:root{
  --bg:#f8fafc;
  --bg-soft:#fff5f6;
  --surface:#ffffff;
  --surface-2:#fff8f8;
  --surface-3:#fff1f3;
  --text:#17181c;
  --text-soft:#5f6675;
  --line:#eadde1;
  --line-strong:#e2c6cc;
  --accent:#c8102e;
  --accent-2:#ef233c;
  --accent-3:#ff6b7a;
  --accent-soft:#ffe1e6;
  --good:#12805c;
  --good-soft:#def7ed;
  --bad:#c1121f;
  --bad-soft:#ffe0e4;
  --warn:#d97706;
  --shadow-sm:0 8px 20px rgba(118, 27, 41, 0.08);
  --shadow-md:0 18px 40px rgba(138, 26, 47, 0.12);
  --shadow-lg:0 26px 70px rgba(160, 23, 50, 0.14);
  --radius:24px;
  --radius-md:18px;
  --radius-sm:14px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  color:var(--text);
  font-family:Inter,system-ui,-apple-system,Segoe UI,Arial,sans-serif;
  min-height:100vh;
  background:
    radial-gradient(circle at 10% 15%, rgba(255,77,109,.14), transparent 22%),
    radial-gradient(circle at 88% 8%, rgba(200,16,46,.10), transparent 18%),
    radial-gradient(circle at 78% 80%, rgba(239,35,60,.11), transparent 22%),
    linear-gradient(180deg, #ffffff 0%, #fff8f8 45%, #f8fafc 100%);
  position:relative;
  overflow-x:hidden;
}
body::before,
body::after{
  content:"";
  position:fixed;
  border-radius:50%;
  filter:blur(10px);
  z-index:-1;
  opacity:.7;
  animation:blobFloat 14s ease-in-out infinite;
}
body::before{
  width:360px;height:360px;left:-120px;top:80px;
  background:radial-gradient(circle, rgba(255,107,122,.28), rgba(255,107,122,0));
}
body::after{
  width:420px;height:420px;right:-160px;bottom:-60px;
  background:radial-gradient(circle, rgba(200,16,46,.16), rgba(200,16,46,0));
  animation-delay:-6s;
}

button,input,select{font:inherit}
button{transition:transform .22s ease, box-shadow .22s ease, background .22s ease, border-color .22s ease, color .22s ease}

.app-shell{
  display:grid;
  grid-template-columns:310px 1fr;
  min-height:100vh;
}

.sidebar{
  border-right:1px solid rgba(200,16,46,.08);
  background:rgba(255,255,255,.74);
  backdrop-filter:blur(18px);
  -webkit-backdrop-filter:blur(18px);
  padding:28px;
  position:sticky;
  top:0;
  height:100vh;
  box-shadow:inset -1px 0 0 rgba(255,255,255,.8);
}

.brand{
  display:flex;
  gap:14px;
  align-items:center;
  margin-bottom:34px;
  animation:slideFade .7s ease both;
}
.brand-mark{
  width:56px;height:56px;border-radius:18px;display:grid;place-items:center;
  font-weight:900;letter-spacing:.02em;color:#fff;
  background:linear-gradient(135deg,var(--accent),var(--accent-2) 60%, var(--accent-3));
  box-shadow:0 16px 32px rgba(200,16,46,.24), inset 0 1px 0 rgba(255,255,255,.25);
  position:relative;overflow:hidden;
}
.brand-mark::after{
  content:"";position:absolute;inset:-40% auto auto -30%;width:80%;height:180%;
  background:linear-gradient(90deg, transparent, rgba(255,255,255,.32), transparent);
  transform:rotate(22deg);
  animation:shine 5s linear infinite;
}
.brand h1{font-size:22px;margin:0;font-weight:850;letter-spacing:-.02em}
.brand p{margin:4px 0 0;color:var(--text-soft);font-size:13px}

.nav{display:grid;gap:10px}
.nav-btn{
  border:1px solid transparent;
  background:transparent;
  color:var(--text-soft);
  text-align:left;
  padding:14px 16px;
  border-radius:16px;
  cursor:pointer;
  font-weight:650;
  position:relative;
  overflow:hidden;
}
.nav-btn::before{
  content:"";position:absolute;inset:0 auto 0 0;width:0;border-radius:16px;
  background:linear-gradient(90deg, rgba(200,16,46,.11), rgba(255,107,122,.07));
  transition:width .28s ease;
}
.nav-btn:hover::before,.nav-btn.active::before{width:100%}
.nav-btn:hover,.nav-btn.active{
  color:var(--accent);
  border-color:rgba(200,16,46,.12);
  box-shadow:var(--shadow-sm);
  transform:translateX(2px);
}
.nav-btn > *,.nav-btn{position:relative;z-index:1}

.side-card{
  margin-top:28px;
  padding:18px 18px 20px;
  border-radius:22px;
  background:linear-gradient(180deg, rgba(255,225,230,.92), rgba(255,246,247,.96));
  border:1px solid rgba(200,16,46,.12);
  box-shadow:var(--shadow-sm);
  animation:slideFade .9s ease both;
}
.mini-label,.eyebrow{
  font-size:12px;
  text-transform:uppercase;
  letter-spacing:.16em;
  color:var(--accent);
  font-weight:800;
}
.side-card strong{display:block;margin:8px 0;font-size:15px}
.side-card p{color:var(--text-soft);font-size:14px;margin:0;line-height:1.5}

.main{padding:30px;max-width:1320px;width:100%;margin:0 auto}

.hero{
  display:flex;
  align-items:flex-end;
  justify-content:space-between;
  gap:24px;
  padding:32px;
  border:1px solid rgba(200,16,46,.10);
  border-radius:30px;
  background:
    radial-gradient(circle at top right, rgba(255,107,122,.20), transparent 28%),
    linear-gradient(135deg, rgba(255,255,255,.98), rgba(255,245,246,.96) 58%, rgba(255,236,239,.95));
  box-shadow:var(--shadow-lg);
  position:relative;
  overflow:hidden;
  animation:riseIn .72s cubic-bezier(.22,1,.36,1) both;
}
.hero::before{
  content:"";
  position:absolute;
  inset:-120px auto auto -120px;
  width:240px;height:240px;border-radius:50%;
  background:radial-gradient(circle, rgba(200,16,46,.16), transparent 70%);
  animation:pulseGlow 7s ease-in-out infinite;
}
.hero::after{
  content:"";position:absolute;inset:0;
  background:linear-gradient(120deg, transparent 25%, rgba(255,255,255,.45) 42%, transparent 58%);
  transform:translateX(-130%);
  animation:heroSweep 8s ease-in-out infinite;
}
.hero > *{position:relative;z-index:1}
.hero h2{font-size:46px;line-height:.98;margin:10px 0 12px;letter-spacing:-.04em}
.hero p{max-width:760px;color:var(--text-soft);margin:0;line-height:1.65;font-size:15px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap}

.primary,.secondary{
  border:0;border-radius:15px;padding:13px 18px;font-weight:800;cursor:pointer
}
.primary{
  color:#fff;
  background:linear-gradient(135deg,var(--accent),var(--accent-2));
  box-shadow:0 14px 30px rgba(200,16,46,.24);
}
.primary:hover{transform:translateY(-2px) scale(1.01); box-shadow:0 18px 36px rgba(200,16,46,.30)}
.secondary{
  background:rgba(255,255,255,.85);
  color:var(--accent);
  border:1px solid rgba(200,16,46,.12);
  box-shadow:var(--shadow-sm);
}
.secondary:hover{transform:translateY(-2px); background:#fff; box-shadow:var(--shadow-md)}

.stats-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px;margin:18px 0 22px}
.stat{
  padding:18px 18px 16px;
  border:1px solid rgba(200,16,46,.08);
  border-radius:20px;
  background:rgba(255,255,255,.88);
  box-shadow:var(--shadow-sm);
  position:relative;
  overflow:hidden;
  animation:riseIn .7s cubic-bezier(.22,1,.36,1) both;
}
.stat:nth-child(2){animation-delay:.06s}
.stat:nth-child(3){animation-delay:.12s}
.stat:nth-child(4){animation-delay:.18s}
.stat::after{
  content:"";position:absolute;left:0;right:0;bottom:0;height:4px;
  background:linear-gradient(90deg,var(--accent),var(--accent-3));
}
.stat span{color:var(--text-soft);font-size:13px}
.stat strong{display:block;font-size:30px;margin-top:6px;letter-spacing:-.03em}

.view{display:none;animation:fadePage .35s ease}
.view.active{display:block}
.section-head{display:flex;align-items:end;justify-content:space-between;gap:16px;margin:28px 0 16px}
.section-head h3,.panel h3{font-size:30px;margin:0 0 6px;letter-spacing:-.03em}
.section-head p,.panel p{color:var(--text-soft);margin:0;line-height:1.55}

.search,select{
  background:rgba(255,255,255,.92);
  border:1px solid rgba(200,16,46,.14);
  color:var(--text);
  border-radius:15px;
  padding:12px 14px;
  min-width:220px;
  box-shadow:var(--shadow-sm);
}
.search:focus,select:focus{outline:none;border-color:rgba(200,16,46,.45);box-shadow:0 0 0 4px rgba(200,16,46,.10)}

.topic-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}
.topic-card{
  border:1px solid rgba(200,16,46,.08);
  border-radius:24px;
  background:linear-gradient(180deg, rgba(255,255,255,.96), rgba(255,247,248,.92));
  padding:20px;
  position:relative;
  overflow:hidden;
  box-shadow:var(--shadow-sm);
  transition:transform .22s ease, box-shadow .22s ease, border-color .22s ease;
}
.topic-card:hover{transform:translateY(-4px); box-shadow:var(--shadow-md); border-color:rgba(200,16,46,.18)}
.topic-card::before{
  content:"";
  position:absolute;
  inset:-75px -75px auto auto;
  width:160px;height:160px;border-radius:50%;
  background:radial-gradient(circle, rgba(200,16,46,.12), transparent 70%);
}
.topic-card::after{
  content:"";
  position:absolute;left:-50px;bottom:-50px;width:120px;height:120px;border-radius:50%;
  background:radial-gradient(circle, rgba(255,107,122,.12), transparent 70%);
}
.topic-card > *{position:relative;z-index:1}
.topic-card .num{color:var(--accent);font-weight:900}
.topic-card h4{font-size:19px;margin:10px 0 6px}
.topic-card p{color:var(--text-soft);min-height:42px;line-height:1.55}
.pill-row{display:flex;gap:8px;flex-wrap:wrap}
.pill{
  font-size:12px;
  padding:6px 10px;
  border:1px solid rgba(200,16,46,.10);
  border-radius:999px;
  color:var(--accent);
  background:var(--surface-3);
  font-weight:700;
}
.topic-actions{display:flex;gap:8px;margin-top:16px}
.topic-actions button{flex:1}

.panel{
  padding:22px;
  border:1px solid rgba(200,16,46,.08);
  border-radius:24px;
  background:rgba(255,255,255,.88);
  margin:22px 0;
  box-shadow:var(--shadow-sm);
}
.controls{display:flex;gap:12px;align-items:end;flex-wrap:wrap}
.controls label{display:grid;gap:7px;color:var(--text-soft);font-size:13px;font-weight:650}
.quiz-area{margin-top:18px}
.empty-state{
  padding:48px 24px;
  border:1px dashed rgba(200,16,46,.18);
  border-radius:24px;
  text-align:center;
  color:var(--text-soft);
  background:linear-gradient(180deg, rgba(255,255,255,.88), rgba(255,246,247,.80));
}
.empty-state h3{margin-top:0;color:var(--text)}

.question-card{
  border:1px solid rgba(200,16,46,.10);
  border-radius:28px;
  background:linear-gradient(180deg, rgba(255,255,255,.98), rgba(255,247,248,.94));
  padding:24px;
  box-shadow:var(--shadow-lg);
  animation:riseIn .45s cubic-bezier(.22,1,.36,1) both;
  position:relative;
  overflow:hidden;
}
.question-card::before{
  content:"";position:absolute;right:-70px;top:-70px;width:160px;height:160px;border-radius:50%;
  background:radial-gradient(circle, rgba(200,16,46,.10), transparent 72%);
}
.question-card > *{position:relative;z-index:1}
.q-meta{display:flex;justify-content:space-between;gap:12px;align-items:center;margin-bottom:15px}
.level{font-weight:900;border-radius:999px;padding:7px 10px;font-size:12px}
.level.basic{background:var(--good-soft);color:var(--good)}
.level.exam{background:#ffe9ed;color:var(--accent)}
.level.trap{background:var(--bad-soft);color:var(--bad)}
.q-topic{color:var(--text-soft);font-size:13px;font-weight:650}
.question-card h3{font-size:26px;line-height:1.25;margin:0 0 18px;letter-spacing:-.02em}
.options{display:grid;gap:12px}
.option{
  border:1px solid rgba(200,16,46,.10);
  background:rgba(255,255,255,.92);
  color:var(--text);
  border-radius:17px;
  padding:15px;
  text-align:left;
  cursor:pointer;
  display:flex;
  gap:12px;
  align-items:flex-start;
  box-shadow:var(--shadow-sm);
}
.option .letter{
  min-width:32px;height:32px;border-radius:11px;display:grid;place-items:center;
  background:var(--surface-3);font-weight:900;color:var(--accent)
}
.option:hover{border-color:rgba(200,16,46,.28);transform:translateY(-1px);box-shadow:var(--shadow-md)}
.option.correct{border-color:rgba(18,128,92,.35);background:var(--good-soft)}
.option.correct .letter{background:#b6ecd9;color:var(--good)}
.option.wrong{border-color:rgba(193,18,31,.35);background:var(--bad-soft)}
.option.wrong .letter{background:#ffc6ce;color:var(--bad)}
.option:disabled{cursor:default}

.feedback{
  margin-top:18px;
  padding:18px;
  border-radius:20px;
  border:1px solid rgba(200,16,46,.10);
  background:rgba(255,255,255,.75);
  animation:fadePage .22s ease;
}
.feedback.good{border-color:rgba(18,128,92,.28);background:linear-gradient(180deg, #f7fffb, #eefcf5)}
.feedback.bad{border-color:rgba(193,18,31,.24);background:linear-gradient(180deg, #fff9fa, #fff0f2)}
.feedback strong{display:block;margin-bottom:8px;line-height:1.45}

.quiz-footer{display:flex;justify-content:space-between;align-items:center;margin-top:18px;gap:12px}
.progress-wrap{height:12px;background:#f3e6e9;border-radius:999px;overflow:hidden;flex:1;box-shadow:inset 0 1px 2px rgba(0,0,0,.06)}
.progress-bar{height:100%;width:0;background:linear-gradient(90deg,var(--accent),var(--accent-3));border-radius:999px;transition:width .35s ease}
.exam-panel{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}
.switch{display:flex;gap:8px;align-items:center;color:var(--text-soft);font-weight:650}

.cheat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:14px}
.cheat{
  padding:18px;
  border:1px solid rgba(200,16,46,.08);
  border-radius:22px;
  background:linear-gradient(180deg, rgba(255,255,255,.95), rgba(255,247,248,.92));
  box-shadow:var(--shadow-sm);
  transition:transform .2s ease, box-shadow .2s ease;
}
.cheat:hover{transform:translateY(-3px); box-shadow:var(--shadow-md)}
.cheat h4{margin:0 0 8px}
.cheat p{color:var(--text-soft);margin:0;line-height:1.55}

.failure-item{
  padding:16px;
  border:1px solid rgba(200,16,46,.08);
  border-radius:20px;
  background:linear-gradient(180deg, rgba(255,255,255,.96), rgba(255,248,249,.94));
  margin-bottom:12px;
  box-shadow:var(--shadow-sm);
}
.failure-item strong{display:block;margin-bottom:7px;line-height:1.45}
.failure-item p{color:var(--text-soft);line-height:1.55}

.result-summary{
  padding:24px;
  border-radius:24px;
  border:1px solid rgba(200,16,46,.10);
  background:linear-gradient(180deg, rgba(255,255,255,.98), rgba(255,242,244,.95));
  box-shadow:var(--shadow-lg)
}
.result-summary h3{margin-top:0;font-size:30px;letter-spacing:-.03em}
.result-summary p{color:var(--text-soft);line-height:1.6}

.explanation-block{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:12px;
  margin-top:14px;
}
.explanation-block > div{
  border:1px solid rgba(200,16,46,.08);
  background:rgba(255,255,255,.82);
  border-radius:18px;
  padding:13px 14px;
  box-shadow:var(--shadow-sm);
}
.explanation-block span{
  display:inline-flex;
  font-size:.72rem;
  text-transform:uppercase;
  letter-spacing:.1em;
  color:var(--accent);
  font-weight:900;
  margin-bottom:6px;
}
.explanation-block p{margin:0;line-height:1.55;color:var(--text-soft)}
.explanation-es span{ color:#9a3412; }

::-webkit-scrollbar{width:12px;height:12px}
::-webkit-scrollbar-thumb{background:#eab2bb;border-radius:999px;border:3px solid #fff7f8}
::-webkit-scrollbar-track{background:#fff7f8}

@keyframes blobFloat{
  0%,100%{transform:translate3d(0,0,0) scale(1)}
  50%{transform:translate3d(22px,-18px,0) scale(1.06)}
}
@keyframes shine{
  0%{transform:translateX(-160%) rotate(22deg)}
  18%,100%{transform:translateX(260%) rotate(22deg)}
}
@keyframes slideFade{
  from{opacity:0;transform:translateY(10px)}
  to{opacity:1;transform:translateY(0)}
}
@keyframes riseIn{
  from{opacity:0;transform:translateY(18px) scale(.985)}
  to{opacity:1;transform:translateY(0) scale(1)}
}
@keyframes pulseGlow{
  0%,100%{transform:scale(1);opacity:.8}
  50%{transform:scale(1.1);opacity:1}
}
@keyframes heroSweep{
  0%, 75%, 100%{transform:translateX(-130%)}
  30%, 45%{transform:translateX(130%)}
}
@keyframes fadePage{
  from{opacity:0}
  to{opacity:1}
}

@media(max-width:1100px){
  .stats-grid{grid-template-columns:repeat(2,1fr)}
}
@media(max-width:900px){
  .app-shell{grid-template-columns:1fr}
  .sidebar{position:relative;height:auto;border-right:0;border-bottom:1px solid rgba(200,16,46,.08)}
  .main{padding:18px}
  .hero{display:block;padding:26px}
  .hero h2{font-size:36px}
  .section-head{display:block}
  .search{width:100%;margin-top:14px}
  .controls{display:grid}
  .controls label,select{width:100%;min-width:0}
  .exam-panel{display:block}
  .exam-panel>*{margin-bottom:12px}
}
@media (max-width: 820px){
  .explanation-block{grid-template-columns:1fr}
}
@media(max-width:620px){
  .stats-grid{grid-template-columns:1fr}
  .hero h2{font-size:32px}
  .question-card h3{font-size:22px}
  .quiz-footer{flex-wrap:wrap}
}

.keyboard-hint{
  margin-top:10px;
  color:var(--text-soft);
  font-size:12px;
  font-weight:750;
  letter-spacing:.02em;
  text-align:right;
}
@media(max-width:620px){
  .keyboard-hint{text-align:left}
}