/**
 * 教师端移动版统一样式
 * 参照用户首页设计风格
 */

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

body {
    background-color: #f8f9fa;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";
    padding-bottom: 80px; /* 为底部导航栏留出空间 */
    overflow-x: hidden;
    opacity: 0;
    transition: opacity 0.4s ease;
}

body.loaded {
    opacity: 1;
}

/* 顶部导航区域 */
.teacher-header {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
    padding: 15px 20px;
    position: relative;
    overflow: hidden;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.teacher-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1000 100" fill="rgba(255,255,255,0.1)"><path d="M0,0v46.29c47.79,22.2,103.59,32.17,158,28,70.36-5.37,136.33-33.31,206.8-37.5C438.64,32.43,512.34,53.67,583,72.05c69.27,18,138.3,24.88,209.4,13.08,36.15-6,69.85-17.84,104.45-29.34C989.49,25,1047.48,9,1000,0Z"/></svg>') repeat-x;
    background-size: 1000px 100px;
    animation: wave 20s linear infinite;
}

@keyframes wave {
    0% { transform: translateX(0); }
    100% { transform: translateX(-1000px); }
}

.header-top {
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.site-info {
    flex: 1;
}

.site-title {
    font-size: 1.2rem;
    font-weight: 700;
    margin: 0 0 8px 0;
    text-shadow: 0 2px 4px rgba(0,0,0,0.3);
}

.teacher-mini-info {
    display: flex;
    align-items: center;
    gap: 10px;
}

.teacher-avatar-mini {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    border: 2px solid rgba(255,255,255,0.3);
    object-fit: cover;
    box-shadow: 0 2px 8px rgba(0,0,0,0.2);
}

.teacher-avatar-mini:not(img) {
    background: rgba(255,255,255,0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    color: rgba(255,255,255,0.8);
    font-size: 0.9rem;
}

.teacher-info-mini {
    flex: 1;
}

.teacher-name-mini {
    font-size: 0.9rem;
    font-weight: 600;
    margin: 0 0 2px 0;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

.teacher-class-mini {
    font-size: 0.75rem;
    opacity: 0.9;
    background: rgba(255,255,255,0.2);
    padding: 2px 8px;
    border-radius: 12px;
    display: inline-block;
}

.header-actions {
    display: flex;
    gap: 8px;
}

.action-btn {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: rgba(255,255,255,0.2);
    border: 1px solid rgba(255,255,255,0.3);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 0.9rem;
}

.action-btn:hover {
    background: rgba(255,255,255,0.3);
    transform: scale(1.1);
}

.action-btn:active {
    transform: scale(0.95);
}

/* 主要内容区域 */
.main-content {
    padding: 20px 15px;
    margin-top: 0;
    position: relative;
    z-index: 10;
}

/* 快速统计概览 */
.stats-overview {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 24px;
    animation: fadeInUp 0.8s ease forwards;
    opacity: 0;
    animation-delay: 0.2s;
}

.stats-card-large {
    background: white;
    border-radius: 16px;
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 16px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.stats-card-large::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #28a745, #20c997);
}

.stats-card-large.students::before {
    background: linear-gradient(90deg, #28a745, #20c997);
}

.stats-card-large.homework::before {
    background: linear-gradient(90deg, #007bff, #0056b3);
}

.stats-card-large.pending::before {
    background: linear-gradient(90deg, #ffc107, #e0a800);
}

.stats-card-large:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(0,0,0,0.15);
}

.stats-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}

.stats-card.active {
    transform: translateY(-1px) scale(0.98);
    box-shadow: 0 2px 12px rgba(0,0,0,0.08);
}

.stats-card-large .stats-icon {
    width: 60px;
    height: 60px;
    border-radius: 16px;
    display: flex !important;
    align-items: center;
    justify-content: center;
    color: white !important;
    font-size: 1.8rem;
    transition: all 0.3s ease;
    flex-shrink: 0;
    box-shadow: 0 6px 20px rgba(0,0,0,0.2);
    background: linear-gradient(135deg, #28a745, #20c997);
}

.stats-card-large .stats-icon i {
    color: white !important;
    font-size: 1.8rem;
}

.stats-card-large.students .stats-icon {
    background: linear-gradient(135deg, #28a745, #20c997) !important;
}

.stats-card-large.homework .stats-icon {
    background: linear-gradient(135deg, #007bff, #0056b3) !important;
}

.stats-card-large.pending .stats-icon {
    background: linear-gradient(135deg, #ffc107, #e0a800) !important;
}

.stats-card-large .stats-icon i.fas {
    color: white !important;
    font-size: 1.8rem !important;
    display: block !important;
    visibility: visible !important;
    opacity: 1 !important;
}

/* 强制显示图标 */
.stats-card-large .stats-icon i {
    color: white !important;
    font-size: 1.8rem !important;
    display: inline-block !important;
    visibility: visible !important;
    opacity: 1 !important;
    font-family: "Font Awesome 5 Free" !important;
    font-weight: 900 !important;
}

.stats-card-large .stats-content {
    flex: 1;
}

.stats-card-large .stats-number {
    font-size: 2rem;
    font-weight: 700;
    color: #333;
    line-height: 1;
    margin-bottom: 4px;
}

.stats-card-large .stats-label {
    font-size: 1rem;
    color: #666;
    font-weight: 500;
}

/* 旧的stats-icon样式已移除，使用新的stats-card-large样式 */

.stats-content {
    flex: 1;
}

.stats-number {
    font-size: 1.6rem;
    font-weight: 700;
    color: #333;
    line-height: 1;
}

.stats-number.animate-number {
    animation: numberPop 0.6s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

@keyframes numberPop {
    0% {
        transform: scale(0.3);
        opacity: 0;
    }
    50% {
        transform: scale(1.1);
    }
    100% {
        transform: scale(1);
        opacity: 1;
    }
}

.stats-label {
    font-size: 0.9rem;
    color: #666;
    margin-top: 2px;
    text-align: center;
    font-weight: 500;
}

/* 区块标题 */
.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.section-title {
    font-size: 1.1rem;
    font-weight: 600;
    color: #333;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 8px;
}

.section-title i {
    color: #28a745;
}

.section-date {
    font-size: 0.8rem;
    color: #999;
}

/* 今日重要事项 */
.today-section {
    background: white;
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
    animation: fadeInUp 0.8s ease forwards;
    opacity: 0;
    animation-delay: 0.4s;
}

.today-content {
    background: linear-gradient(135deg, #f0fff4 0%, #e8f5e8 100%);
    border-radius: 12px;
    padding: 16px;
}

.today-item {
    display: flex;
    align-items: center;
    gap: 12px;
}

.today-icon {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    background: rgba(40, 167, 69, 0.1);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #28a745;
}

.today-info {
    flex: 1;
}

.today-title {
    font-size: 0.95rem;
    font-weight: 500;
    color: #333;
    margin-bottom: 2px;
}

.today-desc {
    font-size: 0.8rem;
    color: #666;
}

/* 快捷操作 */
.quick-actions {
    background: white;
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
    animation: fadeInUp 0.8s ease forwards;
    opacity: 0;
    animation-delay: 0.6s;
}

.action-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 12px;
    transition: all 0.3s ease;
}

.action-grid.collapsed {
    grid-template-rows: 1fr;
    overflow: hidden;
}

.action-grid.collapsed .action-item:nth-child(n+6) {
    display: none;
}

.action-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
    padding: 12px 4px;
    border-radius: 10px;
    text-decoration: none;
    color: #333;
    transition: all 0.3s ease;
    position: relative;
    border: 2px solid transparent;
}

.action-item:hover {
    background: rgba(40, 167, 69, 0.05);
    transform: translateY(-2px);
    text-decoration: none;
    color: #333;
    border-color: #28a745;
}

.action-item.active {
    transform: translateY(-1px) scale(0.96);
    background: rgba(40, 167, 69, 0.1) !important;
}

.action-icon {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.1rem;
    color: white;
    transition: all 0.3s ease;
}

.action-icon.homework {
    background: linear-gradient(135deg, #28a745, #20c997);
}

.action-icon.survey {
    background: linear-gradient(135deg, #17a2b8, #138496);
}

.action-icon.appointment {
    background: linear-gradient(135deg, #ffc107, #e0a800);
}

.action-icon.messages {
    background: linear-gradient(135deg, #6f42c1, #5a32a3);
}

.action-icon.students {
    background: linear-gradient(135deg, #007bff, #0056b3);
}

.action-icon.notifications {
    background: linear-gradient(135deg, #fd7e14, #e8690b);
}

.action-label {
    font-size: 0.7rem;
    font-weight: 500;
    text-align: center;
    line-height: 1.2;
}

/* 展开/收起按钮 */
.expand-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin-top: 16px;
    padding: 8px 16px;
    background: #f8f9fa;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    user-select: none;
    border: 1px solid #e9ecef;
}

.expand-toggle:hover {
    background: #e9ecef;
    transform: translateY(-1px);
}

.expand-text {
    font-size: 0.8rem;
    color: #666;
    font-weight: 500;
}

.expand-icon {
    font-size: 0.7rem;
    color: #666;
    transition: transform 0.3s ease;
}

.expand-toggle.expanded .expand-icon {
    transform: rotate(180deg);
}

/* 通用卡片样式 */
.content-card {
    background: white;
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
}

/* 列表项样式 */
.list-item {
    background: white;
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 12px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
    border: 1px solid rgba(0,0,0,0.05);
    transition: all 0.3s ease;
}

.list-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(0,0,0,0.1);
}

.list-item-header {
    display: flex;
    justify-content: between;
    align-items: flex-start;
    margin-bottom: 8px;
}

.list-item-title {
    font-size: 1rem;
    font-weight: 600;
    color: #333;
    margin-bottom: 4px;
}

.list-item-meta {
    font-size: 0.8rem;
    color: #666;
}

.list-item-content {
    color: #555;
    font-size: 0.9rem;
    line-height: 1.4;
    margin-bottom: 8px;
}

.list-item-actions {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
}

/* 状态标签 */
.status-badge {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.7rem;
    font-weight: 500;
}

.status-badge.draft {
    background: #f8f9fa;
    color: #6c757d;
}

.status-badge.published {
    background: #d4edda;
    color: #155724;
}

.status-badge.completed {
    background: #d1ecf1;
    color: #0c5460;
}

.status-badge.pending {
    background: #fff3cd;
    color: #856404;
}

.status-badge.overdue {
    background: #f8d7da;
    color: #721c24;
}

/* 按钮样式 */
.btn-mobile {
    padding: 8px 16px;
    border-radius: 8px;
    font-size: 0.8rem;
    font-weight: 500;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s ease;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: linear-gradient(135deg, #28a745, #20c997);
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(135deg, #218838, #1c7a70);
    color: white;
    transform: translateY(-1px);
}

.btn-secondary {
    background: #f8f9fa;
    color: #6c757d;
    border: 1px solid #dee2e6;
}

.btn-secondary:hover {
    background: #e9ecef;
    color: #5a6268;
    transform: translateY(-1px);
}

.btn-outline {
    background: transparent;
    border: 1px solid #28a745;
    color: #28a745;
}

.btn-outline:hover {
    background: #28a745;
    color: white;
}

/* 表单样式 */
.form-mobile {
    background: white;
    border-radius: 16px;
    padding: 20px;
    margin-bottom: 24px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    border: 1px solid rgba(0,0,0,0.05);
}

.form-group-mobile {
    margin-bottom: 16px;
}

.form-label-mobile {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: #333;
    font-size: 0.9rem;
}

.form-control-mobile {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-size: 16px;
    transition: border-color 0.3s ease;
}

.form-control-mobile:focus {
    outline: none;
    border-color: #28a745;
    box-shadow: 0 0 0 0.2rem rgba(40, 167, 69, 0.25);
}

.form-text-mobile {
    font-size: 0.8rem;
    color: #666;
    margin-top: 4px;
}

/* 底部固定导航栏 */
.bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: white;
    box-shadow: 0 -2px 20px rgba(0,0,0,0.1);
    z-index: 1000;
    padding: 8px 0 calc(8px + env(safe-area-inset-bottom));
}

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

.nav-item {
    flex: 1;
    text-align: center;
    padding: 6px 2px;
    color: #999;
    text-decoration: none;
    transition: all 0.2s ease;
    position: relative;
}

.nav-item.active {
    color: #28a745;
}

.nav-item:hover {
    color: #28a745;
    text-decoration: none;
}

.nav-icon {
    font-size: 1.2rem;
    margin-bottom: 4px;
    display: block;
}

.nav-label {
    font-size: 0.65rem;
    font-weight: 500;
}

.nav-badge {
    position: absolute;
    top: 2px;
    right: 25%;
    background: #ff4757;
    color: white;
    border-radius: 10px;
    padding: 2px 6px;
    font-size: 0.6rem;
    min-width: 16px;
    height: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* 消息提示 */
.alert-mobile {
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 16px;
    border: 1px solid transparent;
}

.alert-success {
    background: #d4edda;
    color: #155724;
    border-color: #c3e6cb;
}

.alert-danger {
    background: #f8d7da;
    color: #721c24;
    border-color: #f5c6cb;
}

.alert-warning {
    background: #fff3cd;
    color: #856404;
    border-color: #ffeaa7;
}

.alert-info {
    background: #d1ecf1;
    color: #0c5460;
    border-color: #bee5eb;
}

/* 登录页面特殊样式 */
.login-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
}

.login-card {
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.2);
    overflow: hidden;
    max-width: 400px;
    width: 100%;
}

.login-header {
    background: linear-gradient(135deg, #28a745 0%, #20c997 100%);
    color: white;
    padding: 30px 20px;
    text-align: center;
}

.login-body {
    padding: 30px 20px;
}

.teacher-badge {
    background: rgba(255,255,255,0.2);
    color: white;
    padding: 6px 16px;
    border-radius: 20px;
    font-size: 0.8rem;
    margin-top: 10px;
    display: inline-block;
}

/* 页面加载动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInLeft {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

/* 响应式优化 */
@media (max-width: 768px) {
    .teacher-header {
        padding: 12px 15px;
    }
    
    .site-title {
        font-size: 1.1rem;
    }
    
    .teacher-avatar-mini {
        width: 28px;
        height: 28px;
        font-size: 0.8rem;
    }
    
    .teacher-name-mini {
        font-size: 0.85rem;
    }
    
    .teacher-class-mini {
        font-size: 0.7rem;
        padding: 1px 6px;
    }
    
    .action-btn {
        width: 32px;
        height: 32px;
        font-size: 0.8rem;
    }
    
    .stats-overview {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }
    
    .stats-card-large {
        padding: 16px;
        gap: 12px;
    }
    
    .stats-card-large .stats-icon {
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }
    
    .stats-card-large .stats-number {
        font-size: 1.6rem;
    }
    
    .stats-card-large .stats-label {
        font-size: 0.9rem;
    }
    
    .action-grid {
        grid-template-columns: repeat(4, 1fr);
        gap: 10px;
    }
}

@media (max-width: 576px) {
    .stats-overview {
        grid-template-columns: 1fr;
        gap: 8px;
    }
    
    .stats-card-large {
        padding: 12px;
        gap: 10px;
    }
    
    .stats-card-large .stats-icon {
        width: 45px;
        height: 45px;
        font-size: 1.3rem;
    }
    
    .stats-card-large .stats-number {
        font-size: 1.4rem;
    }
    
    .stats-card-large .stats-label {
        font-size: 0.85rem;
    }
    
    .action-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 8px;
    }
    
    .action-item {
        padding: 8px 2px;
    }
    
    .action-icon {
        width: 32px;
        height: 32px;
        font-size: 1rem;
    }
    
    .action-label {
        font-size: 0.65rem;
    }
    
    .today-section, .quick-actions, .content-card {
        margin-bottom: 16px;
        padding: 16px;
    }
    
    .teacher-avatar {
        width: 70px;
        height: 70px;
    }
    
    .section-title {
        font-size: 1rem;
    }
}

@media (max-width: 480px) {
    .main-content {
        padding: 16px 12px;
    }
    
    .stats-overview {
        grid-template-columns: repeat(2, 1fr);
        gap: 8px;
    }
    
    .stats-item {
        padding: 6px 3px;
    }
    
    /* 旧的stats-icon样式已移除 */
    
    .stats-number {
        font-size: 1rem;
    }
    
    .stats-label {
        font-size: 0.7rem;
    }
    
    .action-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 6px;
    }
    
    .action-item {
        padding: 6px 1px;
    }
    
    .action-icon {
        width: 28px;
        height: 28px;
        font-size: 0.9rem;
    }
    
    .action-label {
        font-size: 0.6rem;
    }
    
    .content-card {
        padding: 12px;
        margin-bottom: 12px;
    }
    
    .list-item {
        padding: 12px;
    }
}

/* 作业详情页面专用样式 */
.homework-info {
    padding: 16px 0;
}

.homework-desc {
    background: #f8f9fa;
    border-left: 4px solid #28a745;
    padding: 12px;
    border-radius: 0 8px 8px 0;
    margin: 12px 0;
    font-size: 0.9rem;
    line-height: 1.5;
}

.homework-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 16px;
    padding: 12px;
    background: #f8f9fa;
    border-radius: 8px;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    color: #6c757d;
}

.meta-item i {
    color: #28a745;
}

.homework-attachments {
    margin-top: 16px;
}

.attachment-grid {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 8px;
}

.attachment-item {
    flex: 0 0 auto;
    text-align: center;
}

.attachment-thumb {
    width: 80px;
    height: 80px;
    object-fit: cover;
    border-radius: 6px;
    cursor: pointer;
    border: 2px solid #e9ecef;
    transition: all 0.2s ease;
}

.attachment-thumb:hover {
    border-color: #28a745;
    transform: scale(1.05);
}

.file-preview-trigger {
    width: 80px;
    height: 80px;
    background: #f8f9fa;
    border-radius: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    border: 2px solid #e9ecef;
    margin-bottom: 4px;
    transition: all 0.2s ease;
}

.file-preview-trigger:hover {
    background: #e9ecef;
    border-color: #28a745;
}

/* 提交记录样式 */
.submission-item {
    border: 1px solid #e9ecef;
    border-radius: 8px;
    margin-bottom: 12px;
    background: white;
    transition: all 0.2s ease;
}

.submission-item:hover {
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    border-color: #28a745;
}

.submission-content {
    background: #f8f9fa;
    padding: 12px;
    border-radius: 6px;
    margin: 8px 0;
    font-size: 0.9rem;
    line-height: 1.5;
}

.submission-attachments {
    margin-top: 12px;
}

.submission-time {
    color: #6c757d;
    font-size: 0.8rem;
    margin-top: 8px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.grade-info {
    background: #e8f5e8;
    border: 1px solid #c3e6c3;
    border-radius: 6px;
    padding: 12px;
    margin-top: 12px;
}

.score {
    font-weight: 600;
    color: #28a745;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    gap: 6px;
}

.feedback {
    background: white;
    border-radius: 4px;
    padding: 8px;
    font-size: 0.9rem;
    line-height: 1.4;
}

/* 状态徽章样式 */
.status-badge {
    padding: 4px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 500;
    white-space: nowrap;
}

.status-draft {
    background: #f8f9fa;
    color: #6c757d;
}

.status-published {
    background: #d4edda;
    color: #155724;
}

.status-closed {
    background: #f8d7da;
    color: #721c24;
}

.status-submitted {
    background: #fff3cd;
    color: #856404;
}

.status-graded {
    background: #d4edda;
    color: #155724;
}

/* 空状态样式 */
.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: #6c757d;
}

.empty-state i {
    font-size: 3rem;
    color: #ddd;
    margin-bottom: 16px;
}

.empty-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: #495057;
}

.empty-desc {
    font-size: 0.9rem;
    color: #6c757d;
}

/* 移动端优化 */
@media (max-width: 768px) {
    .homework-meta {
        flex-direction: column;
        gap: 8px;
    }
    
    .attachment-grid {
        justify-content: center;
    }
    
    .attachment-thumb,
    .file-preview-trigger {
        width: 60px;
        height: 60px;
    }
    
    .submission-item {
        margin-bottom: 8px;
    }
    
    .submission-content {
        font-size: 0.85rem;
    }
}

/* 安全区域适配 */
@supports (padding: max(0px)) {
    .bottom-nav {
        padding-bottom: max(8px, env(safe-area-inset-bottom));
    }
}

/* 深色模式支持 */
@media (prefers-color-scheme: dark) {
    body {
        background-color: #1a1a1a;
        color: #e9ecef;
    }
    
    .content-card, .list-item, .stats-card {
        background: #2d2d2d;
        border-color: rgba(255,255,255,0.1);
    }
    
    .form-control-mobile {
        background: #2d2d2d;
        border-color: rgba(255,255,255,0.2);
        color: #e9ecef;
    }
    
    .bottom-nav {
        background: #2d2d2d;
        border-top: 1px solid rgba(255,255,255,0.1);
    }
}