/* Base Variables */
:root {
    /* Colors */
    --primary-color: #4361ee;
    --primary-light: #4895ef;
    --primary-dark: #3f37c9;
    --secondary-color: #f72585;
    --accent-color: #7209b7;
    --text-color: #333333;
    --text-light: #666666;
    --text-lighter: #999999;
    --bg-color: #ffffff;
    --bg-light: #f8f9fa;
    --bg-dark: #e9ecef;
    --success-color: #38b000;
    --warning-color: #ffaa00;
    --error-color: #d90429;
    
    /* Typography */
    --font-family: 'Poppins', sans-serif;
    --heading-line-height: 1.2;
    --body-line-height: 1.6;
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-xxl: 3rem;
    
    /* Borders */
    --border-radius-sm: 4px;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
    --border-radius-xl: 20px;
    --border-width: 1px;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 8px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 16px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 16px 32px rgba(0, 0, 0, 0.1);
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-normal: 300ms ease;
    --transition-slow: 500ms ease;
    
    /* Container */
    --container-max-width: 1200px;
    --container-padding: var(--spacing-lg);
}

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

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

body {
    font-family: var(--font-family);
    font-size: 1rem;
    line-height: var(--body-line-height);
    color: var(--text-color);
    background-color: var(--bg-color);
    overflow-x: hidden;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-family);
    font-weight: 600;
    line-height: var(--heading-line-height);
    margin-bottom: var(--spacing-md);
    color: var(--text-color);
}

h1 {
    font-size: 2.5rem;
}

h2 {
    font-size: 2rem;
}

h3 {
    font-size: 1.5rem;
}

h4 {
    font-size: 1.25rem;
}

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

a {
    color: var(--primary-color);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--primary-dark);
}

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

ul, ol {
    list-style-position: inside;
    margin-bottom: var(--spacing-md);
}

/* Container */
.container {
    width: 100%;
    max-width: var(--container-max-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

/* Sections */
section {
    padding: var(--spacing-xxl) 0;
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
}

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

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

/* Gradient Text */
.gradient-text {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    display: inline-block;
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius-md);
    font-weight: 500;
    font-size: 1rem;
    line-height: 1;
    cursor: pointer;
    transition: all var(--transition-fast);
    border: none;
    outline: none;
    text-align: center;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

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

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

.btn-lg {
    padding: 1rem 2rem;
    font-size: 1.125rem;
}

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

/* Header */
.main-header {
    position: sticky;
    top: 0;
    width: 100%;
    background-color: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    box-shadow: var(--shadow-sm);
    padding: var(--spacing-md) 0;
}

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

.logo a {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 600;
    font-size: 1.25rem;
    color: var(--text-color);
}

.logo img {
    height: 36px;
    width: auto;
}

.main-nav ul {
    display: flex;
    list-style: none;
    margin: 0;
    gap: var(--spacing-lg);
}

.main-nav a {
    color: #333;
    font-weight: 500;
    text-decoration: none;
    padding: 8px 15px;
    transition: color 0.3s ease;
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--primary-color);
    background: none;
}

.main-nav a.active {
    color: var(--primary-color);
}

/* 确保所有导航元素和下拉菜单都没有背景 */
.main-nav a,
.main-nav a:hover,
.main-nav a.active,
.dropdown-menu a,
.dropdown-menu a:hover {
    background-color: transparent !important;
}

/* 确保在移动设备上也没有背景 */
@media (max-width: 768px) {
    .dropdown-menu,
    .main-nav.active ul li.has-dropdown.open .dropdown-menu,
    body.mobile-menu-open .main-nav a,
    body.mobile-menu-open .main-nav a:hover,
    body.mobile-menu-open .main-nav a.active {
        background-color: transparent !important;
    }
}

.auth-buttons {
    display: flex;
    gap: var(--spacing-md);
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background-color: var(--text-color);
    margin: 5px 0;
    transition: var(--transition-fast);
}

/* Profile Button - Universal Style Override */
.profile-button {
    display: flex !important;
    align-items: center !important;
    background: var(--primary-color) !important;
    border: none !important;
    border-radius: var(--border-radius-md) !important;
    color: white !important;
    padding: 0.5rem 1rem !important;
    font-size: 0.875rem !important;
    cursor: pointer !important;
    transition: all 0.3s ease !important;
}

.profile-button:hover {
    background: var(--primary-dark) !important;
    color: white !important;
    transform: translateY(-2px) !important;
    box-shadow: var(--shadow-sm) !important;
}

.profile-button i,
.profile-button svg {
    margin-right: 0.5rem !important;
    color: white !important;
}