/* 基础样式与颜色定义 - 淡蓝色系 */
:root {
    --primary: #5dade2;       /* 主淡蓝色 */
    --primary-light: #81cfe0;  /* 浅淡蓝色 */
    --primary-dark: #4a89dc;   /* 深淡蓝色 */
    --text-1: #111111;        /* 一级文本 */
    --text-2: #333333;        /* 二级文本 */
    --text-3: #666666;        /* 三级文本 */
    --text-4: #999999;        /* 四级文本 */
    --bg-1: #ffffff;          /* 一级背景 */
    --bg-2: #f8f9fa;          /* 二级背景 */
    --bg-3: #f0f5f9;          /* 三级背景 */
    --border: #e6eef7;        /* 边框颜色（淡蓝色调） */
    --highlight: #81cfe0;     /* 高亮色 */
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'PingFang SC', 'Helvetica Neue', 'Arial', 'sans-serif';
    background-color: var(--bg-2);
    color: var(--text-2);
    overflow-x: hidden;
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
}

img {
    max-width: 100%;
    height: auto;
}

.container {
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    padding: 0 16px;
}

/* 5层字体层级系统 */
.text-1 {
    font-size: 22px;
    font-weight: 700;
    color: var(--text-1);
}

.text-2 {
    font-size: 18px;
    font-weight: 600;
    color: var(--text-2);
}

.text-3 {
    font-size: 16px;
    font-weight: 500;
    color: var(--text-2);
}

.text-4 {
    font-size: 14px;
    font-weight: 400;
    color: var(--text-3);
}

.text-5 {
    font-size: 12px;
    font-weight: 400;
    color: var(--text-4);
}

/* 顶部导航栏 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background-color: var(--bg-1);
    border-bottom: 1px solid var(--border);
    z-index: 50;
    height: 56px;
    display: flex;
    align-items: center;
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    background: linear-gradient(90deg, var(--primary-light), var(--primary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    font-size: 22px; /* text-1 级别 */
    font-weight: 700;
    display: flex;
    align-items: center;
    font-family: 'Arial Black', sans-serif;
}

.logo i {
    margin-right: 6px;
    font-size: 24px;
}

.nav-icons {
    display: flex;
    gap: 20px;
}

.nav-icons a {
    color: var(--text-2);
    font-size: 20px;
    transition: color 0.2s;
    display: flex;
    align-items: center;
}

.nav-icons a:hover {
    color: var(--primary);
}

.notify-badge {
    position: relative;
}

.badge {
    position: absolute;
    top: -5px;
    right: -5px;
    width: 16px;
    height: 16px;
    background-color: var(--primary);
    color: white;
    border-radius: 50%;
    font-size: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* 搜索框 */
.search-bar {
    position: fixed;
    top: 56px;
    left: 0;
    right: 0;
    background-color: var(--bg-1);
    border-bottom: 1px solid var(--border);
    z-index: 40;
    padding: 10px 0;
}

.search-box {
    position: relative;
}

.search-box input {
    width: 100%;
    padding: 10px 16px 10px 40px;
    border-radius: 20px;
    background-color: var(--bg-3);
    border: none;
    font-size: 16px; /* text-3 级别 */
    outline: none;
    transition: all 0.2s;
}

.search-box input:focus {
    box-shadow: 0 0 0 2px rgba(93, 173, 226, 0.2);
}

.search-box i {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-4);
    font-size: 16px;
}

/* 主内容区 */
.main-content {
    padding-top: 112px;
    padding-bottom: 20px;
}

/* 推荐关注区域 */
.recommended {
    background-color: var(--bg-1);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    padding: 16px;
    margin-bottom: 24px;
}

.recommended-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 16px;
}

.recommended-header h2 {
    font-size: 18px; /* text-2 级别 */
    font-weight: 600;
    color: var(--text-1);
}

.recommended-header a {
    font-size: 14px; /* text-4 级别 */
    color: var(--primary);
}

.users-container {
    display: flex;
    gap: 16px;
    overflow-x: auto;
    padding-bottom: 8px;
}

.user-card {
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 80px;
}

.user-avatar {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--primary);
    padding: 1px;
    margin-bottom: 8px;
}

.user-name {
    font-size: 16px; /* text-3 级别 */
    font-weight: 500;
    text-align: center;
    margin-bottom: 4px;
}

.user-followers {
    font-size: 12px; /* text-5 级别 */
    color: var(--text-4);
    margin-bottom: 8px;
}

.follow-btn {
    font-size: 14px; /* text-4 级别 */
    color: var(--primary);
    border: 1px solid var(--primary);
    border-radius: 20px;
    padding: 3px 12px;
    transition: all 0.2s;
    background: none;
    cursor: pointer;
}

.follow-btn:hover {
    background-color: var(--primary);
    color: white;
}

/* 发布框 */
.post-box {
    background-color: var(--bg-1);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    padding: 16px;
    margin-bottom: 24px;
}

.post-form {
    display: flex;
    gap: 12px;
}

.post-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
}

.post-input-container {
    flex-grow: 1;
}

.post-input {
    width: 100%;
    padding: 10px 16px;
    border-radius: 20px;
    background-color: var(--bg-3);
    border: none;
    font-size: 16px; /* text-3 级别 */
    outline: none;
    margin-bottom: 12px;
    resize: none;
    height: 44px;
}

.post-input:focus {
    box-shadow: 0 0 0 2px rgba(93, 173, 226, 0.2);
}

.post-actions {
    display: flex;
    justify-content: space-between;
}

.post-options {
    display: flex;
    gap: 16px;
}

.post-option {
    display: flex;
    align-items: center;
    color: var(--text-3);
    font-size: 14px; /* text-4 级别 */
    transition: color 0.2s;
    background: none;
    border: none;
    cursor: pointer;
}

.post-option i {
    margin-right: 4px;
}

.post-option:hover {
    color: var(--primary);
}

.post-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    border-radius: 20px;
    padding: 6px 18px;
    font-size: 14px; /* text-4 级别 */
    font-weight: 500;
    transition: background-color 0.2s;
    cursor: pointer;
}

.post-btn:hover {
    background-color: var(--primary-dark);
}

/* 动态内容列表 */
.posts-container {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.post-item {
    background-color: var(--bg-1);
    border-radius: 12px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
    overflow: hidden;
    animation: fadeIn 0.5s ease forwards;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.post-header {
    padding: 16px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.post-author {
    display: flex;
    align-items: center;
    gap: 12px;
}

.author-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
}

.author-info {
    display: flex;
    flex-direction: column;
}

.author-name {
    font-size: 16px; /* text-3 级别 */
    font-weight: 500;
    color: var(--text-1);
}

.post-time {
    font-size: 12px; /* text-5 级别 */
    color: var(--text-4);
}

.post-menu {
    color: var(--text-4);
    transition: color 0.2s;
}

.post-menu:hover {
    color: var(--text-2);
}

.post-content {
    padding: 0 16px 8px;
}

.post-text {
    font-size: 16px; /* text-3 级别 */
    margin-bottom: 8px;
    line-height: 1.7;
}

.post-tags {
    font-size: 14px; /* text-4 级别 */
    color: var(--primary);
    margin-bottom: 12px;
}

/* 互动按钮 */
.post-actions {
    padding: 8px 16px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
}

.action-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    color: var(--text-3);
    font-size: 16px; /* text-3 级别 */
    transition: color 0.2s;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 4px;
}

.action-btn:hover {
    color: var(--primary);
    background-color: rgba(93, 173, 226, 0.05);
}

.action-btn.liked {
    color: var(--primary);
}

.action-btn.liked i {
    animation: heartBeat 0.5s ease;
}

@keyframes heartBeat {
    0% { transform: scale(1); }
    50% { transform: scale(1.3); }
    100% { transform: scale(1); }
}

/* 评论区 */
.comment-section {
    padding: 0 16px 16px;
    border-top: 1px solid var(--border);
}

.comment-section.hidden {
    display: none;
}

.comments-container {
    max-height: 240px;
    overflow-y: auto;
    margin-bottom: 16px;
}

.comment-item {
    display: flex;
    gap: 8px;
    margin-bottom: 12px;
}

.comment-avatar {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    object-fit: cover;
    flex-shrink: 0;
}

.comment-content {
    background-color: var(--bg-3);
    border-radius: 18px;
    border-top-left-radius: 4px;
    padding: 8px 12px;
    max-width: 85%;
}

.comment-author {
    font-size: 14px; /* text-4 级别 */
    font-weight: 500;
    margin-bottom: 4px;
    color: var(--text-1);
}

.comment-author-tag {
    color: var(--primary);
    margin-left: 4px;
    font-size: 12px; /* text-5 级别 */
    background-color: rgba(93, 173, 226, 0.1);
    padding: 0 4px;
    border-radius: 3px;
}

.comment-text {
    font-size: 14px; /* text-4 级别 */
    line-height: 1.5;
}

.comment-form {
    display: flex;
    gap: 8px;
    align-items: center;
}

.comment-input {
    flex-grow: 1;
    padding: 10px 12px;
    border-radius: 20px;
    background-color: var(--bg-3);
    border: none;
    font-size: 14px; /* text-4 级别 */
    outline: none;
    transition: all 0.2s;
}

.comment-input:focus {
    box-shadow: 0 0 0 2px rgba(93, 173, 226, 0.2);
}

.comment-submit {
    color: var(--primary);
    font-size: 18px;
    transition: color 0.2s;
    background: none;
    border: none;
    cursor: pointer;
}

.comment-submit:hover {
    color: var(--primary-dark);
}

/* 加载更多按钮 */
.load-more {
    text-align: center;
    padding: 24px 0;
}

.load-more-btn {
    padding: 10px 28px;
    border: 1px solid var(--border);
    border-radius: 20px;
    background-color: var(--bg-1);
    color: var(--text-2);
    font-size: 16px; /* text-3 级别 */
    font-weight: 500;
    transition: all 0.2s;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.load-more-btn:hover {
    background-color: var(--bg-3);
    border-color: #d5e4f2;
}

.load-more-btn i {
    font-size: 14px;
}

/* 发布按钮 - 悬浮式设计 */
.fab-post-btn {
    position: fixed;
    right: 20px;
    bottom: 20px;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: linear-gradient(135deg, var(--primary-light), var(--primary));
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: 0 4px 12px rgba(93, 173, 226, 0.3);
    z-index: 40;
    transition: transform 0.2s;
}

.fab-post-btn:hover {
    transform: scale(1.05) rotate(90deg);
}

/* 底部栏 */
.footer {
    background-color: var(--bg-1);
    border-top: 1px solid var(--border);
    padding: 16px 0;
    margin-top: 32px;
}

.footer-content {
    text-align: center;
}

.footer-logo {
    background: linear-gradient(90deg, var(--primary-light), var(--primary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    font-size: 18px; /* text-2 级别 */
    font-weight: 700;
    margin-bottom: 4px;
    display: inline-flex;
    align-items: center;
    font-family: 'Arial Black', sans-serif;
}

.footer-logo i {
    margin-right: 6px;
}

.footer-copyright {
    font-size: 12px; /* text-5 级别 */
    color: var(--text-4);
}

/* 滚动条美化 */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: #c9d9e8;
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: #a9c4e0;
}

/* 无内容状态 */
.no-posts {
    text-align: center;
    padding: 60px 0;
    color: var(--text-3);
    font-size: 16px; /* text-3 级别 */
}

.comment-closed {
    text-align: center;
    padding: 16px;
    color: var(--text-3);
    font-size: 14px; /* text-4 级别 */
}

/* 响应式调整 */
@media (max-width: 640px) {
    .container {
        padding: 0 12px;
    }
    
    /* 在小屏幕上适当调整字体大小 */
    .text-1 { font-size: 20px; }
    .text-2 { font-size: 17px; }
    .text-3 { font-size: 15px; }
}