* {
  margin: 0;
  padding: 0;
  min-width: 0;
}
/* 顶部横幅 */
.header {
  width: 100%;
}

/* 使用 Grid 将背景图与 Logo 叠放在同一单元格，避免 absolute 定位 */
.header .header-banner {
  display: grid;
  grid-template: 1fr / 1fr;
  width: 100%;
}

.header .header-banner-bg {
  grid-area: 1 / 1 / 2 / 2;
  width: 100%;
  height: auto;
  display: block;
}

.header .header-logo {
  grid-area: 1 / 1 / 2 / 2;
  justify-self: start;
  align-self: start;
  /* 341.04 / 1920 ≈ 17.7625% */
  margin-left: 17.7625%;
  /* 73 / 809 ≈ 9.023%，换算为基于容器宽度的 margin-top：9.023% × 42.1354% ≈ 3.802% */
  margin-top: 3.802%;
  /* 247.02 / 1920 ≈ 12.865%，限制最大宽度避免大屏过度放大 */
  width: 12.865%;
  max-width: 247px;
}

.header .header-logo img {
  width: 100%;
  height: auto;
  display: block;
  transition: transform 0.3s ease;
}

.header .header-logo:hover img {
  transform: scale(1.05);
}

/* 教育部特别策划 */
/* 使用 Grid 将背景、标题、卡片叠放在同一单元格 */
/* .part_1 {
  display: grid;
  grid-template: 1fr / 1fr;
  width: 100%;
  height: 38.5938vw;
  min-height: 280px;
  overflow: hidden;
}

.part_1 .part-1-bg {
  grid-area: 1 / 1 / 2 / 2;
  width: 100%;
  height: 100%;
  overflow: hidden;
}

.part_1 .part-1-bg img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  object-position: center top;
}

.part_1 .part-1-title {
  grid-area: 1 / 1 / 2 / 2;
  justify-self: start;
  align-self: start;
 
  margin-left: 37.5521%;
 
  margin-top: 3.4896%;
 
  width: 25.0521%;
  margin-bottom: 0;
}

.part_1 .part-1-title img {
  width: 100%;
  height: auto;
  display: block;
}


.part_1 .part-1-card {
  grid-area: 1 / 1 / 2 / 2;
  justify-self: start;
  align-self: start;
  display: grid;
  grid-template: 1fr / 1fr;
 
  margin-left: 29.6875%;
  
  margin-top: 6.875%;
  
  width: 40.2604%;
  background-color: rgba(255, 255, 255, 0.5);
  border-radius: 20px;
}

.part_1 .part-1-card::before {
  content: "";
  grid-area: 1 / 1 / 2 / 2;
  
  padding-top: 59.7671%;
}

.part_1 .part-1-video {
  grid-area: 1 / 1 / 2 / 2;
  display: block;
  border-radius: 20px;
  overflow: hidden;
}

.part_1 .part-1-video-thumb {
  
  margin-left: 5.1759%;
  
  margin-top: 5.1759%;
  
  width: 89.6507%;
  height: auto;
  display: block;
  transition: transform 0.3s ease;
}

.part_1 .part-1-video:hover .part-1-video-thumb {
  transform: scale(1.03);
} */

.part_1 {
  height: 740px;
  padding: 50px 0;
  background-image: url(../images/part-1-bg.png);
  background-size: 100% 100%;
}
.part_1 .part-1-title {
  width: 500px;
  display: block;
  margin: 0 auto;
}

.part-1-card {
  width: 772px;
  padding: 20px;
  background-color: rgba(255, 255, 255, 0.5);
  margin: 0 auto;
  border-radius: 20px;
  margin-top: 20px;
  position: relative;
}
.part-1-video-thumb {
  width: 100%;
  display: block;
}

/* 要闻头条 */
.part_2 {
  width: 100%;
  background-color: #fff;
  padding: 50px 0;
  overflow: hidden;
  background-image: url(../images/part-2-bg.png);
  background-size: 100% 100%;
}

.part-2-sprite {
  display: none;
}

.part-2-title {
  width: 500px;
  max-width: 90%;
  margin: 0 auto 52px;
}

.part-2-title img {
  width: 100%;
  height: auto;
  display: block;
}

.part-2-content {
  width: 100%;
  max-width: 1780px;
  margin: 0 auto;
  padding: 0 20px;
}

.part-2-card {
  width: 1200px;
  max-width: 100%;
  margin: 0 auto;
  padding: 20px;
  background-color: rgba(255, 255, 255, 0.5);
  border-radius: 20px;
}

.part-2-card-inner {
  background-color: #fff;
  border-radius: 20px;
}

.part-2-body {
  display: grid;
  grid-template-columns: 633px 1fr;
  gap: 25px;
  padding: 20px;
  border: 1px solid #dddddd;
  border-radius: 20px;
}

.part-2-featured {
  display: flex;
  flex-direction: column;
}

.part-2-featured-image {
  width: 100%;
  height: auto;
  overflow: hidden;
}

.part-2-featured-image img {
  width: 100%;
  height: auto;
  display: block;
}

.part-2-featured-info {
  padding: 26.5px 40px;
}

.part-2-featured-title {
  color: #000;
  font-size: 22px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  font-weight: 400;
  line-height: 1.5;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.part-2-featured-summary {
  margin-top: 20px;
  color: #999;
  font-size: 14px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  line-height: 1.6;
  text-align: justify;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
  overflow: hidden;
  text-overflow: ellipsis;
}

.part-2-list {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-width: 0;
  gap: 25px;
}

.part-2-item {
  display: flex;
  flex-direction: column;
}

.part-2-item-title {
  color: #333;
  font-size: 20px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  font-weight: 400;
  line-height: 1.5;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.part-2-item-summary {
  margin-top: 20px;
  color: #333;
  font-size: 14px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  line-height: 1.6;
  display: -webkit-box;
  -webkit-box-orient: vertical;
  -webkit-line-clamp: 3;
  overflow: hidden;
  text-overflow: ellipsis;
  text-align: justify;
}

.part-2-meta {
  display: flex;
  align-items: center;
  gap: 20px;
  margin-top: 20px;
}

.part-2-date {
  display: flex;
  align-items: center;
  gap: 5px;
  color: #999;
  font-size: 16px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
}

.part-2-date-icon {
  width: 19px;
  height: 19px;
  display: block;
}

.part-2-source {
  color: #999;
  font-size: 16px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
}

.part-2-video {
  width: 1200px;
  display: flex;
  margin: 0 auto;
  gap: 20px;
  margin-top: 20px;
}
.part-2-video-item {
  padding: 20px;
  background-color: rgba(255, 255, 255, 0.5);
  flex: 1;
  border-radius: 20px;
  height: 348px;
}
.part-2-video-item video {
  width: 100%;
  height: 348px;
  display: block;
}

/* 校园新闻 */
.part_3 {
  padding: 50px 0;
  width: 100%;
  background-color: #fbf7f0;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.part-3-title {
  width: 500px;
  max-width: 90%;
  margin-bottom: 47px;
}

.part-3-title img {
  width: 100%;
  height: auto;
  display: block;
}

.part-3-content {
  width: 100%;
  max-width: 1195px;
  padding: 0 20px;
}

.part-3-grid {
  display: grid;
  grid-template-columns: repeat(3, 361px);
  gap: 20px 24px;
  justify-content: center;
}

.part-3-card {
  width: 360px;
  height: 100%;
  background-color: #fff;
  border: 1px solid #dddddd;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.part-3-card-image {
  width: 100%;
  height: 243px;
  overflow: hidden;
}

.part-3-card-image img {
  width: 100%;
  height: 100%;
  display: block;
  object-fit: cover;
  transition: transform 0.3s ease;
}

.part-3-card:hover .part-3-card-image img {
  transform: scale(1.05);
}

.part-3-card-info {
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 34px;
  justify-content: space-between;
  flex: 1;
}

.part-3-card-title {
  color: #000;
  font-size: 20px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  font-weight: 400;
  line-height: 1.5;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  text-align: justify;
}

.part-3-card-summary {
  margin-top: 13px;
  color: #999;
  font-size: 14px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  line-height: 1.6;
  overflow: hidden;
  display: -webkit-box;
  -webkit-line-clamp: 5;
  -webkit-box-orient: vertical;
  text-align: justify;
}

.part-3-card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.part-3-card-date {
  display: flex;
  align-items: center;
  gap: 5px;
  color: #999;
  font-size: 12px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
}

.part-3-date-icon {
  width: 16px;
  height: 16px;
  display: block;
}

.part-3-card-source {
  color: #999;
  font-size: 12px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
}

.part-3-more {
  width: 280px;
  height: 52px;
  margin-top: 68px;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: #c70915;
  border-radius: 10px;
  color: #fafafa;
  font-size: 24px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  text-decoration: none;
  transition: background-color 0.3s ease;
}

.part-3-more:hover {
  background-color: #a80712;
}

/* 少年致敬 */
.part_4 {
  width: 100%;
  background-color: #fbf7f0;
  display: flex;
  flex-direction: column;
  align-items: center;
  overflow: hidden;
  padding: 50px 0;
}

.part-4-title {
  width: 742px;
  max-width: 90%;
  margin-bottom: 26px;
}

.part-4-title img {
  width: 100%;
  height: auto;
  display: block;
}

.part-4-card {
  width: 1417px;
  max-width: 90%;
}

.part-4-card img {
  width: 100%;
  height: auto;
  display: block;
}

/* 致敬榜样 海淀优师 */
.part_5 {
  width: 100%;
  overflow: hidden;
  padding: 32px 0 170px;
  background-image: url(../images/part-5-bg.png);
  background-size: 100% 100%;
  background-repeat: no-repeat;
}

.part-5-title {
  position: relative;
  width: 716px;
  max-width: 90%;
  margin: 0 auto 60px;
}

.part-5-title-img {
  width: 100%;
  height: auto;
  display: block;
}

/* 标题两侧的爱心涂鸦装饰，左侧镜像、右侧按设计稿旋转 180 度 */
.part-5-title-hearts {
  position: absolute;
  top: 30px;
  width: 170px;
  height: auto;
}

.part-5-title-hearts-left {
  left: -200px;
  transform: scaleX(-1);
}

.part-5-title-hearts-right {
  right: -200px;
  transform: rotate(180deg);
}

/* 学生来信卡片组：三张卡片横向等距排列、高度一致 */
.part-5-letters {
  display: flex;
  justify-content: center;
  align-items: stretch;
  gap: 38px;
  max-width: 1370px;
  margin: 0 auto 54px;
  padding: 0 20px;
}

.part-5-letter {
  width: 418px;
  flex-shrink: 0;
  display: flex;
  flex-direction: column;
  gap: 27px;
  padding: 30px 18px;
  background-color: rgba(255, 255, 255, 0.5);
  border-radius: 30px;
  transition:
    transform 0.3s ease,
    box-shadow 0.3s ease;
}

.part-5-letter:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 30px rgba(11, 37, 170, 0.15);
}

.part-5-letter-image {
  overflow: hidden;
}

.part-5-letter-image img {
  width: 100%;
  height: auto;
  display: block;
}

/* 第三张卡片的画作宽度较窄，居中展示 */
.part-5-letter-image-center img {
  width: 342px;
  max-width: 100%;
  margin: 0 auto;
}

/* 第二张卡片为"上文下图"布局，画作始终贴齐卡片底部 */
.part-5-letter-reverse .part-5-letter-image {
  margin-top: auto;
}

.part-5-letter-body {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 10px;
  background-color: #fff;
  border-radius: 10px;
}

/* 第三张卡片的信件内容整体垂直居中 */
.part-5-letter-body-center {
  justify-content: center;
}

.part-5-letter-text {
  color: #333;
  font-size: 16px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  line-height: 1.6;
  text-align: justify;
}

.part-5-letter-sign {
  margin-top: auto;
  padding-top: 15px;
  color: #333;
  font-size: 16px;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  line-height: 1.5;
  text-align: right;
}

/* 垂直居中的信件正文不落底署名，与正文成组居中 */
.part-5-letter-body-center .part-5-letter-sign {
  margin-top: 0;
  padding-top: 20px;
}

/* 学生画作展示区 */
.part-5-arts {
  display: flex;
  justify-content: center;
  gap: 54px;
  max-width: 1382px;
  margin: 0 auto 54px;
  padding: 0 20px;
}

.part-5-art {
  width: 409px;
}

.part-5-art img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: 20px;
  transition: transform 0.3s ease;
}

.part-5-art:hover img {
  transform: scale(1.03);
}

.part-5-art-caption {
  margin-top: 20px;
  font-size: 28px;
  font-weight: 500;
  font-family: "Source Han Sans CN", "Microsoft YaHei", "PingFang SC", sans-serif;
  text-align: center;
}

.part-5-art-school {
  color: #0b25aa;
  margin-right: 12px;
}

.part-5-art-name {
  color: #045afe;
}

/* 优师照片轮播：当前照片居中放大，两侧照片缩小 */
.part-5-gallery {
  position: relative;
  max-width: 1402px;
  margin: 0 auto;
}

.part-5-gallery-swiper {
  padding: 57px 0;
}

.part-5-gallery-swiper .swiper-slide {
  /* 中间图宽度 520px（设计稿 609px 基础上适当收小）；视口高度不足时按高宽比 772/609 反推宽度，保证整组轮播一屏可见（上下各留 57px 内边距与 40px 余量） */
  width: 520px;
  width: min(520px, calc((100vh - 154px) * 609 / 772));
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 缩放作用于幻灯片内图片：Swiper 会占用 slide 元素的 transform，故缩放改在 img 上实现 */
.part-5-gallery-swiper .swiper-slide img {
  width: 100%;
  aspect-ratio: 609 / 772;
  object-fit: cover;
  border-radius: 20px;
  display: block;
  transform: scale(0.5);
  transition: transform 0.6s ease;
}

.part-5-gallery-swiper .swiper-slide-active img {
  transform: scale(1);
}

/* 仅保留中间及左右相邻三张可见，更远的幻灯片隐藏，避免窄视口下边缘露出残影 */
.part-5-gallery-swiper .swiper-slide:not(.swiper-slide-active):not(.swiper-slide-prev):not(.swiper-slide-next) {
  visibility: hidden;
}

/* 轮播左右切换按钮：半透明黑色圆形底 + CSS 绘制的白色箭头 */
.part-5-gallery-btn {
  position: absolute;
  top: 50%;
  z-index: 10;
  width: 44px;
  height: 44px;
  margin-top: -22px;
  padding: 0;
  border: none;
  border-radius: 50%;
  background-color: rgba(6, 6, 6, 0.5);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.3s ease;
}

.part-5-gallery-btn:hover {
  background-color: rgba(6, 6, 6, 0.7);
}

.part-5-gallery-prev {
  left: 17.5px;
}

.part-5-gallery-next {
  right: 17.5px;
}

.part-5-gallery-arrow {
  display: block;
  width: 12px;
  height: 12px;
  border-top: 3px solid #fff;
  border-right: 3px solid #fff;
}

.part-5-gallery-prev .part-5-gallery-arrow {
  transform: rotate(-135deg);
  margin-left: 4px;
}

.part-5-gallery-next .part-5-gallery-arrow {
  transform: rotate(45deg);
  margin-right: 4px;
}

/* 底部区域 */
.footer {
  padding: 32px;
  background-color: #0d62bd;
  display: flex;
  justify-content: center;
  gap: 20px;
  align-items: center;
  color: #fff;
  font-size: 14px;
}
.footer .footer-shield img {
  width: 62px;
  height: 72px;
  display: block;
}
.footer .footer-info {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 4px;
}
.footer .footer-info .footer-filing {
  display: flex;
  gap: 20px;
}
.footer .footer-info .footer-filing .footer-filing-link {
  display: flex;
  align-items: center;
  gap: 4px;
}
.footer .footer-placeholder {
  width: 62px;
}
.play {
  width: 80px;
  height: 80px;
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

/* 平板适配：1024px 及以下 */
@media (max-width: 1024px) {
  /* 横幅与 Logo 按百分比自适应，无需额外覆盖 */

  .part-2-title {
    width: 60%;
    margin-bottom: 40px;
  }
  .part-2-card {
    padding: 16px;
  }
  .part-2-card-inner {
    padding: 16px;
  }
  .part-2-body {
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    padding: 16px;
  }
  .part-2-featured-info {
    padding: 20px;
  }
  .part-2-item-title {
    font-size: 20px;
  }

  .part-2-video {
    width: 100%;
    display: flex;
    flex-direction: column;
    margin: 0 auto;
    gap: 20px;
    margin-top: 20px;
  }
  .part-2-video-item {
    height: 232px;
    padding: 10px;
    background-color: rgba(255, 255, 255, 0.5);
    flex: unset;
    border-radius: 20px;
  }
  .part-2-video-item video {
    width: 100%;
    height: 232px;
    display: block;
  }

  .part-3-title {
    width: 60%;
    margin-bottom: 40px;
  }
  .part-3-grid {
    grid-template-columns: repeat(2, 361px);
    gap: 20px 24px;
  }

  .part-4-title {
    width: 60%;
    margin-bottom: 20px;
  }
  .part-4-card {
    max-width: 95%;
  }

  .part-5-title {
    width: 60%;
    margin-bottom: 40px;
  }
  .part-5-title-hearts {
    width: 90px;
    top: 16px;
  }
  .part-5-title-hearts-left {
    left: -100px;
  }
  .part-5-title-hearts-right {
    right: -100px;
  }
  /* 平板端信件卡片改为纵向堆叠，画作允许换行 */
  .part-5-letters {
    flex-direction: column;
    align-items: center;
    gap: 30px;
    margin-bottom: 40px;
  }
  .part-5-arts {
    flex-wrap: wrap;
    gap: 30px;
    margin-bottom: 40px;
  }
  .part-5-gallery-swiper .swiper-slide {
    width: 400px;
  }
}

/* 手机适配：768px 及以下 */
@media (max-width: 768px) {
  .play {
    width: 72px;
    height: 72px;
    position: absolute;
    left: 50%;
    right: 50%;
    transform: translate(-50%, -50%);
  }
  .header .header-logo {
    /* 移动端适当放大 Logo 并贴近左上角，提升可识别性与触控体验 */
    width: 18%;
    margin-left: 4%;
    /* 5% × 42.1354% ≈ 2.1068% */
    margin-top: 2.1068%;
    max-width: none;
  }

  .part_2 {
    padding-top: 40px;
  }
  .part-2-title {
    width: 80%;
    margin-bottom: 30px;
  }
  .part-2-content {
    padding: 0 16px;
  }
  .part-2-card {
    padding: 0;
  }
  .part-2-card-inner {
    padding: 0;
  }
  .part-2-body {
    grid-template-columns: 1fr;
    gap: 30px;
    padding: 12px;
  }
  .part-2-featured-info {
    padding: 0;
    margin-top: 16px;
  }
  .part-2-featured-title {
    font-size: 18px;
  }
  .part-2-item-title {
    font-size: 18px;
  }
  .part-2-meta {
    flex-wrap: wrap;
    gap: 10px;
  }

  .part_3 {
    padding-bottom: 60px;
  }
  .part-3-title {
    width: 80%;
    margin-bottom: 30px;
  }
  .part-3-content {
    padding: 0 16px;
  }
  .part-3-grid {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .part-3-card {
    width: 100%;
  }
  .part-3-card-info {
    padding: 16px;
    height: auto;
  }
  .part-3-card-meta {
  }
  .part-3-more {
    width: 62%;
    max-width: 314px;
    height: 48px;
    margin-top: 40px;
    font-size: 18px;
  }

  .part-4-title {
    width: 80%;
    margin-bottom: 16px;
  }
  .part-4-card {
    max-width: 100%;
  }

  .footer {
    flex-direction: column;
  }
  .footer .footer-placeholder {
    display: none;
  }
  .footer .footer-info .footer-filing {
    flex-direction: column;
    align-items: center;
    gap: 4px;
  }

  .part-2-title img {
    width: 68%;
    height: auto;
    display: block;
    margin: 0 auto;
  }
  .part-3-title img {
    width: 68%;
    height: auto;
    display: block;
    margin: 0 auto;
  }

  .part_5 {
    padding: 30px 0 60px;
  }
  .part-5-title {
    width: 80%;
    margin-bottom: 30px;
  }
  /* 手机端隐藏纯装饰的爱心涂鸦，避免遮挡标题 */
  .part-5-title-hearts {
    display: none;
  }
  .part-5-letters {
    padding: 0 16px;
  }
  .part-5-letter {
    width: 100%;
    max-width: 418px;
    padding: 20px 14px;
    gap: 20px;
    border-radius: 20px;
  }
  .part-5-arts {
    padding: 0 16px;
  }
  .part-5-art {
    width: 100%;
    max-width: 409px;
  }
  .part-5-art-caption {
    margin-top: 14px;
    font-size: 20px;
  }
  .part-5-gallery-swiper {
    padding: 30px 0;
  }
  .part-5-gallery-swiper .swiper-slide {
    width: 240px;
  }
  .part-5-gallery-prev {
    left: 10px;
  }
  .part-5-gallery-next {
    right: 10px;
  }

  .part_1 {
    height: 420px;
    padding: 50px 20px;
    background-image: url(../images/part-1-bg.png);
    background-size: 100% 100%;
  }
  .part_1 .part-1-title {
    width: 68%;
    display: block;
    margin: 0 auto;
  }

  .part-1-card {
    width: 100%;
    padding: 20px;
    background-color: rgba(255, 255, 255, 0.5);
    margin: 0 auto;
    border-radius: 20px;
    margin-top: 20px;
    position: relative;
  }
  .part-1-video-thumb {
    width: 100%;
    display: block;
  }
}