/* 基础样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: "PingFang SC", "Microsoft YaHei", sans-serif;
    background-color: #f5f5f5;
    color: #333;
    line-height: 1.6;
}

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

.notes-layout {
    display: flex;
    gap: 30px;
    min-height: 100vh;
}

/* 侧边栏样式 */
.notes-sidebar {
    flex: 0 0 250px;
    background-color: #fff;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 20px;
    height: fit-content;
}

.back-button {
    display: block;
    margin-bottom: 20px;
    padding: 10px 15px;
    background-color: #4a6fa5;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    text-align: center;
    font-weight: bold;
    transition: background-color 0.3s;
}

.back-button:hover {
    background-color: #3a5a80;
}

.nav-title {
    font-size: 18px;
    font-weight: bold;
    margin-bottom: 15px;
    color: #333;
    border-bottom: 2px solid #eaeaea;
    padding-bottom: 10px;
}

.nav-list {
    list-style: none;
}

.nav-item {
    margin-bottom: 10px;
}

.nav-item a {
    display: block;
    padding: 10px;
    text-decoration: none;
    color: #555;
    border-radius: 5px;
    transition: all 0.3s;
}

.nav-item.active a {
    background-color: #e6f0ff;
    color: #4a6fa5;
    font-weight: bold;
}

.nav-item:not(.disabled) a:hover {
    background-color: #f0f5ff;
}

.nav-item.disabled a {
    color: #aaa;
    cursor: not-allowed;
}

/* 主内容区样式 */
.notes-main {
    flex: 1;
    background-color: #fff;
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

header {
    margin-bottom: 30px;
    text-align: center;
}

header h1 {
    font-size: 32px;
    color: #333;
    margin-bottom: 10px;
}

header p {
    color: #777;
    font-size: 16px;
}

.notes-display {
    margin-bottom: 40px;
}

.note-card {
    background-color: #fff;
    border-radius: 8px;
    padding: 25px;
    margin-bottom: 20px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    border: 1px solid #eaeaea;
}

.note-title {
    font-size: 24px;
    color: #333;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid #eaeaea;
}

.note-content {
    font-size: 16px;
    line-height: 1.8;
    color: #444;
}

.note-content p {
    margin-bottom: 20px;
}

.note-content hr {
    margin: 25px 0;
    border: none;
    border-top: 1px dashed #ddd;
}

.note-content em {
    display: block;
    font-style: italic;
    color: #777;
    padding: 15px;
    background-color: #f9f9f9;
    border-left: 4px solid #ddd;
    margin-top: 20px;
}

.note-content ul, .note-content ol {
    margin-left: 25px;
    margin-bottom: 20px;
}

.note-content li {
    margin-bottom: 10px;
}

.note-date {
    text-align: right;
    color: #999;
    font-size: 14px;
    margin-top: 20px;
}

footer {
    text-align: center;
    color: #999;
    font-size: 14px;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid #eaeaea;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .notes-layout {
        flex-direction: column;
    }
    
    .notes-sidebar {
        flex: none;
        width: 100%;
        margin-bottom: 20px;
        position: static;
    }
    
    .note-title {
        font-size: 22px;
    }
}