/* Basic Reset & Typography */
:root {
    --primary-color: #007bff;
    --secondary-color: #6c757d;
    --accent-color: #28a745;
    --text-color: #333;
    --bg-light: #f8f9fa;
    --bg-dark: #343a40;
    --border-color: #dee2e6;
    --font-family-sans: 'Helvetica Neue', 'Arial', sans-serif;
    --font-family-serif: 'Georgia', serif;
}

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

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

body {
    font-family: var(--font-family-sans);
    line-height: 1.6;
    color: var(--text-color);
    background-color: #fff;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

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

ul {
    list-style: none;
}

h1, h2, h3, h4, h5, h6 {
    margin-bottom: 0.5em;
    font-weight: 700;
    line-height: 1.2;
}

p {
    margin-bottom: 1em;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 15px;
}

/* Header Styles */
.main-header {
    background-color: var(--bg-dark);
    color: #fff;
    padding: 1rem 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

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

.logo {
    display: flex;
    align-items: center;
}

.logo a {
    display: flex;
    align-items: center;
    color: #fff;
    font-size: 1.8rem;
    font-weight: bold;
    text-decoration: none;
}

.logo-img {
    height: 40px;
    margin-right: 10px;
}

.main-nav .nav-list {
    display: flex;
    gap: 25px;
}

.main-nav .nav-link {
    color: #fff;
    font-weight: 500;
    padding: 8px 0;
    position: relative;
}

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

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

.cta-button {
    background-color: var(--accent-color);
    color: #fff !important;
    padding: 8px 15px;
    border-radius: 5px;
    transition: background-color 0.3s ease;
}

.cta-button:hover {
    background-color: #218838;
    text-decoration: none !important;
}

.user-actions .btn {
    background-color: transparent;
    border: 1px solid #fff;
    color: #fff;
    padding: 8px 15px;
    border-radius: 5px;
    margin-left: 10px;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

.user-actions .btn:hover {
    background-color: var(--primary-color);
    border-color: var(--primary-color);
}

.menu-toggle {
    display: none; /* Hidden by default on desktop */
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
    color: #fff;
    font-size: 1.5rem;
}

.menu-toggle .icon-bar {
    display: block;
    width: 25px;
    height: 3px;
    background-color: #fff;
    margin: 5px 0;
    transition: all 0.3s ease;
}

/* Footer Styles */
.main-footer {
    background-color: var(--bg-dark);
    color: #fff;
    padding: 3rem 0;
    font-size: 0.9rem;
}

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

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

.footer-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
    margin-bottom: 2rem;
}

.footer-col h3 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

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

.footer-col ul li {
    margin-bottom: 0.8rem;
}

.social-media {
    margin-top: 1rem;
    display: flex;
    gap: 15px;
}

.social-media img {
    width: 28px;
    height: 28px;
    filter: invert(1); /* Make icons white */
    transition: filter 0.3s ease;
}

.social-media a:hover img {
    filter: invert(0.7) sepia(1) saturate(5) hue-rotate(175deg); /* Tint to primary color on hover */
}

.newsletter-form {
    display: flex;
    margin-top: 1rem;
}

.newsletter-form input[type="email"] {
    flex-grow: 1;
    padding: 10px 15px;
    border: none;
    border-radius: 5px 0 0 5px;
    outline: none;
}

.newsletter-form button {
    background-color: var(--primary-color);
    color: #fff;
    border: none;
    padding: 10px 15px;
    border-radius: 0 5px 5px 0;
    cursor: pointer;
    transition: background-color 0.3s ease;
}

.newsletter-form button:hover {
    background-color: #0056b3;
}

.footer-bottom {
    text-align: center;
    padding-top: 1.5rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    margin-top: 2rem;
}

.footer-bottom p {
    margin-bottom: 0.5rem;
    color: #bbb;
}

/* Responsive adjustments */
@media (max-width: 992px) {
    .main-header .container {
        flex-wrap: wrap;
    }
    .main-nav {
        order: 3; /* Move nav below logo/user-actions on smaller screens */
        flex-basis: 100%;
        margin-top: 1rem;
    }

    .main-nav .nav-list {
        flex-direction: column;
        display: none; /* Hidden by default for mobile */
        width: 100%;
        background-color: var(--bg-dark);
        padding: 10px 0;
    }

    .main-nav .nav-list.active {
        display: flex; /* Show when active */
    }

    .main-nav .nav-item {
        text-align: center;
        margin: 5px 0;
    }

    .main-nav .nav-link {
        padding: 10px 0;
        display: block;
    }

    .menu-toggle {
        display: block; /* Show menu toggle on smaller screens */
        margin-left: auto;
    }

    .user-actions {
        order: 2;
        margin-left: 15px;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        text-align: center;
    }

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

    .footer-col ul li {
        display: inline-block; /* For better mobile layout of links */
        margin: 0 10px 8px;
    }

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

    .newsletter-form {
        max-width: 350px;
        margin-left: auto;
        margin-right: auto;
    }
}

@media (max-width: 768px) {
    .main-header .container {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
    .logo {
        flex-grow: 1;
    }
    .user-actions {
        margin-left: auto;
        order: 2;
    }
    .main-nav {
        order: 3;
        flex-basis: 100%;
        margin-top: 1rem;
    }
}

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