* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background-color: #ffffff;
}

body {
  font-family:
    -apple-system,
    BlinkMacSystemFont,
    "Helvetica Neue",
    "Hiragino Kaku Gothic ProN",
    "Yu Gothic",
    Meiryo,
    sans-serif;

  color: #222222;
}

/* LP全体 */
.lp {
  width: 100%;
  max-width: 750px;
  margin: 0 auto;
  background-color: #ffffff;
}

/* 漫画画像 */
.lp img {
  display: block;
  width: 100%;
  height: auto;
  margin: 0;
}

/* 見出し */
.section-heading {
  margin: 40px 20px 24px;
  padding: 10px 15px;

  color: #0070c9;
  font-size: 28px;
  font-weight: 700;
  line-height: 1.5;

  border-left: 8px solid #18b9df;
}

/* 説明文章 */
.text-section,
.article-section {
  padding: 24px 30px;
  background-color: #ffffff;
}

.text-section p,
.article-section p {
  margin: 0 0 20px;
  font-size: 18px;
  line-height: 2;
}

/* スマートフォン */
@media screen and (max-width: 600px) {
  .section-heading {
    margin: 28px 15px 18px;
    padding: 8px 12px;
    font-size: 22px;
    border-left-width: 6px;
  }

  .text-section,
  .article-section {
    padding: 20px;
  }

  .text-section p,
  .article-section p {
    font-size: 16px;
    line-height: 1.9;
  }
}