@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');
:root{--bg:#f5f7fb;--bg2:#f5f3ff;--card:#ffffff;--primary:#4f46e5;--primary-2:#6366f1;--primary-3:#818cf8;--text:#1f2937;--muted:#6b7280;--border:#e0e7ff;--ok:#10b981;--bad:#ef4444;}
*{box-sizing:border-box;-webkit-tap-highlight-color:transparent;}
html,body{margin:0;padding:0;min-height:100vh;overflow-x:hidden;overscroll-behavior:none;background:radial-gradient(1200px 600px at 10% -10%, #ddd6fe 0%, transparent 60%), radial-gradient(900px 500px at 110% 10%, #c7d2fe 0%, transparent 55%), linear-gradient(180deg,var(--bg) 0%, var(--bg2) 100%);color:var(--text);font-family:'Inter',system-ui,-apple-system,sans-serif;font-size:16px;line-height:1.55;-webkit-font-smoothing:antialiased;}
.app{max-width:640px;margin:0 auto;min-height:100vh;padding:0 0 90px;}
.header{background:linear-gradient(135deg,#4338ca 0%,#6d28d9 50%,#7c3aed 100%);color:#fff;padding:28px 22px 34px;border-radius:0 0 32px 32px;box-shadow:0 12px 40px rgba(99,102,241,.35);position:relative;overflow:hidden;}
.header::before{content:'';position:absolute;inset:0;background:radial-gradient(400px 200px at 80% 20%, rgba(255,255,255,.18), transparent 70%);pointer-events:none;}
.header h1{margin:0;font-size:26px;font-weight:800;letter-spacing:-.5px;position:relative;}
.header p{margin:6px 0 0;opacity:.9;font-size:13px;font-weight:500;position:relative;}
.header-top{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;position:relative;}
.theme-toggle{background:rgba(255,255,255,.18);border:1.5px solid rgba(255,255,255,.25);color:#fff;width:46px;height:46px;border-radius:14px;font-size:20px;cursor:pointer;transition:transform .25s,background .25s;flex-shrink:0;backdrop-filter:blur(8px);}
.theme-toggle:hover{background:rgba(255,255,255,.3);transform:rotate(20deg);}
.stats{display:flex;gap:10px;margin-top:18px;position:relative;}
.stat{flex:1;background:rgba(255,255,255,.18);border:1px solid rgba(255,255,255,.25);border-radius:16px;padding:12px 8px;text-align:center;transition:transform .2s;}
.stat:active{transform:scale(.96);}
.stat b{display:block;font-size:20px;font-weight:800;}
.stat span{font-size:11px;opacity:.9;font-weight:500;}
.controls{padding:18px 18px 10px;display:flex;flex-direction:column;gap:10px;}
select,input{width:100%;padding:14px 16px;border:1.5px solid var(--border);border-radius:16px;font-size:15px;background:rgba(255,255,255,.85);backdrop-filter:blur(8px);color:var(--text);outline:none;transition:all .25s;font-weight:500;box-shadow:0 2px 8px rgba(99,102,241,.06);}
select:focus,input:focus{border-color:var(--primary);background:#fff;box-shadow:0 0 0 4px rgba(99,102,241,.15),0 4px 12px rgba(99,102,241,.1);}
.count{font-size:13px;color:var(--muted);text-align:right;padding:0 6px;font-weight:600;}
.tabs{display:flex;gap:8px;padding:0 18px 14px;position:sticky;top:0;background:linear-gradient(180deg,var(--bg) 0%,transparent 100%);z-index:5;padding-top:10px;backdrop-filter:blur(10px);}
.tab-btn{flex:1;padding:12px 8px;border:none;border-radius:16px;background:rgba(255,255,255,.7);color:var(--muted);font-size:13px;font-weight:700;cursor:pointer;transition:all .25s;box-shadow:0 2px 8px rgba(0,0,0,.04);border:1.5px solid transparent;}
.tab-btn.active{background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff;box-shadow:0 8px 20px rgba(99,102,241,.35);transform:translateY(-1px);}
.section{padding:0 18px;display:none;animation:fadeIn .3s ease;}
.section.active{display:block;}
@keyframes fadeIn{from{opacity:0;transform:translateY(6px);}to{opacity:1;transform:translateY(0);}}
.card{cursor:pointer;margin-bottom:14px;touch-action:none;user-select:none;-webkit-user-select:none;}
.card-inner{position:relative;min-height:240px;transition:transform .6s cubic-bezier(.34,1.56,.64,1);transform-style:preserve-3d;will-change:transform;backface-visibility:hidden;-webkit-backface-visibility:hidden;background:var(--card);border-radius:24px;}
.card.flipped .card-inner{transform:rotateY(180deg);}
.card-face{position:absolute;inset:0;background:rgba(255,255,255,.92);border:1.5px solid rgba(255,255,255,.6);border-radius:24px;padding:22px;box-shadow:0 12px 36px rgba(99,102,241,.12),0 2px 8px rgba(0,0,0,.04);backface-visibility:hidden;-webkit-backface-visibility:hidden;display:flex;flex-direction:column;}
.card-back{transform:rotateY(180deg);background:linear-gradient(135deg,rgba(238,242,255,.95),rgba(245,243,255,.95));}
.card-meta{font-size:12px;color:var(--muted);margin-bottom:12px;display:flex;justify-content:space-between;font-weight:600;}
.card-q{font-size:18px;font-weight:700;line-height:1.4;flex:1;display:flex;align-items:center;letter-spacing:-.2px;}
.card-a{font-size:15px;line-height:1.65;overflow:auto;max-height:280px;font-weight:500;}
.card-hint{font-size:11px;color:var(--muted);margin-top:12px;text-align:center;font-weight:600;opacity:.7;}
PY
.actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:4px;}
.btn{flex:1;min-width:90px;padding:14px 12px;border:none;border-radius:16px;font-size:14px;font-weight:700;cursor:pointer;transition:transform .15s,box-shadow .25s,filter .2s;letter-spacing:-.2px;}
.btn:active{transform:scale(.95);}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff;box-shadow:0 8px 20px rgba(99,102,241,.35);}
.btn-primary:hover{filter:brightness(1.05);}
.btn-ghost{background:rgba(255,255,255,.85);color:var(--text);box-shadow:0 2px 8px rgba(0,0,0,.06);border:1.5px solid var(--border);}
.btn-ok{background:linear-gradient(135deg,#10b981,#059669);color:#fff;box-shadow:0 6px 16px rgba(16,185,129,.3);}
.btn-bad{background:linear-gradient(135deg,#ef4444,#dc2626);color:#fff;box-shadow:0 6px 16px rgba(239,68,68,.3);}
.progress{font-size:13px;color:var(--muted);text-align:center;margin-top:10px;font-weight:600;}
.quiz-card{background:rgba(255,255,255,.92);border:1.5px solid rgba(255,255,255,.6);border-radius:24px;padding:22px;box-shadow:0 12px 36px rgba(99,102,241,.12);}
.quiz-meta{font-size:12px;color:var(--muted);margin-bottom:10px;font-weight:600;}
.quiz-q{font-size:18px;font-weight:700;margin-bottom:18px;line-height:1.4;letter-spacing:-.2px;}
.opt{width:100%;text-align:left;padding:16px 18px;margin-bottom:12px;border:1.5px solid var(--border);border-radius:18px;background:rgba(255,255,255,.9);font-size:14px;line-height:1.55;cursor:pointer;transition:all .25s;font-weight:500;display:flex;align-items:flex-start;gap:12px;box-shadow:0 2px 8px rgba(0,0,0,.04);}
.opt:hover{border-color:var(--primary);transform:translateY(-1px);box-shadow:0 6px 16px rgba(99,102,241,.12);}
.opt:active{transform:scale(.99);}
.opt.correct{background:linear-gradient(135deg,#dcfce7,#d1fae5);border-color:var(--ok);color:#14532d;box-shadow:0 6px 16px rgba(16,185,129,.2);}
.opt.wrong{background:linear-gradient(135deg,#fee2e2,#fecaca);border-color:var(--bad);color:#7f1d1d;box-shadow:0 6px 16px rgba(239,68,68,.2);}
.opt:disabled{cursor:default;}
.opt-letter{flex-shrink:0;width:32px;height:32px;border-radius:10px;background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff;font-size:13px;font-weight:800;display:flex;align-items:center;justify-content:center;box-shadow:0 3px 10px rgba(99,102,241,.3);margin-top:2px;}
.opt.correct .opt-letter{background:linear-gradient(135deg,#10b981,#059669);}
.opt.wrong .opt-letter{background:linear-gradient(135deg,#ef4444,#dc2626);}
.opt-text{flex:1;}
.feedback{margin-top:14px;font-size:15px;font-weight:700;min-height:22px;}
.feedback.ok{color:var(--ok);}
.feedback.bad{color:var(--bad);}
.score{font-size:13px;color:var(--muted);margin-top:10px;font-weight:600;}
.item{background:rgba(255,255,255,.9);backdrop-filter:blur(8px);border:1.5px solid rgba(255,255,255,.6);border-radius:18px;margin-bottom:10px;box-shadow:0 4px 16px rgba(99,102,241,.08);overflow:hidden;transition:transform .2s,box-shadow .2s;}
.item:hover{transform:translateY(-2px);box-shadow:0 8px 24px rgba(99,102,241,.12);}
.item-head{display:flex;align-items:center;gap:12px;padding:16px 18px;cursor:pointer;}
.item-num{flex-shrink:0;width:40px;height:40px;border-radius:12px;background:linear-gradient(135deg,var(--primary),var(--primary-2));color:#fff;font-size:12px;font-weight:800;display:flex;align-items:center;justify-content:center;box-shadow:0 4px 12px rgba(99,102,241,.3);}
.item-q{flex:1;font-size:14px;font-weight:600;line-height:1.45;}
.item-chevron{color:var(--muted);transition:transform .3s cubic-bezier(.34,1.56,.64,1);font-size:14px;font-weight:700;}
.item.open .item-chevron{transform:rotate(180deg);}
.item-body{max-height:0;overflow:hidden;transition:max-height .35s ease;}
.item.open .item-body{max-height:700px;}
.item-answer{padding:0 18px 18px 68px;font-size:14px;color:#374151;line-height:1.65;font-weight:500;}
.item-tag{font-size:10px;font-weight:700;padding:3px 9px;border-radius:8px;background:linear-gradient(135deg,#eef2ff,#e0e7ff);color:var(--primary);margin-left:8px;white-space:nowrap;}
.empty{text-align:center;padding:50px 20px;color:var(--muted);font-weight:600;}
.bottom-nav{position:fixed;bottom:0;left:0;right:0;background:rgba(255,255,255,.85);backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);border-top:1.5px solid rgba(224,231,255,.8);display:flex;justify-content:space-around;padding:10px 0 calc(10px + env(safe-area-inset-bottom));z-index:10;max-width:640px;margin:0 auto;border-radius:24px 24px 0 0;box-shadow:0 -8px 30px rgba(99,102,241,.12);}
.nav-btn{flex:1;display:flex;flex-direction:column;align-items:center;gap:3px;border:none;background:none;color:var(--muted);font-size:10px;font-weight:700;cursor:pointer;padding:6px;transition:color .2s,transform .2s;}
.nav-btn:active{transform:scale(.9);}
.nav-btn.active{color:var(--primary);}
.nav-icon{font-size:22px;}
.hidden{display:none !important;}
@media (min-width:640px){.bottom-nav{display:none;}.app{padding-bottom:24px;}}
PY.actions{gap:12px;margin-top:12px;}
.btn{border-radius:16px;font-size:14px;font-weight:700;letter-spacing:-.2px;padding:15px 14px;transition:transform .15s,box-shadow .25s,filter .2s,background .2s;}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--primary-2));}
.btn-ghost{background:rgba(255,255,255,.9);backdrop-filter:blur(8px);}
.btn-ok{background:linear-gradient(135deg,#10b981,#059669);}
.btn-bad{background:linear-gradient(135deg,#ef4444,#dc2626);}
.btn:hover{transform:translateY(-2px);box-shadow:0 10px 24px rgba(99,102,241,.2);}
.btn:active{transform:scale(.96);}
.card.swipe-left .card-face{background:linear-gradient(135deg,#fee2e2,#fecaca);border-color:#ef4444;box-shadow:0 12px 36px rgba(239,68,68,.25);}
.card.swipe-right .card-face{background:linear-gradient(135deg,#dcfce7,#bbf7d0);border-color:#10b981;box-shadow:0 12px 36px rgba(16,185,129,.25);}
.powtorka-info{background:rgba(255,255,255,.85);border:1.5px solid var(--border);border-radius:14px;padding:12px 16px;margin-bottom:14px;font-size:13px;color:var(--muted);font-weight:600;text-align:center;}

.swipe-overlay{position:absolute;inset:0;border-radius:24px;pointer-events:none;opacity:0;transition:opacity .12s;}
.swipe-overlay::before{position:absolute;top:16px;font-size:40px;font-weight:900;opacity:.8;pointer-events:none;}
.card.swipe-right .swipe-overlay{opacity:1;background:radial-gradient(circle at 85% 25%, rgba(16,185,129,.22) 0%, transparent 55%);}
.card.swipe-left .swipe-overlay{opacity:1;background:radial-gradient(circle at 15% 25%, rgba(239,68,68,.22) 0%, transparent 55%);}
.card.swipe-right .swipe-overlay::before{content:"✓";right:16px;color:#10b981;}
.card.swipe-left .swipe-overlay::before{content:"✗";left:16px;color:#ef4444;}