body {

    font-family: Arial, sans-serif;
    margin: 0;
    padding: 0;
}

main {
    margin: 30px;
}

header {
    background-color: #007bff;
    color: #fff;
    padding: 20px;
    text-align: center;
}

nav ul {
    list-style-type: none;
    padding: 0;
}

nav ul li {
    display: inline;
    margin-right: 20px;
}

nav ul li a {
    color: #fff;
    text-decoration: none;
}

main {
    padding: 20px;
}

section {
    margin-bottom: 40px;
}

h2 {
    color: #007bff;
}

.video {
    margin-bottom: 20px;
}

footer {
    background-color: #f8f9fa;
    padding: 20px;
    text-align: center;
}

.video-container {
    position: relative;
    width: 100%;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    overflow: hidden;
    margin-bottom: 20px; /* Video arasına boşluk bırak */
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#experiments {
    margin-bottom: 40px;
}

#experiments h2 {
    color: #333;
    font-size: 24px;
    margin-bottom: 20px;
}

#experiments ol {
    list-style-type: none;
    counter-reset: step-counter;
    padding-left: 0;
}

#experiments ol li {
    margin-bottom: 20px;
}

#experiments ol li h3 {
    color: #666;
    font-size: 18px;
    margin-bottom: 10px;
}

#experiments ol li ul {
    list-style-type: none;
    counter-reset: sub-step-counter;
}

#experiments ol li ul li {
    margin-bottom: 10px;
}

#experiments ol li ul li::before {
    content: counter(sub-step-counter) ". ";
    counter-increment: sub-step-counter;
    font-weight: bold;
    color: #666;
    margin-right: 5px;
}

#experiments ol li ol {
    list-style-type: none;
    counter-reset: sub-sub-step-counter;
}

#experiments ol li ol li::before {
    content: counter(sub-sub-step-counter, lower-alpha) ") ";
    counter-increment: sub-sub-step-counter;
    font-weight: bold;
    color: #888;
    margin-right: 5px;
}

#experiments ol li ol li {
    margin-bottom: 5px;
}

#exams {
    margin-bottom: 40px;
}

#exams h2 {
    color: #333;
    font-size: 24px;
    margin-bottom: 20px;
}

#exams ol {
    list-style-type: none;
    counter-reset: question-counter;
    padding-left: 0;
}

#exams ol li {
    margin-bottom: 20px;
}

#exams ol li h3 {
    color: #666;
    font-size: 18px;
    margin-bottom: 10px;
}

#exams ol li p {
    color: #444;
    font-size: 16px;
    margin-bottom: 10px;
}

#exams ol li ul {
    list-style-type: none;
}

#exams ol li ul li {
    margin-bottom: 5px;
}

#exams ol li ul li::before {
    content: "• ";
    color: #666;
    margin-right: 5px;
}

footer {
    bottom: 0;
    left: 0;
    background-color: #007bff;
    color: white;
    text-align: center;
    padding: 20px;
}

button#scroll-to-top {
    background-color: transparent;
    border: none;
    color: #fff;
    cursor: pointer;
    transition: background-color 0.3s;
    font-size: 16px;
    padding: 10px 20px;
}

button#scroll-to-top:hover {
    background-color: rgba(255, 255, 255, 0.2);
}

button#scroll-to-top:active {
    background-color: rgba(255, 255, 255, 0.4);
}

.correct-answer {
    display: none;
    color: green;
    cursor: pointer;
}

.correct-answer:hover {
    text-decoration: underline;
}

#answer-key {
    margin-top: 40px;
}

#answer-key h3 {
    color: #333;
    font-size: 20px;
    margin-bottom: 10px;
}

#answer-key ul {
    list-style-type: none;
    padding-left: 0;
}

#answer-key ul li {
    color: #666;
    font-size: 16px;
    margin-bottom: 5px;
}