f0f4ff; border:2px dashed var(--primary); border-radius:6px; cursor:pointer; font-weight:700; text-align:center; }
.fb-blank.correct { background:#c8e6c9; border-color:var(--success); border-style:solid; color:var(--success); }
.fb-blank.wrong { background:#fce8e8; border-color:var(--danger); border-style:solid; color:var(--danger); }
.fb-bank { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; padding:16px; background:#f0f4ff; border-radius:12px; margin-top:16px; }
.fb-word { padding:8px 16px; background:var(--card); border:2px solid var(--border); border-radius:10px; cursor:pointer; font-weight:600; font-size:15px; transition:all .15s; }
.fb-word:hover { border-color:var(--primary); }
.fb-word.selected { border-color:var(--warning); background:#fff3e0; }
.fb-word.used { opacity:.3; pointer-events:none; }

.seq-placed { display:flex; flex-direction:column; gap:8px; margin-bottom:16px; }
.seq-item { display:flex; align-items:center; gap:10px; padding:12px 16px; border-radius:10px; font-size:16px; font-weight:600; }
.seq-item.correct { background:#c8e6c9; color:var(--success); }
.seq-item.wrong { background:#fce8e8; color:var(--danger); }
.seq-num { display:inline-flex; align-items:center; justify-content:center; width:28px; height:28px; background:rgba(0,0,0,.1); border-radius:50%; font-size:14px; }
.seq-remaining { display:flex; flex-wrap:wrap; gap:8px; justify-content:center; padding:16px; background:#f0f4ff; border-radius:12px; }
.seq-item-btn { padding:12px 20px; background:var(--card); border:2px solid var(--primary); border-radius:10px; cursor:pointer; font-weight:600; font-size:15px; transition:transform .1s; }
.seq-item-btn:hover { transform:scale(1.05); }

@media (min-width:480px) {
    .memory-grid { grid-template-columns:repeat(3,1fr); gap:12px; }
    .welcome-banner h1 { font-size:30px; }
    .quiz-question .q-text { font-size:18px; }
    .tf-question .q-text { font-size:18px; }
}

@media (min-width:768px) {
    .welcome-banner { margin:32px 0 24px; }
    .welcome-banner h1 { font-size:36px; }
    .welcome-banner p { font-size:18px; }

    #units-grid { grid-template-columns:repeat(auto-fill,minmax(320px,1fr)); gap:24px; margin-bottom:48px; }
    .unit-card { padding:28px; }
    .unit-card h2 { font-size:24px; }
    .unit-card .unit-icon { font-size:48px; }
    .unit-card .chapters-preview { font-size:14px; }

    #sections-grid { grid-template-columns:repeat(auto-fill,minmax(280px,1fr)); gap:20px; }
    .section-card { padding:24px; }
    .section-card .section-name { font-size:20px; }
    .section-card .meta-badge { font-size:12px; }

    .activity-card { padding:20px 24px; gap:16px; }
    .activity-card .act-icon { font-size:36px; }
    .activity-card .act-title { font-size:18px; }

    .activity-header h2 { font-size:28px; }
    .flashcard-stage { height:300px; }
    .flashcard-back h3 { font-size:22px; }
    .flashcard-img { width:80px; height:80px; }

    .quiz-question { padding:24px; }
    .quiz-question .q-text { font-size:20px; }
    .quiz-option { padding:16px; font-size:16px; }
    .tf-question { padding:24px; }
    .tf-question .q-text { font-size:20px; }
    .tf-btn { padding:16px; font-size:18px; }

    .match-pair { flex-direction:row; align-items:center; gap:16px; }
    .match-left { flex:1; }
    .match-select { flex:1; width:auto; font-size:16px; }

    .memory-grid { grid-template-columns:repeat(4,1fr); }
    .memory-front { font-size:32px; }
    .memory-back { font-size:14px; }

    .label-slot { padding:6px 12px; font-size:14px; min-width:80px; }

    .experiment-step { padding:24px; }
    .experiment-step .step-num { width:36px; height:36px; }
    .experiment-step .step-text { font-size:18px; }
    .experiment-step img { max-width:150px; }
    .experiment-answer-input { font-size:16px; }

    .btn-primary { padding:16px 32px; font-size:18px; }
    .result-screen { padding:40px; }
    .result-screen .score-circle { width:120px; height:120px; font-size:36px; }
    .result-screen h2 { font-size:28px; }
    .result-screen .points-earned { font-size:24px; }
    .badge-popup .badge-icon { font-size:80px; }
    .badge-popup h2 { font-size:24px; }

    .ws-grid { max-width:420px; gap:3px; }
    .ws-cell { font-size:15px; }
    .ws-word { font-size:14px; }
    .scramble-letter { width:48px; height:48px; font-size:24px; }
    .fb-word { font-size:16px; }
    .seq-item { font-size:18px; }
    .seq-item-btn { font-size:16px; }
}

@media (min-width:1024px) {
    .sort-categories { grid-template-columns:repeat(auto-fit,minmax(200px,1fr)); }
}