@import "https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap";:root{--primary:#4f46e5;--primary-hover:#4338ca;--bg-color:#f9fafb;--surface:#fff;--text-main:#111827;--text-muted:#6b7280;--border:#e5e7eb;--success:#10b981;--success-bg:#d1fae5;--warning:#f59e0b;--warning-bg:#fef3c7;--danger:#ef4444;--danger-bg:#fee2e2}*{box-sizing:border-box;margin:0;padding:0}body{background-color:var(--bg-color);color:var(--text-main);font-family:Inter,system-ui,sans-serif;line-height:1.5}a{color:inherit;text-decoration:none}button{cursor:pointer;background:0 0;border:none;font-family:inherit}.container{max-width:1200px;margin:0 auto;padding:0 1rem}.app-layout{min-height:100vh;display:flex}.sidebar{background-color:var(--surface);border-right:1px solid var(--border);flex-direction:column;width:280px;height:100vh;display:flex;position:sticky;top:0;overflow-y:auto}.sidebar-header{border-bottom:1px solid var(--border);padding:1.5rem}.sidebar-header h1{color:var(--text-main);font-size:1.25rem;font-weight:700}.sidebar-nav{flex:1;padding:1rem 0}.nav-item{color:var(--text-muted);align-items:center;gap:.75rem;padding:.75rem 1.5rem;font-weight:500;transition:all .2s;display:flex}.nav-item:hover{background-color:var(--bg-color);color:var(--text-main)}.nav-item.active{color:var(--primary);border-right:3px solid var(--primary);background-color:#eef2ff}.main-content{flex:1;padding:2rem}.page-header{margin-bottom:2rem}.page-title{margin-bottom:.5rem;font-size:2rem;font-weight:700}.page-subtitle{color:var(--text-muted)}.card{background:var(--surface);border:1px solid var(--border);border-radius:.75rem;margin-bottom:1rem;padding:1.5rem;box-shadow:0 1px 3px #0000000d}.badge{text-transform:uppercase;border-radius:9999px;padding:.25rem .75rem;font-size:.75rem;font-weight:600;display:inline-block}.badge-easy{background:var(--success-bg);color:var(--success)}.badge-medium{background:var(--warning-bg);color:var(--warning)}.badge-hard{background:var(--danger-bg);color:var(--danger)}.btn{border-radius:.5rem;justify-content:center;align-items:center;gap:.5rem;padding:.75rem 1.5rem;font-weight:500;transition:background-color .2s;display:inline-flex}.btn-primary{background-color:var(--primary);color:#fff}.btn-primary:hover{background-color:var(--primary-hover)}.btn-secondary{border:1px solid var(--border);color:var(--text-main);background-color:#fff}.btn-secondary:hover{background-color:var(--bg-color)}.question-index-grid{grid-template-columns:repeat(5,1fr);gap:.5rem;display:grid}.index-btn{border:1px solid var(--border);border-radius:.25rem;justify-content:center;align-items:center;padding:.5rem;font-weight:600;transition:all .2s;display:flex}.index-btn:hover{background-color:var(--bg-color)}.index-btn.attempted{background-color:var(--danger-bg);color:var(--danger);border-color:var(--danger)}@media (width<=768px){.desktop-only{display:none!important}.app-layout{flex-direction:column}.sidebar{width:100%;height:auto;position:static}.sidebar-nav{padding:0;display:flex;overflow-x:auto}.nav-item{white-space:nowrap;border-bottom:3px solid #0000;border-right:none;padding:1rem}.nav-item.active{border-right:none;border-bottom:3px solid var(--primary)}.main-content{padding:1rem}}