:root{font-family:system-ui,Avenir,Helvetica,Arial,sans-serif;line-height:1.5;font-weight:400;color-scheme:light dark;color:#ffffffde;background-color:#242424;font-synthesis:none;text-rendering:optimizeLegibility;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;width:100vw}a{font-weight:500;color:#646cff;text-decoration:inherit}a:hover{color:#535bf2}body{margin:0;place-items:center;min-width:320px;min-height:100vh;display:flex;justify-content:center}h1{font-size:3.2em;line-height:1.1}button{border-radius:8px;border:1px solid transparent;padding:.6em 1.2em;font-size:1em;font-weight:500;font-family:inherit;background-color:#1a1a1a;cursor:pointer;transition:border-color .25s}button:hover{border-color:#646cff}button:focus,button:focus-visible{outline:4px auto -webkit-focus-ring-color}@media (prefers-color-scheme: light){:root{color:#213547;background-color:#fff}a:hover{color:#747bff}button{background-color:#f9f9f9}}*{margin:0;padding:0;box-sizing:border-box}#root{overflow-x:hidden}body{font-family:Segoe UI,Tahoma,Geneva,Verdana,sans-serif;background:linear-gradient(135deg,#1e3c72,#2a5298);min-height:100vh;color:#333;overflow-x:hidden}.app{max-width:1200px;margin:0 auto;padding:20px;min-height:100vh;display:flex;flex-direction:column;overflow-x:hidden}.app-header{background:#fffffff2;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-radius:20px;padding:30px;margin-bottom:30px;box-shadow:0 10px 30px #0000001a;text-align:center}.app-header h1{font-size:2.5rem;color:#4a5568;margin-bottom:30px;font-weight:700}.controls{display:flex;justify-content:center;gap:40px;margin-bottom:20px;flex-wrap:wrap}.unit-selector,.mode-selector{display:flex;align-items:center;gap:10px}.unit-selector label,.mode-selector label{font-weight:600;color:#4a5568;font-size:1.1rem}.unit-selector select{padding:12px 16px;border:2px solid #e2e8f0;border-radius:12px;background:#fff;font-size:1rem;font-weight:500;color:#4a5568;cursor:pointer;transition:all .3s ease}.unit-selector select:hover{border-color:#667eea}.unit-selector select:focus{outline:none;border-color:#667eea;box-shadow:0 0 0 3px #667eea1a}.mode-buttons{display:flex;gap:10px}.mode-buttons button{padding:12px 20px;border:2px solid #e2e8f0;border-radius:12px;background:#fff;color:#4a5568;font-size:1rem;font-weight:600;cursor:pointer;transition:all .3s ease}.mode-buttons button:hover{border-color:#667eea;background:#f7fafc}.mode-buttons button.active{background:#667eea;color:#fff;border-color:#667eea;box-shadow:0 4px 12px #667eea4d}.stats{display:flex;justify-content:center;gap:30px;font-weight:600;color:#4a5568;font-size:1.1rem}.main-content{flex:1;display:flex;flex-direction:column;align-items:center;gap:30px}.flashcard-container{perspective:1000px;width:100%;max-width:600px}.flashcard{width:100%;height:400px;position:relative;transform-style:preserve-3d;transition:transform .6s ease;cursor:pointer}.flashcard.flipped{transform:rotateY(180deg)}.card-front,.card-back{position:absolute;width:100%;height:100%;backface-visibility:hidden;border-radius:20px;padding:40px;display:flex;flex-direction:column;justify-content:center;align-items:center;gap:20px;box-shadow:0 15px 35px #0000001a;background:linear-gradient(135deg,#fff,#f8fafc)}.card-back{transform:rotateY(180deg);background:linear-gradient(135deg,#48bb78,#38a169);color:#fff}.topic-badge{background:#667eea1a;color:#667eea;padding:8px 16px;border-radius:20px;font-size:.9rem;font-weight:600;text-transform:uppercase;letter-spacing:.5px}.card-back .topic-badge{background:#fff3;color:#fff}.german-word{font-size:2.5rem;font-weight:700;text-align:center;line-height:1.2;color:#2d3748}.card-back .german-word{color:#fff;font-size:2rem}.translation{font-size:2rem;font-weight:600;text-align:center;color:#fff;margin-top:10px}.audio-btn{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;border:none;padding:12px 24px;border-radius:12px;font-size:1rem;font-weight:600;cursor:pointer;transition:all .3s ease;box-shadow:0 4px 12px #667eea4d}.audio-btn:hover{transform:translateY(-2px);box-shadow:0 6px 20px #667eea66}.card-back .audio-btn{background:#fff3;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px)}.reveal-btn{background:linear-gradient(135deg,#48bb78,#38a169);color:#fff;border:none;padding:15px 30px;border-radius:12px;font-size:1.1rem;font-weight:600;cursor:pointer;transition:all .3s ease;box-shadow:0 4px 12px #48bb784d}.reveal-btn:hover{transform:translateY(-2px);box-shadow:0 6px 20px #48bb7866}.reveal-btn2{background:linear-gradient(135deg,#7f9cf5,#667eea);color:#fff;border:none;padding:15px 30px;border-radius:12px;font-size:1.1rem;font-weight:600;cursor:pointer;transition:all .3s ease;box-shadow:0 4px 12px #7f9cf54d}.reveal-btn2:hover{transform:translateY(-2px);box-shadow:0 6px 20px #667eea66}.quiz-container{width:100%;max-width:600px;background:#fffffff2;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-radius:20px;padding:40px;box-shadow:0 15px 35px #0000001a}.quiz-question{text-align:center;margin-bottom:30px}.quiz-question h2{font-size:1.5rem;color:#4a5568;margin:20px 0;font-weight:600}.quiz-options{display:grid;grid-template-columns:1fr;gap:15px;margin-bottom:30px}.option-btn{padding:20px;border:2px solid #e2e8f0;border-radius:12px;background:#fff;color:#4a5568;font-size:1.1rem;font-weight:500;cursor:pointer;transition:all .3s ease;text-align:left;min-height:60px;display:flex;align-items:center;justify-content:center}.option-btn:hover:not(:disabled){border-color:#667eea;background:#f7fafc;transform:translateY(-2px);box-shadow:0 4px 12px #667eea26}.option-btn.selected{border-color:#667eea;background:#ebf4ff;color:#667eea}.option-btn.correct{border-color:#48bb78;background:#f0fff4;color:#48bb78;box-shadow:0 4px 12px #48bb7833}.option-btn.incorrect{border-color:#f56565;background:#fff5f5;color:#f56565;box-shadow:0 4px 12px #f5656533}.option-btn:disabled{cursor:not-allowed;opacity:.7}.result{text-align:center;padding:20px;border-radius:12px;font-weight:600;font-size:1.2rem}.result.correct{background:#f0fff4;color:#48bb78;border:2px solid #48bb78}.result.incorrect{background:#fff5f5;color:#f56565;border:2px solid #f56565}.result-explanation{margin-top:10px;font-size:1rem;opacity:.8}.navigation{display:flex;justify-content:center;gap:20px;flex-wrap:wrap}.navigation button{padding:15px 25px;border:2px solid #e2e8f0;border-radius:12px;background:#fff;color:#4a5568;font-size:1rem;font-weight:600;cursor:pointer;transition:all .3s ease;min-width:120px}.navigation button:hover:not(:disabled){border-color:#667eea;background:#f7fafc;transform:translateY(-2px);box-shadow:0 4px 12px #667eea26}.navigation button:disabled{opacity:.5;cursor:not-allowed}.shuffle-btn{background:linear-gradient(135deg,#ed8936,#dd6b20)!important;color:#fff!important;border-color:transparent!important;box-shadow:0 4px 12px #ed89364d}.shuffle-btn:hover{box-shadow:0 6px 20px #ed893666!important}.app-footer{background:#ffffff1a;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-radius:20px;padding:20px;margin-top:30px;text-align:center;color:#fff;font-weight:500}.loading,.error{display:flex;justify-content:center;align-items:center;height:50vh;font-size:1.5rem;font-weight:600;color:#fff;text-align:center}.error{color:#f56565;background:#ffffffe6;border-radius:20px;padding:40px;margin:50px}.matching-container{background:#fffffff2;-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-radius:20px;padding:30px;box-shadow:0 15px 35px #0000001a;animation:fadeIn .5s ease;width:100%;max-width:800px}.matching-header{text-align:center;margin-bottom:30px}.matching-header h2{color:#4a5568;font-size:1.8rem;margin-bottom:15px}.matching-complete{background:linear-gradient(135deg,#48bb78,#38a169);color:#fff;padding:15px 25px;border-radius:15px;font-weight:600;font-size:1.1rem;margin-top:15px;animation:fadeIn .5s ease}.matching-grid{display:grid;grid-template-columns:1fr 1fr;gap:30px;margin-bottom:30px}.german-column,.english-column{display:flex;flex-direction:column;gap:12px}.german-column h3,.english-column h3{text-align:center;color:#4a5568;font-size:1.3rem;margin-bottom:15px;padding:10px;background:linear-gradient(135deg,#f7fafc,#edf2f7);border-radius:12px;border:2px solid #e2e8f0}.matching-word{background:linear-gradient(135deg,#fff,#f8f9fa);border:2px solid #e2e8f0;border-radius:12px;padding:15px 20px;font-size:1.1rem;font-weight:500;color:#4a5568;cursor:pointer;transition:all .3s ease;position:relative;min-height:55px;display:flex;align-items:center;justify-content:center;text-align:center}.matching-word:hover:not(:disabled){transform:translateY(-2px);box-shadow:0 8px 25px #00000026;border-color:#667eea}.matching-word.selected{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;border-color:#5a67d8;transform:translateY(-2px);box-shadow:0 8px 25px #667eea66}.matching-word.matched{background:linear-gradient(135deg,#48bb78,#38a169);color:#fff;border-color:#38a169;cursor:default}.matching-word:disabled{opacity:.7;cursor:not-allowed}.match-indicator{position:absolute;top:-8px;right:-8px;background:#38a169;color:#fff;border-radius:50%;width:24px;height:24px;display:flex;align-items:center;justify-content:center;font-size:14px;font-weight:700;border:2px solid white;box-shadow:0 2px 8px #0003}.matching-controls{text-align:center}.reset-matching-btn{background:linear-gradient(135deg,#ed8936,#dd6b20);color:#fff;border:none;border-radius:12px;padding:12px 24px;font-size:1rem;font-weight:600;cursor:pointer;transition:all .3s ease;box-shadow:0 4px 15px #ed89364d}.reset-matching-btn:hover{transform:translateY(-2px);box-shadow:0 6px 20px #ed893666}.reset-matching-btn:active{transform:translateY(0)}@media (max-width: 768px){.app{padding:15px}.app-header{padding:20px}.app-header h1{font-size:2rem}.controls{flex-direction:column;gap:20px;align-items:center}.card-front,.card-back{height:350px;padding:30px}.german-word{font-size:2rem}.card-back .german-word,.translation{font-size:1.5rem}.quiz-container{padding:25px}.navigation{flex-direction:column;align-items:center}.navigation button{width:100%;max-width:300px}.matching-container{padding:20px}.matching-grid{grid-template-columns:1fr;gap:20px}.german-column h3,.english-column h3{font-size:1.2rem;padding:8px}.matching-word{font-size:1rem;padding:12px 16px;min-height:50px}.matching-header h2{font-size:1.5rem}}@keyframes fadeIn{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}.flashcard-container,.quiz-container{animation:fadeIn .5s ease}.flashcard:hover{transform:translateY(-5px);box-shadow:0 20px 40px #00000026}.flashcard.flipped:hover{transform:rotateY(180deg) translateY(-5px)}button:focus,select:focus{outline:2px solid #667eea;outline-offset:2px}::-webkit-scrollbar{width:8px}::-webkit-scrollbar-track{background:#ffffff1a;border-radius:4px}::-webkit-scrollbar-thumb{background:#ffffff4d;border-radius:4px}::-webkit-scrollbar-thumb:hover{background:#ffffff80}