/* ============================================
   现代化样式增强优化
   改善字体、间距、视觉效果
   ============================================ */

/* ============================================
   全局字体和排版优化
   ============================================ */

:root {
    /* 优化字体栈 */
    --font-primary: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    --font-heading: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --font-mono: "SF Mono", Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

    /* 优化颜色系统 */
    --color-primary: #667eea;
    --color-primary-dark: #5568d3;
    --color-secondary: #764ba2;
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    --color-text: #1f2937;
    --color-text-light: #6b7280;
    --color-bg: #ffffff;
    --color-bg-gray: #f9fafb;
    --color-border: #e5e7eb;

    /* 优化间距系统 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 0.75rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* 优化圆角 */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 24px;

    /* 优化阴影 */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.08);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 25px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
}

/* 全局基础样式 */
body {
    font-family: var(--font-primary);
    font-size: 16px;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg-gray);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

/* 标题字体优化 */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-heading);
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-text);
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 2.5rem; letter-spacing: -0.02em; }
h2 { font-size: 2rem; letter-spacing: -0.01em; }
h3 { font-size: 1.5rem; }
h4 { font-size: 1.25rem; }
h5 { font-size: 1.125rem; }
h6 { font-size: 1rem; }

/* 段落优化 */
p {
    margin-bottom: var(--spacing-md);
    color: var(--color-text-light);
    font-weight: 400;
}

/* ============================================
   导航栏优化
   ============================================ */

.nav-menu {
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: all 0.3s ease;
}

.nav-content {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.nav-brand h2 {
    font-size: 1.5rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin: 0;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    list-style: none;
    margin: 0;
    padding: 0;
}

.nav-links li a {
    color: var(--color-text);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.95rem;
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    transition: all 0.2s ease;
    position: relative;
}

.nav-links li a:hover {
    color: var(--color-primary);
    background: rgba(102, 126, 234, 0.08);
}

.nav-links li a.active {
    color: var(--color-primary);
    font-weight: 600;
}

.nav-links li a.active::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 50%;
    transform: translateX(-50%);
    width: 60%;
    height: 2px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary));
    border-radius: 2px;
}

/* 按钮优化 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-size: 0.95rem;
    font-weight: 600;
    font-family: var(--font-primary);
    border-radius: var(--radius-md);
    border: none;
    cursor: pointer;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    text-decoration: none;
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
    color: white;
    box-shadow: 0 4px 12px rgba(102, 126, 234, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.btn-outline {
    background: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
}

.btn-outline:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
}

/* ============================================
   Hero区域优化
   ============================================ */

.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: var(--spacing-2xl) var(--spacing-lg);
    text-align: center;
    position: relative;
    overflow: hidden;
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="white" opacity="0.05"/><circle cx="75" cy="75" r="1" fill="white" opacity="0.05"/><circle cx="50" cy="10" r="0.5" fill="white" opacity="0.03"/></pattern></defs><rect width="100" height="100" fill="url(%23grain)"/></svg>');
    pointer-events: none;
}

.hero-title {
    font-size: 3rem;
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-lg);
    position: relative;
    z-index: 1;
    letter-spacing: -0.03em;
}

.text-gradient {
    background: linear-gradient(135deg, #ffd89b 0%, #19547b 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.125rem;
    line-height: 1.7;
    max-width: 700px;
    margin: 0 auto var(--spacing-xl);
    opacity: 0.95;
    position: relative;
    z-index: 1;
    font-weight: 400;
}

.hero-actions {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-xl);
    position: relative;
    z-index: 1;
}

/* ============================================
   内容容器优化
   ============================================ */

.main-container {
    min-height: 100vh;
    background: var(--color-bg-gray);
}

.content-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--spacing-xl) var(--spacing-lg);
}

/* ============================================
   卡片优化
   ============================================ */

.card {
    background: white;
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

/* ============================================
   表单优化
   ============================================ */

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1rem;
    font-family: var(--font-primary);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    background: white;
    transition: all 0.2s ease;
    color: var(--color-text);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.form-label {
    display: block;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
    font-size: 0.95rem;
}

/* ============================================
   表格优化
   ============================================ */

.data-table {
    background: white;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    border: 1px solid var(--color-border);
}

table {
    width: 100%;
    border-collapse: collapse;
}

thead {
    background: var(--color-bg-gray);
}

th {
    padding: var(--spacing-md);
    text-align: left;
    font-weight: 600;
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--color-text-light);
    border-bottom: 2px solid var(--color-border);
}

td {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border);
}

tr:last-child td {
    border-bottom: none;
}

tr:hover {
    background: var(--color-bg-gray);
}

/* ============================================
   章节优化
   ============================================ */

section {
    padding: var(--spacing-2xl) 0;
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
    max-width: 800px;
    margin-left: auto;
    margin-right: auto;
}

.section-header h2 {
    font-size: 2.25rem;
    margin-bottom: var(--spacing-sm);
}

.section-header p {
    font-size: 1.125rem;
    color: var(--color-text-light);
}

/* ============================================
   徽章和标签优化
   ============================================ */

.badge {
    display: inline-block;
    padding: 0.35em 0.65em;
    font-size: 0.75rem;
    font-weight: 700;
    line-height: 1;
    text-align: center;
    white-space: nowrap;
    vertical-align: baseline;
    border-radius: var(--radius-sm);
    background: var(--color-primary);
    color: white;
}

/* ============================================
   动画优化
   ============================================ */

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.6s ease-out;
}

/* ============================================
   实用工具类
   ============================================ */

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

.mt-1 { margin-top: var(--spacing-xs); }
.mt-2 { margin-top: var(--spacing-sm); }
.mt-3 { margin-top: var(--spacing-md); }
.mt-4 { margin-top: var(--spacing-lg); }
.mt-5 { margin-top: var(--spacing-xl); }

.mb-1 { margin-bottom: var(--spacing-xs); }
.mb-2 { margin-bottom: var(--spacing-sm); }
.mb-3 { margin-bottom: var(--spacing-md); }
.mb-4 { margin-bottom: var(--spacing-lg); }
.mb-5 { margin-bottom: var(--spacing-xl); }

.p-1 { padding: var(--spacing-xs); }
.p-2 { padding: var(--spacing-sm); }
.p-3 { padding: var(--spacing-md); }
.p-4 { padding: var(--spacing-lg); }
.p-5 { padding: var(--spacing-xl); }

/* ============================================
   打印优化
   ============================================ */

@media print {
    .no-print {
        display: none !important;
    }

    body {
        background: white;
    }

    .card {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}

/* ============================================
   可访问性优化
   ============================================ */

/* 焦点样式优化 */
*:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 2px;
}

/* 跳转到主内容链接 */
.skip-to-content {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--color-primary);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    z-index: 10000;
    transition: top 0.3s;
}

.skip-to-content:focus {
    top: 0;
}