<div id="features" class="section_3">
         <h1 id="titulo_section">...</h1>

         <section class="section_first">...</section>
         <section class="section_first">...</section>

    </div>
    <div id="features" class="section_3">
         <h1 id="titulo_section">...</h1>

         <section class="section_second">...</section>
         <section class="section_second">...</section>

    </div>

    <div id="features" class="section_3">
         <h1 id="titulo_section">...</h1>

         <section class="section_third">...</section>
         <section class="section_third">...</section>
         <section class="section_third">...</section>

    </div>

    <div id="features" class="section_4">
         <h1 id="titulo_section">...</h1>

         <section class="section_fourth">...</section>
         <section class="section_fourth">...</section>
         <section class="section_fourth">...</section>

    </div>

.section_1 {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

.section_2 {
    background-color: snow;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

.section_3 {
    background-color: lightgray;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

.section_4 {
    background-color: snow;
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
}

/* css das seções dentro da div's */

.section_first {
    word-wrap: break-word;
    background-color: cornflowerblue;
    padding: 2%;
    text-align: justify;
    font-size: 20px;
    border: 1px solid gray;
}

.section_second {
    word-wrap: break-word;
    word-spacing: -2px;
    background-color: inherit;
    width: 400px;
    margin: 20px;
    margin-top: -10px;
    margin-bottom: 40px;
    padding: 2%;
    text-align: justify;
    font-size: 20px;
}

.section_third{
    word-wrap: break-word;
    background-color: snow;
    width: 200px;
    margin: 20px;
    margin-bottom: 40px;
    padding: 2%;
    text-align: justify;
    font-size: 18px;
    box-shadow: 0px 0px 1px 1px gray;
}

.section_fourth{
    word-wrap: break-word;
    background-color: snow;
    width: 200px;
    margin: 20px;
    margin-bottom: 40px;
    padding: 2%;
    text-align: justify;
    font-size: 18px;
    box-shadow: 0px 0px 1px 1px gray;
}