:root{--primary: #2563eb;--primary-hover: #1d4ed8;--secondary: #10b981;--bg-app: #f8fafc;--bg-card: rgba(255, 255, 255, .85);--bg-input: #ffffff;--text-dark: #1e293b;--text-light: #64748b;--border: #e2e8f0;--white: #ffffff;--danger: #ef4444;--success: #22c55e;--shadow: 0 10px 15px -3px rgba(0, 0, 0, .1), 0 4px 6px -4px rgba(0, 0, 0, .1);--radius: 20px}[data-theme=dark]{--bg-app: #0f172a;--bg-card: rgba(30, 41, 59, .85);--bg-input: #1e293b;--text-dark: #f1f5f9;--text-light: #94a3b8;--border: #334155;--shadow: 0 20px 25px -5px rgba(0, 0, 0, .3)}*{box-sizing:border-box;transition:background-color .3s,color .3s,border-color .3s,transform .2s cubic-bezier(.4,0,.2,1)}body{margin:0;padding:0;background-color:var(--bg-app);background-image:radial-gradient(at 0% 0%,rgba(37,99,235,.08) 0px,transparent 50%),radial-gradient(at 100% 100%,rgba(16,185,129,.08) 0px,transparent 50%);color:var(--text-dark);font-family:Inter,-apple-system,sans-serif;-webkit-font-smoothing:antialiased;min-height:100vh}.container{max-width:1300px;margin:0 auto;padding:2rem 1.5rem}.card{background:var(--bg-card);-webkit-backdrop-filter:blur(16px);backdrop-filter:blur(16px);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:2.5rem}.btn{padding:12px 24px;border-radius:14px;border:1px solid var(--border);font-weight:700;cursor:pointer;font-family:inherit;background:var(--bg-input);color:var(--text-dark);display:flex;align-items:center;justify-content:center;gap:8px}.btn:hover{border-color:var(--primary);transform:translateY(-2px);box-shadow:0 5px 15px #0000000d}.btn-primary{background:var(--primary);color:#fff;border:none}.btn-primary:hover{background:var(--primary-hover);box-shadow:0 8px 20px #2563eb4d}.dropdown-container{position:relative;width:100%;min-width:200px;z-index:100}.dropdown-trigger{width:100%;background:var(--bg-input);border:2px solid var(--border);padding:12px 16px;border-radius:14px;display:flex;justify-content:space-between;align-items:center;cursor:pointer;font-weight:800;font-size:.9rem;color:var(--text-dark)}.dropdown-trigger:hover{border-color:var(--primary)}.dropdown-menu{position:absolute;top:calc(100% + 8px);left:0;width:100%;background:var(--bg-card);-webkit-backdrop-filter:blur(30px);backdrop-filter:blur(30px);border:1px solid var(--border);border-radius:18px;box-shadow:0 25px 50px -12px #00000040;z-index:9999;padding:10px;transform-origin:top;animation:dropdownFadeIn .2s cubic-bezier(.4,0,.2,1) forwards;max-height:350px;overflow-y:auto}.dropdown-item{padding:12px 16px;border-radius:12px;cursor:pointer;font-weight:700;font-size:.9rem;display:flex;align-items:center;justify-content:space-between;color:var(--text-dark);margin-bottom:4px;transition:all .2s}.dropdown-item:last-child{margin-bottom:0}.dropdown-item:hover{background:var(--primary);color:#fff!important;transform:translate(5px)}.dropdown-item.selected{background:#2563eb1a;color:var(--primary)}@keyframes dropdownFadeIn{0%{opacity:0;transform:translateY(-15px) scale(.98)}to{opacity:1;transform:translateY(0) scale(1)}}.modal-overlay{position:fixed;top:0;left:0;width:100%;height:100%;background:#00000080;-webkit-backdrop-filter:blur(8px);backdrop-filter:blur(8px);display:flex;align-items:center;justify-content:center;z-index:10000;padding:1rem}.modal-content{background:var(--bg-card);width:100%;max-width:550px;border-radius:24px;border:1px solid var(--border);box-shadow:0 25px 50px -12px #00000080;padding:2.5rem;position:relative;animation:modalScaleIn .3s cubic-bezier(.34,1.56,.64,1) forwards}@keyframes modalScaleIn{0%{opacity:0;transform:scale(.9) translateY(20px)}to{opacity:1;transform:scale(1) translateY(0)}}.grid-modes{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1.5rem}.mode-card{cursor:pointer;text-align:center;padding:2rem;background:var(--bg-card)}.mode-card:hover{transform:translateY(-8px) scale(1.02);border-color:var(--primary);box-shadow:0 20px 30px #0000001a}.mode-icon{font-size:3rem;margin-bottom:1.2rem;display:block}.choice-btn{width:100%;text-align:left;background:var(--bg-input);border:2px solid var(--border);border-radius:15px;margin-bottom:.8rem;padding:1.2rem;font-size:1.05rem;color:var(--text-dark);font-weight:600}.choice-btn:hover:not(:disabled){border-color:var(--primary);background:#2563eb0d}.choice-correct{border-color:var(--success)!important;background:#22c55e1a!important;color:var(--success)!important;box-shadow:0 0 20px #22c55e33}.choice-wrong{border-color:var(--danger)!important;background:#ef44441a!important;color:var(--danger)!important}@keyframes fadeIn{0%{opacity:0;transform:translateY(15px)}to{opacity:1;transform:translateY(0)}}.animate-fade{animation:fadeIn .5s cubic-bezier(.4,0,.2,1) forwards}::-webkit-scrollbar{width:6px}::-webkit-scrollbar-track{background:transparent}::-webkit-scrollbar-thumb{background:var(--border);border-radius:10px}