/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f8fafc;
    color: #334155;
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部样式 */
header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 1.5rem 0;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 100;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    text-decoration: none;
    color: white;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 1.5rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
}

.nav-links a:hover {
    text-decoration: underline;
    opacity: 0.9;
}

/* 移动端菜单按钮 */
.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: white;
    border-radius: 3px;
    transition: all 0.3s ease;
}

/* 卡片样式 */
.card {
    background-color: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
    padding: 2rem;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
}

.card:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.1);
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 8px;
    font-weight: 500;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.btn-primary {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

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

.btn-secondary:hover {
    background-color: #cbd5e1;
}

.btn-danger {
    background-color: #ef4444;
    color: white;
}

.btn-danger:hover {
    background-color: #dc2626;
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
    color: #475569;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

/* 公告卡片样式 */
.announcement-card {
    border-left: 4px solid #667eea;
}

.announcement-title {
    font-size: 1.5rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 0.5rem;
}

.announcement-meta {
    font-size: 0.875rem;
    color: #94a3b8;
    margin-bottom: 1rem;
}

.announcement-content {
    color: #475569;
    line-height: 1.7;
}

/* 操作按钮组 */
.action-buttons {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
}

/* 消息提示样式 */
.flash-messages {
    margin: 1rem 0;
    list-style: none;
}

.flash-message {
    padding: 1rem;
    border-radius: 8px;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.flash-message.success {
    background-color: #dcfce7;
    color: #166534;
    border: 1px solid #bbf7d0;
}

.flash-message.error {
    background-color: #fee2e2;
    color: #991b1b;
    border: 1px solid #fecaca;
}

/* 页脚样式 */
footer {
    background-color: #f1f5f9;
    padding: 2rem 0;
    text-align: center;
    color: #64748b;
    margin-top: 3rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    /* 移动端导航 */
    .menu-toggle {
        display: flex;
    }
    
    .nav-links {
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
        flex-direction: column;
        align-items: center;
        padding: 1rem 0;
        gap: 1rem;
        opacity: 0;
        visibility: hidden;
        transform: translateY(-10px);
        transition: all 0.3s ease;
    }
    
    .nav-links.active {
        opacity: 1;
        visibility: visible;
        transform: translateY(0);
    }
    
    /* 调整卡片和容器 */
    .card {
        padding: 1.5rem;
    }
    
    .announcement-title {
        font-size: 1.25rem;
    }
    
    /* 操作按钮组在移动端垂直排列 */
    .action-buttons {
        flex-direction: column;
    }
}

/* 加载动画 */
.loading {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* 文本对齐和间距 */
.text-center {
    text-align: center;
}

.mb-1 {
    margin-bottom: 0.5rem;
}

.mb-2 {
    margin-bottom: 1rem;
}

.mb-3 {
    margin-bottom: 1.5rem;
}

.mt-1 {
    margin-top: 0.5rem;
}

.mt-2 {
    margin-top: 1rem;
}

.mt-3 {
    margin-top: 1.5rem;
}

/* 页面标题 */
.page-title {
    font-size: 2rem;
    font-weight: 700;
    color: #1e293b;
    margin-bottom: 2rem;
    text-align: center;
}

/* 登录和验证页面样式 */
.auth-container {
    max-width: 400px;
    margin: 4rem auto;
}

.auth-header {
    text-align: center;
    margin-bottom: 2rem;
}

.auth-header h1 {
    font-size: 1.75rem;
    color: #1e293b;
    margin-bottom: 0.5rem;
}

.auth-header p {
    color: #64748b;
}

/* 管理员页面样式 */
.admin-section {
    margin-bottom: 2rem;
}

.admin-section h2 {
    font-size: 1.25rem;
    color: #1e293b;
    margin-bottom: 1rem;
    font-weight: 600;
}

/* 邀请码显示样式 */
.invite-code-display {
    background-color: #f8fafc;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    padding: 1rem;
    font-family: 'Courier New', Courier, monospace;
    font-size: 1.125rem;
    font-weight: 600;
    color: #667eea;
    word-break: break-all;
}

/* 响应式调整 */
@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .card {
        padding: 1.25rem;
    }
    
    .page-title {
        font-size: 1.5rem;
    }
}