/* 航空主题CSS变量 */
:root {
    --sky-blue: #4A90E2;
    --cloud-white: #F8FAFE;
    --horizon-blue: #6BB6FF;
    --deep-blue: #2C5282;
    --aircraft-silver: #C0C8D1;
    --sunset-orange: #FF8C42;
    --gold: #FFD700;
    --silver: #C0C0C0;
    --bronze: #CD7F32;
    --header-height: 70px;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--sky-blue) 0%, var(--horizon-blue) 50%, var(--cloud-white) 100%);
    min-height: 100vh;
    padding-top: var(--header-height);
    line-height: 1.6;
}

/* 浮动云朵装饰 */
.cloud-decoration {
    position: fixed;
    top: 20%;
    right: -100px;
    width: 100px;
    height: 60px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 50px;
    opacity: 0.6;
    animation: float 15s infinite ease-in-out;
    z-index: 1;
}

.cloud-decoration::before {
    content: '';
    position: absolute;
    top: -25px;
    left: 10px;
    width: 50px;
    height: 50px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 50%;
}

.cloud-decoration::after {
    content: '';
    position: absolute;
    top: -25px;
    right: 10px;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 50%;
}

@keyframes float {
    0%, 100% { transform: translateX(0) translateY(0); }
    25% { transform: translateX(-50px) translateY(-10px); }
    50% { transform: translateX(-100px) translateY(5px); }
    75% { transform: translateX(-75px) translateY(-15px); }
}

/* 容器样式 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    position: relative;
    z-index: 2;
}

/* 页面标题 */
.page-header {
    text-align: center;
    margin-bottom: 2rem;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
}

.page-title {
    font-size: 2.5rem;
    color: var(--deep-blue);
    margin-bottom: 1rem;
    font-weight: 700;
}

.page-subtitle {
    color: #666;
    font-size: 1.1rem;
    margin-bottom: 1.5rem;
}

.date-range {
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    color: white;
    padding: 0.5rem 1rem;
    border-radius: 25px;
    font-size: 0.9rem;
    display: inline-block;
}

/* 统计卡片 */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
    margin-bottom: 2rem;
}

.stat-card {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 1.5rem;
    text-align: center;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
}

.stat-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    color: var(--deep-blue);
    margin-bottom: 0.5rem;
}

.stat-label {
    color: #666;
    font-size: 0.9rem;
}

/* 排行榜切换 */
.ranking-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.tab-btn {
    padding: 0.75rem 1.5rem;
    background: rgba(255, 255, 255, 0.8);
    border: none;
    border-radius: 25px;
    color: var(--deep-blue);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    cursor: pointer;
}

.tab-btn:hover, .tab-btn.active {
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(74, 144, 226, 0.3);
}

/* 小组卡片网格 */
.groups-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
}

.group-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.1);
    transition: all 0.3s ease;
    cursor: pointer;
}

.group-card:hover {
    transform: translateY(-8px);
    box-shadow: 0 15px 35px rgba(0, 0, 0, 0.15);
}

.group-background {
    width: 100%;
    height: 150px;
    object-fit: cover;
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
}

.group-content {
    padding: 1.5rem;
}

.group-rank {
    position: absolute;
    top: 1rem;
    left: 1rem;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    color: white;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

.rank-1 { background: linear-gradient(135deg, var(--gold), #FFA500); }
.rank-2 { background: linear-gradient(135deg, var(--silver), #A0A0A0); }
.rank-3 { background: linear-gradient(135deg, var(--bronze), #8B4513); }
.rank-other { background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue)); }

.group-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
}

.group-name {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--deep-blue);
    margin-bottom: 0.5rem;
}

.group-founder {
    font-size: 0.9rem;
    color: #666;
    display: flex;
    align-items: center;
    gap: 0.3rem;
}

.group-description {
    color: #555;
    font-size: 0.9rem;
    line-height: 1.5;
    margin-bottom: 1rem;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.group-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
    gap: 1rem;
    padding-top: 1rem;
    border-top: 1px solid #eee;
}

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

.stat-value {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--sky-blue);
    display: block;
}

.stat-name {
    font-size: 0.8rem;
    color: #666;
}

/* 分页样式 */
.pagination-nav {
    margin: 3rem 0 2rem 0;
    display: flex;
    justify-content: center;
}

.pagination {
    display: flex;
    gap: 0.5rem;
    align-items: center;
}

.page-btn {
    padding: 0.75rem 1rem;
    background: rgba(255, 255, 255, 0.9);
    border: none;
    border-radius: 10px;
    color: var(--deep-blue);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    min-width: 45px;
    text-align: center;
}

.page-btn:hover, .page-btn.active {
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    color: white;
    transform: translateY(-2px);
}

.page-btn.disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* 用户状态提示 */
.user-status {
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    text-align: center;
}

.status-icon {
    font-size: 2rem;
    margin-bottom: 1rem;
}

.status-message {
    margin-bottom: 1rem;
    color: #555;
}

.action-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 25px;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.btn-primary {
    background: linear-gradient(135deg, var(--sky-blue), var(--horizon-blue));
    color: white;
}

.btn-secondary {
    background: rgba(255, 255, 255, 0.8);
    color: var(--deep-blue);
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .page-title {
        font-size: 2rem;
    }
    
    .groups-grid {
        grid-template-columns: 1fr;
    }
    
    .ranking-tabs {
        flex-direction: column;
        align-items: center;
    }
    
    .stats-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

/* 无数据提示 */
.no-data {
    text-align: center;
    padding: 3rem 2rem;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 20px;
    color: #666;
}

.no-data-icon {
    font-size: 4rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}