/* =========================================
   Qualitell R&D Article
   Desktop / Tablet / Mobile
========================================= */

.qualitell-article {
  max-width: 1180px;
  margin: 0 auto;
  padding: 24px 24px 70px;
  font-family: Arial, "Helvetica Neue", "Microsoft YaHei", sans-serif;
  color: #333;
  box-sizing: border-box;
}

.qualitell-article * {
  box-sizing: border-box;
}

/* 主标题 */
.qualitell-article .article-title {
  max-width: 980px;
  margin: 0 auto 28px;
  font-size: 32px;
  line-height: 1.35;
  font-weight: 700;
  color: #20242a;
}

/* Brand News Brief */
.qualitell-article .news-brief {
  max-width: 920px;
  margin: 0 auto 26px;
  padding: 24px 28px;
  background: #f6f8fb;
  border-left: 4px solid #0072e7;
  border-radius: 0 8px 8px 0;
  font-size: 17px;
  line-height: 1.85;
  color: #444;
}

.qualitell-article .news-brief strong {
  color: #222;
}

/* 正文 */
.qualitell-article p {
  max-width: 920px;
  margin: 0 auto 26px;
  font-size: 17px;
  line-height: 1.85;
  color: #444;
}

/* Step 标题 */
.qualitell-article .section-title {
  max-width: 920px;
  margin: 54px auto 22px;
  font-size: 24px;
  line-height: 1.45;
  font-weight: 700;
  color: #222;
}

/* 列表 */
.qualitell-article .article-list {
  max-width: 900px;
  margin: 10px auto 30px;
  padding-left: 24px;
}

.qualitell-article .article-list li {
  margin-bottom: 12px;
  padding-left: 5px;
  font-size: 16px;
  line-height: 1.75;
  color: #444;
}

/* 图片 */
.qualitell-article .article-image {
  width: 100%;
  margin: 38px auto;
}

.qualitell-article .article-image img {
  display: block;
  width: 100%;
  max-width: 1100px;
  height: auto;
  margin: 0 auto;
  border-radius: 10px;
}

/* 双图 */
.qualitell-article .image-grid-2 {
  max-width: 1100px;
  margin: 38px auto;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.qualitell-article .image-grid-2 img {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 270px;
  object-fit: cover;
  border-radius: 10px;
}

/* 三图 */
.qualitell-article .image-grid-3 {
  max-width: 1100px;
  margin: 38px auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.qualitell-article .image-grid-3 img {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 240px;
  object-fit: cover;
  border-radius: 10px;
}

/* 四图 */
.qualitell-article .image-grid-4 {
  max-width: 1100px;
  margin: 38px auto;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.qualitell-article .image-grid-4 img {
  display: block;
  width: 100%;
  height: 100%;
  min-height: 260px;
  object-fit: cover;
  border-radius: 10px;
}

/* 重点词 */
.qualitell-article strong {
  color: #222;
}

/* Conclusion */
.qualitell-article .conclusion {
  max-width: 960px;
  margin: 50px auto 0;
  padding: 32px 36px;
  background: #f6f8fb;
  border-radius: 12px;
}

.qualitell-article .conclusion h2 {
  margin: 0 0 18px;
  font-size: 23px;
  line-height: 1.4;
  color: #222;
}

.qualitell-article .conclusion p {
  max-width: none;
}

.qualitell-article .conclusion p:last-child {
  margin-bottom: 0;
}

/* Tablet */
@media (max-width: 991px) {
  .qualitell-article {
    padding: 20px 20px 55px;
  }

  .qualitell-article .article-title {
    font-size: 27px;
  }

  .qualitell-article p,
  .qualitell-article .news-brief {
    font-size: 16px;
  }

  .qualitell-article .section-title {
    font-size: 22px;
  }
}

/* Mobile */
@media (max-width: 600px) {
  .qualitell-article {
    padding: 10px 15px 45px;
  }

  .qualitell-article .article-title {
    margin-bottom: 22px;
    font-size: 23px;
    line-height: 1.4;
  }

  .qualitell-article p {
    margin-bottom: 20px;
    font-size: 15px;
    line-height: 1.8;
  }

  .qualitell-article .news-brief {
    margin-bottom: 24px;
    padding: 20px 18px;
    font-size: 15px;
  }

  .qualitell-article .section-title {
    margin-top: 38px;
    margin-bottom: 16px;
    font-size: 20px;
  }

  .qualitell-article .article-list li {
    font-size: 15px;
  }

  .qualitell-article .article-image {
    width: calc(100% + 10px);
    margin-left: -5px;
    margin-top: 28px;
    margin-bottom: 28px;
  }

  .qualitell-article .article-image img {
    border-radius: 6px;
  }

  .qualitell-article .image-grid-2,
  .qualitell-article .image-grid-3,
  .qualitell-article .image-grid-4 {
    width: calc(100% + 10px);
    margin: 28px 0 28px -5px;
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .qualitell-article .image-grid-2 img,
  .qualitell-article .image-grid-3 img,
  .qualitell-article .image-grid-4 img {
    height: auto;
    min-height: 0;
    border-radius: 6px;
  }

  .qualitell-article .conclusion {
    margin-top: 34px;
    padding: 24px 20px;
    border-radius: 8px;
  }

  .qualitell-article .conclusion h2 {
    font-size: 20px;
  }
}