:root {
    --arduino-green: #00979D;
    --arduino-dark: #2A3B47;
    --arduino-light: #F5F7FA;
    --correct: #4CAF50;
    --wrong: #F44336;
}

body {
    font-family: 'Roboto', sans-serif;
    background: linear-gradient(135deg, #e6f4f5 0%, #f0f9ff 100%);
    min-height: 100vh;
    color: #333;
    margin: 0;
}

.quiz-header {
    background: linear-gradient(135deg, var(--arduino-green), #007B80);
    color: white;
    padding: 40px 20px;
    text-align: center;
    border-bottom: 6px solid #004D52;
    box-shadow: 0 4px 15px rgba(0, 151, 157, 0.3);
    position: relative;
}

.quiz-header h1 {
    font-family: 'Roboto Mono', monospace;
    font-size: 2.8rem;
    font-weight: 700;
    margin: 0;
    text-shadow: 0 2px 10px rgba(0,0,0,0.3);
}

.quiz-header p {
    font-size: 1.2rem;
    opacity: 0.95;
    margin-top: 10px;
}


#timer {
    position: absolute;
    top: 15px;
    right: 20px;
    background: rgba(0,0,0,0.4);
    padding: 8px 18px;
    border-radius: 30px;
    font-weight: bold;
    font-size: 1.2rem;
    font-family: 'Roboto Mono', monospace;
}

  
#startScreen {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 90vh;
    flex-direction: column;
    text-align: center;
    padding: 20px;
}

#startBtn {
    background: var(--arduino-green);
    border: none;
    color: white;
    padding: 18px 50px;
    font-size: 1.6rem;
    font-weight: 600;
    border-radius: 50px;
    box-shadow: 0 10px 30px rgba(0, 151, 157, 0.4);
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
}

#startBtn:hover {
    background: #007B80;
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(0, 151, 157, 0.5);
}

  
#quiz-section {
    padding: 50px 0;
}

.quiz-card {
    background: white;
    border-radius: 20px;
    box-shadow: 0 10px 30px rgba(0, 151, 157, 0.15);
    padding: 35px;
    border: 2px solid #e0e0e0;
    transition: all 0.3s ease;
}

.quiz-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 40px rgba(0, 151, 157, 0.2);
}

.question-number {
    background: var(--arduino-green);
    color: white;
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.3rem;
    margin: 0 auto 20px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
}


.form-check {
    padding: 14px 18px;
    margin: 12px 0;
    border-radius: 12px;
    border: 2px solid #e2e8f0;
    background-color: #f8ffff;
    transition: all 0.3s ease;
}

.form-check:hover {
    border-color: var(--arduino-green);
    background-color: #e6f4f5;
    transform: translateX(5px);
}

.form-check-input:checked {
    background-color: var(--arduino-green);
    border-color: var(--arduino-green);
}

.form-check-input:checked + .form-check-label {
    color: var(--arduino-green);
    font-weight: 600;
}

.input-answer {
    padding: 14px 18px;
    border-radius: 12px;
    border: 2px solid #e2e8f0;
    background-color: #f8ffff;
    transition: all 0.3s ease;
    font-size: 1.1rem;
}

.input-answer:focus {
    outline: none;
    border-color: var(--arduino-green);
    box-shadow: 0 0 0 4px rgba(0, 151, 157, 0.2);
    background-color: white;
}

.input-answer.correct {
    border-color: var(--correct);
    background-color: #d4edda !important;
    color: #155724;
}

.input-answer.incorrect {
    border-color: var(--wrong);
    background-color: #f8d7da !important;
    color: #721c24;
}

   
#nextBtn {
    background: var(--arduino-green);
    border: none;
    border-radius: 50px;
    padding: 16px;
    font-size: 1.2rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: white;
    box-shadow: 0 6px 20px rgba(0, 151, 157, 0.4);
    transition: all 0.3s ease;
}

#nextBtn:hover:not(:disabled) {
    background: #007B80;
    transform: translateY(-3px);
    box-shadow: 0 10px 25px rgba(0, 151, 157, 0.5);
}

#nextBtn:disabled {
    background: #95A5A6;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

  
.progress {
    height: 10px;
    background: #ddd;
    border-radius: 5px;
    margin: 30px 0;
    overflow: hidden;
}

.progress-bar {
    background: var(--arduino-green);
    transition: width 0.6s ease;
}

  
footer {
    background: var(--arduino-dark);
    color: white;
    padding: 25px;
    text-align: center;
    font-family: 'Roboto Mono', monospace;
    margin-top: auto;
}

 
.hidden {
    display: none !important;
}

.text-success { color: var(--correct) !important; }
.text-danger { color: var(--wrong) !important; }

  
#arduinoLogoContainer {
    margin: 20px 0 10px;
}

#arduinoLogo {
    height: 110px;     
    width: auto;
    filter: drop-shadow(0 4px 10px rgba(0,0,0,0.3));
    transition: transform 0.3s ease;
}

#arduinoLogo:hover {
    transform: scale(1.08);
}

@media (max-width: 576px) {
    #arduinoLogo {
        height: 80px;
    }
    #startScreen .quiz-card {
        margin: 20px;
        padding: 30px 20px !important;
    }
    .quiz-header h1 {
        font-size: 2.2rem;
    }
}

#arduinoLogo {
    animation: fadeInDown 1s ease-out;
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-50px) scale(0.8);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}