<div class="layer showed">
                    <h2>Упражнение 1</h2>
                    <p>Добавьте "всплывающую подсказку" в абзац ниже с текстом "School".</p>
                    <div class="task-box">
                        <p>&lt;p <input id="task11" type="text" maxlength="5" style="width: 50px;">="School"&gt;School - школа для детей и взрослых.&lt;/p&gt;</p>
                        <p class="result">&lt;p title="School"&gt;School - школа для детей и взрослых.&lt;/p&gt;</p>
                        <div class="true">
                            <h3>Правильно!</h3>
                            <a href="#" onclick="showLayer(1)">Дальше &gt;</a>
                        </div>
                    </div>
                    <input id="check" class="btn" type="button" value="Проверить &gt;">
                </div>

// layer
.layer {
    display: none;
}
.showed {
    display: block;
    .task-box {
        position: relative;
        background: #eeeeee;
        margin-top: 50px;
        padding: 50px 30px;
        font-size: 20px;
        line-height: 3;
        color: #000000;
        input {
            border: none;
            height: 25px;
            font-size: 20px;
            color: #333333;
            text-align: center;
            letter-spacing: 2px;
        }
        .result {
            color: #0059ff;
            opacity: 0;
        }
        .true {
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            padding: 50px 30px;
            background: #dff0d8;
            color: #468847;
            display: flex;
            flex-direction: column;
            align-items: flex-start;
            justify-content: flex-start;
            display: none;
            a {
                color: #468847;
                font-size: 18px;
            }
        }
        h3 {
            font-weight: 300;
        }
    }
    .btn {
        margin-top: 30px;
        height: 70px;
        padding: 0 25px;
        font-size: 18px;
        letter-spacing: 1px;
        border: none;
        background: #ffcc00;
        cursor: pointer;
        transition: opacity .5s;
        &:hover {
            opacity: .7;
        }
    }
}

// task 11
let userVal = document.getElementById('task11').value
let trueVal = 'title'
let check = document.getElementById('check')

check.onclick = function() {
    if (userVal === trueVal) {
        document.getElementsByClassName('true').style.display = 'block';
    }
    return false
}