:root {
    --primary-color: #3a5065;
    --secondary-color: #5d7fa3;
    --text-color: #333;
    --light-bg: #f5f7fa;
    --border-color: #e0e0e0;
    /* 新增base64页面变量 */
    --tab-active-color: #0078d4;
    --tab-hover-color: #005a9e;
    --input-bg-color: #fff;
    --input-border-color: #d0d7de;
    --button-bg-color: #2196f3;
    --button-hover-bg-color: #1976d2;
    --result-bg-color: #f6f8fa;
    --result-border-color: #e1e4e8;
    --notification-bg-color: #0078d4;
    --notification-text-color: #fff;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Georgia', serif;
}

body {
    color: var(--text-color);
    line-height: 1.6;
    background-color: var(--light-bg);
}

header {
    background-color: var(--primary-color);
    color: white;
    padding: 2rem;
    text-align: center;
    margin-bottom: 2rem;
}

h1 {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
}

.container {
    display: flex;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
    gap: 2rem;
}

.sidebar {
    flex: 0 0 300px;
    position: sticky;
    top: 2rem;
    align-self: flex-start;
}

.content {
    flex: 1;
}

.toc {
    background: white;
    border-radius: 8px;
    padding: 1.5rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.toc h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

.section-title {
    font-weight: bold;
    margin: 1rem 0 0.5rem 0;
    color: var(--secondary-color);
}

.toc ul {
    list-style: none;
    padding-left: 1rem;
}

.toc li {
    margin: 0.5rem 0;
}

.toc a {
    color: var(--text-color);
    text-decoration: none;
    transition: color 0.3s;
}

.toc a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

.section {
    background: white;
    border-radius: 8px;
    padding: 2rem;
    margin-bottom: 2rem;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.section h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
}

.chapter {
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid var(--border-color);
}

.chapter:last-child {
    border-bottom: none;
}

.chapter h3 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.chapter-content {
    text-align: justify;
    white-space: pre-line;
}

.placeholder {
    color: #777;
    font-style: italic;
    background-color: #f9f9f9;
    padding: 1rem;
    border-radius: 4px;
}

.link {
    color: #33c9f7;
    font-weight: bold;
    text-decoration: none;
}

a:hover {
    text-decoration: underline;
}

.back-to-top {
    display: none; /* 默认隐藏 */
    position: fixed; /* 固定定位，不随滚动移动 */
    right: 1rem; /* 距离右侧1rem */
    top: 1rem; /* 距离顶部1rem */
    z-index: 100; /* 确保在其他内容上方 */
}

.back-to-top a {
    display: inline-block;
    width: 3rem;
    height: 3rem;
    background-color: var(--primary-color); /* 使用主题主色 */
    color: white;
    text-align: center;
    line-height: 3rem; /* 垂直居中箭头 */
    border-radius: 50%; /* 圆形按钮 */
    text-decoration: none;
    font-size: 1.5rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2); /* 轻微阴影 */
    transition: background-color 0.3s;
}

.back-to-top a:hover {
    background-color: var(--secondary-color); /* hover时变色 */
}

/* 应用头部样式 */
.app-header {
    display: flex;
    gap: 2rem;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.app-header img {
    width: 100px;
    height: 100px;
    border-radius: 8px;
    background: var(--primary-color);
    padding: 1rem;
}

.app-intro h2 {
    margin-bottom: 0.5rem;
    border-bottom: none;
    padding-bottom: 0;
}

.app-intro p {
    font-size: 1.1rem;
    color: var(--secondary-color);
    margin: 0.5rem 0;
}

.download-btn {
    display: inline-block;
    padding: 0.8rem 1.5rem;
    background: var(--primary-color);
    color: white;
    border-radius: 4px;
    text-decoration: none;
    font-weight: bold;
    transition: background 0.3s;
}

.download-btn:hover {
    background: var(--secondary-color);
    text-decoration: none;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        flex-direction: column;
    }

    .sidebar {
        position: static;
        margin-bottom: 2rem;
    }

    .back-to-top {
        display: block;
    }
}

/* Base64页面专用样式 */
.tab {
    display: inline-block;
    padding: 10px 20px;
    cursor: pointer;
    border: 1px solid var(--border-color);
    border-bottom: none;
    border-radius: 5px 5px 0 0;
    margin-right: 5px;
    background-color: var(--light-bg);
    transition: background-color 0.3s;
}

.tab.active {
    background-color: white;
    color: var(--tab-active-color);
    font-weight: bold;
}

.tab:hover:not(.active) {
    background-color: #e3e6e9;
}

.tab-content {
    display: none;
    padding: 20px;
    border: 1px solid var(--border-color);
    border-radius: 0 5px 5px 5px;
    background-color: white;
    margin-bottom: 20px;
}

.tab-content.active {
    display: block;
}

.form-group {
    margin-bottom: 15px;
}

.input-group {
    display: flex;
    margin-bottom: 10px;
    gap: 10px;
}

.input-group input[type="text"] {
    flex: 1;
    padding: 8px;
    border: 1px solid var(--input-border-color);
    border-radius: 4px;
}

.input-group select {
    flex: 1;
    padding: 8px;
    border: 1px solid var(--input-border-color);
    border-radius: 4px;
    background-color: var(--input-bg-color);
}

textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--input-border-color);
    border-radius: 4px;
    min-height: 150px;
    font-family: inherit;
    resize: vertical;
}

button {
    background-color: var(--button-bg-color);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    margin-right: 10px;
    margin-bottom: 10px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: var(--button-hover-bg-color);
}

button:disabled {
    background-color: #cccccc;
    cursor: not-allowed;
}

.result {
    background-color: var(--result-bg-color);
    border: 1px solid var(--result-border-color);
    border-radius: 4px;
    padding: 15px;
    margin-top: 15px;
    position: relative;
}

.result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}

.result-header h3 {
    margin: 0;
    color: var(--primary-color);
}

.copy-btn {
    padding: 5px 10px;
    background-color: var(--button-bg-color);
    color: white;
    border: none;
    border-radius: 3px;
    cursor: pointer;
    font-size: 12px;
}

.copy-btn:hover {
    background-color: var(--button-hover-bg-color);
}

.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    background-color: var(--notification-bg-color);
    color: var(--notification-text-color);
    padding: 10px 20px;
    border-radius: 4px;
    display: none;
    z-index: 1000;
    animation: slideIn 0.3s ease-out;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

footer {
    margin-top: 20px;
    padding: 10px;
    text-align: center;
    font-size: 12px;
    color: #777;
    border-top: 1px solid var(--border-color);
}

/* 确保base64页面和其他页面样式兼容 */
.base64-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
}

.base64-container h1 {
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 20px;
}