/* General Resets and Base Styles */
:root {
    --primary-color: #0056b3;
    --secondary-color: #007bff;
    --accent-color: #28a745;
    --text-color: #333;
    --light-text-color: #f8f9fa;
    --background-color: #f4f7f6;
    --header-bg: #212529;
    --footer-bg: #343a40;
    --border-color: #dee2e6;
    --font-family-sans: 'Arial', sans-serif;
    --font-family-serif: 'Georgia', serif;
    --max-width: 1200px;
}

*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    font-size: 16px; /* Base font size */
}

body {
    font-family: var(--font-family-sans);
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--background-color);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 1.5rem;
}

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

a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* Skip Link for Accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary-color);
    color: var(--light-text-color);
    padding: 8px;
    z-index: 1000;
    transition: top 0.3s ease;
}

.skip-link:focus {
    top: 0;
}

/* Header Styles */
.site-header {
    background-color: var(--header-bg);
    color: var(--light-text-color);
    padding: 1rem 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.2);
    position: sticky;
    top: 0;
    z-index: 999;
}

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

.logo a {
    display: block;
    padding: 0.5rem 0;
}

.logo img {
    height: 40px; /* Adjust as needed */
    width: auto;
}

.main-navigation .menu {
    display: flex;
    gap: 1.5rem;
    align-items: center;
}

.main-navigation .menu-item a {
    color: var(--light-text-color);
    padding: 0.5rem 0;
    display: block;
    white-space: nowrap;
}

.main-navigation .menu-item a:hover,
.main-navigation .menu-item a:focus {
    color: var(--secondary-color);
    text-decoration: none;
}

.main-navigation .has-submenu {
    position: relative;
}

.main-navigation .submenu {
    display: none;
    position: absolute;
    background-color: var(--header-bg);
    min-width: 160px;
    box-shadow: 0px 8px 16px 0px rgba(0,0,0,0.2);
    z-index: 1;
    top: 100%;
    left: 0;
    padding: 0.5rem 0;
    border-top: 3px solid var(--secondary-color);
}

.main-navigation .has-submenu:hover .submenu,
.main-navigation .has-submenu:focus-within .submenu {
    display: block;
}

.main-navigation .submenu li a {
    padding: 0.75rem 1rem;
    color: var(--light-text-color);
    display: block;
}

.main-navigation .submenu li a:hover {
    background-color: rgba(255,255,255,0.1);
    color: var(--secondary-color);
}

.main-navigation .menu-toggle {
    display: none; /* Hidden by default for desktop */
    background: none;
    border: none;
    color: var(--light-text-color);
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0.5rem;
}

.main-navigation .menu-toggle .icon-bar {
    display: block;
    width: 25px;
    height: 3px;
    background-color: var(--light-text-color);
    margin: 5px 0;
    transition: all 0.3s ease;
}

.main-navigation .cta-button a {
    background-color: var(--accent-color);
    color: var(--light-text-color);
    padding: 0.75rem 1.25rem;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.main-navigation .cta-button a:hover {
    background-color: #218838; /* Darken for hover */
    text-decoration: none;
}

/* Hero Section */
.hero-section {
    background: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)), url('/static/images/hero-background.jpg') no-repeat center center/cover;
    color: var(--light-text-color);
    padding: 6rem 0;
    text-align: center;
    box-shadow: inset 0 -3px 5px rgba(0,0,0,0.2);
}

.hero-section h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    line-height: 1.2;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.5);
}

.hero-section p {
    font-size: 1.25rem;
    max-width: 800px;
    margin: 0 auto 2rem auto;
    opacity: 0.9;
}

.hero-actions {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    margin-top: 2rem;
}

.button {
    display: inline-block;
    padding: 1rem 2rem;
    border-radius: 5px;
    font-weight: bold;
    text-transform: uppercase;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.button.primary {
    background-color: var(--secondary-color);
    color: var(--light-text-color);
    border-color: var(--secondary-color);
}

.button.primary:hover {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

.button.secondary {
    background-color: transparent;
    color: var(--light-text-color);
    border-color: var(--light-text-color);
}

.button.secondary:hover {
    background-color: rgba(255,255,255,0.1);
    border-color: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}

/* Main Content Area */
main {
    flex-grow: 1; /* Ensures main content takes up available space */
    padding: 2rem 0;
}

/* Footer Styles */
.site-footer {
    background-color: var(--footer-bg);
    color: var(--light-text-color);
    padding: 3rem 0;
    font-size: 0.9rem;
    border-top: 5px solid var(--primary-color);
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-col h3 {
    color: var(--secondary-color);
    margin-bottom: 1rem;
    font-size: 1.1rem;
    position: relative;
    padding-bottom: 0.5rem;
}

.footer-col h3::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: 0;
    width: 50px;
    height: 2px;
    background-color: var(--accent-color);
}

.footer-col ul {
    margin: 0;
    padding: 0;
}

.footer-col ul li {
    margin-bottom: 0.7rem;
}

.footer-col ul li a {
    color: var(--light-text-color);
    transition: color 0.3s ease;
}

.footer-col ul li a:hover {
    color: var(--secondary-color);
    text-decoration: underline;
}

.footer-col address p {
    margin-bottom: 0.5rem;
}

.footer-col .social-icons {
    display: flex;
    gap: 1rem;
    margin-top: 1rem;
}

.footer-col .social-icons li a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 35px;
    height: 35px;
    border-radius: 50%;
    background-color: rgba(255,255,255,0.1);
    transition: background-color 0.3s ease;
}

.footer-col .social-icons li a:hover {
    background-color: var(--secondary-color);
}

.footer-col .social-icons img {
    width: 20px;
    height: 20px;
    filter: invert(1); /* Makes SVG icons white */
}

.newsletter-signup {
    margin-top: 1.5rem;
}

.newsletter-signup h4 {
    margin-bottom: 0.8rem;
    color: var(--secondary-color);
}

.newsletter-signup form {
    display: flex;
    gap: 0.5rem;
}

.newsletter-signup input[type="email"] {
    flex-grow: 1;
    padding: 0.75rem 1rem;
    border: 1px solid rgba(255,255,255,0.3);
    border-radius: 5px;
    background-color: rgba(0,0,0,0.2);
    color: var(--light-text-color);
}

.newsletter-signup input[type="email"]::placeholder {
    color: rgba(255,255,255,0.7);
}

.newsletter-signup button[type="submit"] {
    padding: 0.75rem 1.25rem;
    background-color: var(--accent-color);
    color: var(--light-text-color);
    border: none;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.newsletter-signup button[type="submit"]:hover {
    background-color: #218838; /* Darken for hover */
}

.newsletter-privacy {
    margin-top: 0.5rem;
    font-size: 0.8rem;
    opacity: 0.8;
}

.footer-bottom {
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 1.5rem;
    margin-top: 1.5rem;
    text-align: center;
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
}

.footer-bottom p {
    margin: 0;
}

.footer-bottom a {
    color: var(--secondary-color);
}

.footer-bottom a:hover {
    text-decoration: underline;
}

.back-to-top a {
    display: inline-block;
    background-color: rgba(255,255,255,0.1);
    color: var(--light-text-color);
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.back-to-top a:hover {
    background-color: var(--primary-color);
    text-decoration: none;
}

/* Responsive Design */
@media (max-width: 992px) {
    .main-navigation .menu {
        gap: 1rem;
    }
    .hero-section h1 {
        font-size: 2.5rem;
    }
    .hero-section p {
        font-size: 1.1rem;
    }
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    .button {
        width: 80%;
        max-width: 300px;
    }
}

@media (max-width: 768px) {
    .header-content {
        flex-direction: column;
        align-items: flex-start;
    }
    .main-navigation {
        width: 100%;
        margin-top: 1rem;
    }
    .main-navigation .menu {
        flex-direction: column;
        width: 100%;
        display: none; /* Hidden by default for mobile */
        background-color: var(--header-bg);
        border-top: 1px solid rgba(255,255,255,0.1);
        padding-top: 1rem;
    }
    .main-navigation .menu.active {
        display: flex; /* Show when active */
    }
    .main-navigation .menu-item {
        width: 100%;
        text-align: center;
    }
    .main-navigation .menu-item a {
        padding: 0.75rem 0;
        border-bottom: 1px solid rgba(255,255,255,0.05);
    }
    .main-navigation .has-submenu .submenu {
        position: static;
        width: 100%;
        box-shadow: none;
        border-top: none;
        padding-left: 1rem;
        background-color: rgba(0,0,0,0.1);
    }
    .main-navigation .menu-toggle {
        display: block;
        align-self: flex-end;
        margin-top: -3.5rem; /* Adjust to position correctly next to logo */
    }
    .hero-section {
        padding: 4rem 0;
    }
    .hero-section h1 {
        font-size: 2rem;
    }
    .hero-section p {
        font-size: 1rem;
    }
    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }
    .footer-col h3::after {
        left: 50%;
        transform: translateX(-50%);
    }
    .footer-col .social-icons {
        justify-content: center;
    }
    .newsletter-signup form {
        flex-direction: column;
    }
    .newsletter-signup input[type="email"],
    .newsletter-signup button[type="submit"] {
        width: 100%;
    }
    .footer-bottom {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .site-header .container, .site-footer .container {
        padding: 0 1rem;
    }
    .hero-section h1 {
        font-size: 1.8rem;
    }
    .hero-section p {
        font-size: 0.9rem;
    }
    .button {
        padding: 0.8rem 1.5rem;
    }
}
/* 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;
  }
}