:root {
    --primary: #4F6EF7; --primary-dark: #3B54D4; --secondary: #F59E0B; --accent: #EC4899;
    --success: #10B981; --error: #EF4444; --bg: #F0F4FF; --card-bg: #FFFFFF;
    --text: #1E293B; --text-light: #64748B; --border: #E2E8F0;
    --shadow: 0 4px 24px rgba(79,110,247,0.10); --shadow-lg: 0 12px 40px rgba(79,110,247,0.18);
    --radius: 20px; --radius-sm: 12px; --font-display: 'Poppins',sans-serif; --font-body: 'Inter',sans-serif;
}
* { box-sizing:border-box; -webkit-tap-highlight-color:transparent; }
html, body { margin:0; padding:0; width:100%; height:100%; overflow:hidden; font-family:var(--font-body); background:#0F172A; color:var(--text); touch-action:manipulation; user-select:none; }
#app { display:flex; flex-direction:column; width:100%; height:100%; max-width:480px; margin:0 auto; background:var(--bg); position:relative; overflow:hidden; box-shadow:0 0 80px rgba(79,110,247,0.25); }
#progress-container { position:absolute; top:0; left:0; right:0; z-index:100; height:5px; background:rgba(79,110,247,0.12); pointer-events:none; }
#progress-bar { height:100%; background:linear-gradient(90deg,#4F6EF7,#7C5CFC,#EC4899); border-radius:0 3px 3px 0; transition:width 0.5s ease; width:0%; box-shadow:0 0 12px rgba(79,110,247,0.5); }
#top-bar { position:absolute; top:8px; left:0; right:0; z-index:101; display:flex; align-items:center; justify-content:space-between; padding:4px 12px; pointer-events:none; }
#top-bar > * { pointer-events:auto; }
#home-btn, #fullscreen-btn { width:34px; height:34px; border-radius:50%; border:none; background:rgba(255,255,255,0.85); color:#4F6EF7; font-size:1rem; cursor:pointer; display:flex; align-items:center; justify-content:center; box-shadow:0 2px 8px rgba(0,0,0,0.08); backdrop-filter:blur(4px); }
#home-btn:active, #fullscreen-btn:active { transform:scale(0.9); background:#4F6EF7; color:#fff; }
#center-info { display:flex; flex-direction:column; align-items:center; gap:2px; pointer-events:none; }
#slide-indicator { font-family:var(--font-display); font-weight:600; font-size:0.78rem; color:#4F6EF7; background:rgba(255,255,255,0.85); padding:4px 12px; border-radius:20px; box-shadow:0 2px 8px rgba(0,0,0,0.08); white-space:nowrap; }
#date-display { font-size:0.65rem; color:#64748B; background:rgba(255,255,255,0.7); padding:2px 8px; border-radius:10px; }
#slide-container { flex:1; display:flex; align-items:center; justify-content:center; padding:48px 44px 10px; position:relative; z-index:10; overflow-y:auto; -webkit-overflow-scrolling:touch; }
#slide-content { width:100%; max-width:420px; display:flex; flex-direction:column; gap:10px; transition:opacity 0.3s, transform 0.35s ease; }
#slide-content.animating { opacity:0; transform:translateY(18px); }
#slide-content.fade-in { opacity:1; transform:translateY(0); }
.content-block { background:var(--card-bg); border-radius:var(--radius-sm); padding:14px 16px; box-shadow:var(--shadow); border:1px solid var(--border); animation:blockAppear 0.4s ease; font-size:0.9rem; line-height:1.55; color:var(--text); word-break:break-word; }
.content-block.math-block { text-align:center; background:#F8FAFF; border:2px dashed #D0D9F8; padding:14px 10px; overflow-x:auto; font-size:0.9rem; }
.content-block.title-block { text-align:center; background:linear-gradient(135deg,#4F6EF7,#6366F1); color:#fff; border:none; font-family:var(--font-display); font-weight:700; font-size:1.2rem; padding:18px 16px; box-shadow:var(--shadow-lg); }
.content-block.author-block { text-align:center; background:#F8FAFF; border:1px solid #D0D9F8; font-size:0.8rem; color:var(--text-light); }
.content-block.highlight-block { border-left:4px solid var(--secondary); background:#FFFDF5; }
.content-block.success-block { border-left:4px solid var(--success); background:#F0FDF6; }
.content-block.info-block { border-left:4px solid var(--primary); background:#F4F6FF; }
@keyframes blockAppear { from { opacity:0; transform:translateY(14px); } to { opacity:1; transform:translateY(0); } }
.interactive-area { pointer-events:auto; user-select:auto; }
.mcq-option, .tf-btn, .drag-source, .sort-item, .drop-zone, .check-btn, .answer-input, select.answer-select { font-family:var(--font-body); }
.mcq-option { display:block; width:100%; padding:12px 14px; margin:6px 0; border:2px solid var(--border); border-radius:10px; background:#fff; cursor:pointer; text-align:left; font-size:0.85rem; }
.mcq-option:active { transform:scale(0.97); }
.mcq-option.selected { border-color:var(--primary); background:#F4F6FF; font-weight:600; }
.mcq-option.correct { border-color:var(--success)!important; background:#ECFDF5!important; color:#065F46!important; }
.mcq-option.incorrect { border-color:var(--error)!important; background:#FEF2F2!important; color:#991B1B!important; }
.tf-btn { display:inline-block; width:48%; padding:14px; margin:6px 1%; border:2px solid var(--border); border-radius:50px; background:#fff; cursor:pointer; font-size:0.95rem; font-weight:600; text-align:center; }
.tf-btn.correct { border-color:var(--success)!important; background:#ECFDF5!important; color:#065F46!important; }
.tf-btn.incorrect { border-color:var(--error)!important; background:#FEF2F2!important; color:#991B1B!important; }
.drag-source { display:inline-block; padding:10px 14px; margin:5px; background:#fff; border:2px solid var(--primary); border-radius:22px; cursor:grab; font-weight:500; font-size:0.8rem; transition:0.2s; pointer-events:auto; touch-action:none; white-space:nowrap; color:var(--primary); }
.drag-source:active { cursor:grabbing; transform:scale(0.93); box-shadow:var(--shadow-lg); }
.drag-source.dragging { opacity:0.4; transform:scale(0.88); }
.drop-zone { display:inline-block; min-width:80px; min-height:42px; padding:8px 12px; margin:5px; border:2px dashed #CBD5E1; border-radius:10px; text-align:center; vertical-align:middle; transition:0.3s; background:#FAFBFC; font-size:0.8rem; color:#94A3B8; pointer-events:auto; }
.drop-zone.highlight { border-color:var(--secondary); background:#FFFDF5; box-shadow:0 0 0 6px rgba(245,158,11,0.12); }
.drop-zone.filled { border-style:solid; border-color:var(--success); background:#ECFDF5; color:#065F46; font-weight:600; }
.drop-zone.wrong { border-color:var(--error)!important; background:#FEF2F2; color:#991B1B; }
.sort-item { display:block; padding:12px 14px; margin:5px 0; background:#fff; border:2px solid var(--border); border-radius:10px; cursor:grab; font-size:0.82rem; pointer-events:auto; touch-action:none; }
.sort-zone { min-height:50px; border:2px dashed #CBD5E1; border-radius:10px; padding:6px; transition:0.3s; background:#FAFBFC; }
.answer-input { width:100%; padding:12px 14px; border:2px solid var(--border); border-radius:22px; font-size:0.9rem; text-align:center; pointer-events:auto; background:#fff; }
.answer-input.correct { border-color:var(--success)!important; background:#ECFDF5!important; }
.answer-input.incorrect { border-color:var(--error)!important; background:#FEF2F2!important; }
textarea.answer-input { text-align:left; min-height:80px; resize:vertical; border-radius:14px; }
.check-btn { display:inline-block; padding:10px 24px; margin-top:6px; background:var(--primary); color:#fff; border:none; border-radius:22px; font-weight:600; cursor:pointer; }
.check-btn:active { transform:scale(0.94); background:var(--primary-dark); }
.check-btn:disabled { opacity:0.5; pointer-events:none; }
.feedback-msg { font-weight:600; margin-top:5px; font-size:0.85rem; }
.feedback-msg.correct { color:var(--success); }
.feedback-msg.incorrect { color:var(--error); }
select.answer-select { width:100%; padding:10px 14px; border:2px solid var(--border); border-radius:22px; font-size:0.9rem; pointer-events:auto; background:#fff; text-align:center; }
#nav-area { padding:6px 20px 16px; display:flex; align-items:center; justify-content:center; gap:10px; }
#next-btn, #send-wa-btn { padding:12px 28px; border-radius:50px; font-weight:600; font-size:0.95rem; cursor:pointer; font-family:var(--font-display); }
#next-btn { background:var(--primary); color:#fff; border:none; box-shadow:0 4px 18px rgba(79,110,247,0.35); }
#send-wa-btn { background:#25D366; color:#fff; border:none; display:none; box-shadow:0 4px 18px rgba(37,211,102,0.35); }
.floating-nav { position:absolute; top:50%; transform:translateY(-50%); z-index:90; width:40px; height:40px; border-radius:50%; border:none; background:rgba(255,255,255,0.8); color:#4F6EF7; font-size:1.2rem; cursor:pointer; display:flex; align-items:center; justify-content:center; box-shadow:0 2px 12px rgba(0,0,0,0.1); backdrop-filter:blur(4px); pointer-events:auto; }
#float-prev { left:6px; } #float-next { right:6px; }
#login-overlay { position:absolute; inset:0; z-index:200; background:#F0F4FF; display:flex; align-items:center; justify-content:center; padding:20px; }
#login-overlay.hidden { display:none; }
#login-card { background:#fff; border-radius:20px; padding:24px 18px; box-shadow:var(--shadow-lg); width:100%; max-width:380px; text-align:center; }
#login-card select, #login-card input { width:100%; padding:11px 14px; border:2px solid var(--border); border-radius:22px; font-size:0.9rem; margin:6px 0; }
#login-card button { width:100%; padding:12px; background:#4F6EF7; color:#fff; border:none; border-radius:25px; font-weight:600; font-size:0.95rem; cursor:pointer; margin-top:4px; }
.author-text { font-size:0.7rem; color:#94A3B8; margin-top:8px; }
@media (max-width:380px) { #slide-container { padding:44px 36px 6px; } .content-block { padding:10px 12px; font-size:0.8rem; } .floating-nav { width:34px; height:34px; } }