* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #e6f2ff; /* 浅蓝色背景 */
    color: #333;
    line-height: 1.6;
    padding: 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    background-color: rgba(255, 255, 255, 0.95);
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 150, 0.1);
    padding: 30px;
}

header {
    text-align: center;
    margin-bottom: 30px;
    padding-bottom: 20px;
    border-bottom: 2px solid #4d94ff;
}

h1 {
    color: #0066cc;
    margin-bottom: 10px;
}

h2 {
    color: #0066cc;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid #99ccff;
}

h3 {
    color: #0066cc;
    margin-bottom: 15px;
}

h4 {
    color: #0066cc;
    margin-bottom: 10px;
}

nav {
    margin-bottom: 30px;
    background-color: #f0f8ff;
    padding: 15px;
    border-radius: 8px;
}

nav ul {
    display: flex;
    justify-content: center;
    list-style: none;
    flex-wrap: wrap;
    gap: 10px;
}

nav ul li a {
    display: block;
    padding: 10px 20px;
    background-color: #4d94ff;
    color: white;
    text-decoration: none;
    border-radius: 5px;
    transition: background-color 0.3s;
}

nav ul li a:hover {
    background-color: #0066cc;
}

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

label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
    color: #0066cc;
}

input[type="text"],
input[type="date"],
select,
textarea {
    width: 100%;
    padding: 12px;
    border: 1px solid #99ccff;
    border-radius: 5px;
    font-size: 16px;
    background-color: #f8fbff;
}

textarea {
    min-height: 100px;
    resize: vertical;
}

button, .btn {
    display: inline-block;
    background-color: #4d94ff;
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    text-decoration: none;
    transition: background-color 0.3s;
    margin-right: 10px;
    margin-bottom: 10px;
}

button:hover, .btn:hover {
    background-color: #0066cc;
}

.btn-secondary {
    background-color: #66b3ff;
}

.btn-success {
    background-color: #33cc33;
}

.btn-danger {
    background-color: #ff6666;
}

.btn-small {
    padding: 6px 12px;
    font-size: 14px;
}

.result-box {
    background-color: #f0f8ff;
    padding: 20px;
    border-radius: 8px;
    border-left: 5px solid #4d94ff;
    margin-bottom: 20px;
}

.student-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.student-card {
    background-color: #f8fbff;
    border: 1px solid #99ccff;
    border-radius: 8px;
    padding: 15px;
    transition: all 0.3s;
}

.student-card.crossed {
    background-color: #f0f0f0;
    border-color: #cccccc;
}

.student-card.crossed .student-info {
    text-decoration: line-through;
    color: #999;
}

.student-id {
    display: inline-block;
    width: 40px;
    height: 40px;
    line-height: 40px;
    text-align: center;
    background-color: #4d94ff;
    color: white;
    border-radius: 50%;
    margin-right: 10px;
    font-weight: bold;
}

.student-info {
    display: inline-block;
    vertical-align: middle;
}

.student-name {
    font-weight: bold;
    display: block;
}

.student-gender {
    font-size: 14px;
    color: #666;
    display: block;
}

.student-checkbox {
    margin-top: 10px;
}

.status-badge {
    display: inline-block;
    padding: 4px 8px;
    border-radius: 4px;
    font-size: 12px;
    font-weight: bold;
}

.status-not-submitted {
    background-color: #ffcccc;
    color: #cc0000;
}

.status-submitted {
    background-color: #ccffcc;
    color: #006600;
}

.message {
    padding: 15px;
    border-radius: 5px;
    margin-bottom: 20px;
}

.message.success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.message.error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

.message.info {
    background-color: #d1ecf1;
    color: #0c5460;
    border: 1px solid #bee5eb;
}

.dashboard {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.item-card {
    background-color: #f8fbff;
    border: 1px solid #99ccff;
    border-radius: 8px;
    padding: 20px;
    transition: all 0.3s;
}

.item-card:hover {
    box-shadow: 0 5px 15px rgba(0, 0, 150, 0.1);
    transform: translateY(-2px);
}

.item-card h3 {
    color: #0066cc;
    margin-bottom: 10px;
    padding-bottom: 10px;
    border-bottom: 1px solid #99ccff;
}

.item-meta {
    display: flex;
    justify-content: space-between;
    margin-bottom: 15px;
    font-size: 14px;
    color: #666;
}

.item-id {
    background-color: #e6f2ff;
    padding: 2px 8px;
    border-radius: 4px;
    font-family: monospace;
}

.item-stats {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-bottom: 15px;
}

.stat-item {
    text-align: center;
    padding: 10px;
    background-color: #f0f8ff;
    border-radius: 5px;
}

.stat-value {
    font-size: 20px;
    font-weight: bold;
    color: #0066cc;
}

.stat-label {
    font-size: 12px;
    color: #666;
}

.unsubmitted-list {
    margin-top: 20px;
}

.unsubmitted-item {
    padding: 10px 15px;
    margin-bottom: 8px;
    background-color: #ffe6e6;
    border-left: 4px solid #ff6666;
    border-radius: 4px;
    display: flex;
    align-items: center;
}

.unsubmitted-item .student-id {
    width: 30px;
    height: 30px;
    line-height: 30px;
    font-size: 14px;
}

.query-result {
    background-color: #f8fbff;
    border: 1px solid #99ccff;
    border-radius: 8px;
    padding: 20px;
    margin-top: 20px;
}

.query-result h3 {
    color: #0066cc;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid #99ccff;
}

.flex-container {
    display: flex;
    gap: 30px;
    margin-top: 20px;
}

.flex-left {
    flex: 2;
}

.flex-right {
    flex: 1;
}

.history-date {
    background-color: #e6f2ff;
    padding: 20px;
    border-radius: 8px;
    margin-bottom: 20px;
}

.history-date h3 {
    color: #0066cc;
    margin-bottom: 15px;
}

.item-detail {
    background-color: #f8fbff;
    border: 1px solid #99ccff;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 15px;
}

footer {
    text-align: center;
    margin-top: 40px;
    padding-top: 20px;
    border-top: 1px solid #99ccff;
    color: #666;
}