:root{--primary:#1E40AF;--primary-dark:#1E3A8A;--primary-light:#3B82F6;--secondary:#0EA5E9;--accent:#FCD34D;--dark:#0F172A;--text:#334155;--text-light:#64748B;--bg:#F8FAFC;--card:#FFFFFF;--border:#E2E8F0;--gradient:linear-gradient(135deg,#1E40AF 0%,#0EA5E9 100%);--shadow:0 4px 6px -1px rgba(0,0,0,0.1);--radius:12px;--radius-lg:16px}
*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth}
body{font-family:'Inter',-apple-system,BlinkMacSystemFont,sans-serif;background:var(--bg);color:var(--text);line-height:1.6;min-height:100vh}
a{color:var(--primary);text-decoration:none}
a:hover{color:var(--primary-dark)}

/* Navbar */
.navbar{background:var(--card);border-bottom:3px solid var(--primary);position:sticky;top:0;z-index:100;box-shadow:var(--shadow)}
.nav-inner{max-width:1200px;margin:0 auto;padding:0 1.5rem;display:flex;align-items:center;justify-content:space-between;height:64px}
.logo{font-size:1.4rem;font-weight:800;color:var(--primary);display:flex;align-items:center;gap:0.4rem}
.logo span{color:var(--secondary)}
.hamburger{display:none;background:none;border:none;cursor:pointer;padding:0.5rem}
.hamburger span{display:block;width:24px;height:2px;background:var(--primary);margin:6px 0;border-radius:2px}
.nav-links{display:flex;list-style:none;gap:0.5rem}
.nav-links a{padding:0.5rem 1rem;border-radius:var(--radius);font-weight:500;transition:all 0.2s;color:var(--text);font-size:0.95rem}
.nav-links a:hover,.nav-links a.active{background:var(--primary);color:#fff}

/* Hero */
.hero{background:var(--gradient);color:#fff;padding:4rem 2rem;text-align:center;position:relative;overflow:hidden}
.hero h1{font-size:2.5rem;font-weight:800;margin-bottom:0.75rem}
.hero p{font-size:1.1rem;opacity:0.9;max-width:600px;margin:0 auto 1.5rem}
.hero-stats{display:flex;gap:2rem;justify-content:center;margin-top:1.5rem}
.hero-stat{text-align:center}
.hero-stat .number{font-size:1.8rem;font-weight:800;display:block}
.hero-stat .label{font-size:0.8rem;opacity:0.8}
.btn-primary{display:inline-block;padding:0.75rem 2rem;background:var(--primary);color:#fff;border-radius:var(--radius);font-weight:600;transition:all 0.2s;border:none;cursor:pointer;font-size:1rem}
.btn-primary:hover{background:var(--primary-dark);color:#fff;transform:translateY(-1px);box-shadow:0 4px 12px rgba(30,64,175,0.3)}

/* Container */
.container{max-width:1200px;margin:0 auto;padding:0 1.5rem}

/* Sections */
.section{padding:3rem 0}
.section-title{font-size:1.5rem;font-weight:700;color:var(--dark);margin-bottom:1.5rem;padding-bottom:0.5rem;border-bottom:3px solid var(--primary);display:inline-block}

/* Grids */
.tests-grid,.articles-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1.5rem}
.test-card,.article-card{background:var(--card);border-radius:var(--radius-lg);overflow:hidden;border:1px solid var(--border);transition:all 0.2s;display:block;color:var(--text)}
.test-card:hover,.article-card:hover{transform:translateY(-4px);box-shadow:0 10px 20px rgba(30,64,175,0.12);border-color:var(--primary-light)}
.test-card-icon,.article-card-img{height:80px;display:flex;align-items:center;justify-content:center;font-size:2.5rem;background:var(--gradient);color:#fff}
.article-card-img img{width:100%;height:180px;object-fit:cover}
.test-card h3,.article-card h3{font-size:1rem;font-weight:700;padding:0.75rem 1rem 0.25rem;color:var(--dark)}
.test-card p,.article-card p{padding:0 1rem 0.75rem;font-size:0.88rem;color:var(--text-light);flex:1}
.test-card-footer,.article-card-footer{padding:0.75rem 1rem;border-top:1px solid var(--border);display:flex;justify-content:space-between;align-items:center;font-size:0.82rem;color:var(--text-light)}
.subject-tag{background:#EFF6FF;color:var(--primary);padding:0.15rem 0.6rem;border-radius:20px;font-weight:600}

/* Article detail */
.article-header{background:var(--gradient);color:#fff;padding:3rem 0;text-align:center;margin-bottom:2rem}
.article-header h1{font-size:2rem;font-weight:800;margin-bottom:0.75rem}
.article-meta{display:flex;gap:1.5rem;justify-content:center;font-size:0.9rem;opacity:0.85}
.article-container{max-width:800px;margin:0 auto;padding:0 1.5rem 3rem}
.article-content{font-size:1.05rem;line-height:1.8}
.article-content h2{font-size:1.4rem;font-weight:700;color:var(--dark);margin:2rem 0 0.75rem;padding-top:1rem;border-top:1px solid var(--border)}
.article-content p{margin-bottom:1.2rem;color:var(--text)}
.article-image{width:100%;height:auto;border-radius:var(--radius);margin:1.5rem 0}

/* Quiz */
.quiz-container{max-width:800px;margin:0 auto;padding:2rem 1.5rem}
.quiz-header{text-align:center;margin-bottom:1.5rem}
.quiz-progress{height:8px;background:var(--border);border-radius:4px;margin:1rem 0;overflow:hidden}
.quiz-progress-bar{height:100%;background:var(--gradient);border-radius:4px;transition:width 0.3s;width:0}
.question-card{background:var(--card);border-radius:var(--radius-lg);padding:2rem;margin-bottom:1.5rem;border:1px solid var(--border);box-shadow:var(--shadow)}
.question-number{font-size:0.85rem;color:var(--text-light);margin-bottom:0.5rem;font-weight:600}
.question-text{font-size:1.15rem;font-weight:600;color:var(--dark);margin-bottom:1.25rem}
.answer-option{padding:0.875rem 1rem;border:2px solid var(--border);border-radius:var(--radius);margin-bottom:0.75rem;cursor:pointer;transition:all 0.15s;font-size:0.95rem;display:flex;align-items:center;gap:0.75rem}
.answer-option:hover{border-color:var(--primary-light);background:#EFF6FF}
.answer-option.selected{border-color:var(--primary);background:#EFF6FF}
.answer-option.correct{border-color:#059669;background:#D1FAE5;color:#065F46}
.answer-option.incorrect{border-color:#DC2626;background:#FEE2E2;color:#991B1B}
.option-letter{width:28px;height:28px;border-radius:50%;background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700;font-size:0.85rem;flex-shrink:0}
.quiz-nav{display:flex;justify-content:space-between;gap:1rem;margin-top:1rem}
.quiz-nav button{padding:0.75rem 1.5rem;border-radius:var(--radius);font-weight:600;cursor:pointer;transition:all 0.2s;border:2px solid var(--primary);background:transparent;color:var(--primary)}
.quiz-nav button:hover{background:var(--primary);color:#fff}
.result-box{background:var(--card);border-radius:var(--radius-lg);padding:2.5rem;text-align:center;border:2px solid var(--primary);margin-bottom:2rem}
.result-score{font-size:4rem;font-weight:800;color:var(--primary)}
.result-label{font-size:1rem;color:var(--text-light);margin:0.5rem 0}
.result-message{font-size:1.2rem;font-weight:700;color:var(--dark);margin:0.75rem 0}
.result-breakdown{display:flex;justify-content:center;gap:2rem;margin:1.5rem 0}
.result-stat{text-align:center}
.result-stat .num{font-size:2rem;font-weight:800}
.correct-color{color:#059669}.incorrect-color{color:#DC2626}.skipped-color{color:#F59E0B}

/* FAQ */
.faq-item{border:1px solid var(--border);border-radius:var(--radius);margin-bottom:0.75rem;overflow:hidden}
.faq-q{padding:1rem 1.25rem;font-weight:600;cursor:pointer;background:var(--card);transition:background 0.2s;font-size:0.95rem;display:flex;justify-content:space-between;align-items:center}
.faq-q:hover{background:#EFF6FF}
.faq-a{padding:0 1.25rem 1rem;background:var(--card);color:var(--text-light);font-size:0.9rem;line-height:1.7;border-top:1px solid var(--border)}
.faq-item.open .faq-q{color:var(--primary)}

/* Footer */
.footer{background:var(--dark);color:#94A3B8;padding:3rem 0 1rem;margin-top:4rem}
.footer-grid{display:grid;grid-template-columns:2fr 1fr 1fr 1fr;gap:2rem;margin-bottom:2rem}
.footer h4{color:#fff;font-size:1rem;margin-bottom:0.75rem}
.footer-links{list-style:none;display:flex;flex-direction:column;gap:0.4rem}
.footer-links a{color:#94A3B8;font-size:0.9rem;transition:color 0.2s}
.footer-links a:hover{color:#fff}
.footer-bottom{border-top:1px solid #334155;padding-top:1.5rem;text-align:center;font-size:0.85rem}
.footer-bottom p{margin:0}

/* Stats bar */
.stats-bar{background:var(--card);border-bottom:1px solid var(--border);padding:1rem 0}
.stats-bar-inner{max-width:1200px;margin:0 auto;padding:0 1.5rem;display:flex;justify-content:space-around;text-align:center}
.stat-item .num{font-size:1.5rem;font-weight:800;color:var(--primary);display:block}
.stat-item .lbl{font-size:0.78rem;color:var(--text-light)}

/* About / Contact forms */
.page-container{max-width:800px;margin:0 auto;padding:3rem 1.5rem}
.page-container h1{font-size:2rem;font-weight:800;color:var(--dark);margin-bottom:1.5rem}
.page-container h2{font-size:1.25rem;font-weight:700;margin:2rem 0 0.75rem;color:var(--dark)}
.page-container p{margin-bottom:1rem;color:var(--text);font-size:1rem;line-height:1.8}
.form-group{margin-bottom:1.25rem}
.form-group label{display:block;font-weight:600;margin-bottom:0.4rem;font-size:0.9rem}
.form-group input,.form-group textarea{width:100%;padding:0.75rem;border:2px solid var(--border);border-radius:var(--radius);font-size:1rem;font-family:inherit;transition:border-color 0.2s}
.form-group input:focus,.form-group textarea:focus{outline:none;border-color:var(--primary)}
.form-group textarea{resize:vertical;min-height:120px}
.faq-section{margin-top:2rem}
.faq-section h2{margin-top:2.5rem}

/* Responsive */
@media(max-width:768px){
  .hamburger{display:block}
  .nav-links{display:none;position:absolute;top:64px;left:0;right:0;background:var(--card);flex-direction:column;padding:1rem;border-bottom:3px solid var(--primary);box-shadow:0 4px 6px rgba(0,0,0,0.1)}
  .nav-links.open{display:flex}
  .nav-links li{width:100%}
  .nav-links a{display:block;padding:0.75rem 1rem}
  .hero h1{font-size:1.8rem}
  .hero-stats{flex-wrap:wrap;gap:1rem}
  .footer-grid{grid-template-columns:1fr 1fr}
  .test-card h3,.article-card h3{font-size:0.9rem}
  .question-text{font-size:1rem}
}
@media(max-width:480px){
  .footer-grid{grid-template-columns:1fr}
  .tests-grid,.articles-grid{grid-template-columns:1fr}
  .hero{padding:2.5rem 1rem}
}