@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800;900&display=swap');

:root{
  --bg:#09090b;
  --bg-elevated:#111113;
  --bg-card:#18181b;
  --bg-hover:#1f1f23;
  --border:rgba(255,255,255,.06);
  --border-hover:rgba(255,255,255,.1);
  --border-active:rgba(139,92,246,.3);
  --text:#fafafa;
  --text-secondary:#a1a1aa;
  --text-muted:#52525b;
  --primary:#a78bfa;
  --primary-dark:#8b5cf6;
  --accent:#34d399;
  --danger:#ef4444;
  --warning:#f59e0b;
  --radius:12px;
  --radius-lg:16px;
  --radius-full:100px;
  --shadow:0 1px 3px rgba(0,0,0,.3);
  --shadow-lg:0 8px 32px rgba(0,0,0,.4);
  --transition:all .2s cubic-bezier(.4,0,.2,1);
}

*{margin:0;padding:0;box-sizing:border-box}
body{
  font-family:'Inter',-apple-system,sans-serif;
  background:var(--bg);
  color:var(--text);
  min-height:100vh;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}
a{color:var(--primary);text-decoration:none;transition:var(--transition)}
a:hover{opacity:.85}

.nav,.site-header{
  position:sticky;top:0;z-index:50;
  padding:14px 24px;
  background:rgba(9,9,11,.85);
  -webkit-backdrop-filter:blur(16px);
  backdrop-filter:blur(16px);
  border-bottom:1px solid var(--border);
}
.nav-inner,.header-inner{
  max-width:1100px;margin:0 auto;
  display:flex;align-items:center;justify-content:space-between;
}
.nav-logo,.site-title{
  display:flex;align-items:center;gap:10px;
  font-size:1.05em;font-weight:800;color:var(--text);text-decoration:none;
}
.nav-logo svg{width:30px;height:30px;flex-shrink:0}
.nav-logo .grad,.site-title span{
  background:linear-gradient(135deg,var(--primary),var(--accent));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.nav-links,.site-nav{display:flex;gap:4px;align-items:center}
.nav-links a,.site-nav a{
  padding:7px 14px;border-radius:var(--radius-full);
  font-size:.82em;font-weight:500;
  color:var(--text-secondary);text-decoration:none;
  transition:var(--transition);
}
.nav-links a:hover,.site-nav a:hover{color:var(--text);background:rgba(255,255,255,.04)}
.nav-links a.active,.site-nav a.active{color:var(--text);background:rgba(255,255,255,.06)}

.container{max-width:1100px;margin:0 auto;padding:0 24px}

.hero{padding:64px 0 48px;text-align:center}
.hero h1{
  font-size:2.5em;font-weight:800;margin-bottom:10px;
  letter-spacing:-.03em;line-height:1.15;
}
.hero h1 .grad{
  background:linear-gradient(135deg,var(--text) 30%,var(--primary) 60%,var(--accent));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.hero p{
  font-size:1em;color:var(--text-secondary);
  max-width:580px;margin:0 auto 28px;line-height:1.7;
}
.hero-stats{display:flex;justify-content:center;gap:40px;flex-wrap:wrap}
.stat{text-align:center}
.stat-num{
  font-size:1.8em;font-weight:900;
  background:linear-gradient(135deg,var(--primary),var(--accent));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.stat-label{font-size:.85em;color:var(--text-muted)}

.section{padding:36px 0}
.section-title{font-size:1.25em;font-weight:700;margin-bottom:4px}
.section-title span{
  background:linear-gradient(135deg,var(--primary),var(--accent));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;
}
.section-sub{color:var(--text-secondary);font-size:.88em;margin-bottom:20px}

.paper-card{
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:18px 22px;margin-bottom:10px;
  display:flex;justify-content:space-between;align-items:center;
  flex-wrap:wrap;gap:12px;
  transition:var(--transition);
}
.paper-card:hover{
  border-color:var(--border-hover);
  background:var(--bg-hover);
  transform:translateY(-1px);
}
.pc-title{font-weight:600;font-size:.93em;color:var(--text)}
.pc-meta{font-size:.8em;color:var(--text-muted);margin-top:2px}
.pc-btn{
  background:linear-gradient(135deg,var(--primary),var(--primary-dark));
  color:#fff;border:none;padding:9px 20px;
  border-radius:var(--radius-full);
  font-size:.8em;font-weight:600;cursor:pointer;
  white-space:nowrap;text-decoration:none;
  transition:var(--transition);display:inline-flex;align-items:center;gap:6px;
}
.pc-btn:hover{
  transform:translateY(-1px);
  box-shadow:0 4px 20px rgba(139,92,246,.3);
}

.feat-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:12px;margin-top:12px}
.feat-card{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:24px;text-align:center;
  transition:var(--transition);
}
.feat-card:hover{border-color:var(--border-hover);background:var(--bg-hover);transform:translateY(-2px)}
.feat-icon{font-size:1.8em;margin-bottom:10px}
.feat-title{font-weight:600;font-size:.88em;margin-bottom:4px;color:var(--text)}
.feat-desc{font-size:.8em;color:var(--text-secondary)}

.paper-page{max-width:800px;margin:0 auto;padding:32px 24px}
.paper-header{margin-bottom:24px}
.paper-header h1{font-size:1.35em;font-weight:700;letter-spacing:-.01em}
.paper-meta{color:var(--text-muted);font-size:.83em;margin-top:6px;display:flex;gap:16px;flex-wrap:wrap}

.question{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--radius);padding:20px;margin-bottom:14px;
  transition:var(--transition);
}
.question:hover{border-color:var(--border-hover)}
.q-number{font-size:.76em;color:var(--text-muted);font-weight:600;margin-bottom:6px}
.q-text{font-size:.93em;margin-bottom:12px;font-weight:500;line-height:1.65}
.q-options{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin-bottom:10px}
.q-option{
  padding:10px 14px;border:1px solid var(--border);
  border-radius:8px;font-size:.85em;cursor:pointer;
  transition:var(--transition);color:#d4d4d8;
}
.q-option:hover{border-color:var(--primary);background:rgba(139,92,246,.06)}
.q-option.correct{
  border-color:var(--accent);background:rgba(52,211,153,.1);
  color:var(--accent);font-weight:600;
}
.q-option.wrong{
  border-color:var(--danger);background:rgba(239,68,68,.1);
  color:var(--danger);
}
.solution-box{
  background:rgba(52,211,153,.04);
  border:1px solid rgba(52,211,153,.1);
  border-radius:8px;padding:14px;margin-top:10px;
  font-size:.83em;display:none;color:#d4d4d8;line-height:1.6;
}
.solution-box.show{display:block}
.solution-box strong{color:var(--accent)}
.show-soln{
  background:rgba(255,255,255,.03);
  border:1px solid var(--border);
  border-radius:var(--radius-full);
  padding:6px 14px;font-size:.78em;cursor:pointer;
  color:var(--text-secondary);transition:var(--transition);
}
.show-soln:hover{border-color:var(--primary);color:var(--primary)}

.section-badge{
  display:inline-block;font-size:.68em;padding:2px 10px;border-radius:var(--radius-full);
  color:#fff;margin-left:6px;font-weight:500;
}
.section-ga{background:#6366f1}
.section-reasoning{background:var(--warning)}
.section-quant{background:var(--danger)}
.section-english{background:var(--primary-dark)}

.site-footer{
  text-align:center;padding:32px 24px;
  color:var(--text-muted);font-size:.8em;
  border-top:1px solid var(--border);margin-top:40px;
}

.timer-bar{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:10px;padding:12px 16px;margin-bottom:20px;
  display:flex;justify-content:space-between;align-items:center;
}
.timer{font-size:1.05em;font-weight:700;color:var(--accent)}
.timer.warning{color:var(--danger)}

@media(max-width:640px){
  .hero{padding:40px 0 32px}
  .hero h1{font-size:1.6em}
  .hero-stats{gap:16px}
  .q-options{grid-template-columns:1fr}
  .paper-card{flex-direction:column;align-items:flex-start}
  .nav-links a,.site-nav a{padding:6px 10px;font-size:.76em}
  .section-title{font-size:1.1em}
}

@media(max-width:480px){
  .nav{padding:12px 16px}
  .nav-links,.site-nav{gap:2px}
  .nav-links a,.site-nav a{padding:5px 8px;font-size:.73em}
  .container{padding:0 16px}
}

/* ===== SHARED FEATURES ===== */
.diff-dot{display:inline-block;font-size:.62em;padding:1px 8px;border-radius:var(--radius-full);margin-left:6px;font-weight:600}
.diff-easy{background:rgba(52,211,153,.12);color:var(--accent)}
.diff-medium{background:rgba(251,191,36,.12);color:var(--warning)}
.diff-hard{background:rgba(239,68,68,.12);color:var(--danger)}

.dash-overlay{
  position:fixed;inset:0;background:rgba(0,0,0,.7);
  z-index:9999;display:flex;align-items:center;
  justify-content:center;padding:24px;
  animation:fadeIn .2s ease;
}
.dash-modal{
  background:var(--bg-elevated);
  border:1px solid var(--border);
  border-radius:var(--radius-lg);padding:28px;
  max-width:420px;width:100%;
  animation:slideUp .25s ease;
}
.dash-grid{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-top:16px}
.dash-stat{
  background:rgba(255,255,255,.02);border:1px solid var(--border);
  border-radius:10px;padding:16px;text-align:center;
}
.dash-num{display:block;font-size:1.5em;font-weight:800;color:var(--text)}
.dash-label{font-size:.75em;color:var(--text-muted);margin-top:2px}
.dash-topics{margin-top:8px}
.dash-topic{
  display:flex;justify-content:space-between;
  padding:6px 0;font-size:.8em;
  border-bottom:1px solid var(--border);color:#d4d4d8;
}
.dash-topic-pct{font-weight:700}

.bookmark-btn{cursor:pointer;font-size:.85em;margin-left:8px;opacity:.3;transition:opacity .2s;user-select:none;filter:grayscale(1)}
.bookmark-btn:hover{opacity:.7}
.bookmark-btn.bm-active{opacity:1;filter:grayscale(0)}
.question.bookmarked{border-color:rgba(251,191,36,.25)!important}

.goal-overlay{
  position:fixed;inset:0;background:rgba(0,0,0,.7);
  z-index:9999;display:flex;align-items:center;
  justify-content:center;padding:24px;
}
.goal-modal{
  background:var(--bg-elevated);border:1px solid var(--border);
  border-radius:var(--radius-lg);padding:28px;max-width:380px;width:100%;
}

.sr-badge{
  display:inline-block;font-size:.62em;padding:2px 8px;
  border-radius:var(--radius-full);margin-left:6px;font-weight:600;
  background:rgba(139,92,246,.12);color:var(--primary);
}

@keyframes fadeIn{from{opacity:0}to{opacity:1}}
@keyframes slideUp{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:translateY(0)}}

@media(max-width:600px){
  .paper-page{padding:16px!important}
  .paper-header h1{font-size:1.1em!important}
  .paper-meta{flex-wrap:wrap;gap:4px}
  .paper-meta span{font-size:.73em}
  .q-text{font-size:.88em;word-break:break-word}
  .q-option{padding:10px 14px;font-size:.85em}
  .site-nav{overflow-x:auto;-webkit-overflow-scrolling:touch;gap:2px}
  .site-nav a{white-space:nowrap;padding:5px 10px;font-size:.78em}
  .header-inner,.nav-inner{flex-wrap:wrap;gap:8px}
  .dash-modal{padding:20px}
  .dash-grid{gap:6px}
  .dash-stat{padding:12px}
  .dash-num{font-size:1.2em}
}