body, html {
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: #f4f7f9;
    color: #333;
}

/* Login Page */
.login-container {
    width: 320px;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 40px;
    background-color: #fff;
    box-shadow: 0 4px 20px rgba(0,0,0,0.05);
    border-radius: 8px;
    text-align: center;
}

.login-container h2 {
    margin-bottom: 24px;
    color: #333;
}

.form-group {
    margin-bottom: 16px;
    text-align: left;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-size: 14px;
    color: #555;
}

.form-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    box-sizing: border-box;
}

button {
    width: 100%;
    padding: 12px;
    border: none;
    border-radius: 4px;
    background-color: #007aff;
    color: white;
    font-size: 16px;
    cursor: pointer;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #005ecb;
}

.error-message {
    color: #ff3b30;
    font-size: 14px;
    margin-top: 16px;
    height: 20px;
}


/* Main App Layout */
.container {
    display: flex;
    height: 100vh;
}

.sidebar {
    width: 240px;
    flex-shrink: 0; /* 核心修改：确保侧边栏宽度固定，不被内容挤压 */
    background-color: #fff;
    border-right: 1px solid #e5e5e5;
    display: flex;
    flex-direction: column;
    padding: 20px;
    box-sizing: border-box;
}

.logo {
    text-align: center;
    padding-bottom: 20px;
    border-bottom: 1px solid #e5e5e5;
}

.logo h1 {
    margin: 0;
    font-size: 24px;
    color: #007aff;
}

.sidebar nav {
    flex-grow: 1;
    margin-top: 20px;
}

.sidebar nav ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.sidebar nav li a {
    display: block;
    padding: 12px 15px;
    text-decoration: none;
    color: #333;
    border-radius: 6px;
    margin-bottom: 8px;
    transition: background-color 0.2s, color 0.2s;
}

.sidebar nav li a:hover {
    background-color: #f0f0f0;
}

.sidebar nav li a.active {
    background-color: #007aff;
    color: #fff;
}

.logout-section {
    padding-top: 20px;
    border-top: 1px solid #e5e5e5;
}

#logout-btn {
    background-color: #ff3b30;
}

#logout-btn:hover {
    background-color: #c70000;
}


.main-content {
    flex-grow: 1;
    padding: 40px;
    overflow-y: auto;
    height: 100vh; /* 固定高度，确保不滚动 */
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
}

.content-section.active {
    display: flex;
    flex-direction: column;
    height: 100%;
}

h2 {
    font-size: 28px;
    margin-top: 0;
    margin-bottom: 20px;
    border-bottom: 1px solid #e5e5e5;
    padding-bottom: 15px;
    flex-shrink: 0;
}

/* Dashboard */
.stats-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
    flex-shrink: 0;
}

.card {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.card h3 {
    margin: 0 0 10px;
    font-size: 16px;
    color: #555;
}

.card p {
    margin: 0;
    font-size: 24px;
    font-weight: bold;
}

.content-section {
    display: none;
}

.chart-container {
    background-color: #fff;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    flex-grow: 1; /* 自动填充剩余空间 */
    display: flex;
    flex-direction: column;
    min-height: 0;
}

.chart-container h3 {
    margin: 0 0 15px;
    font-size: 18px;
    flex-shrink: 0;
}

.chart-canvas-wrapper {
    flex-grow: 1;
    position: relative; /* 为 Chart.js 提供相对定位参考 */
    min-height: 0; /* 防止溢出 */
}

.chart-canvas-wrapper canvas {
    /* 让 Chart.js 响应式调整大小 */
    width: 100% !important;
    height: 100% !important;
}

/* Reports */
.filters {
    display: flex;
    gap: 10px;
    margin-bottom: 20px;
}

.filters input {
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    flex-grow: 1;
}

.filters button {
    width: auto;
    padding: 10px 20px;
}

.table-container {
    background-color: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
    overflow-x: auto;
}

table {
    width: 100%;
    border-collapse: collapse;
}

th, td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid #e5e5e5;
    white-space: nowrap;
}

thead th {
    background-color: #f9f9f9;
    font-weight: 600;
}

tbody tr:hover {
    background-color: #f5f5f5;
}

.pagination {
    margin-top: 20px;
    text-align: center;
}

.pagination button {
    width: auto;
    padding: 8px 16px;
    margin: 0 5px;
}

/* Account */
.account-forms {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
}

.account-forms form {
    background-color: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}

.account-forms h3 {
    margin-top: 0;
    margin-bottom: 20px;
    font-size: 20px;
}

#profile-form .form-group span {
    font-weight: bold;
}