:root {
    --primary-color: #ff6b35;
    --secondary-color: #4ecdc4;
    --dark-color: #2c3e50;
    --light-color: #ecf0f1;
    --success-color: #2ecc71;
    --warning-color: #f39c12;
    --danger-color: #e74c3c;
}

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

body {
    font-family: 'Helvetica Neue', Arial, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

.app-container {
    max-width: 480px;
    margin: 0 auto;
    background: white;
    min-height: 100vh;
    box-shadow: 0 0 20px rgba(0,0,0,0.1);
}

/* 头部样式 */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 1rem;
    text-align: center;
    position: relative;
}

.header h1 {
    font-size: 1.5rem;
    margin: 0;
    font-weight: 600;
}

.user-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    border: 2px solid white;
}

/* 活动卡片 */
.activity-card {
    background: white;
    border-radius: 15px;
    margin: 1rem;
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
    overflow: hidden;
    transition: transform 0.3s ease;
}

.activity-card:hover {
    transform: translateY(-5px);
}

.activity-banner {
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.activity-content {
    padding: 1.5rem;
}

.activity-title {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.activity-description {
    color: #666;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.activity-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.team-size {
    background: var(--light-color);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--dark-color);
}

.activity-status {
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.9rem;
    font-weight: 500;
}

.status-ongoing {
    background: var(--success-color);
    color: white;
}

.status-upcoming {
    background: var(--warning-color);
    color: white;
}

.status-ended {
    background: var(--danger-color);
    color: white;
}

/* 按钮样式 */
.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border: none;
    color: white;
    padding: 0.8rem 2rem;
    border-radius: 25px;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(255, 107, 53, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(255, 107, 53, 0.4);
    color: white;
}

.btn-secondary {
    background: var(--light-color);
    border: none;
    color: var(--dark-color);
    padding: 0.8rem 2rem;
    border-radius: 25px;
    font-weight: 600;
    text-decoration: none;
    display: inline-block;
    text-align: center;
    transition: all 0.3s ease;
}

/* 团队列表 */
.team-list {
    margin: 1rem;
}

.team-item {
    background: white;
    border-radius: 10px;
    padding: 1rem;
    margin-bottom: 1rem;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    border-left: 4px solid var(--primary-color);
}

.team-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.team-code {
    font-weight: 600;
    color: var(--dark-color);
    font-size: 1.1rem;
}

.team-members {
    color: #666;
    font-size: 0.9rem;
}

.team-progress {
    margin: 0.5rem 0;
}

.progress {
    height: 8px;
    background: var(--light-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-bar {
    height: 100%;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 4px;
    transition: width 0.3s ease;
}

/* 加载动画 */
.loading {
    text-align: center;
    padding: 2rem;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 响应式设计 */
@media (max-width: 480px) {
    .app-container {
        margin: 0;
    }
    
    .activity-content {
        padding: 1rem;
    }
    
    .activity-title {
        font-size: 1.1rem;
    }
}

/* 毛玻璃效果 */
.glass-effect {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

/* 动画效果 */
.fade-in {
    animation: fadeIn 0.5s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 登录模态框样式 */
.login-modal .modal-content {
    border-radius: 15px;
    border: none;
    box-shadow: 0 10px 30px rgba(0,0,0,0.2);
}

.login-modal .modal-header {
    border-bottom: 1px solid #e9ecef;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 15px 15px 0 0;
}

.login-modal .modal-header .btn-close {
    filter: invert(1);
}

.login-qrcode {
    border: 1px solid #dee2e6;
    border-radius: 10px;
    padding: 10px;
    background: white;
}

/* 登录状态指示器 */
.login-status {
    display: inline-block;
    width: 10px;
    height: 10px;
    border-radius: 50%;
    margin-right: 8px;
}

.login-status.connecting {
    background-color: #ffc107;
    animation: pulse 1.5s infinite;
}

.login-status.success {
    background-color: #28a745;
}

.login-status.error {
    background-color: #dc3545;
}

@keyframes pulse {
    0% { opacity: 1; }
    50% { opacity: 0.5; }
    100% { opacity: 1; }
}

/* 登录选项卡片 */
.login-option-card {
    border: 2px solid transparent;
    transition: all 0.3s ease;
    cursor: pointer;
}

.login-option-card:hover {
    border-color: #007bff;
    transform: translateY(-2px);
}

.login-option-card.active {
    border-color: #007bff;
    background-color: #f8f9fa;
}

/* 消息提示 */
.alert {
    border: none;
    border-radius: 10px;
}

.alert-success {
    background: linear-gradient(135deg, #d4edda, #c3e6cb);
    color: #155724;
}

.alert-danger {
    background: linear-gradient(135deg, #f8d7da, #f1b0b7);
    color: #721c24;
}

.alert-info {
    background: linear-gradient(135deg, #d1ecf1, #b8dae2);
    color: #0c5460;
}

.alert-warning {
    background: linear-gradient(135deg, #fff3cd, #ffeaa7);
    color: #856404;
}