/* Base Styles */
:root {
    --primary-color: #0056b3;
    --secondary-color: #6c757d;
    --accent-color: #28a745;
    --light-bg: #f8f9fa;
    --dark-text: #212529;
    --border-color: #dee2e6;
    --font-family-sans-serif: 'Roboto', sans-serif;
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family-sans-serif);
    line-height: 1.6;
    color: var(--dark-text);
    background-color: #fff;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-sm);
}

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover {
    color: #003d82;
    text-decoration: underline;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-sm);
    line-height: 1.2;
}

p {
    margin-bottom: var(--spacing-sm);
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    text-align: center;
    white-space: nowrap;
    vertical-align: middle;
    cursor: pointer;
    user-select: none;
    border: 1px solid transparent;
    border-radius: 0.25rem;
    transition: all 0.3s ease;
}

.btn-primary {
    color: #fff;
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-primary:hover {
    background-color: #004494;
    border-color: #004494;
}

.btn-secondary {
    color: #fff;
    background-color: var(--secondary-color);
    border-color: var(--secondary-color);
}

.btn-secondary:hover {
    background-color: #5a6268;
    border-color: #545b62;
}

.btn-subscribe {
    background-color: var(--accent-color);
    border-color: var(--accent-color);
    color: #fff;
    padding: 0.6rem 1.2rem;
    font-size: 0.9rem;
}

.btn-subscribe:hover {
    background-color: #218838;
    border-color: #1e7e34;
}

/* Header */
.main-header {
    background-color: #fff;
    border-bottom: 1px solid var(--border-color);
    padding: var(--spacing-sm) 0;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.main-header .logo img {
    height: 40px;
    width: auto;
}

.main-nav .nav-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
}

.main-nav .nav-item {
    margin-left: var(--spacing-md);
}

.main-nav .nav-item a {
    color: var(--dark-text);
    font-weight: 500;
    padding: 0.5rem 0;
    display: block;
    position: relative;
}

.main-nav .nav-item a:hover {
    color: var(--primary-color);
    text-decoration: none;
}

.main-nav .nav-item a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 0;
    height: 2px;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

.main-nav .nav-item a:hover::after {
    width: 100%;
}

.header-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
}

@media (max-width: 768px) {
    .main-nav .nav-list {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: #fff;
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        padding: var(--spacing-sm) 0;
        border-top: 1px solid var(--border-color);
    }

    .main-nav .nav-list.active {
        display: flex;
    }

    .main-nav .nav-item {
        margin: 0;
        border-bottom: 1px solid var(--border-color);
    }

    .main-nav .nav-item:last-child {
        border-bottom: none;
    }

    .main-nav .nav-item a {
        padding: var(--spacing-sm) var(--spacing-md);
    }

    .menu-toggle {
        display: block;
    }

    .header-actions {
        display: none;
    }
}

/* Footer */
.main-footer {
    background-color: var(--dark-text);
    color: #f8f9fa;
    padding: var(--spacing-xl) 0;
    margin-top: auto;
}

.main-footer a {
    color: #adb5bd;
}

.main-footer a:hover {
    color: #fff;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

.footer-col h3 {
    color: #fff;
    margin-bottom: var(--spacing-sm);
    font-size: 1.25rem;
}

.footer-col ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-col ul li {
    margin-bottom: 0.5rem;
}

.footer-logo {
    max-height: 50px;
    margin-bottom: var(--spacing-sm);
}

.company-info p {
    font-size: 0.9rem;
    line-height: 1.5;
    color: #ced4da;
}

.social-links {
    margin-top: var(--spacing-sm);
    display: flex;
    gap: 0.75rem;
}

.social-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.1);
    color: #fff;
    transition: background-color 0.3s ease;
}

.social-icon:hover {
    background-color: var(--primary-color);
}

.contact-info p {
    margin-bottom: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.9rem;
    color: #ced4da;
}

.contact-info i {
    color: var(--accent-color);
    font-size: 1rem;
}

.newsletter-form {
    display: flex;
    margin-top: var(--spacing-sm);
}

.newsletter-form input[type="email"] {
    flex-grow: 1;
    padding: 0.75rem;
    border: 1px solid #495057;
    border-radius: 0.25rem 0 0 0.25rem;
    background-color: #343a40;
    color: #fff;
    font-size: 0.9rem;
}

.newsletter-form input[type="email"]::placeholder {
    color: #adb5bd;
}

.newsletter-form button {
    border-radius: 0 0.25rem 0.25rem 0;
}

.footer-bottom {
    border-top: 1px solid #495057;
    padding-top: var(--spacing-md);
    margin-top: var(--spacing-md);
    text-align: center;
    font-size: 0.85rem;
    color: #adb5bd;
}

.footer-bottom .legal-links {
    display: flex;
    justify-content: center;
    gap: var(--spacing-md);
    list-style: none;
    padding: 0;
    margin-top: var(--spacing-sm);
}

.footer-bottom .legal-links a {
    color: #adb5bd;
}

.footer-bottom .legal-links a:hover {
    color: #fff;
}

/* Utility Classes */
.skip-to-content {
    position: absolute;
    left: -9999px;
    top: auto;
    width: 1px;
    height: 1px;
    overflow: hidden;
    z-index: -999;
}

.skip-to-content:focus {
    left: 0;
    top: 0;
    width: auto;
    height: auto;
    padding: 10px;
    background-color: #fff;
    color: var(--primary-color);
    z-index: 9999;
    text-decoration: underline;
}

@media (max-width: 992px) {
    .footer-grid {
        grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    }
}

@media (max-width: 576px) {
    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .company-info, .quick-links, .resources, .contact-info {
        display: flex;
        flex-direction: column;
        align-items: center;
    }

    .social-links {
        justify-content: center;
    }

    .newsletter-form {
        width: 100%;
        max-width: 300px;
        margin-left: auto;
        margin-right: auto;
    }

    .footer-bottom .legal-links {
        flex-direction: column;
        gap: 0.5rem;
    }
}

/* General reset and base styles */
*,
*::before,
*::after {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font-family-sans-serif);
    font-size: 1rem;
    font-weight: 400;
    line-height: 1.5;
    color: var(--dark-text);
    text-align: left;
    background-color: #fff;
    -webkit-text-size-adjust: 100%;
    -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

[tabindex="-1"]:focus:not(:focus-visible) {
    outline: 0 !important;
}

hr {
    margin: var(--spacing-md) 0;
    color: inherit;
    background-color: currentColor;
    border: 0;
    opacity: 0.25;
}

hr:not([size]) {
    height: 1px;
}

h1, .h1, h2, .h2, h3, .h3, h4, .h4, h5, .h5, h6, .h6 {
    margin-top: 0;
    margin-bottom: 0.5rem;
    font-weight: 500;
    line-height: 1.2;
}

h1, .h1 {
    font-size: calc(1.375rem + 1.5vw);
}

@media (min-width: 1200px) {
    h1, .h1 {
        font-size: 2.5rem;
    }
}

h2, .h2 {
    font-size: calc(1.325rem + 0.9vw);
}

@media (min-width: 1200px) {
    h2, .h2 {
        font-size: 2rem;
    }
}

h3, .h3 {
    font-size: calc(1.3rem + 0.6vw);
}

@media (min-width: 1200px) {
    h3, .h3 {
        font-size: 1.75rem;
    }
}

h4, .h4 {
    font-size: calc(1.275rem + 0.3vw);
}

@media (min-width: 1200px) {
    h4, .h4 {
        font-size: 1.5rem;
    }
}

h5, .h5 {
    font-size: 1.25rem;
}

h6, .h6 {
    font-size: 1rem;
}

p {
    margin-top: 0;
    margin-bottom: 1rem;
}

abbr[title],
abbr[data-bs-original-title] {
    text-decoration: underline dotted;
    cursor: help;
    text-decoration-skip-ink: none;
}
\address {
    margin-bottom: 1rem;
    font-style: normal;
    line-height: inherit;
}

ol,
ul {
    padding-left: 2rem;
}

ol,
ul,
dl {
    margin-top: 0;
    margin-bottom: 1rem;
}

ol ol,
ul ul,
ol ul,
ul ol {
    margin-bottom: 0;
}

dt {
    font-weight: 700;
}

dd {
    margin-bottom: 0.5rem;
    margin-left: 0;
}

blockquote {
    margin: 0 0 1rem;
}

b,
strong {
    font-weight: 700;
}

small,
.small {
    font-size: 0.875em;
}

mark,
.mark {
    padding: 0.2em;
    background-color: #fcf8e3;
}

sub,
sup {
    position: relative;
    font-size: 0.75em;
    line-height: 0;
    vertical-align: baseline;
}

sub {
    bottom: -0.25em;
}

sup {
    top: -0.5em;
}

img,
svg {
    vertical-align: middle;
}

table {
    caption-side: bottom;
    border-collapse: collapse;
}

caption {
    padding-top: 0.5rem;
    padding-bottom: 0.5rem;
    color: #6c757d;
    text-align: left;
}

th {
    text-align: inherit;
    text-align: -webkit-match-parent;
}

thead,
tbody,
tfoot,
tr,
td,
th {
    border-color: inherit;
    border-style: solid;
    border-width: 0;
}

label {
    display: inline-block;
}

button {
    border-radius: 0;
}

button:focus:not(:focus-visible) {
    outline: 0;
}

input,
button,
select,
optgroup,
textarea {
    margin: 0;
    font-family: inherit;
    font-size: inherit;
    line-height: inherit;
}

button,
select {
    text-transform: none;
}

[role="button"] {
    cursor: pointer;
}

select {
    word-wrap: normal;
}

select:disabled {
    opacity: 1;
}

[list]::-webkit-calendar-picker-indicator {
    display: none;
}

button,
[type="button"],
[type="reset"],
[type="submit"] {
    -webkit-appearance: button;
}

button:not(:disabled),
[type="button"]:not(:disabled),
[type="reset"]:not(:disabled),
[type="submit"]:not(:disabled) {
    cursor: pointer;
}

::-moz-focus-inner {
    padding: 0;
    border-style: none;
}

textarea {
    resize: vertical;
}

fieldset {
    min-width: 0;
    padding: 0;
    margin: 0;
    border: 0;
}

legend {
    float: left;
    width: 100%;
    padding: 0;
    margin-bottom: 0.5rem;
    font-size: calc(1.275rem + 0.3vw);
    line-height: inherit;
    white-space: normal;
}

@media (min-width: 1200px) {
    legend {
        font-size: 1.5rem;
    }
}

legend + * {
    clear: left;
}

::-webkit-datetime-edit-fields-wrapper,
::-webkit-datetime-edit-text,
::-webkit-datetime-edit-minute,
::-webkit-datetime-edit-hour-field,
::-webkit-datetime-edit-day-field,
::-webkit-datetime-edit-month-field,
::-webkit-datetime-edit-year-field {
    padding: 0;
}

::-webkit-inner-spin-button {
    height: auto;
}

::-webkit-search-decoration {
    -webkit-appearance: none;
}

::-webkit-color-swatch-wrapper {
    padding: 0;
}

::-webkit-file-upload-button {
    font: inherit;
    -webkit-appearance: button;
}

output {
    display: inline-block;
}

iframe {
    border: 0;
}

summary {
    display: list-item;
    cursor: pointer;
}

progress {
    vertical-align: baseline;
}

[hidden] {
    display: none !important;
}

/* Accessibility skip link */
#skip-to-content a {
    position: absolute;
    left: -9999px;
    top: auto;
    width: 1px;
    height: 1px;
    overflow: hidden;
    z-index: -999;
}

#skip-to-content a:focus {
    left: 0;
    top: 0;
    width: auto;
    height: auto;
    padding: 10px;
    background-color: #fff;
    color: var(--primary-color);
    z-index: 9999;
    text-decoration: underline;
}

/* Additional common styles */
.text-center {
    text-align: center;
}

.text-right {
    text-align: right;
}

.text-left {
    text-align: left;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Flexbox utilities */
.d-flex {
    display: flex;
}

.justify-content-center {
    justify-content: center;
}

.align-items-center {
    align-items: center;
}

.flex-column {
    flex-direction: column;
}

/* Spacing utilities */
.mb-sm {
    margin-bottom: var(--spacing-sm);
}

.mt-sm {
    margin-top: var(--spacing-sm);
}

.py-lg {
    padding-top: var(--spacing-lg);
    padding-bottom: var(--spacing-lg);
}

.px-md {
    padding-left: var(--spacing-md);
    padding-right: var(--spacing-md);
}

/* Image responsiveness */
img {
    max-width: 100%;
    height: auto;
}

/* Form elements */
input[type="text"],
input[type="email"],
input[type="password"],
textarea {
    width: 100%;
    padding: 0.75rem;
    margin-bottom: var(--spacing-sm);
    border: 1px solid var(--border-color);
    border-radius: 0.25rem;
    font-size: 1rem;
}

input[type="text"]:focus,
input[type="email"]:focus,
input[type="password"]:focus,
textarea:focus {
    border-color: var(--primary-color);
    outline: 0;
    box-shadow: 0 0 0 0.2rem rgba(0, 86, 179, 0.25);
}

/* Cards */
.card {
    background-color: #fff;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    margin-bottom: var(--spacing-md);
    overflow: hidden;
}

.card-header {
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: 0;
    background-color: var(--light-bg);
    border-bottom: 1px solid var(--border-color);
    font-weight: 500;
}

.card-body {
    padding: var(--spacing-md);
}

.card-title {
    margin-bottom: var(--spacing-sm);
    font-size: 1.25rem;
    font-weight: 500;
}

.card-text {
    font-size: 0.95rem;
    color: #495057;
}

/* Grid system for content */
.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

/* Alerts */
.alert {
    padding: 1rem 1.25rem;
    margin-bottom: 1rem;
    border: 1px solid transparent;
    border-radius: 0.25rem;
}

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

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

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

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

/* Table styles */
.table {
    width: 100%;
    margin-bottom: 1rem;
    color: var(--dark-text);
    vertical-align: top;
    border-color: var(--border-color);
}

.table > :not(caption) > * > * {
    padding: 0.5rem 0.5rem;
    background-color: var(--light-bg);
    border-bottom-width: 1px;
    box-shadow: inset 0 0 0 9999px var(--light-bg);
}

.table > tbody {
    vertical-align: inherit;
}

.table > thead {
    vertical-align: bottom;
}

.table > :not(:last-child) > :last-child > * {
    border-bottom-color: currentColor;
}

.table-striped > tbody > tr:nth-of-type(odd) > * {
    background-color: rgba(0, 0, 0, 0.05);
}

.table-bordered > :not(caption) > * {
    border-width: 1px 0;
}

.table-bordered > :not(caption) > * > * {
    border-width: 0 1px;
}

.table-hover > tbody > tr:hover > * {
    background-color: rgba(0, 0, 0, 0.075);
}

/* Pagination */
.pagination {
    display: flex;
    padding-left: 0;
    list-style: none;
    border-radius: 0.25rem;
}

.page-item:not(:first-child) .page-link {
    margin-left: -1px;
}

.page-item.active .page-link {
    z-index: 3;
    color: #fff;
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.page-item.disabled .page-link {
    color: #6c757d;
    pointer-events: none;
    background-color: #fff;
    border-color: var(--border-color);
}

.page-link {
    position: relative;
    display: block;
    color: var(--primary-color);
    text-decoration: none;
    background-color: #fff;
    border: 1px solid var(--border-color);
    padding: 0.375rem 0.75rem;
    transition: color 0.15s ease-in-out, background-color 0.15s ease-in-out, border-color 0.15s ease-in-out, box-shadow 0.15s ease-in-out;
}

.page-link:hover {
    z-index: 2;
    color: #0a58ca;
    background-color: #e9ecef;
    border-color: #dee2e6;
}

.page-link:focus {
    z-index: 2;
    color: #0a58ca;
    background-color: #e9ecef;
    outline: 0;
    box-shadow: 0 0 0 0.25rem rgba(13, 110, 253, 0.25);
}

.page-item:first-child .page-link {
    border-top-left-radius: 0.25rem;
    border-bottom-left-radius: 0.25rem;
}

.page-item:last-child .page-link {
    border-top-right-radius: 0.25rem;
    border-bottom-right-radius: 0.25rem;
}

/* Responsive utilities */
@media (max-width: 768px) {
    .header-actions {
        display: none;
    }

    .main-nav {
        flex-grow: 1;
        text-align: right;
    }

    .main-nav .nav-list {
        flex-direction: column;
        align-items: flex-end;
        position: absolute;
        top: 100%;
        left: 0;
        right: 0;
        background-color: #fff;
        border-top: 1px solid var(--border-color);
        padding: var(--spacing-sm) 0;
        box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        display: none;
    }

    .main-nav .nav-list.active {
        display: flex;
    }

    .main-nav .nav-item {
        width: 100%;
        text-align: right;
        margin: 0;
    }

    .main-nav .nav-item a {
        padding: var(--spacing-sm) var(--spacing-md);
        border-bottom: 1px solid var(--border-color);
    }

    .main-nav .nav-item:last-child a {
        border-bottom: none;
    }

    .menu-toggle {
        display: block;
        order: 2;
    }

    .main-header .logo {
        order: 1;
    }

    .main-header .container {
        justify-content: space-between;
    }
}
/* 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;
  }
}