/* 引入现代字体 */
@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;500;700&display=swap');

/* 统一样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

/* 背景动画 */
.background {
    position: fixed;
    width: 100%;
    height: 100%;
    background: linear-gradient(-45deg, #ff9a9e, #fad0c4, #fad0c4, #fbc2eb);
    background-size: 400% 400%;
    animation: gradientBG 10s ease infinite;
    z-index: -1;
}

/* 头部样式 */
.header {
    text-align: center;
    padding: 60px 20px;
    color: white;
    font-size: 1.5rem;
    font-weight: 500;
    background: rgba(0, 0, 0, 0.4);
    backdrop-filter: blur(10px);
    border-bottom: 3px solid #fff;
}

/* 任务区 */
.tiles {
    display: flex;
    justify-content: center;
    gap: 30px;
    padding: 50px;
    max-width: 1200px;
    margin: auto;
}

/* 任务卡片 */
.tile {
    position: relative;
    width: 250px;
    height: 350px;
    overflow: hidden;
    border-radius: 20px;
    box-shadow: 0px 10px 30px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease-in-out, box-shadow 0.3s ease-in-out;
}

/* 鼠标悬停效果 */
.tile:hover {
    transform: translateY(-8px);
    box-shadow: 0 20px 30px rgba(0, 0, 0, 0.2);
}

/* 卡片图片 */
/* 第一张图片 */
.tile:nth-child(1) .image {
    background-image: url('playground Task2/202528.png');
}

/* 第二张图片 */
.tile:nth-child(2) .image {
    background-image: url('playground Task2/21212.png'); /* 替换为你的第二张图片 */
}

/* 统一样式 */
.tile .image {
    width: 100%;
    height: 100%;
    background-size: cover;
    background-position: center;
    filter: brightness(80%);
    transition: filter 0.3s ease-in-out;
}


.tile:hover .image {
    filter: brightness(100%);
}

/* 任务标题 */
.tile h2 {
    position: absolute;
    bottom: 10px;
    width: 100%;
    text-align: center;
    font-size: 1.5rem;
    color: white;
    font-weight: bold;
    text-transform: uppercase;
    background: rgba(0, 0, 0, 0.5);
    padding: 10px;
    border-radius: 0 0 20px 20px;
}

/* 背景动画关键帧 */
@keyframes gradientBG {
    0% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
    100% { background-position: 0% 50%; }
}

/* 侧边栏样式 */
#sidebar {
    position: fixed;
    left: 0;
    top: 0;
    height: 100%;
    width: 0;
    background-color: #1a202c; /* 深灰色背景 */
    color: white;
    overflow: hidden;
    transition: all 0.3s ease;
    box-shadow: 4px 0 10px rgba(0, 0, 0, 0.3);
}

/* 关闭按钮样式 */
#closeSidebar {
    font-size: 24px;
    color: #a0aec0; /* 浅灰色 */
    border: none;
    background: none;
    cursor: pointer;
}

#closeSidebar:hover {
    color: white;
}

/* 侧边栏标题 */
.sidebar-title {
    color: #63b3ed; /* 淡蓝色 */
    font-size: 20px;
    font-weight: bold;
    margin-top: 16px;
}

/* 侧边栏内的导航菜单 */
.sidebar-menu {
    margin-top: 24px;
}

.sidebar-menu li {
    list-style: none;
    margin-bottom: 16px;
}

/* 按钮样式 */
.sidebar-link {
    display: block;
    padding: 12px;
    border-radius: 6px;
    text-align: center;
    font-size: 18px;
    font-weight: 600;
    color: #a0aec0; /* 浅灰色 */
    background: linear-gradient(to right, #4299e1, #2b6cb0); /* 渐变蓝 */
    transition: all 0.3s ease;
    text-decoration: none;
}

.sidebar-link:hover {
    color: white;
    background: linear-gradient(to right, #3182ce, #2c5282);
}

/* 侧边栏展开按钮 */
#openSidebar {
    position: fixed;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    padding: 12px;
    background-color: #3182ce;
    color: white;
    border-radius: 0 8px 8px 0;
    font-size: 24px;
    cursor: pointer;
    box-shadow: 2px 2px 8px rgba(0, 0, 0, 0.2);
    transition: background 0.3s;
}

#openSidebar:hover {
    background-color: #2c5282;
}

/* Footer */
footer {
    text-align: center;
    padding: 1rem;
    background: #333;
    color: white;
    font-size: 0.9rem;
  }

  .bigimage{
    width: 100%;
  }
  .littleimage{
    width:20%;
    height:20%;
  }