/* 全局变量定义 */
:root {
    --primary-color: #1a2a3a;
    --secondary-color: #3498db;
    --light-color: #f5f5f5;
    --border-color: #e0e0e0;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --primary: #1a2a3a;
    --secondary: #3498db;
    --white: #ffffff;
}

/* 追加PDF浏览器居中样式 */
.pdf-browser {
    display: flex !important;
    justify-content: center !important;
    align-items: center !important;
    margin: 0 auto !important;
    width: 100% !important;
    max-width: 1200px !important;
    height: auto !important;
    min-height: 600px !important;
}

/* 确保PDF内容本身也居中 */
.pdf-browser embed,
.pdf-browser iframe,
.pdf-browser object {
    display: block !important;
    margin: 0 auto !important;
    padding: 0;
}

/* 容器样式 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部样式 */
header {
    background-color: #1a2a3a;
    box-shadow: var(--shadow);
    padding: 1rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
}

header h1 {
    color: #b6c5d4;
    margin: 0;
    font-size: 1.8rem;
}

nav ul {
    display: flex;
    list-style: none;
    margin: 1rem 0 0;
    padding: 0;
}

nav li {
    margin-right: 1.5rem;
}

nav a {
    color: #eeeeee;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

nav a:hover {
    color: #ffffff;
}

/* PDF浏览器布局 */
.pdf-sidebar {
    width: 280px;
    background: white;
    border-right: 1px solid var(--border-color);
    padding: 1.5rem;
    overflow-y: auto;
}

.pdf-sidebar h2 {
    font-size: 1.4rem;
    margin: 0 0 1.5rem;
    color: var(--primary-color);
    font-weight: 600;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.pdf-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.pdf-list li {
    padding: 0.8rem 1rem;
    margin-bottom: 0.5rem;
    border-radius: 4px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 0.95rem;
}

.pdf-list li:hover {
    background-color: var(--light-color);
}

.pdf-list li.active {
    background-color: var(--secondary-color);
    color: #333;
    font-weight: 500;
}

.pdf-viewer {
    flex: 1;
    padding: 1.5rem;
    background: var(--light-color);
}

#pdf-frame {
    width: 100%;
    height: 100%;
    min-height: 70vh;
    border: none;
    background: white;
    box-shadow: var(--shadow);
    border-radius: 4px;
}

/* 页脚样式 */
footer {
    background-color: var(--primary-color);
    color: rgb(175, 175, 175);
    padding: 1.5rem 0;
    text-align: center;
    margin-top: 2rem;
}

footer p {
    margin: 0;
    font-size: 0.9rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .pdf-browser {
        flex-direction: column;
    }
    
    .pdf-sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    nav ul {
        flex-direction: column;
    }
    
    nav li {
        margin: 0.5rem 0;
    }
}

/* 按钮样式 */
.btn {
  display: inline-block;
  background-color: #3498db !important; /* 直接使用颜色值并添加!important */
  color: #ffffff !important; /* 直接使用颜色值并添加!important */
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background-color 0.3s;
}

.btn:hover {
  background-color: #2980b9 !important;
}

/* 确保表单提交按钮样式 */
input[type="submit"], button[type="submit"] {
  display: inline-block;
  background-color: #3498db !important;
  color: #ffffff !important;
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  transition: background-color 0.3s;
}

input[type="submit"]:hover, button[type="submit"]:hover {
  background-color: #2980b9 !important;
}