:root{--background-color: #121212;--surface-color: #1e1e1e;--primary-color: #bb86fc;--primary-variant-color: #3700b3;--secondary-color: #03dac6;--text-primary: #ffffff;--text-secondary: #b3b3b3;--error-color: #cf6679;--success-color: #4caf50;--border-color: #333}*{box-sizing:border-box;margin:0;padding:0}body{font-family:Inter,sans-serif;background-color:var(--background-color);color:var(--text-primary);display:flex;justify-content:center;align-items:center;min-height:100vh;padding:1rem}#root{width:100%;max-width:800px}.container{background-color:var(--surface-color);padding:2rem;border-radius:12px;box-shadow:0 4px 20px #00000040;text-align:center;display:flex;flex-direction:column;gap:1.5rem;transition:all .3s ease}.app-logo{color:var(--secondary-color)}h1{font-size:2.5rem;color:var(--primary-color)}p{color:var(--text-secondary);font-size:1.1rem;line-height:1.6}.final-score{font-size:1.5rem;color:var(--secondary-color);font-weight:700}.btn{background-color:var(--primary-color);color:#000;border:none;padding:.8rem 1.5rem;font-size:1rem;font-weight:700;border-radius:8px;cursor:pointer;transition:background-color .3s ease,transform .1s ease;align-self:center;min-width:150px}.btn:hover{background-color:#a052ff}.btn:active{transform:scale(.98)}.btn:disabled{background-color:#444;color:#888;cursor:not-allowed;transform:none}.btn-secondary{background-color:#333;color:var(--text-primary);border:1px solid var(--border-color)}.btn-secondary:hover{background-color:#444;border-color:var(--primary-color)}.quiz-header{display:flex;justify-content:space-between;align-items:center;width:100%;font-size:1.2rem;font-weight:700}.group-name{color:var(--primary-color)}.score{color:var(--secondary-color)}.question-box{background-color:#2c2c2c;padding:1.5rem;border-radius:8px;min-height:100px;display:flex;justify-content:center;align-items:center;text-align:left}.question-box p{font-size:1.2rem}.options-container{display:grid;grid-template-columns:1fr;gap:1rem}@media (min-width: 600px){.options-container{grid-template-columns:1fr 1fr}}.option-btn{width:100%;padding:1rem;font-size:1rem;text-align:left;background-color:#333;color:var(--text-primary);border:1px solid var(--border-color);border-radius:8px;cursor:pointer;transition:background-color .3s ease,border-color .3s ease}.option-btn:hover:not(:disabled){background-color:#444;border-color:var(--primary-color)}.option-btn:disabled{cursor:not-allowed;opacity:.7}.option-btn.selected{background-color:#4a4a4a;border-color:var(--secondary-color)}.option-btn.correct{background-color:var(--success-color);border-color:var(--success-color);color:#fff}.option-btn.incorrect{background-color:var(--error-color);border-color:var(--error-color);color:#fff}.feedback{margin-top:1rem;font-size:1.1rem;font-weight:700;min-height:2rem}.feedback.correct{color:var(--success-color)}.feedback.incorrect{color:var(--error-color)}.group-selection-container{display:flex;flex-wrap:wrap;justify-content:center;gap:1rem}.button-group{display:flex;justify-content:center;gap:1rem;flex-wrap:wrap}.teacher-login-form{display:flex;flex-direction:column;gap:1rem;align-items:center;width:100%;max-width:300px;margin:0 auto}.password-input{width:100%;padding:.8rem;font-size:1rem;background-color:#2c2c2c;border:1px solid var(--border-color);color:var(--text-primary);border-radius:8px}.dashboard-content{display:flex;flex-direction:column;gap:2rem;width:100%;text-align:left}@media (min-width: 768px){.dashboard-content{flex-direction:row}}.scoreboard,.score-graph{flex:1;background-color:#2c2c2c;padding:1.5rem;border-radius:8px}h2{text-align:center;margin-bottom:1.5rem;color:var(--secondary-color)}.scoreboard table{width:100%;border-collapse:collapse}.scoreboard th,.scoreboard td{padding:.8rem;border-bottom:1px solid var(--border-color);text-align:left}.scoreboard th{color:var(--primary-color)}.scoreboard tr:last-child td{border-bottom:none}.graph-container{display:flex;justify-content:space-around;align-items:flex-end;height:250px;padding:1rem 0;border-left:2px solid var(--border-color);border-bottom:2px solid var(--border-color)}.bar-wrapper{display:flex;flex-direction:column;align-items:center;height:100%;justify-content:flex-end;flex:1}.bar{width:60%;max-width:50px;background:linear-gradient(to top,var(--primary-variant-color),var(--primary-color));border-radius:4px 4px 0 0;transition:height .5s ease-out;display:flex;justify-content:center;align-items:flex-end;color:#fff;font-weight:700;overflow:hidden}.bar-score{position:relative;bottom:5px;font-size:.9rem;text-shadow:1px 1px 2px rgba(0,0,0,.7)}.bar-label{margin-top:.5rem;font-size:.9rem}