/* ===== Tongxue.app 全局样式 ===== */

/* --- CSS 变量定义 --- */
:root {
    --primary: #FF6B6B;
    --primary-dark: #E85555;
    --primary-light: #FFB5B5;
    --secondary: #4ECDC4;
    --secondary-dark: #3DB5AC;
    --accent: #A78BFA;
    --warm: #FFA07A;
    --bg-cream: #FFF8F0;
    --bg-white: #FFFFFF;
    --bg-gray: #F7F7F7;
    --text-dark: #2D3436;
    --text-medium: #636E72;
    --text-light: #B2BEC3;
    --border: #E8E8E8;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --gradient-primary: linear-gradient(135deg, #FF6B6B 0%, #FFA07A 100%);
    --gradient-secondary: linear-gradient(135deg, #4ECDC4 0%, #A78BFA 100%);
    --gradient-warm: linear-gradient(135deg, #FFA07A 0%, #FFD700 100%);
    --transition: all 0.3s ease;
}

/* --- 重置与基础 --- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
    color: var(--text-dark);
    background-color: var(--bg-cream);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

img {
    max-width: 100%;
    display: block;
}

ul, ol {
    list-style: none;
}

button {
    cursor: pointer;
    border: none;
    outline: none;
    font-family: inherit;
    transition: var(--transition);
}

input, textarea, select {
    font-family: inherit;
    outline: none;
}

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

/* --- 按钮样式 --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 10px 24px;
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: var(--gradient-primary);
    color: #fff;
    box-shadow: 0 4px 14px rgba(255,107,107,0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255,107,107,0.4);
}

.btn-secondary {
    background: var(--gradient-secondary);
    color: #fff;
    box-shadow: 0 4px 14px rgba(78,205,196,0.3);
}

.btn-secondary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(78,205,196,0.4);
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--primary);
    color: var(--primary);
}

.btn-outline:hover {
    background: var(--primary);
    color: #fff;
}

.btn-ghost {
    background: var(--bg-gray);
    color: var(--text-medium);
}

.btn-ghost:hover {
    background: var(--border);
}

.btn-lg {
    padding: 14px 36px;
    font-size: 17px;
}

.btn-sm {
    padding: 6px 16px;
    font-size: 13px;
}

.btn-block {
    width: 100%;
}

/* --- 导航栏 --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background: rgba(255,255,255,0.95);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: var(--transition);
}

.navbar .container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 22px;
    font-weight: 700;
    color: var(--primary);
}

.logo-icon {
    width: 36px;
    height: 36px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 18px;
    box-shadow: 0 2px 8px rgba(255,107,107,0.3);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 28px;
}

.nav-menu a {
    font-size: 15px;
    color: var(--text-medium);
    font-weight: 500;
    position: relative;
    padding: 4px 0;
}

.nav-menu a:hover, .nav-menu a.active {
    color: var(--primary);
}

.nav-menu a.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
    border-radius: 2px;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: 12px;
}

.nav-toggle {
    display: none;
    background: none;
    font-size: 24px;
    color: var(--text-dark);
    padding: 4px;
}

/* --- Hero 区域 --- */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
    background: linear-gradient(180deg, #FFF8F0 0%, #FFE8E0 50%, #FFF8F0 100%);
    padding-top: 64px;
}

.hero::before {
    content: '';
    position: absolute;
    top: -10%;
    right: -10%;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(255,107,107,0.12) 0%, transparent 70%);
    border-radius: 50%;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: -10%;
    left: -10%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(78,205,196,0.12) 0%, transparent 70%);
    border-radius: 50%;
}

.hero .container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-content h1 {
    font-size: 48px;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: 20px;
    background: linear-gradient(135deg, #FF6B6B 0%, #A78BFA 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-content .subtitle {
    font-size: 18px;
    color: var(--text-medium);
    margin-bottom: 32px;
    line-height: 1.8;
}

.hero-stats {
    display: flex;
    gap: 32px;
    margin-top: 40px;
}

.hero-stat {
    text-align: center;
}

.hero-stat .num {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.hero-stat .label {
    font-size: 13px;
    color: var(--text-light);
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-top: 36px;
}

.hero-visual {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
}

.hero-card {
    position: absolute;
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    padding: 16px 20px;
    display: flex;
    align-items: center;
    gap: 12px;
    animation: float 3s ease-in-out infinite;
}

.hero-card:nth-child(1) {
    top: 10%;
    left: 5%;
    animation-delay: 0s;
}

.hero-card:nth-child(2) {
    top: 40%;
    right: 0;
    animation-delay: 1s;
}

.hero-card:nth-child(3) {
    bottom: 15%;
    left: 10%;
    animation-delay: 2s;
}

.hero-card .icon {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    color: #fff;
}

.hero-card .text {
    font-size: 14px;
    font-weight: 600;
}

.hero-card .sub {
    font-size: 12px;
    color: var(--text-light);
}

.hero-illustration {
    width: 320px;
    height: 320px;
    background: var(--gradient-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 120px;
    box-shadow: 0 20px 60px rgba(255,107,107,0.3);
    position: relative;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-12px); }
}

/* --- 通用 Section --- */
.section {
    padding: 80px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-header .tag {
    display: inline-block;
    padding: 6px 16px;
    background: var(--primary-light);
    color: var(--primary-dark);
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 16px;
}

.section-header h2 {
    font-size: 36px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 12px;
}

.section-header p {
    font-size: 16px;
    color: var(--text-medium);
    max-width: 600px;
    margin: 0 auto;
}

/* --- 功能卡片 --- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 24px;
}

.feature-card {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    padding: 32px 28px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s ease;
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-light);
}

.feature-card:hover::before {
    transform: scaleX(1);
}

.feature-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    margin-bottom: 20px;
}

.feature-icon.bg-primary { background: linear-gradient(135deg, #FF6B6B, #FFA07A); }
.feature-icon.bg-secondary { background: linear-gradient(135deg, #4ECDC4, #A78BFA); }
.feature-icon.bg-accent { background: linear-gradient(135deg, #A78BFA, #FF6B6B); }
.feature-icon.bg-warm { background: linear-gradient(135deg, #FFA07A, #FFD700); }

.feature-card h3 {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.feature-card p {
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.7;
}

.feature-card .link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    margin-top: 16px;
    color: var(--primary);
    font-size: 14px;
    font-weight: 600;
}

/* --- 页面头部 (非首页) --- */
.page-header {
    background: var(--gradient-primary);
    padding: 100px 0 60px;
    text-align: center;
    color: #fff;
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle at 20% 50%, rgba(255,255,255,0.1) 0%, transparent 50%);
}

.page-header h1 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 12px;
    position: relative;
    z-index: 1;
}

.page-header p {
    font-size: 16px;
    opacity: 0.9;
    position: relative;
    z-index: 1;
}

.breadcrumb {
    display: flex;
    justify-content: center;
    gap: 8px;
    font-size: 13px;
    margin-top: 16px;
    position: relative;
    z-index: 1;
}

.breadcrumb a { opacity: 0.85; }
.breadcrumb a:hover { opacity: 1; }
.breadcrumb span { opacity: 0.6; }

/* --- 布局: 侧边栏 + 主内容 --- */
.page-layout {
    display: grid;
    grid-template-columns: 280px 1fr;
    gap: 32px;
    padding: 40px 0;
}

.sidebar {
    position: sticky;
    top: 84px;
    align-self: start;
}

.sidebar-card {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    padding: 20px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 20px;
}

.sidebar-card h4 {
    font-size: 15px;
    font-weight: 700;
    margin-bottom: 16px;
    color: var(--text-dark);
    display: flex;
    align-items: center;
    gap: 8px;
}

.category-list a {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 10px 12px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    color: var(--text-medium);
    margin-bottom: 4px;
    transition: var(--transition);
}

.category-list a:hover, .category-list a.active {
    background: var(--bg-cream);
    color: var(--primary);
}

.category-list .count {
    background: var(--bg-gray);
    color: var(--text-light);
    padding: 2px 10px;
    border-radius: 12px;
    font-size: 12px;
}

.category-list a.active .count {
    background: var(--primary-light);
    color: var(--primary-dark);
}

/* --- 主内容区 --- */
.main-content {
    min-width: 0;
}

.content-toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 24px;
    flex-wrap: wrap;
    gap: 12px;
}

.tabs {
    display: flex;
    gap: 8px;
    background: var(--bg-white);
    padding: 6px;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-sm);
}

.tab {
    padding: 8px 20px;
    border-radius: 6px;
    font-size: 14px;
    color: var(--text-medium);
    cursor: pointer;
    transition: var(--transition);
}

.tab.active {
    background: var(--primary);
    color: #fff;
}

.tab:hover:not(.active) {
    background: var(--bg-gray);
}

/* --- 话题/帖子卡片 --- */
.post-card {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    padding: 24px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 20px;
    transition: var(--transition);
}

.post-card:hover {
    box-shadow: var(--shadow-md);
}

.post-header {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
}

.avatar {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--gradient-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 18px;
    font-weight: 600;
    flex-shrink: 0;
}

.avatar.sm { width: 32px; height: 32px; font-size: 14px; }
.avatar.lg { width: 64px; height: 64px; font-size: 24px; }
.avatar.xl { width: 100px; height: 100px; font-size: 40px; }

.post-user-info {
    flex: 1;
}

.post-user-info .name {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-dark);
}

.post-user-info .meta {
    font-size: 12px;
    color: var(--text-light);
    display: flex;
    align-items: center;
    gap: 8px;
}

.tag {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 12px;
    font-size: 12px;
    font-weight: 500;
}

.tag-red { background: #FFE5E5; color: #E85555; }
.tag-blue { background: #E0F4F3; color: #3DB5AC; }
.tag-purple { background: #EDE5FF; color: #8B6BE8; }
.tag-orange { background: #FFF0E5; color: #E8804D; }
.tag-green { background: #E5F7ED; color: #2EAD5F; }

.post-title {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 10px;
    line-height: 1.4;
}

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

.post-excerpt {
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.7;
    margin-bottom: 16px;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.post-images {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    margin-bottom: 16px;
}

.post-image {
    aspect-ratio: 1;
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: var(--bg-gray);
}

.post-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.post-footer {
    display: flex;
    align-items: center;
    gap: 24px;
    padding-top: 16px;
    border-top: 1px solid var(--border);
}

.post-action {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    color: var(--text-light);
    cursor: pointer;
    transition: var(--transition);
}

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

.post-action .icon {
    font-size: 18px;
}

/* --- 用户卡片 --- */
.user-card {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    border-radius: var(--radius-sm);
    transition: var(--transition);
    cursor: pointer;
}

.user-card:hover {
    background: var(--bg-cream);
}

.user-card .info {
    flex: 1;
    min-width: 0;
}

.user-card .name {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
}

.user-card .desc {
    font-size: 12px;
    color: var(--text-light);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

/* --- 日记卡片 --- */
.diary-card {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    padding: 28px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 20px;
    border-left: 4px solid var(--primary);
    transition: var(--transition);
}

.diary-card.mood-happy { border-left-color: #FFD700; }
.diary-card.mood-calm { border-left-color: #4ECDC4; }
.diary-card.mood-sad { border-left-color: #A78BFA; }
.diary-card.mood-angry { border-left-color: #FF6B6B; }
.diary-card.mood-love { border-left-color: #FF85B3; }

.diary-card:hover {
    transform: translateX(4px);
    box-shadow: var(--shadow-md);
}

.diary-mood {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 13px;
    color: var(--text-medium);
    margin-bottom: 12px;
}

.diary-mood .emoji {
    font-size: 20px;
}

.diary-card h3 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 8px;
}

.diary-card p {
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.8;
}

/* --- 成长时间线 --- */
.timeline {
    position: relative;
    padding-left: 40px;
}

.timeline::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--border);
}

.timeline-item {
    position: relative;
    padding-bottom: 40px;
}

.timeline-item:last-child {
    padding-bottom: 0;
}

.timeline-dot {
    position: absolute;
    left: -34px;
    top: 4px;
    width: 16px;
    height: 16px;
    border-radius: 50%;
    background: var(--primary);
    border: 3px solid var(--bg-white);
    box-shadow: 0 0 0 3px var(--primary-light);
}

.timeline-date {
    font-size: 13px;
    color: var(--primary);
    font-weight: 600;
    margin-bottom: 8px;
}

.timeline-card {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    padding: 24px;
    box-shadow: var(--shadow-sm);
}

.timeline-card h4 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 8px;
}

.timeline-card p {
    font-size: 14px;
    color: var(--text-medium);
    line-height: 1.7;
}

/* --- 小组卡片 --- */
.group-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
    gap: 20px;
}

.group-card {
    background: var(--bg-white);
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    cursor: pointer;
}

.group-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.group-banner {
    height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 40px;
    color: #fff;
}

.group-banner.bg-1 { background: linear-gradient(135deg, #FF6B6B, #FFA07A); }
.group-banner.bg-2 { background: linear-gradient(135deg, #4ECDC4, #A78BFA); }
.group-banner.bg-3 { background: linear-gradient(135deg, #A78BFA, #FF85B3); }
.group-banner.bg-4 { background: linear-gradient(135deg, #FFA07A, #FFD700); }
.group-banner.bg-5 { background: linear-gradient(135deg, #6BCB77, #4ECDC4); }
.group-banner.bg-6 { background: linear-gradient(135deg, #FF85B3, #A78BFA); }

.group-body {
    padding: 20px;
}

.group-body h4 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 6px;
}

.group-body p {
    font-size: 13px;
    color: var(--text-medium);
    line-height: 1.6;
    margin-bottom: 12px;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.group-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 12px;
    color: var(--text-light);
}

.group-members {
    display: flex;
    align-items: center;
    gap: 4px;
}

/* --- 登录/注册 --- */
.auth-page {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(180deg, #FFF8F0 0%, #FFE8E0 100%);
    padding: 20px;
    padding-top: 84px;
}

.auth-card {
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 440px;
    padding: 40px;
    position: relative;
    overflow: hidden;
}

.auth-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 6px;
    background: var(--gradient-primary);
}

.auth-logo {
    text-align: center;
    margin-bottom: 32px;
}

.auth-logo .logo-icon {
    margin: 0 auto 12px;
    width: 56px;
    height: 56px;
    font-size: 26px;
}

.auth-logo h2 {
    font-size: 24px;
    font-weight: 700;
    color: var(--text-dark);
}

.auth-logo p {
    font-size: 14px;
    color: var(--text-light);
    margin-top: 4px;
}

.auth-tabs {
    display: flex;
    background: var(--bg-gray);
    border-radius: var(--radius-sm);
    padding: 4px;
    margin-bottom: 28px;
}

.auth-tab {
    flex: 1;
    text-align: center;
    padding: 10px;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-medium);
    cursor: pointer;
    transition: var(--transition);
}

.auth-tab.active {
    background: var(--bg-white);
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}

/* --- 表单 --- */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 8px;
}

.form-control {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 15px;
    color: var(--text-dark);
    background: var(--bg-white);
    transition: var(--transition);
}

.form-control:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(255,107,107,0.1);
}

textarea.form-control {
    resize: vertical;
    min-height: 120px;
    line-height: 1.6;
}

.input-group {
    position: relative;
    display: flex;
    align-items: center;
}

.input-group .form-control {
    padding-right: 44px;
}

.input-group .toggle {
    position: absolute;
    right: 12px;
    background: none;
    font-size: 18px;
    color: var(--text-light);
    cursor: pointer;
}

.form-footer {
    text-align: center;
    margin-top: 24px;
    font-size: 14px;
    color: var(--text-light);
}

.form-footer a {
    color: var(--primary);
    font-weight: 600;
}

.form-check {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 20px;
    font-size: 14px;
    color: var(--text-medium);
}

.form-check input {
    width: 16px;
    height: 16px;
    accent-color: var(--primary);
}

.social-login {
    text-align: center;
    margin-top: 28px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
}

.social-login p {
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 16px;
}

.social-btns {
    display: flex;
    gap: 12px;
    justify-content: center;
}

.social-btn {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 22px;
    background: var(--bg-gray);
    transition: var(--transition);
}

.social-btn:hover {
    transform: translateY(-3px);
}

.social-btn.wechat:hover { background: #07C160; color: #fff; }
.social-btn.qq:hover { background: #12B7F5; color: #fff; }
.social-btn.weibo:hover { background: #E6162D; color: #fff; }

/* --- 统计数字 --- */
.stats-section {
    background: var(--gradient-primary);
    padding: 60px 0;
    color: #fff;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    text-align: center;
}

.stat-item .num {
    font-size: 40px;
    font-weight: 800;
    margin-bottom: 4px;
}

.stat-item .label {
    font-size: 14px;
    opacity: 0.9;
}

/* --- CTA 区域 --- */
.cta-section {
    padding: 80px 0;
    text-align: center;
}

.cta-box {
    background: var(--gradient-secondary);
    border-radius: var(--radius-lg);
    padding: 60px 40px;
    color: #fff;
    position: relative;
    overflow: hidden;
}

.cta-box::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 300px;
    height: 300px;
    background: rgba(255,255,255,0.1);
    border-radius: 50%;
}

.cta-box h2 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 16px;
    position: relative;
}

.cta-box p {
    font-size: 16px;
    opacity: 0.9;
    margin-bottom: 32px;
    position: relative;
}

.cta-box .btn {
    background: #fff;
    color: var(--secondary-dark);
    position: relative;
}

.cta-box .btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* --- 页脚 --- */
.footer {
    background: #2D3436;
    color: #B2BEC3;
    padding: 60px 0 24px;
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}

.footer-brand .logo {
    color: #fff;
    margin-bottom: 16px;
}

.footer-brand p {
    font-size: 14px;
    line-height: 1.7;
    max-width: 300px;
}

.footer-col h5 {
    color: #fff;
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-col a {
    display: block;
    font-size: 14px;
    color: #B2BEC3;
    margin-bottom: 10px;
    transition: var(--transition);
}

.footer-col a:hover {
    color: var(--primary);
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 13px;
}

/* --- 回到顶部 --- */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--primary);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    box-shadow: var(--shadow-md);
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
    z-index: 999;
}

.back-to-top.show {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-4px);
    background: var(--primary-dark);
}

/* --- 移动端底部导航 --- */
.mobile-nav {
    display: none;
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: rgba(255,255,255,0.98);
    backdrop-filter: blur(10px);
    box-shadow: 0 -2px 12px rgba(0,0,0,0.08);
    z-index: 999;
    padding: 8px 0;
    padding-bottom: env(safe-area-inset-bottom);
}

.mobile-nav-items {
    display: flex;
    justify-content: space-around;
    align-items: center;
}

.mobile-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    font-size: 11px;
    color: var(--text-light);
    padding: 6px 12px;
    transition: var(--transition);
}

.mobile-nav-item.active {
    color: var(--primary);
}

.mobile-nav-item .icon {
    font-size: 22px;
}

/* ===== 响应式设计 ===== */

@media (max-width: 1024px) {
    .hero .container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

    .hero-content h1 {
        font-size: 38px;
    }

    .hero-actions, .hero-stats {
        justify-content: center;
    }

    .hero-visual {
        order: -1;
    }

    .footer-grid {
        grid-template-columns: 1fr 1fr;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        background: #fff;
        flex-direction: column;
        padding: 20px;
        gap: 0;
        box-shadow: var(--shadow-md);
    }

    .nav-menu.open {
        display: flex;
    }

    .nav-menu a {
        width: 100%;
        padding: 14px 16px;
        border-radius: var(--radius-sm);
    }

    .nav-menu a.active {
        background: var(--bg-cream);
    }

    .nav-menu a.active::after {
        display: none;
    }

    .nav-toggle {
        display: block;
    }

    .nav-actions .btn:not(.btn-primary) {
        display: none;
    }

    .section {
        padding: 56px 0;
    }

    .section-header h2 {
        font-size: 28px;
    }

    .hero-content h1 {
        font-size: 32px;
    }

    .hero-content .subtitle {
        font-size: 16px;
    }

    .hero-illustration {
        width: 240px;
        height: 240px;
        font-size: 90px;
    }

    .hero-card {
        display: none;
    }

    .page-layout {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 28px;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .stat-item .num {
        font-size: 30px;
    }

    .cta-box {
        padding: 40px 24px;
    }

    .cta-box h2 {
        font-size: 24px;
    }

    .auth-card {
        padding: 28px 24px;
    }

    .post-images {
        grid-template-columns: repeat(2, 1fr);
    }

    .content-toolbar {
        flex-direction: column;
        align-items: stretch;
    }

    .tabs {
        overflow-x: auto;
    }

    .tab {
        white-space: nowrap;
    }

    /* 启用移动端底部导航 */
    .mobile-nav {
        display: block;
    }

    body {
        padding-bottom: 64px;
    }

    .back-to-top {
        bottom: 80px;
    }

    .container {
        padding: 0 16px;
    }
}

@media (max-width: 480px) {
    .hero-content h1 {
        font-size: 26px;
    }

    .hero-actions {
        flex-direction: column;
    }

    .hero-actions .btn {
        width: 100%;
    }

    .hero-stats {
        gap: 20px;
    }

    .section-header h2 {
        font-size: 24px;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .stats-grid {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .stat-item .num {
        font-size: 26px;
    }

    .post-card {
        padding: 18px;
    }

    .post-footer {
        gap: 16px;
    }

    .timeline {
        padding-left: 32px;
    }
}

/* --- 工具类 --- */
.text-center { text-align: center; }
.mt-2 { margin-top: 8px; }
.mt-4 { margin-top: 16px; }
.mt-6 { margin-top: 24px; }
.mb-2 { margin-bottom: 8px; }
.mb-4 { margin-bottom: 16px; }
.mb-6 { margin-bottom: 24px; }
.hidden { display: none; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-2 { gap: 8px; }
.gap-4 { gap: 16px; }