:root {
    --primary: #35388e;
    --accent: #fdc500;
    --warning: #dd3131;
    --bg-light: #f8f8f8;
    --text-dark: #2e2e2e;
  }
  
  /* 设置正文使用 Open Sans 字体 */
  body {
    font-family: 'Open Sans', sans-serif;
    margin: 0;
    background-color: var(--bg-light);
    color: var(--text-dark);
  }

  /* 设置所有标题（h1, h2 等）使用 Ubuntu 字体 */
  h1, h2, h3, h4, h5, h6 {
    font-family: 'Ubuntu', sans-serif;
  }

  .chart-heading {
    text-align: center;
    max-width: 1200px;
    margin: 0 auto 30px auto;
  }

  .chart-heading h2 {
    font-size: 2.2em;
    margin-top: 80px;
    margin-bottom: 10px;
  }

  .chart-heading p {
    font-size: 1.05em;
    color: #444;
  }






  
  header {
    background-color: var(--primary);
    color: white;
    padding: 80px 40px;
    text-align: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  }

  /* 主标题带图标横排样式 */
  .header-with-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 25px;
    background-color: var(--primary);
    color: white;
    padding: 80px 20px;
    text-align: center;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
  }

  .header-with-icon h1 {
    margin: 0;
    font-size: 3.2em;
    font-family: 'Ubuntu', sans-serif;
  }

  .header-icon {
    height: 200px;   /* 你可以改为 100px 看效果 */
    width: auto;
    animation: float 4s ease-in-out infinite;
    will-change: transform; /* ✅ 优化性能，确保 GPU 加速 */
  }

  /* 月亮动画关键帧 */
  @keyframes float {
    0%   { transform: translateY(0); }
    50%  { transform: translateY(-15px); }
    100% { transform: translateY(0); }
  }


  /* 名字 */
  .designer-badge {
  position: absolute;
  bottom: -30px;              /* 再往下 */
  left: 0px;
  background-color: #dd3131;
  color: white;
  padding: 8px 20px;        /* 加宽加高 */
  font-size: 1.25em;            /* 字体更大 */
  font-family: 'Ubuntu', sans-serif;
  text-align: left;
  line-height: 1.4;
  border-radius: 0px;
  box-shadow: 0 4px 6px rgba(0,0,0,0.15);
  min-width: 100px;          /* 变宽 */
}

.designer-badge span {
  font-size: 0.9em;
  font-weight: bold;
}

header {
  position: relative; /* 确保定位生效 */
}


  
  h1 {
    margin: 0;
    font-size: 3.0em;
    font-weight: 300;       
  }
  
  /* 副标题 */
  .subtitle {
    font-size: 1.2em;
    font-weight: 400;
    color: #ffffff;
    margin-top: 10px;
    text-align: center;
  }

  .subtext {
    font-size: 1.4em;      /* 放大字体 */
    font-weight: 500;
    color: #ffffff;
    margin-top: 30px;      /* 往下移 */
    text-align: center;
  }


  main {
    padding: 40px 20px;
    max-width: 1500px;
    margin: auto;
  }
  
  /* .intro {
    font-size: 1.2em;
    line-height: 1.8;
    background-color: white;
    padding: 25px 30px;
    border-left: 8px solid var(--accent);
    border-radius: 6px;
    box-shadow: 0 0 8px rgba(0,0,0,0.05);
    margin-bottom: 50px;

    /* 添加或修改以下部分以增加宽度 */
    /* max-width: 1500px;     
    margin-left: auto;
    margin-right: auto;
  } */ 

  /* 黄色框 */
  /* 黄色高亮盒子 + 滑入动画 */
  .intro {
    background-color: #fdc500; /* 整块 */
    border-left: 20px solid #fdc500; /* 左侧黄色标记条 */
    padding: 30px 40px;
    border-radius: 0px;
    margin: 40px auto;
    max-width: 1500px;
    font-size: 18px;
    line-height: 1.6;
    opacity: 0;
    transform: translateX(60px); /* 初始从右边滑入 */
    animation: slideFadeIn 1s ease-out forwards;
  }

  /* 动画定义 */
  @keyframes slideFadeIn {
    0% {
      opacity: 0;
      transform: translateY(40px);
    }
    100% {
      opacity: 1;
      transform: translateY(0);
    }
  }




  .chart {
    background-color: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
  }
  
  footer {
    margin-top: 50px;
    background-color: #35388e;
    color: white;
    text-align: center;
    padding: 20px;
    font-size: 0.9em;
  }
  
  
  .grid line {
    stroke: #ccc;
    stroke-opacity: 0.3;
  }


  /* story 1 SLEEP START TIME VARIES BY AGE */
  .section-title {
    font-size: 28px;        /* 放大标题 */
    text-align: center;
    /* font-weight:normal ; */
    margin-top: 50px;
    margin-bottom: 10px;
  }

  .section-text {
    font-size: 18px;
    font-weight: 100;       /* 加粗正文 */
    text-align: center;
    max-width: 1200px;
    margin: 0 auto;
    line-height: 1.5;
  }


  

  /*Avg. sq图*/
  .chart-image {
    text-align: left;
    margin-top: 50px;
  }

  .chart-image img.svg-chart {
    max-width: 50%;
    height: auto;
  }

  .sleep-illustration-container {
    position: relative;
    height: 400px;
    margin: 100px auto;
    text-align: center;
  }

  .sleep-illustration-container img {
    max-height: 180px;
    margin: 0 20px;
  }


  .flourish-embed {
    max-width: 1200px;     /* 可根据需要改成 800px / 1000px 等 */
    margin: 0 auto;       /* ✅ 居中 */
    padding: 10px 0;
  }

  /* 四张图 */
  .chart-analysis-section {
    max-width: 1500px;
    margin: 80px auto;
    text-align: center;
    padding: 0px 0px;
  }

  .chart-analysis-section h3 {
    font-size: 1.8em;
    margin-bottom: 30px;
  }


  .four-charts img {
    max-width: 100%;
    width: 100%;
    margin: 20px 0;
    border-radius: 0px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }

  .four-charts img:hover {
    transform: scale(1.03);
    box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
  }


  .four-charts {
    display: grid;
    grid-template-columns: 1fr 1fr;  /* 每行2张图 */
    gap: 30px;                       /* 图之间的间距 */
    max-width: 1500px;
    margin: 0 auto;
  }

  .analysis-text {
    text-align: center;
    font-size: 1.1em;
    line-height: 1.7;
    color: #333;
    max-width: 1200px;
    margin: 30px auto;  /* ✅ 水平居中关键设置 */
  }



/* 图1 */
  .chart-section {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
    margin-top: 100px;
    max-width: 1400px;
    margin-left: auto;
    margin-right: auto;
  }

  .chart-left {
    flex: 1 1 50%;
    min-width: 350px;
    text-align: center;
  }

  .chart-left img.svg-chart {
    max-width: 90%;   /* 控制图表宽度 */
    height: auto;
  }

  .chart-left .section {
    margin-bottom: 30px;  /* ✅ 控制标题和图之间的距离，可调节 */
  }


  .chart-right {
    flex: 1 1 40%;
    min-width: 300px;
    font-size: 1.05em;
    line-height: 1.5;
  }

  .chart-right h2 {
    font-size: 2.2em;
    margin-bottom: 10px;
  }

    /* 图2 */
    .chart-section-swap {
    display: flex;
    flex-direction: row;
    justify-content: center;
    align-items: center;
    gap: 40px;
    flex-wrap: wrap;
    margin: 120px auto 60px auto; /* ⬅️ 增大顶部间距为100px */
    max-width: 1400px;
  }

  .chart-section-swap .text-block {
    flex: 1 1 40%;
    min-width: 300px;
    font-size: 1.05em;
    line-height: 1.5;
  }

  .chart-section-swap .text-block h2 {
    font-size: 1.6em;
    margin-bottom: 10px;
  }

  .chart-section-swap .image-block {
    flex: 1 1 50%;
    min-width: 350px;
    text-align: center;
  }

  .chart-section-swap .image-block img.svg-chart {
    max-width: 90%;
    height: auto;
  }

  .conclusion {
    max-width: 1500px;
    margin: 100px auto 60px auto;
    padding: 40px 30px;
    background-color: var(--warning);  /* 红色背景 */
    border-left: 20px solid var(--accent);  /* 黄色竖条 */
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
    font-size: 1.15em;
    line-height: 1.5;
    color: white;  /* ✅ 字体颜色改为白色 */
    border-radius: 0px;
  }

  .conclusion h3 {
    font-family: 'Ubuntu', sans-serif;
    font-size: 2.2em;
    margin-bottom: 20px;
    color: white;  /* ✅ 标题字体也改为白色 */
  }

  .conclusion p {
    margin: 0;
  }


  .references {
    max-width: 1500px;
    margin: 100px auto 50px auto;
    padding: 20px;
    font-size: 1em;
    line-height: 1.6;
    color: #444;
    border-top: 1px solid #ccc;
  }

  .references h3 {
    font-family: 'Ubuntu', sans-serif;
    font-size: 1.4em;
    margin-bottom: 10px;
    color: #2e2e2e;
  }

  .references a {
    color: var(--primary);
    text-decoration: none;
  }

  .references a:hover {
    text-decoration: underline;
  }



/* 卡片3 */
.chart-card {
  background-color: white;
  border-radius: 20px;
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.08);
  padding: 20px 30px;
  margin: 0px auto;
  max-width: 500px;
  max-height: 700px;
  transform-origin: top center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  overflow: hidden;
}

.chart-pair {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: flex-start;
  gap: 10px; /* 控制两个图表之间的距离 */
  flex-wrap: nowrap;
}

.chart-block {
  min-width: 300px;
  max-width: 300px;
  transform: scale(0.4);
  transform-origin: top left;
  margin-right: 60px; /* 缩短图表间距 */
}

.chart-block svg {
  display: block;
}

.chart-title h3 {
  font-size: 1.2em;
  margin-bottom: 5px;
}

.chart-title p {
  font-size: 0.85em;
  color: #444;
  line-height: 1.4;
}






/* 卡片 */
.chart-card {
  background-color: white;
  border-radius: 0px;
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.08);
  padding: 20px 30px;
  margin: 30px 0;         /* ✅ 改这里：上下30px，取消左右auto */
  max-width: 600px;
  max-height: 400px;
  transform-origin: top center;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  overflow: hidden;
}


.chart-card .chart-pair {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: flex-start;
  gap: 10px;                  /* 控制两个图表间距 */
  flex-wrap: nowrap;
}

.chart-card .chart-block {
  min-width: 300px;
  max-width: 300px;
  transform: scale(0.35);      /* 缩小图表本体尺寸 */
  transform-origin: top left;
  margin-right: 30px;         /* 控制图表之间“收拢”的距离 */
}

.chart-card .chart-block svg {
  display: block;
}

.chart-card .chart-title h3 {
  font-size: 1.2em;
  margin-bottom: 1px;
}

.chart-card .chart-title p {
  font-size: 0.85em;
  color: #444;
  line-height: 1.4;
}

/* 卡片容器布局（每行两个） */
.card-row {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  gap: 40px;
  flex-wrap: wrap;
  margin-top: 60px;
}

/* 外层卡片容器 */
.flip-card {
  perspective: 1000px;
  width: 600px;
  height: 360px;
  margin: 30px;
  position: relative;
}

/* 内部旋转体 */
.flip-card-inner {
  width: 100%;
  height: 100%;
  transition: transform 0.8s ease;
  transform-style: preserve-3d;
  position: relative;
}

/* 翻转状态 */
.flip-card.flipped .flip-card-inner {
  transform: rotateY(180deg);
}

/* 放大状态 */
.flip-card.zoomed .flip-card-inner {
  transform: scale(1.2);
}

/* 正面和背面通用 */
.flip-card-front,
.flip-card-back {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 0px;
  box-shadow: 0 8px 18px rgba(0, 0, 0, 0.08);
}

/* 背面样式 */
.flip-card-back {
  background-color: #dd3131;
  color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 3.2em;
  font-family: 'Ubuntu', sans-serif;
  transform: rotateY(0deg);
}

/* 正面样式 */
.flip-card-front {
  background-color: white;
  transform: rotateY(180deg);
  overflow: hidden;
  padding: 20px 30px;
}

/* 正面内容结构：图表标题 */
.chart-title h3 {
  font-size: 1.2em;
  margin-bottom: 5px;
}

.chart-title p {
  font-size: 0.85em;
  color: #444;
  line-height: 1.4;
}

/* 图表区域（两个图表并排） */
.chart-pair {
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: flex-start;
  gap: 10px;
  flex-wrap: nowrap;
}

/* 每个图表块大小与缩放 */
.chart-block {
  min-width: 300px;
  max-width: 300px;
  transform: scale(0.35);
  transform-origin: top left;
  margin-right: 30px;
}

.chart-block svg {
  display: block;
}

/* 时间标签文本在背面卡片中 */
.time-label {
  font-weight: bold;
}