body {
    font-family: Arial, sans-serif;
    background: #f7f7f7;
    margin: 0;
    padding: 0;
}

header {
    padding: 15px;
    background: #222;
    color: white;
}

button {
    padding: 10px 15px;
    cursor: pointer;
}

section {
    padding: 20px;
}

.question {
    background: white;
    margin-bottom: 12px;
    padding: 15px;
    border-radius: 8px;
    cursor: pointer;
    transition: 0.2s;
}

.question:hover {
    background: #f0f0f0;
}

.answers, .explanation {
    margin-top: 10px;
}

.explanation {
    background-color: #c8f7c533;
    padding: 20px;
    border-radius: 10px;
}

.hidden {
    display: none;
}

.option.correct {
    background: #c8f7c5;
    font-weight: bold;
}

.option {
    padding: 4px;
}

.toolbar {
    position: sticky;
    top: 0;
    z-index: 10;
    background: rgba(247, 247, 247, 0.9);
    backdrop-filter: blur(6px);
    padding: 12px 20px;
    margin-bottom: 15px;
    border-bottom: 1px solid #ddd;
}

#toggleAllBtn {
    padding: 10px 16px;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    background: #222;
    color: white;
    font-weight: 500;
    transition: all 0.2s ease;
}

#toggleAllBtn:hover {
    background: #444;
    transform: translateY(-1px);
}

#toggleAllBtn:active {
    transform: translateY(0px);
}