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

body {
    background-color: #f5f7fa;
    color: #333;
    line-height: 1.6;
}

/* 登录页面样式 */
.login-container {
    max-width: 400px;
    margin: 5rem auto;
    padding: 2rem;
    background: white;
    border-radius: 10px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
    text-align: center;
}

.login-container h1 {
    margin-bottom: 1.5rem;
    color: #2c3e50;
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #2c3e50;
}

input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 1rem;
    transition: border-color 0.3s;
}

input:focus {
    border-color: #3498db;
    outline: none;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
}

/* 按钮样式 */
.btn {
    display: inline-block;
    background: #3498db;
    color: white;
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    font-weight: 600;
    transition: background 0.3s;
    text-decoration: none;
}

.btn:hover {
    background: #2980b9;
}

.logout-btn {
    background: #e74c3c;
}

.logout-btn:hover {
    background: #c0392b;
}

/* 管理后台样式 */
header {
    background: #2c3e50;
    color: white;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.container {
    max-width: 1200px;
    margin: 2rem auto;
    padding: 0 1rem;
    display: grid;
    grid-template-columns: 1fr;
    gap: 2rem;
}

@media (min-width: 992px) {
    .container {
        grid-template-columns: 1fr 2fr;
    }
}

.card {
    background: white;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    padding: 1.5rem;
}

.card h2 {
    margin-bottom: 1.5rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid #eee;
    color: #2c3e50;
}

/* 表格样式 */
table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 1rem;
}

th, td {
    padding: 0.75rem;
    text-align: left;
    border-bottom: 1px solid #eee;
}

th {
    background-color: #f8f9fa;
    font-weight: 600;
    color: #2c3e50;
}

tr:hover {
    background-color: #f8f9fa;
}

.actions {
    display: flex;
    gap: 0.5rem;
}

.edit-btn {
    background: #f39c12;
}

.edit-btn:hover {
    background: #d35400;
}

.delete-btn {
    background: #e74c3c;
}

.delete-btn:hover {
    background: #c0392b;
}

/* 模态框样式 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: white;
    padding: 2rem;
    border-radius: 8px;
    width: 90%;
    max-width: 500px;
    position: relative;
}

.close {
    position: absolute;
    top: 1rem;
    right: 1.5rem;
    font-size: 1.5rem;
    cursor: pointer;
    color: #7f8c8d;
}

/* 警告消息 */
.alert {
    padding: 1rem;
    margin-bottom: 1.5rem;
    border-radius: 4px;
}

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