/* Reset default browser styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* Body styling */
body {
    font-family: Arial, sans-serif;
    background-color: #f9f9f9;
    color: #333;
    padding: 20px;
    line-height: 1.6;
}

/* Main checklist container */
.todo-list {
    list-style-type: none;
    max-width: 700px;
    margin: auto;
    background: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

/* Top-level items */
.todo-list>li {
    margin-bottom: 15px;
}

/* Checkbox and label styling */
.todo-list input[type="checkbox"] {
    margin-right: 8px;
    transform: scale(1.2);
    cursor: pointer;
}

.todo-list label {
    font-weight: bold;
    font-size: 1.1rem;
    cursor: pointer;
}

/* Sub-item list */
.sub-item {
    list-style-type: disc;
    margin-left: 28px;
    margin-top: 5px;
}

/* Links inside sub-items */
.sub-item-link {
    text-decoration: none;
    color: #0077cc;
    font-size: 1rem;
    display: inline-block;
    padding: 2px 0;
    transition: color 0.2s, background-color 0.2s;
}

/* Hover, focus, and active states for links */
.sub-item-link:hover {
    color: #005fa3;
    background-color: #eef6fb;
    padding: 2px 4px;
    border-radius: 4px;
}

.sub-item-link:focus {
    outline: 2px solid #ff9800;
    outline-offset: 2px;
}

.sub-item-link:active {
    color: #004080;
}

/* Visited link color */
.sub-item-link:visited {
    color: #800080;
}

/* Responsive design */
@media (max-width: 600px) {
    body {
        padding: 10px;
    }

    .todo-list {
        padding: 15px;
    }

    .todo-list label {
        font-size: 1rem;
    }

    .sub-item-link {
        font-size: 0.95rem;
    }
}