body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: #333;
    margin: 0;
    padding: 20px;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
    box-sizing: border-box;
}

.app-container {
    background-color: #fff;
    padding: 30px 40px;
    border-radius: 12px;
    box-shadow: 0 5px 30px rgba(0, 0, 0, 0.2);
    width: 100%;
    max-width: 600px;
    text-align: center;
}

.back-button {
    display: inline-block;
    padding: 10px 15px;
    margin-bottom: 20px;
    background-color: #f0f0f0;
    color: #333;
    text-decoration: none;
    border-radius: 5px;
    border: 1px solid #ccc;
    font-size: 0.9em;
    cursor: pointer;
    transition: background-color 0.2s;
}

.back-button:hover {
    background-color: #e0e0e0;
}

h1 {
    color: #333;
    margin-bottom: 10px;
    font-size: 2em;
}

.quiz-description {
    font-size: 1.1em;
    color: #555;
    margin-bottom: 25px;
}

#question-counter {
    font-size: 0.9em;
    color: #555;
    margin-bottom: 15px;
}

#question-word {
    font-size: 2.5em;
    font-weight: bold;
    color: #333;
    margin-bottom: 30px;
    padding: 15px 25px;
    background-color: #f8f9fa;
    border-radius: 8px;
    display: inline-block;
    border: 2px solid #4facfe;
}

.options-container {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 25px;
    flex-wrap: wrap;
}

.option-btn {
    background-color: #4facfe;
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.1em;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s, transform 0.1s;
    min-width: 140px;
    font-weight: 500;
}

.option-btn:hover:not(:disabled) {
    background-color: #3a9de8;
    transform: translateY(-2px);
}

.option-btn:active:not(:disabled) {
    transform: translateY(0);
}

.option-btn:disabled {
    cursor: not-allowed;
}

.option-btn.correct {
    background-color: #28a745 !important;
}

.option-btn.wrong {
    background-color: #dc3545 !important;
}

#feedback {
    font-size: 1.2em;
    font-weight: bold;
    min-height: 30px;
    margin-bottom: 20px;
}

#feedback[style*="green"] {
    color: #28a745;
}

#feedback[style*="red"] {
    color: #dc3545;
}

#next-btn, #restart-btn {
    background-color: #27ae60;
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.1em;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.2s;
    margin-top: 10px;
    display: inline-block;
}

#next-btn:hover, #restart-btn:hover {
    background-color: #219d55;
}

#score-container {
    text-align: center;
}

#score-container h2 {
    color: #333;
    margin-bottom: 20px;
}

#score-text {
    font-size: 1.2em;
    color: #555;
    margin-bottom: 25px;
    line-height: 1.6;
}

/* Responsiv design */
@media (max-width: 600px) {
    .app-container {
        padding: 20px 25px;
    }
    
    h1 {
        font-size: 1.6em;
    }
    
    #question-word {
        font-size: 2em;
        padding: 12px 20px;
    }
    
    .options-container {
        flex-direction: column;
        gap: 10px;
    }
    
    .option-btn {
        width: 100%;
        min-width: auto;
    }
}