*{margin:0;padding:0;box-sizing:border-box}body{font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Oxygen,Ubuntu,Cantarell,Fira Sans,Droid Sans,Helvetica Neue,sans-serif;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;background-color:#f5f5f5;color:#333}.container{max-width:800px;margin:0 auto;padding:20px;background-color:#fff;min-height:100vh;box-shadow:0 0 10px #0000001a}h1{text-align:center;margin-bottom:30px;color:#2c3e50}h2{margin:20px 0;color:#34495e}.question{margin-bottom:30px;padding:20px;border:1px solid #e0e0e0;border-radius:8px;background-color:#f9f9f9}.question-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:15px}.question-type{font-size:14px;color:#7f8c8d;font-weight:500}.question-content{margin-bottom:20px;font-size:16px;line-height:1.5}.options{display:flex;flex-direction:column;gap:10px;margin-bottom:20px}.option{display:flex;align-items:center;padding:12px;border:1px solid #e0e0e0;border-radius:4px;cursor:pointer;transition:all .2s ease}.option:hover{background-color:#f0f0f0}.option input{margin-right:10px;cursor:pointer}.option.selected{background-color:#e3f2fd;border-color:#2196f3}.option.correct{background-color:#e8f5e8;border-color:#4caf50}.option.incorrect{background-color:#ffebee;border-color:#f44336}.option.red-border{border:2px solid #f44336;border-radius:4px;background-color:#ffebee}.submit-btn{display:block;width:100%;padding:12px;background-color:#2196f3;color:#fff;border:none;border-radius:4px;font-size:16px;font-weight:500;cursor:pointer;transition:background-color .2s ease;margin:20px 0}.submit-btn:hover{background-color:#1976d2}.submit-btn:disabled{background-color:#bdbdbd;cursor:not-allowed}.result{margin-top:30px;padding:20px;border:1px solid #e0e0e0;border-radius:8px;background-color:#f5f5f5}.result h3{margin-bottom:15px;color:#34495e}.result-item{margin-bottom:10px;padding:10px;border-radius:4px;background-color:#fff}.result-item.correct{border-left:4px solid #4caf50}.result-item.incorrect{border-left:4px solid #f44336}.explanation{margin-top:10px;padding:10px;background-color:#f0f8ff;border-radius:4px;font-size:14px;color:#34495e}.navigation{display:flex;justify-content:space-between;margin-top:20px}.nav-btn{padding:8px 16px;background-color:#f0f0f0;border:1px solid #e0e0e0;border-radius:4px;cursor:pointer;transition:all .2s ease}.nav-btn:hover{background-color:#e0e0e0}.nav-btn:disabled{background-color:#f5f5f5;color:#bdbdbd;cursor:not-allowed}.filter{display:flex;gap:10px;margin-bottom:20px;flex-wrap:wrap}.filter-btn{padding:8px 16px;background-color:#f0f0f0;border:1px solid #e0e0e0;border-radius:4px;cursor:pointer;transition:all .2s ease}.filter-btn.active{background-color:#2196f3;color:#fff;border-color:#2196f3}.filter-btn:hover{background-color:#e0e0e0}.filter-btn.active:hover{background-color:#1976d2}.summary{display:flex;justify-content:space-between;margin-bottom:20px;padding:15px;background-color:#f0f8ff;border-radius:8px}.summary-item{text-align:center}.summary-item h4{font-size:14px;color:#7f8c8d;margin-bottom:5px}.summary-item p{font-size:20px;font-weight:500;color:#34495e}.loading{display:flex;justify-content:center;align-items:center;height:200px;font-size:18px;color:#7f8c8d}.error{display:flex;justify-content:center;align-items:center;height:200px;font-size:18px;color:#f44336;text-align:center}