* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
}

.container {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    max-width: 800px;
    width: 100%;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.3);
    color: white;
}

.header {
    text-align: center;
    margin-bottom: 30px;
}

.header h1 {
    font-size: 2.5em;
    margin-bottom: 10px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
}

.header p {
    font-size: 1.2em;
    opacity: 0.9;
}

.name-section {
    text-align: center;
    margin-bottom: 30px;
}

.name-section input {
    padding: 15px 20px;
    font-size: 1.1em;
    border: none;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    width: 300px;
    margin: 10px;
    text-align: center;
}

.name-section input::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

.quiz-section {
    display: none;
}

.question-container {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 15px;
    padding: 25px;
    margin-bottom: 20px;
    border-left: 4px solid #ffd700;
}

.question-number {
    background: #ffd700;
    color: #333;
    padding: 5px 15px;
    border-radius: 20px;
    font-weight: bold;
    display: inline-block;
    margin-bottom: 15px;
}

.question-text {
    font-size: 1.3em;
    margin-bottom: 20px;
    line-height: 1.5;
}

.code-block {
    background: rgba(0, 0, 0, 0.7);
    border-radius: 10px;
    padding: 15px;
    margin: 15px 0;
    font-family: 'Courier New', monospace;
    font-size: 1em;
    overflow-x: auto;
}

.options {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.option {
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 10px;
    padding: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.1em;
}

.option:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateX(5px);
}

.option.selected {
    background: rgba(255, 215, 0, 0.3);
    border-color: #ffd700;
}

.option.correct {
    background: rgba(76, 175, 80, 0.3);
    border-color: #4caf50;
}

.option.incorrect {
    background: rgba(244, 67, 54, 0.3);
    border-color: #f44336;
}

.controls {
    display: flex;
    justify-content: space-between;
    margin-top: 30px;
}

.btn {
    padding: 15px 30px;
    font-size: 1.1em;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: bold;
}

.btn-primary {
    background: #ffd700;
    color: #333;
}

.btn-primary:hover {
    background: #ffed4a;
    transform: translateY(-2px);
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.2);
    color: white;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.3);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 4px;
    margin-bottom: 20px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: #ffd700;
    transition: width 0.3s ease;
}

.results {
    display: none;
    text-align: center;
}

.score {
    font-size: 3em;
    font-weight: bold;
    color: #ffd700;
    margin: 20px 0;
}

.score-details {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 15px;
    padding: 20px;
    margin: 20px 0;
}

.wrong-answers {
    background: rgba(244, 67, 54, 0.1);
    border-radius: 10px;
    padding: 15px;
    margin: 15px 0;
    border-left: 4px solid #f44336;
}

.sending-status {
    margin-top: 20px;
    padding: 15px;
    border-radius: 10px;
    font-weight: bold;
}

.sending-status.success {
    background: rgba(76, 175, 80, 0.2);
    color: #4caf50;
}

.sending-status.error {
    background: rgba(244, 67, 54, 0.2);
    color: #f44336;
}

.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: #ffd700;
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.emoji {
    font-size: 1.5em;
    margin-right: 10px;
}