/* Basic Reset & Global Styles */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Open Sans', 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f4f7f6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: #3498db;
    text-decoration: none;
    transition: color 0.3s ease, text-decoration 0.3s ease;
}

a:hover {
    color: #2980b9;
    text-decoration: underline;
}

h1, h2, h3, h4, h5, h6 {
    font-family: 'Montserrat', sans-serif;
    margin-bottom: 0.8rem;
    color: #2c3e50;
    font-weight: 700;
}

p {
    margin-bottom: 1rem;
}

ul, ol {
    margin-left: 1.5rem;
    margin-bottom: 1rem;
}

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

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

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.py-1 { padding-top: 0.5rem; padding-bottom: 0.5rem; }
.py-2 { padding-top: 1rem; padding-bottom: 1rem; }
.py-3 { padding-top: 1.5rem; padding-bottom: 1.5rem; }
.py-4 { padding-top: 2rem; padding-bottom: 2rem; }

.btn {
    display: inline-block;
    background-color: #3498db;
    color: white;
    padding: 10px 20px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: 600;
    transition: background-color 0.3s ease, transform 0.2s ease;
    border: none;
    cursor: pointer;
}

.btn:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
    text-decoration: none;
}

.btn-secondary {
    background-color: #2c3e50;
}

.btn-secondary:hover {
    background-color: #1a242f;
}

.card {
    background-color: white;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.08);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

/* Forms */
.form-group {
    margin-bottom: 1rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: #555;
}

.form-group input[type="text"],
.form-group input[type="email"],
.form-group input[type="password"],
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #ccc;
    border-radius: 5px;
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.form-group input[type="text"]:focus,
.form-group input[type="email"]:focus,
.form-group input[type="password"]:focus,
.form-group textarea:focus,
.form-group select:focus {
    border-color: #3498db;
    box-shadow: 0 0 0 3px rgba(52, 152, 219, 0.2);
    outline: none;
}

.form-group textarea {
    resize: vertical;
    min-height: 100px;
}

/* Accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: #3498db;
    color: white;
    padding: 8px;
    z-index: 9999;
    transition: top 0.3s ease;
}

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

/* Responsive Design - General breakpoints */
@media (max-width: 768px) {
    .container {
        padding: 0 10px;
    }
    h1 { font-size: 2rem; }
    h2 { font-size: 1.7rem; }
    .btn {
        padding: 8px 15px;
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    h1 { font-size: 1.8rem; }
    h2 { font-size: 1.5rem; }
    body {
        font-size: 0.95rem;
    }
}

/* Font Awesome for icons (assuming CDN or local import) */
/* @import url('https://cdnjs.cloudflare.com/ajax/libs/font-awesome/5.15.3/css/all.min.css'); */
/* This comment is just to note the dependency, not to include it directly here as it's CSS */
/* 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;
  }
}