/* Global Reset and Box Sizing */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

/* Base Body Styles */
body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f4f4f4;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Container for Centering Content */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    margin-bottom: 0.5em;
    color: #2c3e50;
    font-weight: 700;
}

p {
    margin-bottom: 1em;
}

a {
    color: #007bff;
    text-decoration: none;
    transition: color 0.3s ease, text-decoration 0.3s ease;
}

a:hover {
    color: #0056b3;
    text-decoration: underline;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 10px 20px;
    font-size: 1em;
    font-weight: 600;
    text-align: center;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
    border: 1px solid transparent;
}

.btn-primary {
    background-color: #007bff;
    color: #ffffff;
    border-color: #007bff;
}

.btn-primary:hover {
    background-color: #0056b3;
    border-color: #0056b3;
}

.btn-secondary {
    background-color: #6c757d;
    color: #ffffff;
    border-color: #6c757d;
}

.btn-secondary:hover {
    background-color: #5a6268;
    border-color: #5a6268;
}

.btn-outline-primary {
    background-color: transparent;
    color: #007bff;
    border-color: #007bff;
}

.btn-outline-primary:hover {
    background-color: #007bff;
    color: #ffffff;
}

/* Forms */
input[type="text"],
input[type="email"],
input[type="password"],
textarea,
select {
    width: 100%;
    padding: 10px;
    margin-bottom: 15px;
    border: 1px solid #ccc;
    border-radius: 4px;
    font-size: 1em;
    transition: border-color 0.3s ease;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
textarea:focus,
select:focus {
    border-color: #007bff;
    outline: none;
}

/* Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }
.margin-top-20 { margin-top: 20px; }
.margin-bottom-20 { margin-bottom: 20px; }
.padding-20 { padding: 20px; }

/* Flexbox utilities */
.d-flex { display: flex; }
.justify-content-center { justify-content: center; }
.align-items-center { align-items: center; }
.flex-column { flex-direction: column; }

/* Responsive Image */
img {
    max-width: 100%;
    height: auto;
    display: block; /* Remove extra space below image */
}

/* Card Component */
.card {
    background-color: #ffffff;
    border: 1px solid #e0e0e0;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    padding: 20px;
    margin-bottom: 20px;
}

.card-header {
    font-size: 1.2em;
    font-weight: 600;
    margin-bottom: 15px;
    color: #2c3e50;
    border-bottom: 1px solid #eee;
    padding-bottom: 10px;
}

.card-body {
    /* flex grow or content */
}

.card-footer {
    margin-top: 15px;
    border-top: 1px solid #eee;
    padding-top: 10px;
    font-size: 0.9em;
    color: #666;
}

/* Alert Messages */
.alert {
    padding: 15px;
    margin-bottom: 20px;
    border-radius: 5px;
    border: 1px solid transparent;
}

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

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

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

/* List Styles */
ul, ol {
    margin-left: 20px;
    margin-bottom: 1em;
}

ul.no-style, ol.no-style {
    list-style: none;
    margin-left: 0;
}

/* Table Styles */
table {
    width: 100%;
    border-collapse: collapse;
    margin-bottom: 1em;
    background-color: #fff;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    border-radius: 8px;
    overflow: hidden; /* For rounded corners */
}

table th, table td {
    padding: 12px 15px;
    text-align: left;
    border-bottom: 1px solid #ddd;
}

table thead th {
    background-color: #007bff;
    color: #ffffff;
    font-weight: 600;
}

table tbody tr:nth-child(even) {
    background-color: #f2f2f2;
}

table tbody tr:hover {
    background-color: #e9f7ff;
}

/* Responsive Table (basic) */
@media screen and (max-width: 600px) {
    table, thead, tbody, th, td, tr {
        display: block;
    }
    thead tr {
        position: absolute;
        top: -9999px;
        left: -9999px;
    }
    tr { border: 1px solid #ccc; margin-bottom: 10px; }
    td {
        border: none;
        border-bottom: 1px solid #eee;
        position: relative;
        padding-left: 50%;
        text-align: right;
    }
    td:before {
        position: absolute;
        top: 6px;
        left: 6px;
        width: 45%;
        padding-right: 10px;
        white-space: nowrap;
        text-align: left;
        font-weight: bold;
    }
    /* You'd need to add content for each td:before here */
    /* Example: td:nth-of-type(1):before { content: "First Name"; } */
}

/* Scroll to top button */
.scroll-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: #007bff;
    color: white;
    width: 40px;
    height: 40px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5em;
    cursor: pointer;
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.3s ease, visibility 0.3s ease;
    z-index: 1000;
}

.scroll-to-top.show {
    opacity: 1;
    visibility: visible;
}

/* Dark Mode Toggle (example) */
.dark-mode-toggle {
    background-color: #333;
    color: #fff;
    padding: 10px 15px;
    border-radius: 5px;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9em;
    transition: background-color 0.3s ease;
}
.dark-mode-toggle:hover {
    background-color: #555;
}
.dark-mode-toggle .icon {
    font-size: 1.2em;
}

/* Grid System (simple) */
.row {
    display: flex;
    flex-wrap: wrap;
    margin-left: -15px;
    margin-right: -15px;
}
.col-1, .col-2, .col-3, .col-4, .col-5, .col-6, .col-7, .col-8, .col-9, .col-10, .col-11, .col-12 {
    padding-left: 15px;
    padding-right: 15px;
}
.col-12 { width: 100%; }
.col-6 { width: 50%; }
.col-4 { width: 33.333%; }
.col-3 { width: 25%; }
/* Add more columns as needed, and responsive variations */

@media (max-width: 768px) {
    .col-md-12 { width: 100%; }
    .col-md-6 { width: 50%; }
}
/* 移动端内容区防溢出（系统追加，请勿删除） */
@media (max-width: 768px) {
  .page-content img {
    max-width: 100% !important;
    height: auto !important;
    display: block;
  }
  .page-content {
    overflow-x: hidden;
    max-width: 100%;
  }
  body {
    overflow-x: hidden;
  }
}