/* 整个网页 */
body {
    margin: 0;
    font-family: Arial, sans-serif;
   background-color: #0f172a;
    color: #e2e8f0;
}

/* 顶部导航栏 */
header {
    background-color: #1e293b;
    padding: 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    color: #38bdf8;
    margin: 0;
}

/* 导航链接 */
nav a {
    color: white;
    text-decoration: none;
    margin-left: 20px;
}

/* 主体内容 */
main {
    max-width: 900px;
    margin: 40px auto;
    padding: 0 20px;
}

/* 章节标题 */
h2 {
    color: #38bdf8;
    margin-top: 35px;
}

/* 论坛板块和帖子 */
section, article {
    background-color: #1e293b;
    padding: 20px;
    margin-top: 15px;
    border-radius: 12px;
}

/* 鼠标经过帖子 */
article:hover {
    background-color: #334155;
}

/* 发帖按钮 */
button {
    background-color: #38bdf8;
    color: #0f172a;
    border: none;
    padding: 12px 20px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: bold;
}

button:hover {
    background-color: #7dd3fc;
}

/* 发帖表单 */
.post-form {
    background-color: #1e293b;
    padding: 24px;
    margin-top: 20px;
    border-radius: 12px;
}

/* 保证隐藏属性正常工作 */
.post-form[hidden] {
    display: none;
}

.post-form label {
    display: block;
    margin-top: 16px;
    margin-bottom: 8px;
}

.post-form input,
.post-form select,
.post-form textarea {
    width: 100%;
    box-sizing: border-box;
    padding: 12px;
    border: 1px solid #475569;
    border-radius: 8px;
    background-color: #0f172a;
    color: white;
    font: inherit;
}

#submitPost,
#cancelPost {
    margin-top: 16px;
    margin-right: 8px;
}

/* 帖子所属板块 */
.post-category {
    color: #38bdf8;
    font-size: 14px;
}

/* 板块筛选按钮 */
.post-filters {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 20px 0;
}

.filter-btn {
    background-color: #334155;
    color: #e2e8f0;
}

.filter-btn:hover {
    background-color: #475569;
}

/* 当前选中的板块 */
.filter-btn.active {
    background-color: #38bdf8;
    color: #0f172a;
}

/* 没有帖子时的提示 */
.empty-message {
    color: #94a3b8;
    text-align: center;
    padding: 24px;
}